• Mohammed Et-Touhami added an answer:
    How to correlate marine and continental Lower Triassic beds?
    A topic on problems of correlation with using of biostratigraphy and paleomagnetic data.
    Mohammed Et-Touhami · Université Mohammed Premier

    Dear Vladlen Lozovsky,

    For pre-Jurassic time, the geomagnetic polarity reference scale is much less well developed than that for the Jurassic to Recent because of the absence of the sea floor and hence marine magnetic anomalies. Nevetheless, there is a published astronomically calibrated Geomagnetic Polarity Timescale (GPTS) for Late Triassic and Early Jurassic based on scientific coring of the Newark basin (NY, NJ, PA; USA) [1]. There are attempts to correlate marines sections to this geomagnetic polarity record which provides a well-dated chronostratigraphic framework [2] [3]. Furthermore, preliminary data from Morocco, suggests the possibility to extend this timescale down into the Middle Triassic [4]. So I think, it would be interesting if your Lower Triassic nonmarine magnetostratigraphic sections are continuous and have some chronostratigraphic control and lacustrine intervals for cyclostratigraphy to calibrate in time the relative spacing of polarity intervals.


    [1] Kent, D.V. and Olsen, P.E., 1999, Astronomically tuned geomagnetic polarity time scale for the Late Triassic, Journal of Geophysical Research, v. 104, p. 12,831-12,841.[2] Kent, D. V., Olsen, P. E., and Witte, W. K., 1995, Late Triassic-Early Jurassic geomagnetic polarity and paleolatitudes from drill cores in the Newark rift basin (Eastern North America). Journal of Geophysical Research, v. 100 (B8), p. 14,965-14,998.[3] Muttoni, G., Kent, D.V., Olsen, P.E., DiStefano, P., Lowrie, W., Bernasconi, S., Hernandez, F.M., 2004, Tethyan magnetostratigraphy from Pizzo Mondello (Sicily) and correlation to the Late Triassic Newark astrochronological polarity time scale, Geological Society of America Bulletin, v. 116; no. 9/10; p. 1043–1058[4] Olsen, P. E., Kent, D. V, LeTourneau, P. M., Et-Touhami, M., 2002, Astronomically calibrated GPTS for the Late Triassic and Early Jurassic based on the Newark Hartford and Taylorsville basins of Eastern North America. in McRoberts, C. A. and Olsen, P. E., (eds.), Triassic-Jurassic Non-marine Boundary Events in the Newark, and Hartford basins (New Jersey, Pennsylvania, Connecticut, and Massachusetts), Eastern United States, 2nd Field Workshop, June 7th-12th, 2002, Abstracts with Programs, p. 13.

  • Massih Afghah added an answer:
    Can anyone give me any suggestions of why there is not any Ostracods in a marine formation dated of Miocene?

    I am working on a marine sediment dated as Miocene, from the northwestern of Madagascar (Ramihangihajason et al., 2014. « Miocene benthic foraminifera from Nosy Makamby and Amparafaka, Mahajanga Basin, northwestern Madagascar, Journal of African Earth Sciences 100, 409-417)

    Last month, I processed those samples in order to check the diatoms into them, but I didn't find even one specimen. So, I wonder if there is any explanation for that. Thank you

    Massih Afghah · Islamic Azad University Shiraz branch

    Dear Tootra

    There are many records of presence of Miocene Ostracods in marine facies particularly in Late Miocene strata. Some of documents reflected mix of marine and non marine Ostracods.  You can find some of them below:

    Witt, W.(2011) have been reported mix of faunal assemblage of marine and non marine Ostracods in Turkey as:Mixed ostracod faunas, co-occurrence of marine
    Oligocene and non-marine Miocene taxa at
    Pınarhisar, Thrace, Turkey


    Moreover Ikeya (2011)  obtained many studies which have been confirmed marine Miocene Ostracods.


