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Travaux de Géologie sédimentaire et Paléontologie
Série 1 : communications
Editeurs:
Bernard Mottequin, Julien Denayer,
Peter Königshof, Cyrille Prestianni & Sébastien Olive
IGCP 596 - SDS SYMPOSIUM
Climate change and Biodiversity patterns
in the Mid-Palaeozoic
ABSTRACTS
September 20-22, 2015
Brussels - Belgium
volume 16 - 2015
ISSN 0761-2443
ISBN 978-2-9548452-4-1
S
T
R
A
T
A
STRATA
Secrétaire de rédaction : Philippe Fauré
Editeur : Association STRATA,
http://strata.fr
Dépôt légal : 3ème trimestre 2015
ISSN : ISSN 0761-2443
IGCP 596–SDS Symposium
AB
STRACTS
September 20–22, 2015
Brussels, Belgium
Edited by
Bernard MOTTEQUIN, Julien DENAYER, Peter KÖNIGSHOF, Cyrille PRESTIANNI & Sébastien
OLIVE
STRATA, série 1: Communications, volume 16, 2015, 157 p.
In
ternational Geoscience Programme (IGCP) Project 596: Climate change and
The organising committee gratefully acknowledges the support of
International Geoscience Programme (IGCP) Project 596: Climate change and
The organising committee gratefully acknowledges the support of
Institut royal des Sciences naturelles de Belgique
Senckenberg Gesellschaft für Naturforschung
Westfälische Wilhelms
International Geoscience Programme (IGCP) Project 596: Climate change and
biodiversity patterns in the Mid
Subcommission on Devonian Stratigraphy (SDS)
The organising committee gratefully acknowledges the support of
Institut royal des Sciences naturelles de Belgique
Carmeuse S.A.
Université de Liège
Senckenberg Gesellschaft für Naturforschung
Westfälische Wilhelms
International Geoscience Programme (IGCP) Project 596: Climate change and
biodiversity patterns in the Mid
Subcommission on Devonian Stratigraphy (SDS)
The organising committee gratefully acknowledges the support of
In
stitut royal des Sciences naturelles de Belgique
FNRS
Ca
rmeuse S.A.
Université de Liège
Senckenberg Gesellschaft für Naturforschung
Westfälische Wilhelms
-
Univ
ersität Münster
International Geoscience Programme (IGCP) Project 596: Climate change and
biodiversity patterns in the Mid
Subcommission on Devonian Stratigraphy (SDS)
The organising committee gratefully acknowledges the support of
Institut royal des Sciences naturelles de Belgique
Carmeuse S.A.
Univ
ersité de Liège
Senck
enberg Gesellschaft für Naturforschung
Universität Münster
International Geoscience Programme (IGCP) Project 596: Climate change and
biodiversity patterns in the Mid
-
Palae
ozoic
Subcommission on Devonian Stratigraphy (SDS)
The organising committee gratefully acknowledges the support of
Institut royal des Sciences naturelles de Belgique
Senckenberg Gesellschaft für Naturforschung
Universität Münster
International Geoscience Programme (IGCP) Project 596: Climate change and
Palaeozoic
Su
bcommission on Devonian Stratigraphy (SDS)
The organising committee gratefully acknowledges the support of
Institut royal des Sciences naturelles de Belgique
In
ternational Geoscience Programme (IGCP) Project 596: Climate change and
Subcommission on Devonian Stratigraphy (SDS)
The organising committee gratefully acknowledges the support of
In
ternational Geoscience Programme (IGCP) Project 596: Climate change and
ST
RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
1
Con
tents
Prefac
e .................................................................................................................................................................. 5
Introduction .......................................................................................................................................................... 6
Ariunchimeg Y.: Upper Devonian bryozoans from western Mongolia................................................................ 7
Bábek O., Famĕra M., Hladil J., Poukarová H. & Šimíček D.: Lower Devonian red pelagic carbonates of the
Barrandian area, Czech Republic: how red is red and why to bother about? ....................................................... 8
Bahrami A., Boncheva I., Königshof P., Yazdi M. & Parsanejad H.: Biostratigraphy of the Late Devonian
(Famennian) deposits of the Kuh-e-Kaftar section (Chah-Riseh area), Central Iran ......................................... 10
Batchelor C., Carmichael S., Waters J., Coleman D., Kido E. & Suttner T.: Constraining the ages of Late
Devonian Extinction events in the Central Asian Orogenic Belt (COAB): U-Pb zircon ages and igneous
petrology ............................................................................................................................................................. 12
Becker R.T., Aboussalam Z.S., El Hassani A., Hartenfels S. & Baidder L.: The timing of Eovariscan block
faulting, reworking and re-deposition in the Moroccan Meseta ......................................................................... 14
Blieck A.: An Early Devonian peak of biodiversity: the case of heterostracan vertebrates ............................... 16
Boncheva I., Bahrami A., Königshof P., Yazdi M., Hoveida M. & Razi Allipour B.: Devonian deposits of
Bahram Formation in the Kuh-e-Reza-Abad and the Kuh-e-Shorab sections (southwest Damghan), Central
Iran ...................................................................................................................................................................... 18
Brazeau M.D., Jerve A., Sansom R., Ariunchimeg Ya. & Zorig E.: Devonian vertebrates of Mongolia .......... 20
Brett C.E., Baird G.C., Bartholomew A.J., Ver Straeten C. & Zambito J.: Revised Devonian time scales and
evidence for variable eustatic, climatic, and biotic volatility: example from the Lower-Middle Devonian of the
Appalachian Basin .............................................................................................................................................. 21
Brice D. & Mottequin B.: New insights on Uppermost Famennian brachiopods from north-western France
(Avesnois) .......................................................................................................................................................... 23
Brocke R., Kneidl V., Riegel W. & Wilde V.: The Lower Devonian “Hunsrückschiefer” of the Rheinisches
Schiefergebirge: new insights from palynology ................................................................................................. 25
Bultynck P. & Narkiewicz K.: New data on Middle Devonian conodonts from New York State with emphasis
on the Icriodontidae ............................................................................................................................................ 26
Carmichael S. & Waters J.: A decade of deciphering the Late Devonian: more answers, but many more
questions ............................................................................................................................................................. 27
Carpenter D.K., Marshall J.E.A., Beerling D.J. & Wellman C.H.: Wildfire activity as a proxy for atmospheric
oxygen content during Romer’s Gap .................................................................................................................. 30
Casier J.-G., Maillet S. & Préat A.: Ostracods from the Emsian–Eifelian and Eifelian–Givetian boundaries in
the Dinant Synclinorium: paleoenvironmental implications .............................................................................. 31
Clack J.A. & Smithson T.R.: Tetrapod diversity in the Tournaisian .................................................................. 33
Clément G., Olive S., Gueriau P., Lagebro L., Prestianni C. & Denayer J.: Assessment on the Late Devonian
fauna of Strud, Belgium ..................................................................................................................................... 35
Corradini C., Aretz M. & the working group: The redefinition of the Devonian–Carboniferous boundary:
recent developments ........................................................................................................................................... 37
Crônier C., Khaldi A.Y., Hainaut G., Abbache A. & Ouali Mehadji A.: Biodiversity and
palaeobiogeographical affinities of Lower Devonian trilobites from Algeria .................................................... 38
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2
Da Silva A.-C., Chadimová L., Hladil J., Slavík L., Hilgen F.J. & Dekkers M.J.: Unravelling orbital climatic
cycles from Devonian magnetic susceptibility signal – The quest for a better age model for the Lochkovian
and Pragian stages (Czech Republic) ................................................................................................................. 39
Denayer J. & Mottequin B.: Middle and Upper Devonian Events in Belgium: review and new insights ......... 40
Denayer J. & Webb G.E.: Post-extinction recovery of the earliest Carboniferous rugose corals, a glimpse from
eastern Australia ................................................................................................................................................. 43
Derycke C., Maillet S., Vachard D., Randon C., Nicollin J.-P., Armynot du Châtelet E., Crônier C., Hubert B.,
Recourt P. & Abbache A.: Palaeoenvironmental input of new faunas from Upper Famennian levels at
Ouarourout (Ougarta, Algeria) ........................................................................................................................... 44
Dreesen R., Vachard D., Marion J.-M. & Mottequin B.: The Red Marble of Baelen, an exceptional mid-
Famennian mud mound complex in a carbonate ramp setting from Eastern Belgium ....................................... 46
Evdokimova I.O.: New data on the Frasnian ostracods from the Middle Timan Region, Russia: taxonomy,
biostratigraphy, palaeoecology ........................................................................................................................... 48
Farabegoli E., Joachimski M.M., Perri M.C., Pondrelli M. & Spalletta C.: Physical and biological events
across the Frasnian–Famennian boundary in oxic carbonate successions in the Carnic Alps (Italy–Austria) ... 50
Gatovsky Y.A.: Famennian–Tournaisian boundary on the western slope of the South Urals, Russia: new
look ..................................................................................................................................................................... 51
Giesen P. & Berry C.M.: A reassessment of the Lindlar Flora (Devonian, Mid Eifelian), Germany ................ 53
Girard C., Charruault A.-L., Corradini C., Cornée J.-J., Weyer D., Bartzsch K. & Feist R.: Paleoenvironmental
trends in two Famennian sections of “Galantian” Superterranes: Col des Tribes (Montagne Noire, France) and
Buschteich (Thuringia, Germany) ...................................................................................................................... 55
Glinskiy V. & Ivanov A.: The assemblages of psammosteid agnathans from the Middle-Late Devonian of the
Andoma Hill (Russia) ......................................................................................................................................... 57
Gonchigdorj S. & Kido E.: Tabulate corals from the Samnuuruul Formation (Upper Devonian) in
southwestern Mongolia ...................................................................................................................................... 60
Goolaerts S. & Gouwy S.: The Lahonry quarry at Lompret, Belgium: an extraordinary new site to study Upper
Frasnian cephalopods during the onset of anoxia in the Dinant Basin ............................................................... 61
Gouwy S. & Goolaerts S.: Upper Frasnian deposits at the Lahonry quarry (Lompret, Belgium): conodont
biostratigraphy, microvertebrates and bentonites ............................................................................................... 63
Gouwy S., Liao J.-C. & Valenzuela-Ríos J.I.: Upper Eifelian–Lower Frasnian (Middle–Upper Devonian)
conodont biostratigraphy improved by graphic correlation in the Spanish Central Pyrenees ............................ 64
Gueriau P.: The early continental aquatic arthropod fauna from the Late Devonian of Strud, Belgium:
implications for terrestrialization strategies ....................................................................................................... 65
Hartenfels S. & Becker R.T.: Revised conodont stratigraphy of the famous Ballberg section (Famennian,
Rhenish Massive, Germany) .............................................................................................................................. 66
Helling S. & & Becker R.T.: A new Pragian trilobite assemblage from Aïn-Al-Aliliga (western Meseta, NW
Morocco) ............................................................................................................................................................ 68
