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January 2001 - April 2012
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Publications (88)
The ultimate driver of the end-Permian mass extinction is a topic of much debate. Here, we used a multiproxy and paleoclimate modeling approach to establish a unifying theory elucidating the heightened susceptibility of the Pangean world to the prolonged and intensified El Niño events leading to an extinction state. As atmospheric partial pressure...
The Permian−Triassic mass extinction (PTME) interval is marked by major excursions in both inorganic and organic carbon (C) isotopes. Carbon cycle models predict that these trends were driven by large increases in productivity, yet organic C−rich rocks are not recorded in most PTME shelf sedimentary successions. Anomalous C-rich facies have been re...
The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos (e.g. brachiopods, corals, bryozoans, foraminifers, ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulp...
The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos (e.g. brachiopods, corals, bryozoans, foraminifers, ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulp...
Evolution has not been a simple path. Since the first appearance of complex life, there have been several mass extinctions on Earth. This was exemplified by the most severe event during the Phanerozoic, the end-Permian mass extinction that occurred 252 million years ago and saw a loss of 90% and 70% of all marine and terrestrial species, respective...
The timing and connections between global cooling, marine redox conditions, and biotic turnover are underconstrained for the Late Ordovician. The second most severe mass extinction occurred at the end of the Ordovician period, resulting in ~85% loss of marine species between two extinction pulses. As the only “Big 5” extinction that occurred during...
The end-Triassic (∼201 Mya) records one of the five largest mass extinction events of the Phanerozoic. Extinction losses were coincident with large igneous province volcanism in the form of the Central Atlantic Magmatic Province (CAMP) and major carbon isotope excursions (CIEs), suggesting a link between these phenomena. Marine anoxia has been impl...
The Late Ordovician Mass Extinction wiped out 85% of animal species in two phases (LOME1 and LOME2). The kill mechanisms for the extinction phases are debated, but deteriorating climate and the expansion of marine anoxia appear to have been important factors. Nevertheless, the spatial extent and intensity of marine anoxia and its temporal relations...
Both the duration and severity of deep-water anoxic conditions across the Permian-Triassic mass extinction (PTME) are controversial. Panthalassa Ocean circulation models yield varying results, ranging from a well-ventilated deep ocean to rapidly developing northern-latitude, but not southern-latitude, anoxia in response to Siberian Traps-driven glo...
An emerging consensus suggests that large igneous provinces (LIPs) are a significant driver
of dramatic global environmental and biological changes, including several Phanerozoic
mass extinctions, leading to plausible links with geological time scale (GTS) boundaries. LIP-
induced environmental changes are now being identified in the Precambrian re...
The coincidence of large igneous province (LIP) eruptions with at least three, if not all, of the Big Five biotic crises of the Phanerozoic implies that volcanism is a key driver of mass extinctions. Many LIP‐induced extinction scenarios invoke global warming, caused primarily (but not exclusively) by greenhouse gases emitted at the site of LIP emp...
We measured the concentrations of trace elements in Late Permian to Early Triassic sediments from Spitsbergen. High mercury concentrations in sediments from the level of the Permo‐Triassic Mass Extinction (PTME) at this location were previously attributed to the emplacement of the Siberian Traps Large Igneous Province and used to link the timing of...
The final 10 Myr of the Paleozoic saw two of the biggest biological crises in Earth history: the middlePermian extinction (often termed the Guadalupian–Lopingian extinction [GLE]) that was followed 7–8 Myr later by Earth's most catastrophic loss of diversity, the Permian–Triassic mass extinction (PTME). These crises are not only manifest as sharp d...
The Permian-Triassic mass extinction, the greatest biotic crisis in Earth history, triggered the complete replacement of ecosystems with the 5–10% surviving species giving rise to the Mesozoic fauna. Despite a long history of systematic studies on Permian-Triassic foraminifera, there have been few investigations into spatial and temporal patterns o...
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The Ordovician saw major diversification in marine life abruptly terminated by the Late Ordovician mass extinction (LOME). Around 85% of species were eliminated in two pulses 1 m.y. apart. The first pulse, in the basal Hirnantian, has been linked to cooling and Gondwanan glaciation. The second pulse, later in the Hirnantian, is attributed to warmin...