    Marine Miocene Ostracods are recorded previously by Meireles et al (2012) which is entitled: Late Miocene marine ostracods from Santa Maria island, Azores (NE Atlantic): Systematics, palaeoecology and palaeobiogeography


    The other report is assigned to Late-Oligocene to Early-Miocene marine sediments of Upper Rhine Graben and Hanau Basin by Gebhardt, H. (2003) link below:

    link: file:///C:/Users/chapar/Downloads/2003_BiogeoPaper03.pdf



  • Asheesh Kumar added an answer:
    Can someone help me about the formation of gas hydrate ?

    hi, can you helpe me about the formation of gaz hydrate ? 

    Asheesh Kumar · National Chemical Laboratory

    Find the attached ppt. it will help you to understand the gas hydrates.

  • Roger Spurr added an answer:
    Does anyone know locations of Arnheim Fm outcrops along the Nashville Dome, TN?

    I am looking to measure and correlate as many Arnheim Fm outcrops along the Nashville Dome as possible however the literature is scarce. The few papers I do have with location data are on the older side and the locations don't all appear to exist anymore when checked on Google Earth.


    Roger Spurr

    I cannot help with locations but may I ask what you are looking for in the outcrops?

    Could it be concentrates, I have been studying intrusions and chemical concentration patterns. I could use some stratigraphy help and may be able to help you as well.  The story is long but these things have a direct relation to my other work...mud fossils. I would like your thoughts on these videos of giant primate CT scans. If interested in a little collaboration rspurr@gmail please contact me.

  • Bhawanisingh G Desai added an answer:
    Can anyone help me with this bioturbation?

    I appreciate any help on this vertical-oblique bioturbation (ichnofossil, trackmaker..). Info: Continental setting (alluvial-coastal plan), Cretaceous, located in lutites overlying a sandstone-microconglomerate level. Thanks in advance!!

    Bhawanisingh G Desai · Pandit Deen Dayal Petroleum University

    The Vertically oriented, "Y" shaped trace fossils are usually attributted to Ichnogenus Psilonichnus. This seems more like Psilonichnus rather than Thalassinoides. 

  • Nathan j Wright added an answer:
    How can I estimate haplotype richness with analytic rarefaction 1.3?

    I will be happy if someone help me to use Analytic Rarefaction for estimate haplotype richness of samples with different sample sizes.

    what input file is needed when I have data; sample size=20,30,50,30, haplotype diversity=0.3, 0.5, 0.5, 0.4 ?

    Or, I should make haplotype frequency table (in text) like;

    10 5 0 0 5

    I would like to see example file, but can not find.

    for each sample?

    Nathan j Wright · University of Queensland

    Here is some more info on PAST

    The website to download the program is the University of Oslo:

    Attached is the pdf manual and a screen shot of the program.

    Across the top (columns) are the different samples if used and down the side (rows) are the categories, in this case species. The data is simple abundance data.

    Hope this helps.

    Cheers Nathan

  • Mohamed Abdelghany Khalifa added an answer:
    What do you think of this textural relationship of gypsum and anhydrite crystallized in a dolostone?

    Dear Colleagues,

    I am currently working on a problematic evaporite-carbonate sequence. The dominant lithology is dolostone with different but minor siliciclast content. One of the most obvious feature is the overall presence of evaporites; satin spar filled fractures, gypsum rosettes, evaporite cemented dolomitized carbonate framework components (coated grains, bioclasts) and chicken wire structures can be find as well. The whole appearance of the sequence suggests an evaporitic sabkha environment. My question is whether the anhydrite hydrolized to gypsum or gypsum transformed to anhydrite?

    Many thanks for your answer in advance!