Hušková A., Suttner T.J., Slavík L., Valenzuela-Ríos J.I., Liao J.-C., Gatovsky Y.A., Ariunchimeg Ya., Kido
E., Gonchigdorj S.,. Waters J.A., Carmichael S.K. & Batchelor C.: Late Devonian conodonts of western
Mongolia: preliminary results ............................................................................................................................ 70
Jansen U.: Brachiopod diversity, biofacies and events of the Rhenish Lower Devonian (Germany) ................ 71
Jiang Q., Xu H.-H., Wang Y & Feng J.: Aneurophytalean plants from the Middle Devonian of North Xinjiang,
China and their ecosystematic inference in the associated Hujiersite flora ........................................................ 73
ST
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3
Köni
gshof P., Bahrami A., Boncheva I., Yazdi M. & Talebi Torghabeh E.: Middle to Late Devonian carbonate
ramp sedimentation in Central Iran (Zefreh section, NE Isfahan) ...................................................................... 74
Königshof P., Phuong T.H., Carmichael S., Waters J., Batchelor C. & Komatsu T.: Events in the Mid-
Palaeozoic: examples from the eastern Palaeotethys (NE Vietnam) .................................................................. 75
Kumpan T., Bábek O., Kalvoda J., Matys Grygar T. & Frýda J.: High-resolution stratigraphy of the Devonian-
Carboniferous boundary in Europe: multidisciplinary approach ........................................................................ 77
Kurilenko A.V. & Minina O.R.: The correlation of Devonian deposits of Eastern and Western Transbaikal
(Eastern Russia) .................................................................................................................................................. 79
Lukševičs E.: The latest Famennian vertebrate and trace fossils from the Ketleri site, Latvia .......................... 81
Lukševičs E. & Stinkulis Ģ.: Signatures of biotic crisis in the Frasnian–Famennian boundary beds from
Latvia .................................................................................................................................................................. 83
Maillet S., Danelian T., Monnet C., Crônier C. & Milhau B.: Biodiversity changes of ostracods across the late
Mid-Devonian global Taghanic biocrisis ........................................................................................................... 85
Maillet S., Milhau B., Vreulx M. & Sánchez de Posada L.-C.: Givetian ostracods of the Candás Formation
(Asturias, north-western Spain): taxonomy, stratigraphy, palaeoecology, relationship to global events and
palaeogeographical implications ........................................................................................................................ 87
Malti F.Z., Benyoucef M., Samar L. & Sid Houm R.: The Devonian–Carboniferous boundary in the Saoura
Valley (western Algerian Sahara)....................................................................................................................... 89
Manchuk N. & Kazuhiro T.: The Siluro-Devonian age confirmation based on radiolarian biostratigraphy and
zircon dating ....................................................................................................................................................... 91
Marshall J.E.A.: An early Carboniferous palaeoclimate record from East Greenland ....................................... 92
Matyja H., Sobień K., Marynowski L., Stempień-Sałek M. & Małkowski K. The expression of the
Hangenberg Event (Latest Devonian) in a relatively shallow-marine succession in Poland ............................. 94
Mavrinskaya T.M. & Artyushkova O.V.: Conodonts from Pragian and Emsian boundary intervals in different
facies of the South Urals ..................................................................................................................................... 95
Meyer-Berthaud B., Decombeix A.-L., Dunstone R., Gerrienne P., Momont N. & Young G.: New Middle to
early Late Devonian aneurophytales showing dissected appendages from southeastern Australia ................... 98
Millward D., Davies S.J., Bennett C.B., Kearsey T., Browne M.A.E., Sherwin J., Curtis R. & Brand P.:
Environment and habitat variation on the Tournaisian (early Carboniferous) coastal plain of northern Great
Britain ................................................................................................................................................................. 99
Mottequin B. & Denayer J.: Pridolian–Lochkovian macrofaunas from southern Belgium and northern France:
de Koninck (1876) revisited ............................................................................................................................. 101
Mottequin B. & Simon E.: Diversity of athyridide brachiopods during the Late Devonian–Tournaisian in
southern Belgium .............................................................................................................................................. 103
Munkhjargal A.: Devonian trilobites from The Samnuuruul Formation in the Baitag Bogd area (western
Mongolia) ......................................................................................................................................................... 105
Narkiewicz K., Narkiewicz N., Bultynck P. & Krzemińska E.: Conodont biostratigraphy, biofacies and apatite
isotope records of the late Eifelian Kačák Event in the shallow marine Belarusian Basin .............................. 106
Navas-Parejo P. & Königshof P.: Devonian and Carboniferous shallow-water successions from Sonora (NW
Mexico) and their importance in global event studies ...................................................................................... 109
Navas-Parejo P., Sandberg C.A. &. Poole F.G.: Paleogeographic implications of early Famennian crepida
Zone conodont faunas, Sonora, NW Mexico ................................................................................................... 111
Nikolaeva S., Kim A. & Erina M.: Early Devonian ammonoids from Shakhimardan (South Tien-Shan) ...... 113
Olive S.: What’s new with the Famennian vertebrate fauna from Belgium? ................................................... 115
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Ponciano L.: Devonian fossils of the Amazonas and Parnaíba basins, Brazil.................................................. 118
Ponciano L. & Carvalho M.: Devonian trilobites of the Amazonas and Parnaíba basins, Brazil .................... 120
Poty E., Mottequin B. & Denayer J.: Orbitally forced sequences and climate reconstruction around the
Devonian–Carboniferous boundary, and the Hangenberg Extinction Event .................................................... 121
Prestianni C., Gess R., Rustán J.J., Balseiro D., Vaccari E. & Sterren A.F.: Continental ecosystems at high
palaeolatitude before and after the Devonian–Carboniferous boundary: two examples from South Africa and
Argentina .......................................................................................................................................................... 122
Reeves E. (and team TW:eed): Vegetational recovery on an Early Carboniferous coastal plain following the
End Devonian Mass Extinction Event .............................................................................................................. 123
Rustán J.J., Vaccari E. & Balseiro D.: Infaunal molting in Mid Paleozoic trilobites: new insights based on data
from South America ......................................................................................................................................... 124
Sardar Abadi M., Kulagina E., Voeten Dennis F.A.E., Da Silva A.-C. & Boulvain F. Foraminiferal
proliferation in the Alborz basin (Northern Iran): global response to Carboniferous glaciations .................... 126
Schindler E., Gereke M., Piecha M., Luppold F.W. & Stoppel D.: The Kellwasser type locality in the Harz
Mountains (Germany) revisited – new results after widening of the classical outcrop .................................... 128
Slavík L., Hladil J., Chadimová L., Valenzuela-Ríos J.I., Hušková A. & Liao J.-C.: Cooling or warming in the
Pragian? The sedimentary records and petrophysical logs from the key peri-Gondwanan sections ................ 130
Smithson T., Richards K. & Clack J.: Romer’s Gap: the beginning of the modern fish fauna ........................ 132
Soboleva M., Sobolev D. & Königshof P.: Conodont stratigraphy of Frasnian deposits of the western slope of
the Polar Urals .................................................................................................................................................. 134
Spalletta C., Perri M.C., Corradini C. & Over J.D.: Proposed revision of the Famennian (Upper Devonian)
standard conodont zonation .............................................................................................................................. 135
Stephenson C., Bond D. & Rogerson M.: Palynology and palaeobotany of the Devonian Samnuuruul
Formation, western Mongolia – an update ....................................................................................................... 137
Stichling S., Aboussalam Z.S., Becker R.T., Eichholt S. & Hartenfels S.: Event-controlled reef drowning and
extinction in the Hönne Valley (northern Rhenish Massif, Hagen-Balve reef complex .................................. 138
Streel M.: Palynomorphs (miospores, acritarchs, prasinophytes) before and during the Hangenberg crisis ... 140
Tonarová P., Vodrážková S. & Ferrová L.: Microfossils across the Daleje Event (Lower Devonian, Emsian)
from the Pekárek Mill section (Prague Basin, Czech Republic) ...................................................................... 144
Valenzuela-Ríos J.I., Liao J.C. & Calvo H.: Achievements in the Pyrenean Lochkovian conodont evolution
and biodiversity and its global role in correlations: from Graz 2011 to Brussels 2015, an IGCP-596 ongoing
research ............................................................................................................................................................. 146
Vodrážková S., Vodrážka R., Munnecke A., Tonarová P. & Franců J.: Microbial activity exemplified by
wrinkle structures in the Middle Devonian siliciclastics of the Prague Basin, Czech Republic ...................... 148
Waters J., Suttner T., Kido E. & Carmichael S.: Echinoderm ecosystem rebound and diversification after the
Frasnian–Famennian extinction: data from the Central Asian Orogenic belt .................................................. 149
Xu H.H., Jiang Q. & Wang Y.: On the Mid Devonian Hujiersite flora from west Junggar, Xinjiang (China)
and its characteristics, age and palaeoenvironment .......................................................................................... 151
Zambito J. & Day J.: Integrated stratigraphic analysis of the Middle Devonian (late Givetian) Geneseo Event
in the Appalachian and Michigan basins .......................................................................................................... 152
Zambito J., Day J. & Narkiewicz K.: New insights into the trilobite and conodont biostratigraphy of the
Middle–Upper Devonian Genesee Group in eastern New York State ............................................................. 154
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Prefa
ce
Dea
r colleagues and friends,
We cordially welcome you, some ninety participants from 19 countries around the globe, to the IGCP 596–
SDS International Symposium in Brussels, 20–22 September 2015.
This symposium is the final meeting of the 4-year International Geoscience Programme (IGCP) Project
596 (climate change and biodiversity patterns in the Mid-Palaeozoic; 2011-2015), which is associated for the
fourth time to the Subcommission on Devonian Stratigraphy (SDS), after a first joint meeting in Russia
(2011), a second in Morocco (2013), and a third in Argentina (2014).
Organizing this meeting in Belgium was obvious as this small country has a long history of research
dedicated to the Devonian and Carboniferous. This is mainly due to the fact that Belgium is the cradle of the
internationally recognized Frasnian, Famennian, Tournaisian and Viséan stages. Although disused nowadays,
terms such as Gedinnian and Couvinian, which sound probably familiar to many of us, were also first defined
in southern Belgium. The symposium is flanked by a pre-symposium field trip dedicated to the Devonian–
Mississippian succession of the Namur–Dinant Basin organized by the Royal Belgian Institute of Natural
Sciences and the University of Liège (Belgium), and a post-symposium field trip devoted to the Devonian–
Tournaisian succession of the Eifel area and the Rhenish Massif (Germany) organized by the University of
Münster and the Senckenberg Research Institute and Natural History Museum.