Until recently, the biotic crisis that occurred within the Capitanian Stage (Middle Permian, ca. 262 Ma) was known only from equatorial (Tethyan) latitudes, and its global extent was poorly resolved. The discovery of a Boreal Capitanian crisis in Spitsbergen, with losses of similar magnitude to those in low latitudes, indicated that the event was g...
Microbially induced sedimentary structures (MISS) are reportedly widespread in the Early Triassic and their occurrence is attributed to either the extinction of marine grazers (allowing mat preservation) during the Permo-Triassic mass extinction or the suppression of grazing due to harsh, oxygen-poor conditions in its aftermath. Here we report on t...
The largest extinction in Earth history, in the latest Permian, was followed throughout most of the Early Triassic by a prolonged period of ecologic recovery. What factors delayed biotic recovery are still under debate and partly revolve around impacts of global warming on primary marine productivity. We examined N isotope records from the Festning...
It is generally accepted that wide stretches of the world's oceans turned anoxic during the Permian-Triassic transition. Although it is often invoked that these anoxic regions experienced an extreme redox state signified by free hydrogen sulfide in the water column (euxinia), recent studies employing iron speciation suggest that some regions were a...
Based on seven measured sections from Svalbard, the marine strata of the Permian Kapp Starostin Formation are arranged into seven transgressive–regressive sequences (TR1–TR7) of c . 4–5 Ma average duration, each bound by a maximum regressive surface. Facies, including heterozoan-dominated limestones, spiculitic cherts, sandstones, siltstones and sh...
Permian strata from the Tieqiao section (Jiangnan Basin, South China) contain several distinctive conodont assemblages. Early Permian (Cisuralian) assemblages are dominated by the genera Sweetognathus, Pseudosweetognathus and Hindeodus with rare Neostreptognathodus and Gullodus. Gondolellids are absent until the end of the Kungurian stage—in contra...
The temporal link between large igneous province (LIP) eruptions and at least half of the major extinctions of the Phanerozoic implies that large scale volcanism is the main driver of mass extinction. Here we review almost twenty biotic crises between the early Cambrian and end Cretaceous and explore potential causal mechanisms. Most extinctions ar...
Water column oxygen deficiency has been considered as a potent driver of the extinction of marine benthos, and is a main feature of marine environments in the aftermath of the end-Permian mass extinction. The record of Permian-Triassic anoxia is more complex than previously thought, and is seen to vary between different palaeogeographic settings, b...
The Carnian Humid Episode (CHE), also known as the Carnian Pluvial Event, and associated biotic changes are major enigmas of the Mesozoic record in western Tethys. We show that the CHE also occurred in eastern Tethys (South China), suggestive of a much more widespread and probably global climate perturbation. Oxygen isotope records from conodont ap...
The stratigraphic variability and geochemistry of Llandovery/Wenlock (L/W) Series boundary sediments in Poland reveals that hemipelagic sedimentation under an anoxic/euxinic water column was interrupted by low-density bottom currents or detached diluted turbid layers that resulted in intermittent seafloor oxygenation. Total organic carbon values an...
Major advances in our understanding of mass extinctions have resulted from greater resolution in the fossil record, better dating, and improved proxies for paleoenvironmental change. Despite these, consensus is far from reached on the drivers of extinction. In recent years the realization that Earth is once again facing some of the stresses implica...
Lower Triassic marine strata in Spitsbergen accumulated on a mid-to-high latitude ramp in which high-energy foreshore and shoreface facies passed offshore into sheet sandstones of probable hyperpycnite origin. More distal facies include siltstones, shales and dolomitic limestones. Carbon isotope chemostratigraphy comparison allows improved age dati...
Strata of Permian – Early Triassic age that include a record of three major extinction events (Capitanian Crisis, Latest Permian Extinction and the Smithian/Spathian Extinction) were examined at the Festningen section, Spitsbergen. Over the
c
. 12 Ma record examined, mercury in the sediments shows relatively constant background values of 0.005–0.01...