    Sincerely yours,


    Mohamed Abdelghany Khalifa · Geology Dept.Faculty of Science, Menoufia University

    The presence of sequence in lithofacies evaporites and dolomite is most probably sabkha environment. The presence of evaporites in between dolomite is normal mode of deposition in sabkha, since the evaporite can be deposited at first consuming the ca ions from saline water, this gave rise to enrichment with Mg ions and hence the dolomite can be formed, you can see the Peritidal to intrashelf basin, facies transition of the Adgham Formation (Late Triassic) Al Qasim Province, Saudi Arabia
    M. A. Khalifa.Carbonates Evaporites (2012) 27:299–319
    DOI 10.1007/s13146-012-0091-8

  • Massih Afghah added an answer:
    What are the best ways to determine paleoclimate in the Pennsylvanian (ex Upper Carboniferous) and Permian?

    These two periods of time were characterized by widespread peat (coal) deposits, great shifts in sea level as observed in cyclothems, and by continental glaciation. What was (were) the driving force (s) behind these great changes.

    Massih Afghah · Islamic Azad University Shiraz branch

    Dear Paul

    I recommend to check the Meyer (2007)A Review of Paleotemperature–Lapse Rate Methods for Estimating Paleoelevation from Fossil Floras, Reviews in Mineralogy and Geochemistry,v. 66, p. 155-171



  • Sean Ulm added an answer:
    When calibrating radiocarbon dates taken from marine Cardium edule shells in beach barrier sediments, should we use the Marine13 calibration curve?

    I'm trying to build a Bayesian model for a coastal dune stratigraphy. The oldest date is taken from marine beach barrier sediments, while the other, more recent, dates are taken from gyttja layers (associated with archaeological remains) embedded within dune sediments

    Sean Ulm · James Cook University

    Hi Jos,

    Yes, you should use Marine13 and apply the appropriate local/regional deltaR value (see 14CHRONO Marine Reservoir Database at Although the species appears to be a suspension-feeder, I note that it is densest in in-shore zones ( so may be influences by terrestrial run-off or restricted in-shore/embayment circulation patterns. See the following for an interesting case study of the potential differences in bivalves living in different zones and with different dietary habits:

    Petchey, F., S. Ulm, B. David, I.J. McNiven, B. Asmussen, H. Tomkins, N. Dolby, K. Aplin, T. Richards, C. Rowe, M. Leavesley and H. Mandui 2013 High-resolution radiocarbon dating of marine materials in archaeological contexts: Radiocarbon marine reservoir variability between Anadara, Gafrarium, Batissa, Polymesoda spp. and Echinoidea at Caution Bay, southern coastal Papua New Guinea. Archaeological and Anthropological Sciences 5(1):69-80.



  • Laura Maydagán added an answer:
    Can someone recommend some articles about the influence of oxygen fugacity on arc mamgma and its relation to the formation of porphyry deposits?

    I want to learn about the influence of oxygen fugacity on arc mamgma and its relation to the formation of porphyry deposits. Can someone recommend some articles on this topic to me. Thanks a lot.

    Laura Maydagán · National Scientific and Technical Research Council

    Also to this paper... Cheers,  Laura

  • Mary Elizabeth Bernardes de Oliveira added an answer:
    Do you know of a multidisciplinary team to carry out studies on stratigraphical sequences reaching at least 20 m deep?

    We are looking for a multidisciplinary team to carry out geological, chronological and environmental studies on stratigraphical sequences reaching at least 20 m deep. Our initial evaluations suggest that the deposits may present a continuous chronostratigraphical sequence dating from around 1.5 Myrs. The two volcanic structures are in a closed depression context linked to soil subsidence at the base of their lava emission centers. This situation is due either to the collapse of the craters under the weight of the lava or to the retraction of the lava during its cooling phase. These depression structures functioned as sediment traps which have yielded archaeological surface remains attributable to the Middle Pleistocene and through to the Holocene. They are located in the south of France, in the Baumes volcanic complex (communes of Caux, Nizas, Pézenas, Lezignan-la-Cebe ...). Exceptional sediment traps, the exhaustive study of these infillings would be a major asset for the paleoenvironmental restitution of the sector and more broadly of Western Europe since 1.5 Ma.
    Please contact me if you are interested and I will be able to provide you with more information.