The symposium is organized around 10 sessions (45 talks and 40 posters):
S1: Lower to Upper Devonian palaeontology and sedimentology
S2: Lower and Middle Devonian events and biostratigraphy
S3: Tetrapod World: early evolution and diversification (TW:eed)
S4: Devonian continental flora and fauna
S5: Devonian–Carboniferous boundary
S6: Devonian of Mongolia
S7: Devonian marine fauna
S8: Devonian climates
S9: Upper Devonian stratigraphy
S10: Frasnian–Famennian boundary
We would like to express our sincere thanks to the organizations, which have contributed to this
symposium, namely the Royal Belgian Institute of Natural Sciences, the Fonds National de la Recherche
Scientifique (FNRS), Carmeuse S.A., STRATA and the University of Liège. Moreover, we would like to use
this opportunity to honor the memory of Paul Sartenaer, a former voting member of the SDS, who passed
away on 1
st
July
2015, at the age of 90. He was a famous specialist of the Devonian rhynchonellide
brachiopods and his death is a great loss for our Devonian worker community.
We hope that this symposium will be a successful and enjoyable meeting providing you with new insights,
ideas and friends. We wish you an excellent stay in the capital of Europe!
Bernard Mottequin, Julien Denayer, Xavier Devleeschouwer, Valentin Fischer, Vincent Hallet, Jean-Marc
Marion, Edouard Poty, Sébastien Olive and Cyrille Prestianni
Brussels, September 2015
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
6
Intro
duction
Th
e International Union of Geological Sciences (IUGS) is one of the largest and most active non-
governmental scientific organizations in the world. Founded in 1961, IUGS is a member of the International
Council of Science. IUGS fosters dialogue and communication among the various specialists in earth sciences
around the world. IUGS, amongst other tasks, features the International Commission on Stratigraphy (ICS),
which is composed of individual Subcommissions on individual Geological Periods and the Precambrian that
build the formal, officially and internationally defined time units (chronostratigraphic units) of Earth History.
The Subcommission on Devonian Stratigraphy (SDS) has been one of the most active Subcommissions of ICS
since it formed in 1973, which is mostly based on a highly successful integration of all leading specialists of
Devonian stratigraphy, regardless of their specialization or their origin.
For forty years, UNESCO (United Nations, Educational, Scientific and Cultural Organization) has worked
with IUGS to mobilize global cooperation in the Earth sciences through the International Geoscience
Programme (IGCP). This Programme has provided a platform for scientists from across the world to push the
frontiers of knowledge forward through concrete projects.
IGCP and SDS locking back on a long-lasting, fruitful cooperation (e.g., IGCP, 216, 293, 421, 499 and,
currently 596). IGCP 596-SDS are specifically interested in the interaction between climate change and
biodiversity in the mid-Palaeozoic (Devonian and Carboniferous Periods, 416–299 million years ago) when
the terrestrial ecosystems experienced a biodiversity boom and oceanic ecosystems suffered catastrophic
extinctions of different magnitudes such as in the Devonian Period with the two 1
st
or
der mass extinctions at
the Frasnian-Famennian boundary (Upper Kellwasser Event) and in the latest Famennian (Hangenberg
Events). Greenhouse climates dominated the Early and Mid Devonian (416–385 Ma) world, but changed to
icehouse conditions in the latest Devonian (~385–380 Ma). The Early Carboniferous world was relatively
warm until cooling in the early Late Carboniferous (318–299 Ma) resulted in a huge polar southern
hemisphere ice shield that covered most of Gondwana. The Mid-Palaeozoic was also a time of very active
plate tectonics that caused major palaeogeographic changes. During the Devonian two supercontinents,
Euramerica and Gondwana, together with Siberia formed the biggest landmasses of our planet. They
successively amalgamated into the supercontinent Pangaea during the Late Carboniferous. As the continental
landmass grew, vascular plants, arthropods, hexapods and first tetrapods spread on land. Their radiation
formed the base of new terrestrial ecosystems unknown before the Devonian Period. The unique rise among
the land plants and the formation of biogeochemical soil profiles led to distinctive changes in environmental
conditions. Based on proxy-data, we can show that the rapid rise of land plants was coupled with strongly
decreasing atmospheric CO
2
values from 4000 ppm to nearly present day values of about 350 ppm during the
latest Devonian. Increased weathering activity and soil formation by rooted plants lead to intensified run-off
and changed water chemistry, which seriously affected marine communities globally.
IGCP 596 in cooperation with SDS have focused within their joint symposia, conferences, and field trips
on sudden extinctions, anoxic, climatic and eustatic events, building up a detailed event stratigraphy that
enables non-biostratigraphic correlations. Results of IGCP 596 project should help to clarify whether climate
change (e.g. interaction of CO
2
and
temperature) from greenhouse conditions during the Early–Mid Devonian
to icehouse conditions during the Late Devonian–Early Carboniferous represents a major trigger for variations
in biodiversity or if a combination of multiple factors is responsible for such changes. During the last years of
research knowledge on the above topics increased fundamentally even if there are many scientific questions
still unanswered. We are looking forward to seeing a good number of interesting presentations as summarized
in this abstract volume.
First, on behalf of the IGCP 596 and SDS we would like to thank the organizers for their tremendous work
to prepare the Conference in Brussels and field trips to Belgium and Germany. We welcome all participants to
Brussels and wish you stimulating discussions, and a successful and pleasant stay both in Brussels and during
the field trips.
Kind regards,
Peter Königshof (Chairman of the IGCP 596) & John Marshall (Chairman of the SDS)
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
7
Upp
er Devonian bryozoans from western Mongolia
Ya
rinpil Ariunchimeg
In
stitute of Paleontology and Geology, Mongolian Academy of Sciences, S. Danzanstreet 3/1, Chingeltei District,
Ulaanbaatar, Mongolia. E-mail: ariunchimeg@mail.ru
Bry
ozoans rank among the more widespread and taxonomically diverse invertebrate fossils in the Palaeozoic
deposits. The first discovery of bryozoans within Devonian deposits from Mongolia was reported in 1926.
Until now, 127 species from 66 genera, 27 families and 5 orders have been recognized and described on the
basis of Devonian material from Mongolia. Incomplete bryozoan distribution in the sections makes it
nevertheless difficult to distinguish uninterrupted bryozoan associations. On the basis of a study of the
bryozoans from well-known Devonian type sections (Fig. 1), and on an analysis of their distribution, we are
here able to establish eight associations of bryozoans among which two are upper Devonian in age.
Fig. 1: Schematic map of Mongolia with indication of the Devonian deposits. Upper Devonian bryozoans were recovered
from the Baruunhuurai (46) and Samnuuruul (47) formations (western Mongolia).
The Frasnian bryozoan associations are represented by 9 species belonging to 9 genera: Pileotrypella
lautissima, Boardmanella richardi, Bactropora granistriata, Semicoscinium sp., Mirifenestella sp.,
Sulcoretepora consona, Shulgapora devonica, Reteporidra sp. and Narynella sp. (Goryunova, 1993;
Ariunchimeg, 2010). The bryozoans come from the Middle–Upper Devonian Baruunhuurai Formation.
The Famennian bryozoan association consists of 12 species from 12 genera (Ariunchimeg, 2000, 2003):
Cyclotrypa gigantea, Cheilotrypa subtilis, Neotrematopora baitagensis, Pseudonematopora hextolgayensis,
Nemacanthopora cellaris, Orthopora tomensis, Intrapora lanceolata, Streblotrypa sp., Nikiforovella sp.,
Fenestella sp., Alternifenestella sp., and Minilya sp. Bryozoans come from the Upper Devonian Samnuuruul
Formation.
Upper Devonian invertebrates are known only from the Baruunhuurai terrane in the south-western part of
Mongolia and, except bryozoans, are represented by brachiopods, corals, trilobites, gastropods and rare
conodonts (Ruzhentsev, 2001).
Referenc
es
Gor
junova R.V. (1993). On morphology, terminology and classification of Bryozoans order Cystoporida.
Paleontologicheskii Zhurnal, 1993 (4): 69-79. (In Russian).
Ariunchimeg Ya. (2000). The first finds of Famennian bryozoans in Mongolia. Paleontologicheskii Zhurnal, 2000 (1):
45-48. (In Russian).
Ariunchimeg Ya. (2003). Famennian Bryozoans from the Baruunhuurai zone and their analogies. Scientific Transactions,
Mongolian University of Science and Technology, Geology, 9: 58-62. (In Russian).
Ariunchimeg Ya. (2010). Palaeozoic bryozoans of Mongolia. Unpublished Ph.D. thesis, Paleontological Institute,
Russian Academy of Sciences, 54 p. (In Russian).
Ruzhentsev S.V. (2001).The Variscan belt of South Mongolia and Dzungaria.The Indo-Sinides of Inner Mongolia. In:
DergunovA.B. (Ed.), Tectonics, Magmatism and Metallogeny of Mongolia. Routledge, London, 61-94.
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8
Lowe
r Devonian red pelagic carbonates of the Barrandian area, Czech
Republic: how red is red and why to bother about?
Ond
řej Bábek
1
, Mart
in Famĕra
1
, Jin
dřich Hladil
2
, Hedv
ika Poukarová
3
& D
aniel
Šimíček
1
1
Dep
artment of Geology, Palacky University of Olomouc, 17. listopadu 12, Olomouc, Czech Republic. E-mails:
babek@prfnw.upol.cz, mafam@post.cz, daniel.simicek@upol.cz
2
In
stitute of Geology of the CAS, v. v. i., Rozvojová 269, 165 00 Praha 6, Czech Republic. E-mail: hladil@gli.cas.cz
3
Dep
artment of Geological Sciences, Masaryk University, Kotlářská 2, Brno, Czech Republic. E-mail:
357488@mail.muni.cz
Carbo
nate successions in the Barrandian area, a classical region for Lower Devonian stratigraphy, contain a
marked, more than 15 m thick band of red pelagic carbonate of Early Devonian (earliest Emsian) age. Situated
in the upper levels of the Praha Formation, the red band can traced on several tens of kilometres providing an
important local stratigraphic key level. Red coloured deep-marine sediments are known from many
Phanerozoic stratigraphic levels. The best known examples are perhaps the Upper Cretaceous ocean red beds
(CORB) which feature a conspicuous spatial and temporal coincidence with the Cretaceous ocean anoxic
events (OAS) and thus represent time specific facies of palaeoceanographic / palaeoclimatic significance.
To make an insight into the genesis of the Devonian pelagic red beds and their palaeoclimatic meaning, we
have made a detailed study of the red horizon and its stratigraphic context. The aim was to find the mineral
carriers of the red colour and to investigate the conditions of their genesis, to examine the prerequisites for the
red pigmentation, to locate the red horizon in the sea-level cycle and to interpret the local
paleogeographic/bathymetric context of their formation. In this effort, we used detailed facies logging at 7
large sections (17 to 255 m thick) in the Prague basin, accompanied with field spectral gamma-ray logging (>
1600 points with 0.25 to 1.0 m vertical step), quantitative colorimetry (spectral reflectance in visible light, ca.
3500 samples), quantitative microfacies analysis (ca. 90 samples), element geochemistry (EDXRF, 215
samples), total organic carbon concentrations (80 samples), magneto-mineralogical analysis (12 samples) and
electron microprobe analysis (WDX SEM, 12 samples).
The best exposure of the red band is provided in a 120 m thick section of the Branžovy quarry located ca.
20 km WSW of the Prague city centre. Bound to the underlying Lochkov Formation by a basal unconformity,
the basal layers of the Praha Formation are composed of coarse-grained crinoidal calcarenite (grainstone) that
pass upward into dark nodular calcisiltite and calcilutite (lime mudstone / wacke-packstone) with abundant
dacryoconarid tentaculites, trilobites, bryozoans and ostracods, and with stromatactis-like structures (sheet
cracks) forming an upward fining (transgressive) sequence. The upper parts of the Praha Formation contain
the target layer of deep red limestone, which is overlain by about 1m thick interval of light-grey limestone,
followed by a regionally significant interval of eight limestone layers sandwiched with black shale laminae (so
called Bohemian Graptolite Event). The Praha Formation is then overlain by grey platy calcarenites and
calcilutites of the Zlíchov Formation. The Lochkov/Praha Formation boundary and the Praha/Zlíchov
Formation boundary can be correlated all over the Barrandian area based on their gamma-ray patterns, namely
U/Th ratios. The computed gamma-ray (CGR) values based on K and Th concentrations are low at the base of
the Praha Formation, but they markedly increase upwards consistently with the facies and microfacies trends
constituting a prominent deepening-upward (transgressive) trend. Element geochemistry data indicate a
gradual decrease in Ca (calcium carbonate) at the expense of terrigenous elements such as Al, K, Ti, Rb and
Fe. Consistently with the microfacies data, this pattern is interpreted as gradually decreasing marine carbonate
production on the background of steady influx of suspended clay minerals from dry land.
The red carbonates fall within the peak transgressive strata (as documented by CGR, EDXRF and
microfacies). The intensity of the red pigmentation was expressed in such colorimetric parameters as CIEa*
(dimensionless), percentage of red reflectance (%) and red/yellow reflectance ratios. The red colour intensity
was found to be highest in the most distal sections of the Prague basin (Branžovy, Požár 3 and Na Chlumu
quarries) where the thickness of the Praha Formation is extremely low. However, the red coloration quickly
fades away towards the thicker and more-shallow water parts of the basin fill suggesting that its intensity is
closely related to low sediment accumulation rates. The red colour is mainly carried by hematite, as indicated
by magneto-mineralogy study and prominent peaks at 565 nm wavelength band on the 1
st
d
erivatives of
reflectance curves. The red coloration is well visible in thin sections under plane polarized light, often inside
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
9
th
e dacryoconarid shells, fenestrate bryozoans or echinoderm fragments. Under WDX SEM, the red fields are
characterized by domains enriched in Fe-bearing clay minerals but hematite crystal individuals were never
found. This suggests that hematite forms a dispersed mass of submicronic crystals associated with clays. The
EDXRF analyses show that Al and Fe concentrations are well correlated (R
2
=
0.8) but the red colour intensity
is uncorrelated with the Fe concentrations. There is no Fe enrichment associated with the hematite-rich red
carbonates so we infer that the hematite formed in situ by mineral transformation of Fe-bearing clays. The red
band is characterized by extremely low concentrations of TOC (0.02 to 0.03 %) while TOC values are slightly
higher in the remaining, non-red parts of the Praha Formation (0.02 to 0.05 %). This indicates a very good
bottom oxygenation during deposition.
In summary, the red coloured band formed in deep-water, distal parts of the Lower Devonian carbonate
system of the Praha Formation during peak transgression and minimum calcium carbonate supply. Hematite
as the main carrier of the red colour formed by mineral transformation of clays under oxidizing conditions,
presumably during very early diagenesis (as indicated by hematite impregnation inside echinoderm shells,
which tend to be obstructed by blocky calcite during very early diagenesis). The red carbonates are confined
to a specific stratigraphic level, which quickly passes into the Bohemian Graptolite Event horizon enriched in
black shales. Interestingly, there are more black shale/carbonate levels (e.g., Kačák Event) and more red
carbonate horizons (e.g., Suchomasty Limestone) in the Lower–Middle Devonian of the Barrandian area. In
many respects, the Devonian red carbonates conform to the Cretaceous CORB and may indicate a similar
palaeoclimatic regime of atmospheric CO
2
-driven switching between dysoxic and super-oxic sea-bottom
conditions.
Ackn
owledgements: This study was supported by Czech Science Foundation (GACR) project GA 14-18183S.
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10
Biost
ratigraphy of the Late Devonian (Famennian) deposits of the
Kuh-e-Kaftar section (Chah-Riseh area), Central Iran
Ali B
ahrami
1
, Iliana
Boncheva
2
,
Peter Königshof
3
, M
ehdi Yazdi
1
& Has
san
Parsanejad
1
1
Dep
artment of Geology, University of Isfahan, 81764, Iran. E-mails: Bahrami_geo@yahoo.com,
Meh.Yazdi@gmail.com, h.parsanejad1348@gmail.com
2
Geo
logical Institute, Bulgarian Academy of Sciences, Sofia 113, Bulgaria. E-mail: boncheva2005@yahoo.com
3
Sen
ckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, 60325 Frankfurt am
Main, Germany. E-mail: peter.koenigshof@senckenberg.de
Th
e studied section is located southwest of the Chah-Riseh village (Kuh-e-Kaftar mountains), 55 km northeast
of Isfahan, Central Iran. Middle to latest Famennian deposits of the 110 m-thick Shishtu Formation
correspond to limestone, sandy limestone, marly limestone, shale and sandstone levels mainly reflecting
shallow-water environments (Fig. 1). The fossiliferous levels yield diverse macro- and microfaunas such as
bivalves, brachiopods, invertebrate micro-remains, bryozoans, crinoid stems and conodonts (Djafarian &
Brice, 1973; Golamalian, 2003, 2007).
Fig.
1: Biostratigraphic
column of the Chah-
Riseh section.
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1
An alternation of black shales and medium-bedded limestones at the base of the section is assigned to the
Frasnian–Famennian boundary. The Shishtu Formation is disconformably overlain by the Permian Jamal
Formation. In order to establish the biostratigraphical framework for the Shishtu Formation, 44 samples were
collected systematically and yielded the following conodonts: Bispathodus aculeatus aculeatus, Bispathodus
aculeatus plumulus, Bispathodus costatus, Bispathodus stabilis, Branmehla bohlenana, Icriodus cornutus,
Mehlina strigosa, Pandorinellina insita, Pelekysgnathus inclinatus, Polygnathus delicatulus, Polygnathus
deplanatus, Polygnathus nodocostatus nodocostatus, Polygnathus berevilaminus, Polygnathus semicostathus,
Polygnathus communis group, and Scaphignatus velifer velifer.
The abundance and distribution of conodont elements as well as the sedimentary record suggest fully
marine conditions of an inner shelf environment. The conodonts are related to the following conodont
biozones as: Upper marginifera, Uppermost marginifera, Upper trachytera, Middle expansa, and Upper
expansa zones. In terms of biofacies, the conodonts can be assigned to the icriodid–polygnatid, polygnatid–
bispathodid and bispatodid–polygnatid biofacies.
References
Dj
afarian, M.A. & Brice D. (1973). Biostratigraphie des brachiopodes dans le Famennien supérieur de la région
d’Ispahan (Iran central). Comptes Rendus de l’Académie des Sciences, 276: 2125-2128.
Gholamalian H. (2003). Age-implications of Late Devonian conodonts from the Chah-riseh area, northeast of Esfahan,
central Iran. Courier Forschungsinstitut Senckenberg, 245: 201-207.
Gholamalian H. (2007). Conodont biostratigraphy of the Frasnian–Famennian boundary in the Esfahan and Tabas areas,
Central Iran. Geological Quarterly, 51: 453-476.
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12
Co
nstraining the ages of Late Devonian Extinction events in the
Central Asian Orogenic Belt (COAB): U-Pb zircon ages and igneous
petrology
Came
ron Batchelor
1
, Sara
h Carmichael
1
, J
ohnny Waters
1
, Dr
ew Coleman
2
, E
rika
Kido
3
& T
homas Suttner
3
1
Dep
artment of Geology, Appalachian State University, ASU Box 32067, Boone, NC 28608, USA. E-mail:
batchelorcj@appstate.edu
2
Dep
artment of Geological Sciences, University of North Carolina - Chapel Hill, Chapel Hill, NC 27599-3315, USA
3
Karl-Franzens-University of Graz, NAWI-Graz, Institute for Earth Sciences (Geology & Paleontology), Heinrichstrasse
26, A-8010 Graz, Austria
The Late Devonian was a time of extreme ecological crisis containing two of the top six most devastating
extinction events in Earth’s history. The Kellwasser Anoxia Event at the Frasnian–Famennian (F–F) boundary
and the Hangenberg Anoxia Event at the Devonian–Carboniferous (D–C) boundary decimated coral reefs,
changed the evolutionary trajectory of fishes, and negatively impacted colonization of land by animals. Most
studies of these mass extinction events have been conducted on the continental margins of Europe and North
America, but evidence of these extinction events have also been identified in sediments located in an
understudied area: the Central Asian Orogenic Belt (CAOB). In the Late Devonian, the CAOB consisted of a
series of island arcs in an open oceanic setting far from continental-driven sediments, and represents an ideal
location to study these events as they are outside of well-studied epeiric sea environments or shallow
carbonate platforms associated with cratonic blocks.
Late Devonian sediments from the CAOB have been collected from both China and Mongolia. In China,
sediments include the Zhulumute, Hongguleleng, Hebukehe, and Heishantou Formations, which are from the
Boulongour Reservoir section of the Junggar Basin in Xinjiang Province, China. Tectonic models for the Late
Devonian suggest that these sediments formed as part of the West Junggar/Balkash accretionary wedge,
deposited on a Marianas Island type island arc complex, which is consistent with sedimentary geochemical
signatures in the Boulongour Reservoir sediments (Carmichael et al., 2015). Mongolian samples are from the
Samnuuruul Formation, which is located at the Gerelt Hoshoo site, the Mongolia-China Border locality and
the Hushoot Shiveetiin Gol site, all in the southwest end of the Gobi fold megazone in the Baruunhuurai
Terrane, Mongolia. Trace element concentrations associated with these Mongolian basalts and mudstones
suggest that the sediments collected in Mongolia also have an island arc volcanic signature (Fig. 1), consistent
with tectonic models of the CAOB.