    Je cherche une équipe pluri-disciplinaire pour l'étude géologique, chronologique et environnementale sur des séquences stratigraphiques de minimum 20 m de profondeur susceptibles de recouvrir une chronologie continue depuis 1,5 Ma. Il s'agit de deux structures volcaniques en dépression fermées dues à l’affaissement de sol à l’aplomb de centres d’émission de lave soit liées à un effondrement des structures du cratère sous le poids de la lave soit à la rétractation de la matière lors du refroidissement de la lave. Ces structures dépressionnaires ont fonctionné comme des pièges sédimentaires et livrent des éléments archéologiques en surface depuis le pléistocène moyen jusqu’à l’holocène. Elles sont localisées dans le sud de la France, dans le complexe volcanique des Baumes (communes de Caux, Nizas, Pézenas, Lézignan-La-Cèbe ...). Pièges sédimentaires exceptionnels, l’étude exhaustive de leur remplissage serait un atout majeur pour la restitution paléo-environnementale de ce secteur et plus largement de l’Europe de l’ouest depuis 1.5 Ma.
    Merci de me contacter pour de plus amples renseignements.

    Mary Elizabeth Bernardes de Oliveira · University of São Paulo


  • Lionello Morandi added an answer:
    Does anyone have a clue to this Holocene microfossil?

    In polar view it appears circular and strongly resembles HdV-119, whereas in equatorial view it is more similar to a fern spore. It's got a characteristic circular/polygonal rupture pattern (this latter feature is shown also by some smooth dinocysts).

    It is from a coastal fresh/brackish-water alluvial plain.


    Lionello Morandi · University of Reading

    Dear Gonzalo,

    thanks for your suggestion.

    I think it does look similar to Isoetes in one plane, but it's circular in polar view, and sistematically has a rounded break, features that should not be found on a monolete spore.

    I also have reference slides for Isoetes here and I have checked them today.



  • Rogerio de Lucena Alves added an answer:
    Can anyone provide a reference for papers about rare elements (Ag, Au) in black shales?

    It is known that rare elements (e.g., Ni, Cu, Zn) can be enriched in black shales. Can anyone provide papers on trace element analysis on the Toarcian Posidonia Shale and/or the Middle Jurassic Opalinus Clay (Opalinuston-Formation)? In particular, I'm interested in a possible Ag and Au content in these deposits.

    Rogerio de Lucena Alves · Dusolo Fertilizers


    I beleive that the bigest gold deposit in black shale is the Paracatu mine in Brazil from Kinross. The deposit is formed by deformed quartz veins hosted by black shales. Paracatu is a low grade (around 0.3g/t cutoff) high tonnage deposite. I know that some Ag, Pb and As are also present. There are several papers available on internet about Paracatu, you for sure will find what are you looking for.


    Rogerio Alves

  • Mateen Hafiz added an answer:
    Can anyone provide the information on vindhyan basin and its prospectivity for shale gas exploration?

    I have been looking for the detailed information about the vindhyan basin evolution, its stratigraphy and also its prosectivity for shale gas exploration. I found some links online but are not accessible. Can anyone provide the links from where I can directly download? Thank you in advance.

    Mateen Hafiz · University of Jammu

    In Vindhyans, the Rampur and Bijaigarh shales seems to be promising for shale resources exploration. Other formations are organically lean. I have attached few articles which discuss the source quality of different shales of Vindhyan Basin. 

  • Bing Song added an answer:
    Which perspective of age-depth modeling is better, regression analysis or interpolation?
    Two perspectives of age-depth modeling prevail: (1) regression analysis, which represents a statistical expression of the data; (2) Interpolation, which reveals a deterministic relationship of the data. Which one is better?
    Bing Song · Korean Institute of Geoscience and Mineral Resources

    Hi, Prof. Yu,

    Where are you service now? Do you remember me? I am very interesting about your research.