Fig. 1: T
race element discrimination diagrams of basalts, sandstones, and mudstones from the Mongolia-China Border
locality and the Hushoot Shiveetiin Gol site show an island arc geochemical signature, consistent with the Devonian
tectonic models of the region.
At the base of the Boulongour Reservoir, the lowermost Zhulumute Formation contains volcanicalastic
sandstones and conglomerates that grade upwards towards the base of the Hongguleleng Formation.
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3
Prominent porphyritic basalt pebbles are also evident in the Zhulumute Formation with albite sand and detrital
zircons in the matrix. Fieldwork conducted in western Mongolia during the summer of 2014 revealed a
fossiliferous Samnuuruul Formation that exposed what was tentatively identified in this field as the F–F
boundary, and possibly the D–C boundary. The Samnuuruul Formation consists mainly of conglomerate beds
with interbedded limestone beds that grade into sandstone, siltstone, and tuffite layers. Pillow basalts (Fig. 2)
and lava flows are also found within the Samnuuruul Formation in the Hushoot Shiveetiin gol and the
Mongolian Border localities.
Fig. 2: Im
age of a transmitted light microscopy photomicrograph of sample MBL 7 from the Mongolian Border locality
that shows a filled amygdule containing serpentine and needle-like white mica flakes with surrounding plagioclase and
altered pyroxene.
In
the summer of 2014, sample ZH01-10 from the Zhulumute Formation in China was selected for U/Pb
geochronology at the University of North Carolina at Chapel Hill (UNC-CH) using standard hydrodynamic
and heavy-liquid techniques, using a VG Sector 54 Thermal Ionization Mass Spectrometer (TIMS). Initial
results from sample ZH01-10 suggest an age of 452 ± 2 Ma, which fits in the Middle Ordovician and is
consistent with tectonic models of Marianas-type island arc development around the Hongguleleng Ocean
(Choulet et al., 2012), but results cannot be confirmed until more zircons are dated for comparison.
Two samples from within the Samnuuruul Formation in Mongolia have been selected for zircon analysis at
UNC-CH during the summer of 2015. The first sample, SAM 4/8, was collected from the Gerelt Hoshoo
locality and consists of a coarse sandstone bed that fines slightly upwards. The second sample, MBL 7, was
collected from the Mongolian Border locality and consists of a pillow basalt showing minor hydrothermal
alteration (Fig. 2).
The Kellwasser and Hangenberg Events are both present in the Boulongour Reservoir sediments in China,
and have been detected via multiproxy geochemical evidence rather than visible black shales commonly
associated with these intervals (Carmichael et. al., 2014; Carmichael et al., 2015), but the presence of anoxic
events have not yet been confirmed for the analogous Mongolian sections at this time. Zircon analysis will be
used to constrain the ages of the Kellwasser and Hangenberg ocean anoxia events in China, and to constrain
the biostratigraphy of the fossils in the Mongolian sections. These results will be the first radiometric ages for
Late Devonian sediments in the CAOB thought to contain both the F–F boundary and the D–C boundary in an
open oceanic setting.
Referenc
es
Ca
rmichael S.K., Waters J.A., Suttner T.J., Kido E. & DeReuil A.A. (2014). A new model for the Kellwasser anoxia
even
ts (Late Devonian): shallow water anoxia in an open oceanic setting in the Central Asian Orogenic Belt.
Pala
eogeography, Palaeoclimatology, Palaeoecology, 39: 394-403.
Carmichael S.K., Waters J.A., Batchelor C.J., Coleman D.M., Suttner T.J., Kido E., Moore L.M., Chadimová L. (2015).
Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic
island arc in the Central Asian Orogenic Belt. Gondwana Research, doi:10.1016/j.gr.2015.02.009.
Choulet F., Faure M., Cluzel D., Chen Y., Lin W.,Wang B., Jahn B.-M. (2012). Architecture and evolution of
accretionary orogens in the Altaids collage: the early Paleozoic West Junggar (NW China). American Journal of
Science, 312: 1098-1145.
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14
Th
e timing of Eovariscan block faulting, reworking and re-deposition
in the Moroccan Meseta
R.
Thomas Becker
1
, Z. S
arah Aboussalam
1
, A
hmed El Hassani
2
, Sven H
artenfels
1
&
La
hssen Baidder
3
1
W
estfälische Wilhelms-Universität, Institut für Geologie und Paläontologie, Corrensstr. 24, D-48149 Münster,
Germany. E-mails: taghanic@uni-muenster.de, rbecker@uni-muenster.de, shartenf@uni-muenster.de
2
In
stitut Scientifique, Department of Geology, Mohammed V – Agdal University, Avenue Ibn Batouta, B.P. 703 Rabat-
Agdal, Morocco. E-mail: elhassani@israbat.ac.ma
3
Laboratoir
e de Géodynamique, Faculté des Sciences Aïn Chok, B.P. 5366 Maârif, Casablanca, Morocco. E-mails:
l.baidder@fsac.ac.ma, lbaidder@gmail.com
Th
e Moroccan Meseta, including some outcrops in tectonic windows of the High Atlas and small belts just to
the South (e.g., Tinerhir region), forms the southern external Variscides, which were continuous in the
Devonian with the much less deformed Anti-Atlas region of stable cratonic NW Gondwana. Understanding
the palaeogeographic and synsedimentary tectonic evolution of the Moroccan Hercynides is crucial for the
plate tectonic reconstruction of the western Prototethys between Gondwana and the more internal Variscides
(southern European and Armorica terrain assemblages). Beyond, a comparison with the external Variscides at
the southern margin of Laurussia/Avalonia (Rhenohercynian Zone), N of the Rheic Ocean, gives fundamental
insights into the history of a highly complex and controversial (very wide or rather narrow) ocean system,
which controlled the migration/distribution of marine and terrestrial biota and, potentially, globally significant
palaeoceanographical, climatic, and geochemical patterns. Within the frame of a joint DFG Germany-CNRST
Maroc research programme, we focused on the Eovariscan interval (upper Emsian to Tournaisian), the time
when the Rheic Ocean was largely subducted under Avalonia Terrains and before the Viséan onset of the
main, oblique Variscan Gondwana-Laurussia collision.
The Meseta is a complex patchwork of individual autochthonous blocks and of partly allochthonous units
(nappes, “Klippen”), each with a distinctive history of faunas, facies; and synsedimentary tectonics (e.g.,
Piqué & Michard, 1981, 1989; Michard et al., 2008). An overall extensional tectonic regime, at least of the
western Meseta N/NW of the Middle Atlas, lead to significant block faulting and tilting, which resulted in
uplift, erosion, reworking, and re-deposition in adjacent basins, often as mass-flows and olistolites. Piqué
(1975) coined the term “Famennian Revolution” because this was the time when the rapidly subsiding Sidi
Bettache Basin opened and when Eovariscan reworking units were most wide-spread. However, the
reconstruction of palaeogeography and block movements in space and time suffered badly from a very
imprecise stratigraphy, with common age assignments based on superficial lithological similarities and a lack
of reliable biostratigraphic ages. Therefore, our programme concentrated on the precise dating of major facies
and subsidence changes and especially of reworking units with the help of conodonts and, to a lesser extent, of
ammonoids and brachiopods (identifications by D. Brice).
New data from ca. 30 different successions provide a refined and complex picture of polyphase reworking
in the Meseta, which can be assigned to five synsedimentary tectonic phases of the Devonian-Tournaisian, an
interval of 65 Ma duration. Block movements can be identified variably by intraformational breccias and
slump units (without reworking from significantly older strata), polymict breccias and conglomerates with
clasts of very different age (often increasing upsection) and lithology, olistostromes and isolated olistolites in
basinal facies, often with evidence of double reworking (cannibalized conglomerates preserved as isolated
olistolites), angular unconformities with evidence of basal reworking, sudden lateral facies differentiation,
sudden long-term non-deposition or extreme condensation, especially when not correlated with major eustatic
falls, onset of thick flyschoid sedimentation with turbidites and debris flows, and evidence of rapid deepening
and increased subsidence, especially when not correlated with known eustatic rises. Dating of reworking units
was variably achieved by samples from in-situ underlying, interbedded and overlying carbonates, by sampling
individual components of conglomerates/breccias (searching for the youngest clasts), by whole rock samples
of fine-grained units, and by the local/regional geological context. A range of literature records had to be
incorporated and was partly revised. Not all reworking units could be dated with sufficient precision and some
contradictions are still to be solved.
A general and very distinctive feature of the Meseta is the fact that all successions were affected by
Eovariscan movements. The most stable region was the Coastal Block near Oulad Abbou, S of Casablanca,
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which also received the least post-sedimentary overprint. However, the local Eifelian and Frasnian are rather
condensed, as in most other successions.
The first Middle Palaeozoic tectonic phase of the Meseta comprises the Lochkovian to Eifelian, an
“Eovariscan prelude” or “Antevariscan Interval” with restricted and often localized uplift events. Still limited
evidence comes from a coarse conglomerate of Taliouine with late lower Lochkovian conodonts (large
Ancyrodelloides), which overlies upper Silurian black shales. It belongs to the Skoura succession just S of the
High Atlas, which, in the absence of typical Variscan deformation, can be regarded as a northern Anti-Atlas
extension. But Lochkovian breccias/conglomerates have also been reported from the High Atlas basement and
eastern Rehamna, which gives a common pattern restricted to the southern margin of the Variscides. Thin
lower Emsian breccias and small olistolites were found at Jebel ben Arab (between Azrou and Meknes). The
thick conglomerate of Immouzer-du-Kandar (S of Fes) ranges from the lower to upper Emsian. The supposed
Emsian polymict, coarse conglomerate at the base of the Jebel Ardouz (western Jebilet) is much younger. It
yielded a middle Frasnian Ancyrodella and includes Middle Devonian reefal clasts. Alleged Eifelian
conglomerates and reworked carbonates from the Khatouat Massif require a restudy.
The first true Eovariscan phase, the middle/upper Givetian, can be recognized almost throughout the
Meseta as a highly important time of brecciation, reworking, and of a subsequent hiatus, caused by non-
deposition due to submarine uplift and long-lasting current exposure. This lower main Eovariscan phase may
have been masked by subsequent, renewed reworking in the Famennian. For example, recycled conglomeratic
clasts within the olistolites of the Oued Cherrat Zone and Khatouat (“Biar Setla Conglomerate”) yielded
Givetian or mixed Eifelian-Givetian conodonts. In the Al Attamna region a Givetian red conglomerate with
colonial corals is partly overlain by a more massive second unit with mostly reworked Givetian conodonts
(ansatus Zone) and very rare Famennian palmatolepids, probably from the matrix. Middle Givetian
conglomerate successions are especially well preserved NW of Benahmed and, as an exception, are followed
by an upper Givetian deepening interval that lead eventually to a Frasnian hypoxic goniatite shale succession.
Apart from this subsiding block, the third phase, the Frasnian and lower Famennian, is characterized in the
western successions by wide-spread gaps (non-deposition) or extreme condensation. Middle Frasnian
polymict conglomerates occur in the western Jebilet (see above) and characterize the eastern Mrirt-Azrou
region. This is the area with the most intensive reworking and re-deposition, persisting at Dechra-Ait-
Abdallah and N of Azrou (Bab-el-Ari) into the lower Famennian and higher.
The peak episode of Eovariscan block faulting was the middle/early upper Famennian (phase four). A
precise dating is often difficult (e.g., in the case of the famous Oued Tiflet conglomerate) since limestone
conglomerates/breccias yield mostly reworked conodonts. Elsewhere (Oued Cherrat, Khatouat, Sidi Bettache
Basin) the shale matrix of olistolites or debris flows has provided a few miospore ages. The main reworking
clearly predates the LL Zone. It is still middle Famennian in age at Azrou (velifer Zone) and Ziyyar (Lower
trachytera Zone) but partly older (rhomboidea-marginifera Zone) and partly younger (“Etrœungt
conglomerates”) in the allochthonous Mrirt sucession. Last movements extended into the uppermost
Famennian in the autochthonous Famennian at Dechra-Ait-Abdallah (ultimus Zone). Stable pelagic basins
developed contemporaneously only in the Coastal Block (Oulad Abbou) and southern Mdakra Massive (Oued
Aricha).
Phase 5 is the “Eo-Variscan 2 Event” of Michard et al. (2008) and falls in the Tournaisian. Impressive,
very thick mass flow and olistolite successions of this age are well exposed N of Oulmes (Ta´araft) and lie
above the Hangenberg Sandstone equivalents of Ain Jemaa. In the allochthonous successions between Azrou
and Mrirt (Bou Khedra), Tournaisian shales transgressed with angular unconformity above a deeply eroded
Lower Devonian sequence and contain reworked middle Givetian clasts (ansatus Zone) at the base.
Referenc
es
Mi
chard A., Hoepffner C., Soulaimani A. & Baidder A. (2008). The Variscan Belt. In: Michard A., Saddiqi O., Chalouan
A. & Frizon de Lamotte D. (Eds), Continental Evolution: The Geology of Morocco. Lecture Notes in Earth Sciences,
116: 65-132.
Piqué A. (1975). Différenciation des aires de sédimentation au Nord-Ouest de la Meseta marocaine: la distension
dévono-dinantienne. Comptes rendus de l´Academie des Sciences Paris, 282: 957-960.
Piqué A. & Michard A. (1981). Les zones structurales du Maroc hercynien. Sciences Géologiques, Bulletin, 34: 135-146.
Piqué A. & Michard A. (1989). Moroccan Hercynides: A synopsis. The Paleozoic sedimentary and tectonic evolution at
the northern margin of West Africa. American Journal of Science, 289: 286-330.
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
16
An Ea
rly Devonian peak of biodiversity: the case of heterostracan
vertebrates
Alain Bli
eck
Un
iversité de Lille – Sciences et technologies, UFR Sciences de la Terre, UMR 8198 EvoEcoPaléo du CNRS, F-59655
Villeneuve d’Ascq cedex, France. E-mail: alain.blieck@univ-lille1.fr
The Pteraspidomorphi are jawless vertebrates that lived from the Middle Ordovician to the Late Devonian
(470-370 My). Their head is covered by a bony dermal armour organized into dorsal, lateral and ventral
plates, and the trunk and tail by scales. The histology of both their head carapace and the scales typically
includes acellular bone (aspidine). They had no paired or midline fins, except the caudal one. Four clades are
included in the Pteraspidomorphi: the Arandaspida, Astraspida, Eriptychiida and Heterostraci. Here I focus on
the Heterostraci that are known from the Early Silurian to the Late Devonian (Frasnian) and were mostly
living on Laurentia, Avalonia and Baltica in the Silurian, and the Old Red Sandstone Continent (ORSC) and
Siberia in the Devonian. They are characterised by the occurrence of a single paired external branchial
opening and the honeycomb structure of their bone. More than 300 species have been described to date. They
inhabited all environments of the Silurian marine platforms, and various environments from shallow marine to
intermediate (coastal, estuarian, “brackish”) around the Devonian ORSC (refs in Blieck & Elliott, in press).
The head carapace of Heterostraci consists of a series of plates, the number and morphology of which varies
among their different taxa. Basically there are a large median dorsal and a large median ventral plate, plus
anterior and lateral plates and platelets (oral, branchial, etc.). The two main groups of heterostracans are
Cyathaspidiformes (including amphiaspids) and Pteraspidiformes (including psammosteids). Other more
problematical groups include the traquairaspids, cardipeltids, corvaspids, ctenaspids, Nahanniaspis, and
various tessellated forms (tesseraspids, Lepidaspis, etc.) (Janvier, 1996). The Cyathaspidiformes (Cyathaspis,
Poraspis, Anglaspis, Ariaspis, Capitaspis, etc.) had a head armour composed of a large median dorsal plate
and a large median ventral plate separated by a pair of elongated branchial plates, plus a series of plates in the
oral cover (refs in Lundgren & Blom, 2013). Amphiaspids are derived cyathaspids where the head carapace is
fused into a single bony element. The Pteraspidiformes (Pteraspis, Althaspis, Rhinopteraspis, Doryaspis,
Protaspis, etc.) had a head armour composed of a more complex arrangement of plates, basically a median
dorsal disc, rostral, pineal and spinal plates, bordered by paired orbital, branchial and cornual plates, plus the
small plates of the oral cover (refs in Pernègre & Elliott, 2008). Psammosteids are derived pteraspids where
the armour includes additional platelets (“tesserae”) in between the various plates of the head. In this
communication, the most recent data on Late Silurian to Middle Devonian heterostracans are presented after a
selection of papers from 2010 to 2015. They include two cyathaspids from the Přidoli of the Canadian Arctic
(Ariaspis arctata, Capitaspis giblingi); a series of faunas from the Lochkovian of Chukotka, Arctic far-eastern
Russia (traquairaspids, Lepidaspis?, Oniscolepis?, poraspids), of northern France (Rhinopteraspis crouchi and
traquairaspids), from the Lochkovian and Pragian of Belgium (Althaspis leachi, Europrotaspis?
wiheriesiensis, Rhinopteraspis dunensis); a review of Lochkovian and Pragian heterostracans of Podolia,
Ukraine (cyathaspids, Ctenaspis, tesseraspids, corvaspids, pteraspids, traquairaspids); Zaphoctenaspis
meemannae and Poraspis thomasi in the Emsian of Nevada and California, USA, respectively; a
“Drepanaspis-like ” species in the Emsian of Germany; and psammosteids in the Givetian of the Leningrad
Region, Russia (Pycnosteus palaeformis, Psammolepis proia, Schizosteus? sp. and Tartuosteus giganteus).
These results are in accordance with various diversity curves that have been published for early vertebrates
in general, and heterostracans in particular: the Cyathaspidiformes, amphiaspids and Pteraspidiformes (excl.
psammosteids) (Ludlow to Givetian) show all a peak of diversity in the Lochkovian, and a second one in the
Pragian for pteraspids (Blieck, 1984; Novitskaya, 2007, 2008); the heterostracans show a peak in the late
Lochkovian of Severnaya Zemlya (Blieck et al., 2002) and Spitsbergen (Blieck et al., 1987), and in the
“middle” Lochkovian of northern France (Blieck et al., 1995). This corresponds to the Lochkovian peak of
biodiversity shown at a global scale for heterostracans (pteraspidomorphs, Klug et al., 2010) and for agnathan
(ostracoderm) vertebrates, both at the family- and genus-level (Blieck, 2011; Friedman & Sallan, 2012;
Sansom et al., 2015). It is thus a component of the genus-level Early Devonian diversity peak shown for
marine organisms (metazoans less tetrapods) by Alroy et al. (2008; also Alroy, 2010), a result of both a high
origination rate (Aberhan & Kiessling, 2012: fig. 4a) and a low extinction rate (ibid.: fig. 4b). This Early
Devonian peak marks the beginning of the Devonian Nekton Revolution for both demersal organisms (such as
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
1
7
most heterostracans as, e.g., amphiaspids, Drepanaspis) and nektonic organisms (such as some heterostracans
as, e.g., poraspids, Torpedaspis) (Klug et al., 2010, fig. 1). It may be related to various physical characteristics
of the Earth dynamics of that time, viz., a rise in both atmospheric (Dahl et al., 2010) and oceanic oxygen
(Joachimski et al., 2009), and a rise in mean annual continental temperature (Nardin et al., 2011). This kind of
correlation has been hypothesized for the occurrence of new arthropod orders, the number of genera of
autotrophic reefs, the body volume and genus-level diversity of marine invertebrates, in relation with an
increasing oxygen level (refs in George & Blieck, 2011) — but bizarrely with a rather low eustatic level (Haq
& Schutter, 2008). It is thus suggested “that the co-occurrence of a series of bio-events and physical
properties of the oceans on Earth during the Early Devonian is not merely a coincidence, but reflects a global
rearrangement of the biosphere” (George & Blieck, 2011) which would have triggered the diversity of
vertebrates, including the ostracoderms (in particular the heterostracans) and tetrapods (ibid.). And I propose
to name that series of bio-events the ‟Great Eodevonian Biodiversification Event”.
References
Ab
erhan M. & Kiessling W. (2012). Phanerozoic marine biodiversity: a fresh look at data, methods, patterns and
processes. In: Talent J.A. (Ed.), Earth and Life: Global biodiversity, extinction intervals and biogeographic
perturbations through time. Springer, IYPE Series, Dordrecht, 3-22.
Alroy J. (2010). The shifting balance of diversity among major marine animal groups. Science, 329: 1191-1194.
Alroy J. et al. (2008). Phanerozoic trends in the global diversity of marine invertebrates. Science, 321: 97-100.
Blieck A. (1984). Les Hétérostracés Ptéraspidiformes, Agnathes du Silurien-Dévonien du Continent nord-atlantique et
des blocs avoisinants : révision systématique, phylogénie, biostratigraphie, biogéographie. Cahiers de Paléontologie
(Vertébrés), C.N.R.S. édit., Paris, 199 p.
Blieck A. (2011). From adaptive radiations to biotic crises in Palaeozoic vertebrates: a geobiological approach.
Geologica Belgica, 14 (3-4): 203-227.
Blieck A., Goujet D. & Janvier P. (1987). The vertebrate stratigraphy of the Lower Devonian (Red Bay Group and Wood
Bay Formation) of Spitsbergen. Modern Geology, 11 (3): 197-217.