    I think the second method is better than the first one. Because the age model always effected by sediment hiatuses. If we use the first statistic method, the hiatus will affect all the age-depth line, but the second method will decrease the effected, maybe only make err in a short span.

    Best wishes,

    Bing Song

  • Jooly Jaiswal added an answer:
    What are the main points during Speleothem sampling?

    Can somebody tell me the proper site for speleothem sampling?

    I am little bit confused whether is taken from the location where it is equilibrium with external atmosphere or deep from the cave where humidity is near about 100. Some one told me the sample collected near from the cave entrance are most significant for the climatic study because it records the diurnal variation of the atmosphere. but here the kinetic fractionation also goverened the precipitation process please tell me the exact things.

    Jooly Jaiswal · Wadia Institute of Himalayan Geology

    Thank you so much Mr. Silviu Costantin for your answer. Now I am understand the point of consideration during the speleothem sampling.

  • Syed Haroon Ali added an answer:
    What is the Sequence Stratigraphy, High Resolution Stratigraphy and Cyclicity of Mixed Carbonate-Clastic Successions?

    Hi all,

    While working with Mixed Carbonate-Clastic successions, how do we mark Sequences and High Resolution Stratigraphy? Any recommendation of reference or research paper will be appreciated.



    Syed Haroon Ali · King Fahd University of Petroleum and Minerals

    Thanks Sir for sharing your experience and research!

  • M. Levent Artüz added an answer:
    Will anyone be able to identify the foraminifera?
    Image is attached.
    M. Levent Artüz · Sevinç-Erdal İnönü Foundation

    Dear Priscilla Philip,

    Take a look at Haynesina germanica (Ehrenberg, 1840) 

    best wishes,

  • Diego Kietzmann added an answer:
    Could you recommend me a software for creating stratigraphic column (for Mac)?

    I've googled and I've found a bunch I was just wondering if anyone had used any that they particularly enjoyed.

    Diego Kietzmann · University of Buenos Aires

    I usually use StratDraw, which builds logs in CorelDraw and then you can edited easily there.

    Best wishes

  • Paul Aharon added an answer:
    Can somebody help me about the trace element incorporation in speleothem in Lesser Himalayan Region?

    In general Mg incarporation in speleothem is temperature dependent and Sr and ba is not dependent on Temperature. Their incarporation in Spoeleothem is depend on soil dust activity. Can some body  tell how trace element  incarporated, the source and the governing factor of their concentration,the relation  between them.What can be other trace element other than Mg,Sr,Ba,U, Na,P  incarporated in speleothem and the importance?

    Paul Aharon · University of Alabama

    Interpretation of trace element ratios (typically E/Ca)  in speleothems in terms of climate is complicated by their partitioning in the epikarst. There are a number of papers dealing with the subject, some suggested by other responders.

    Additionally check the papers by Dan Sinclair who dealt with trace element partitioning in the epikarst.

  • M.Cemal Göncüoglu added an answer:
    Are there any recent publications on Silurian and/or Devonian "Orthoceras Limestones" in NE Gondwana?
    We are compiling a correlation and would appreciate any (published/unpublished) data with reliable ages.
    M.Cemal Göncüoglu · Middle East Technical University

    Danke Mike

    alles Gute


  • Ioannis T. Alexandridis added an answer:
    What kind of structure is this?
    I found this suspicious structure in fragments of Iron ore (magnetite). Its original structure is difficult to me. The main belt is a metamorphic volcano-sedimentary environment with relative proposed age of Neoproterozoic to lower Paleozoic.
    It resembles some volcanic structure, sedimentary structure or even fossil or stromatolite?
    Ioannis T. Alexandridis · Aristotle University of Thessaloniki

    You could also check the case of having "fold rodding lineation" (crenulation lineation). The specific sample, could easily be a remnant of fold limp, so the parallel structures could be the aformentioned structure.

    About the network of fractures I agree with Michael.