Blieck A., Goujet D., Janvier P. & Meilliez F. (1995). Revised Upper Silurian-Lower Devonian ichthyostratigraphy of
northern France and southern Belgium (Artois-Ardenne). Bulletin du Muséum National d’Histoire Naturelle, 4
ème
série, 17, C (
1-4): 447-459.
Blieck A.R.M., Karatajute-Talimaa V.N. & Mark-Kurik E. (2002). Upper Silurian and Devonian heterostracan
pteraspidomorphs (Vertebrata) from Severnaya Zemlya (Russia): a preliminary report with biogeographical and
biostratigraphical implications. Geodiversitas, 24 (4): 805-820.
Blieck A. & Elliott D.K. (in press). Pteraspidomorphs (Vertebrata) and the Old Red Sandstone. In: Howe, S.R. (Organ.),
ORS Symposium Volume. Proceedings of the Geologists’ Association.
Dahl T.W. et al. (2010). Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large
predatory fish. Proceedings of the National Academy of Sciences of the U.S.A., 107 (42): 17911-17915.
Friedman M. & Sallan L.C. (2012). Five hundred million years of extinction and recovery: a Phanerozoic survey of
large-scale diversity patterns in fishes. Palaeontology, 55 (4): 707-742.
George D. & Blieck A. (2011). Rise of the Earliest Tetrapods: An Early Devonian Origin from Marine Environment.
PloS ONE, 6(7), e22136, doi:10.1371/journal.pone.0022136.
Haq B.U. & Schutter S.R. (2008). A chronology of Paleozoic sea level changes. Science, 322: 64-68.
Janvier P. (1996). Early Vertebrates. Oxford Science Publ. & Clarendon Press, Oxford, 393 p.
Joachimski M.M. et al. (2009). Devonian climate and reef evolution: Insights from oxygen isotopes in apatite. Earth and
Planetary Science Letters, 284 (3-4): 599-609.
Klug C. et al. (2010). The Devonian nekton revolution. Lethaia, 43: 465-477.
Lundgren M. & Blom H. (2013). Phylogenetic relationships of the cyathaspidids (Heterostraci). Geologiska föreningens i
Stockholm förhandlingar (GFF), 135 (1): 74-84.
Nardin E. et al. (2011). Modeling the early Paleozoic long-term climatic trend. Geological Society of America Bulletin,
123(5-6): 1181-1192.
Novitskaya L.I. (2007). Evolution of generic and species diversity in agnathans (Heterostraci: Orders Cyathaspidiformes,
Pteraspidiformes). Paleontological Journal, 41 (3): 268-280.
Novitskaya L.I. (2008). Evolution of taxonomic diversity in amphiaspids (Agnatha, Heterostraci: Amphiaspidiformes)
and the causes of extinction in ecologically favorable conditions. Paleontological Journal, 42 (2): 181-191.
Pernègre V.N. & Elliott D.K. (2008). Phylogeny of the Pteraspidiformes (Heterostraci), Silurian-Devonian jawless
vertebrates. Zoologica Scripta, 37 (4): 391-403.
Sansom R.S., Randle E. & Donoghue P.C.J. (2015). Discriminating signal from noise in the fossil record of early
vertebrates reveals cryptic evolutionary history. Proceedings of the Royal Society, B, 282, doi:
10.1098/rspb.2014.2245.
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
18
Devo
nian deposits of Bahram Formation in the Kuh-e-Reza-Abad and
the Kuh-e-Shorab sections (southwest Damghan), Central Iran
Il
iana Boncheva
1
,
Ali Bahrami
2
,
Peter Königshof
3
, M
ehdi Yazdi
2
, Mehd
i Hoveida
2
&
Ba
hram Razi Allipour
2
1
Geo
logical Institute, Bulgarian Academy of Sciences, Sofia 113, Bulgaria. E-mail: boncheva2005@yahoo.com
2
Dep
artment of Geology, University of Isfahan, 81764, Iran. E-mails: Bahrami_geo@yahoo.com,
Meh.Yazdi@gmail.com, Hoveida_geology@yahoo.com, Bahramallipour@yahoo.com
3
Sen
ckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, 60325 Frankfurt am
Main, Germany. E-mail: peter.koenigshof@senckenberg.de
Th
e studied sections belong to the northern border of Central Iranian Structural Domain (Alavi-Naini, 1972;
1975). The area is characterised by strong tectonic deformation, and consequently, sedimentary sequences
exhibit many thrusts and faults leading to thickness differences and lateral facies changes. The sections exhibit
mainly Late Devonian sediments of the Bahram Formation, but also Middle Devonian, which is proven by
conodont stratigraphy. The studied sections are located close to the Reza-Abad village and to the north of the
Shorab village, 55 km southwest from Damghan city.
The Kuh-e-Reza-Abad section has a thickness of 166 m. Based on field observations and sedimentological
criteria, this section can be subdivided into three lithological units. The unit A consists of gray to dark grey
limestones, rich in brachiopods and ostracods. The unit B is mainly composed of gypsum levels with some
marly intercalations. The unit C is composed of grey limestones, rich in fossils. Among the conodonts, the
following species have been identified (Fig. 1): Icriodus excavatus, I. arkonensis, I. expansus, I. iowaensis,
Polygnathus politus, P. webbi, P. aequalis, P. pollocki, and P. xylus.
The Kuh-e-Shorab section is about 307 m thick and is mainly composed of an alternation of limestones,
sandstones and dolomites. The sediments contain a number of fossils such as brachiopods, corals, crinoid
stems, holothurian remains, sponge spicules and conodonts. Four genera and 29 conodont species have been
identified: Icriodus excavatus, I. expansus, I. cedarensis, I. subterminus, I. iowaensis, I. alternatus, I.
tafilaltensis, I. brevis, Polygnathus brevilaminus, P. angustidiscus, P. pollocki, P. cf. webbi, P. cf. aequalis, P.
politus, P. prepolitus, P. brevilamiformis, P. cf. olgae, P. dubius, P. xylus, P. zinaidae, Pelekysgnathus
inclinatus, Pel. serradentattus, Ancyrodella pristina, and A. cf. pristina
The identified taxa provide a stratigraphic range from Upper Givetian (subterminus Zone) into Lower
Frasnian (transitans Zone). Based on the studied fauna, it was possible to prove the presence of uppermost
Givetian at the base of the sections. The Middle Devonian is continuously overlain by Late Devonian
sediments, which can be assigned to the Bahram Formation in the Kuh-e-Shorab and the Kuh-e-Raza-Abad
sections.
The sections exhibit shallow-marine sediments that led to discontinuous conodont successions. Thus, the
biostratigraphic interpretation of the conodont fauna requires the application of an alternative conodont
zonation for neritic facies settings because the Standard Conodont Zonation by Ziegler & Sandberg (1990) is
not useful. This problem is well known in Central Iran (e.g., Bahrami et al., 2015) and the future challenge
might be to establish a shallow-water conodont zonation, which is mainly based on icriodontids.
References
Alavi-Naini M
. (1972). Etude géologique de la région de Djam. Geological Survey of Iran, Report, 23: 1-288.
Alavi-Naini M. (1975). Geological map of the Djam Area (scale1:100,000). Geological Survey of Iran, Tehran, 1 sheet.
Bahrami A., Königshof P., Boncheva I., Tabatabaei M.S., Yazdi M. & Safari Z. (2015). Middle Devonian (Givetian)
conodonts from the northern margin of Gondwana (Soh- and Natanz regions, north-west Isfahan, Central Iran):
biostratigraphy and palaeoenvironmental implications. Palaeobiodiversity and Palaeoenvironments,
doi:10.1007/s12549-015-0205-0.
Ziegler W. & Sandberg C.A. (1990). The Late Devonian Standard Conodont Zonation. Courier Forschungsinstitut
Senckenberg, 121: 1-115.
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
1
9
Fig.
1: Conodonts from the Barham Formation. (1) Icriodus excavatus Weddige, 1984; sample. (=s.) H 23. (2) I.
expansus Branson & Mehl, 1938; s. H 23. (3) I. cedarensis Narkiewicz & Bultynck 2010; s. H 23. (4) I. subterminus
Youngquist, 1947; s. H 22. (5) I. sp. indet.; s. H 22. (6). I. iowaensis Youngquist & Peterson, 1947; s. H 21. (7) I.
alternatus Branson & Mehl, 1934; s. H 21. (8) I. tafilaltensis Narkiewicz & Bultynck, 2010; s. H 08. (9) I. brevis
Stauffer, 1940; s. H 03. (10) Polygnathus brevilaminus Branson & Mehl, 1934; s. H 22. (11) Pol. angustidiscus
Youngquist, 1947; s. H 22. (12) Pol. pollocki Druce, 1976; s. H 20. (13) Pol. cf. webbi Stauffer, 1938; s. H 16. (14) Pol.
cf. aequalis Klapper & Lane, 1985; s. H 16. (15) Pol. politus Ovnatanova, 1969; s. H 09. (16) Pol. prepolitus Kononova,
Alekseev, Barskov & Reimers, 1996; s. H 08. (17) Pol. brevilamiformis Ovnatanova, 1976; s. H 08. (18)- Pol. aspelundi
Savage & Funai, 1980; s. H 08. (19) Pol. cf. webbi Stauffer, 1938; s. H 08. (20) Pol. sp.; s. H 08. (21) Pol. alatus Hinde,
1934; s. H 08. (22) Pol. cf. webbi Stauffer, 1938; s. H 07. (23) Pol. cf. olgae Ovnatanova & Kuzmin, 1991; s. H 07. (24)
Pol. pollocki Druce, 1976; s. H 04. (25) Pol .dubius sensu Kapper & Philip, 1971; s. H 04. (26) Pol. xylus Stauffer, 1940;
s. H 04. (27) Pol. zinaidae Kononova, Alekseev, Barskov & Reimers, 1996; s. H 08. (28) Pelekysgnathus planus
Sanneman, 1955a: s. H 23. (29) Pel. inclinatus Thomas, 1949; s. H 23. (30) Pel. serradentattus Capkinoglu, 1991; s. H
22. (31a-b) Ancyrodella pristina Khalymbadzha & Tchernyshova, 1970; s. H 09. (32a-b) Anc. cf. pristina Khalymbadzha
& Tchernyshova, 1970; s. H 05.
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
20
Devo
nian vertebrates of Mongolia
Ma
rtin D. Brazeau
1
, An
na Jerve
1
, Rob
ert Sansom
2
,
Yarinpil Ariunchimeg
3
&
Enk
htaivan Zorig
3
1
Dep
artment of Life Sciences, Silwood Park Campus, Imperial College London, Buckhurst Rd. SL6 4ET, Ascot, UK. E-
mails: m.brazeau@imperial.ac.uk, a.jerve@imperial.ac.uk
2
Faculty
of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK. E-mail:
robert.sansom@manchester.ac.uk
3
In
stitute of Paleontology and Geology, Mongolian Academy of Sciences, P.O.Box 46/52, Ulaanbaatar 14201, Mongolia.
E-mail: ariunchimeg@mail.ru, paleozorigoo@yahoo.com
Th
e Devonian is a particularly important time as it records a turnover from faunas dominated by jawless fishes
to those dominated by jawed vertebrates, as well as the rise of tetrapods. Much of our knowledge of vertebrate
evolution during this time is derived from Euramerican deposits, and increasing numbers of exceptional
discoveries from Australia and China. The Siberian palaeocontinent and related terranes are underrepresented
in phylogenetic studies of early jawed vertebrate evolution, leaving a major palaeobiogeographic gap in these
studies. Devonian vertebrates from Mongolia, which formed part of the Siberian palaeocontinent, have been
poorly documented, even though extensive Devonian outcrops are known in the region. To date, published
records are limited to fragmentary placoderm remains from eastern Mongolia, although diverse vertebrate
microremains are known from the Silurian of western Mongolia. To address this gap, we have been
undertaking a multi-year field project in Mongolia to prospect for Palaeozoic vertebrate localities, with a
particular focus on the Devonian of western Mongolia. Mongolia has extensive Devonian marine and near-
shore sequences which should yield vertebrate remains. Our work has uncovered new Devonian vertebrate
localities in Early, Middle, and Late Devonian deposits. Early Devonian deposits yield acanthothoracid
placoderms and acanthodian remains. Acanthothoriacids comprise at least three distinct genera, at least two of
which are new, highly unusual forms. The Early-Middle Devonian yields a diverse assemblage of placoderms
and osteichthyans. The Late Devonian has produced abundant Bothriolepis remains and rare osteolepidid
material. Most significantly is a lack of jawless vertebrate macroremains. These new records have the
potential to inform our understanding of vertebrate diversification and distribution during the Devonian
period. Jawed vertebrate records in Mongolia are characterised by groups with global or
palaeobiogeographically very broad distributions. The absence of jawless vertebrates is consistent with their
presumed low rates of dispersal and high levels of endemism.
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RATA, 2015, série 1, vol. 16. IGCP596–SDS Symposium (Brussels, September 2015)
2
1
Revis
ed Devonian time scales and evidence for variable eustatic,
climatic, and biotic volatility: example from the Lower-Middle
Devonian of the Appalachian Basin
Ca
rlton E. Brett
1
, Go
rdon C. Baird
2
, A
lex J. Bartholomew
3
, Cha
rles Ver Straeten
4
&
Ja
mes Zambito
5
1
Dep
artment of Geology, University of Cincinnati, Cincinnati, OH 45221-0013, USA. E-mail: carlton.brett@uc.edu
2
Dep
artment of Geosciences, SUNY College at Fredonia, Fredonia, NY 14603, USA. E-mail:
Gordon.Baird@fredonia.edu
3
Geology Department, SUNY College at New Paltz, New Paltz, NY 12561-2443, USA. E-mail: barthola@newpaltz.edu
4
NY
State Museum & Geological Survey, 3140 Cultural Education Center, Albany, NY 12230, USA. E-mail:
Charles.VerStraeten@nysed.gov
5
W
isconsin Geological and Natural History Survey, University of Wisconsin Extension, 3817 Mineral Point Road,
Madison, WI 53705, USA. E-mail: jay.zambito@wgnhs.uwex.edu
Revised
time-scales for the Devonian Period (e.g., Becker et al., 2012), together with increasingly precise
studies of oxygen isotopes and correlated sea level fluctuations has brought major discrepancies in the
frequency and amplitude of eustatic, isotopic, physical and biotic fluctuations through various parts of the
Devonian into sharp focus. Revised correlation charts for the Lower-Middle Devonian of the Appalachian
Basin highlight these anomalies.
The record of eustatic events is highly uneven. Thus, the relatively minor evidence of sea level variation in
the Emsian (five rather minor fluctuations over ~17 million years) contrasts sharply with the high-frequency
and strong definition of sea level fluctuations during the late Eifelian to early Frasnian interval (some 10
recognized third order sequences over about 10 million years as well as many recognized fourth- and fifth-
order sequences; Brett et al., 2011).
Recent studies of carbon isotopes in Devonian brachiopods and whole-rock carbonates (Buggisch & Mann,
2004; Buggisch & Joachimski, 2006; Becker et al., 2012) have led to refined understanding of isotopic trends:
there are about 15 positive
1
3
C
carb
excu
rsions and about six stronger negative excursions in the Devonian. The
volatility is again very low during the long Emsian interval (no major excursions), and strongest in the late
Eifelian to early Famennian (9 major positive excursions and 6 fairly pronounced negative excursions). This
evidence of variable volatility of the global carbon cycle roughly parallels the reduced sea level, climatic and
biotic variability of the Emsian as compared to the Middle Devonian. Perhaps the abrupt positive isotopic
shifts are related to intervals of eutrophication and burial of organic carbon. The rising phases of these shifts
may be associated with bioevents.
Many studies have focused on hypoxic events and their close association with minor and major extinctions,
and biotic turnovers, typically identified as “bioevents” (for summary see House, 2002; Becker &
Kirchgasser, 2007). The Lower-Middle Devonian record of the Appalachian Basin and elsewhere, provides
strong evidence that widespread hypoxic conditions and abrupt bioevents are linked. At present, there some 12
named global bioevents in the Early to Middle Devonian and three of these are doublets (i.e., two closely
spaced events). Of named bioevents, one is in the Lochkovian, four minor ones in the Pragian-Emsian, three
in the Eifelian, and four in the Givetian. These are variably recorded in the Appalachian Basin. Those of the
Emsian are relatively minor, in contrast to those of the subsequent Middle Devonian (e.g., Kacak, Taghanic),
which bound ecological-evolutionary subunits and are nearly as strong as the better known Late Devonian
events (Brett et al., 2009).
Together, the strong evidence for a change in environmental and biotic volatility in the Appalachian Basin
record may well reflect a transition from strong greenhouse, (Pragian to Emsian), to transitional or moderate
icehouse conditions in the Middle Devonian. The development of an oxygen isotopic curve for the Devonian
based largely on conodont apatite values (Joachimski et al., 2009) appears to give more reasonable
temperature estimates than brachiopod shell values and outlines a broad trend of cooling from high oceanic
temperatures in the Lochkovian-Emsian into the Middle Devonian followed by warming into the Frasnian.
Superimposed on this general curve are a series of peaks, especially warming spikes, associated with the
global late Lochkovian, Bakoven (late Eifelian), and Taghanic (late Givetian) extinction and hypoxic events.
These fluctuations suggest a connection between brief episodes of abrupt warming (during a generally cool
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period), intervals of sea level rise, hypoxia recorded in black shale, and biotic turnovers. The widespread,
probably global, nature of these events suggests a eustatic connection. Elrick et al. (2009) have argued that
high-resolution variation in
1
8
O
values in Middle Devonian suggests not only fluctuations consistent with sea
level variations (high values during lowstands and vice versa), but also a glacial "reservoir" effect based on
Rayleigh distillation. This provides indirect proxy evidence for glacioeustasy at a time interval for which
actual glacial deposits are as yet unknown. The recent discovery of these deposits in a very well known area in
very recent years suggests that our knowledge of glacial deposits remains very incomplete.
Regardless of mechanism, there appear to be prolonged intervals characterized by weak fluctuations in sea
level, oxygenation, carbon isotopes, and biotic change. In contrast, are intervals of much stronger
environmental volatility. The latter show a series of relatively quasi-stable conditions punctuated by major
turnovers with abrupt sea level rise, widespread hypoxia, and changes in the carbon cycle. It is during these
intervals that much net evolutionary and ecological change appears to take place.
References
Becker R.T. & Kirchgasser W.T. (2007). Devonian Events and Correlations. The Geological Society of London, Special
Publication, 278: 1-280.
Becker R.T. Gradstein F.M. & Hammer O. (2012). The Devonian Period. In: Gradstein F.M., Ogg J.G., Schmitz M., Ogg
G. (Eds), The Geologic Time Scale 2012. Elsevier Publishing, Amsterdam, 573-614.
Brett C.E., Bartholomew A., DeSantis M. & Baird G.C. (2011). Sequence stratigraphy and revised sea level curve for the
Middle Devonian of eastern North America. Paleogeography, Palaeoclimatology, Palaeoecology, 304: 21-53.
Brett C.E., Ivany L.C., Bartholomew A.J., DeSantis M.K. & Baird G.C. (2009). Devonian ecological-evolutionary
subunits in the Appalachian Basin: a revision and a test of persistence and discreteness. Geological Society of
London, Special Publications, 314: 7-36.
Buggisch W. & Mann W. (2004). Carbon isotope stratigraphy of Lochkovian to Eifelian limestones from the Devonian
of central and southern Europe. International Journal of Earth Sciences, 93: 521-541.
Buggisch W. & Joachimski M.M. (2006). Carbon isotope stratigraphy of the Devonian of Central and Southern Europe.
Palaeogeography, Palaeoclimatology, Palaeoecology, 240: 68-88.
Elrick M., Berkyova´ S., Klapper G., Sharp Z., Joachimski M. & Fryda J. (2009). Stratigraphic and oxygen isotope
evidence for My-scale glaciation driving eustasy in the Early-Middle Devonian greenhouse world.
Palaeogeography, Palaeoclimatology, Palaeoecology, 276: 170-181.
House M.R. (2002). Strength, timing, setting and cause of mid-Palaeozoic extinctions. Palaeogeography,
Palaeoclimatology, Palaeoecology, 181: 5-25.
Joachimski M.M., Breisig S., Buggisch W., Talent J.A., Mawson R., Gereke M., Morrow J.R., Day J. & Weddige K.
(2009). Devonian climate and reef evolution: insights from oxygen isotopes in apatite. Earth and Planetary Science
Letters, 284: 599-609.
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3
New in
sights on Uppermost Famennian brachiopods from north-
western France (Avesnois)
De
nise Brice
1
& Ber
nard Mottequin
2
1
Un
iversité Catholique de Lille, Groupe ISA, Boulevard Vauban 48, F59046 Lille Cedex, France. E-mail: d.brice@isa-
lille.fr
2
Roya
l Belgian Institute of Natural Sciences, O.D. Earth and History of Life, rue Vautier 29, B 1000 Brussels, Belgium.
E-mail: bmottequin@naturalsciences.be
Th
e uppermost Famennian is characterized by radiations among several brachiopod orders such as the
Productida, Rhynchonellida and Spiriferida, which developed morphological features heralding the
Carboniferous brachiopod faunas (e.g., Gosselet, 1857; Simakov, 1990; Mottequin et al., 2014). In common
with other groups such as ammonoids (Kullmann, 2002), fishes (Friedman & Sallan, 2012), rugose corals