    Ioannis Alexandridis

  • M.Cemal Göncüoglu added an answer:
    Can someone advise on the sample preparation techniques of isotope dating of dolerite?
    I have collected some dolerite samples from Proterozoic sedimentary sequence. I want to know about the sample preparation techniques of isotope dating of dolerite.
    M.Cemal Göncüoglu · Middle East Technical University

    Do you have the thin-section view of the rock?

    Are there any unaltered primary minerals?

  • Valentina Yanko added an answer:
    Who is interested in collaborating on a project on quaternary freshwater and brackish water ostracods of the Lower Volga and Caspian region?
    We have samples from several boreholes and outcrops. Please contact me if interested.
    Valentina Yanko · Odessa National University

    Dear Guzel,

    We would be intresetd in collaborating with  you on the project. We have enormous data bank on forams and ostracods of the Ponto-Caspian region used for Quaternary stratigraphy and paleogeographic reconstrauctions.

    Best wishes,

    Prof. Dr. Valentina Yanko
    Head of the Department of Physical and Marine Geology
    Geological-Geographical Faculty
    Odessa I.I.Mechnikov National University
    2, Shampansky Per.
    Odessa, Ukraine 65058
    Tel: +380 (482) 63-33-17, +380 (48) 723-02-08

  • Kenneth M Towe added an answer:
    Is there a simple method to differentiate coal from charcoal?
    Maybe at the petrographic microscope there are some details like fractures that indicate burning.
  • André Klicpera added an answer:
    Can anyone help with lithological patterns to draw a stratigraphic column in Corel Draw?
    Particularly I need sedimentary rocks patterns.
  • Kenneth M Towe added an answer:
    What is the best estimate for the duration of the Cambrian Explosion?
    Which animal and protistan phyla appear simultaneously (within the resolution of chronostratigraphy)?
  • Om N. Bhargava added an answer:
    Does anyone have information about Ordovician diamictite in the Indian subcontinent?
    I'm referring to Gondwana sedimentary rocks.
    Om N. Bhargava · Geological Survey of India
    In Bhutan Nake Chu Fm was regarded as Ordovician, our work found that it rests below the Cambrian hence could not be Ordovician, it is Neoproterozoic equvalent of Blaini in the Himalaya and Nantuo in China.
  • Jahn Hornung added an answer:
    For a species is a stratigraphical range up to 140 Ma realistic ? (e.g. the dinocyst "Spiniferites ramosus" is mentioned from Valanginian to Present)
    To reflect on the limits of the application of actualism in paleoecology, I wonder about the significance of paleontological species that have a wide stratigraphic range.
    Jahn Hornung
    It depends on how reliable you consider the morphological information preserved in the fossil record. Lungfish teeth from the Early Cretaceous of Australia have been considered to be identical to those of the living species Neoceratodus forsteri. This would give this species a range of 100 myr, the longest known for a vertebrate. However, we do not know whether the Cretaceous lungfish would not have been quite different in other body parts than the tooth-plates. However, if you have most of the animal preserved you can make better assumptions. The tadpole shrimp (Triops cancriformis) is known from morphological indistinguishable fossils dating back to the Late Triassic (220 Ma). Single-celled organisms may be prone to very slow evolution, there have been records of amoebae indistinguishable from extant species from Triassic and Cretaceous amber. They may also have extremely long individual lifes, as they are not subjected to cell death and may theoretically enjoy an eternal live, if they are not destroyed by predators or environment. There have been repeated reports of Permian, possibly even Cambrian, bacteria from rock salt deposits which went into stasis when their water environment dried up and they were encapsulated by a salt crystal. It was reported that it was possible to revive them in the lab, though these reports are somewhat disputed...
  • John M McArthur added an answer:
    Can anyone recommend a good text book or papers on the red colored, carbonate free paleosol? What are the physical features? How do you identify them in the field? What is their geochememistry?
    John M McArthur · University College London
    The second paper on the last-glacial-maximum palaeosol is attached.

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