Plume-induced lithospheric uplift and erosion are widely regarded as key features of large igneous province (LIP) emplacement, as is the coincidence of LIP eruption with major extinction and oceanic anoxic events (OAE). The Emeishan LIP, which erupted during the Capitanian (previously termed ‘end Guadalupian’) extinction event, has provided the mos...
The Early Triassic was a time of remarkably high temperatures, large carbon cycle perturbations and episodes of widespread ocean anoxia. The sediments in the Nanpanjiang Basin of South China provide superb opportunities to examine the sedimentary response to these extreme conditions especially during the crisis interval at the Smithian–Spathian (S-...
The controversial Capitanian (Middle Permian, 262 Ma) extinction event is only known from equatorial latitudes, and consequently its global extent is poorly resolved. We demonstrate that there were two, severe extinctions amongst brachiopods in northern Boreal latitudes (Spitsbergen) in the Middle to Late Permian, separated by a recovery phase. New...
Stratigraphic records from northwestern Pangea provide unique insight into global processes that occurred during the latest Permian extinction (LPE). We examined a detailed geochemical record of the Festningen section, Spitsbergen. A stepwise extinction is noted as: starting with (1) loss of carbonate shelly macrofauna, followed by (2) loss of sili...
The temporal link between mass extinctions and large igneous provinces is well known. Here, we examine this link by focusing on the potential climatic effects of large igneous province eruptions during several extinction crises that show the best correlation with mass volcanism: the Frasnian-Famennian (Late Devonian), Capitanian (Middle Permian), e...
The Frasnian–Famennian extinction witnessed the global devastation of both level-bottom and reef communities in low latitudes. Marine extinctions in offshore level-bottom communities are associated with two widespread, transgressive, anoxic ‘Kellwasser Events’ that support an anoxia–extinction link. Typical Kellwasser facies of bituminous limestone...
A detailed, 20 myr redox history of Permian to Triassic oceans (Changhsingian to Carnian stages) has been constructed using Ce-anomaly (ΩCe) and Th/U ratios from conodont albid crown apatite material. The results show that the well-established phenomenon of intense ocean anoxia (coincident with the end-Permian mass extinction) is faithfully recorde...
The end-Ordovician extinction consisted of two discrete pulses, both linked, in various ways, to glaciation at the South Pole. The first phase, starting just below the Normalograptus extraordinarius Zone, particularly affected nektonic and planktonic species, while the second pulse, associated with the Normalograptus persculptus Zone, was less sele...
The Capitanian (middle Permian) extinction and recovery event is examined in carbonate platform settings from western Tethys (Hungary and Hydra, Greece). The age model for these sections is poorly resolved and we have constructed a δ13C chemostratigraphic correlation scheme, supported by conodont and foraminifer data, which attempts correlation wit...
The Capitanian (middle Permian) extinction and recovery event is examined in carbonate platform settings from western Tethys (Hungary and Hydra, Greece). The age model for these sections is poorly resolved and we have constructed a δ¹³C chemostratigraphic correlation scheme, supported by conodont and foraminifer data, which attempts correlation wit...
High-resolution sampling of more than 10,000 microfossils from seven Late Permian-Middle Triassic paleoequatorial sections in south China refutes claims for a 5 m.y. recovery delay after the end-Permian mass extinction. We show that level-bottom seafloor diversity began to recover in the early Smithian, little more than 1 m.y. after the mass extinc...
We welcome this opportunity to clarify the conclusions and implications of our recent publication in PNAS. Butterfield (1) raises four issues regarding the oxygenation of the Paleozoic Earth's surface and its correlation to animal evolution. Our geochemical and paleontological data supported ocean oxygenation in the Silurian-Early Devonian (2), a c...
Permian continental sequences from North China contain previously unrecognized episodes of plant radiation and elevated extinction. The earliest extinction, in the Lower Shihhotse Formation (Roadian, Guadalupian), records a 45% floral species loss and is tentatively correlated with global extinctions amongst dinocephalian reptiles. Two younger exti...
The Middle Permian Emeishan large igneous province of SW China is regard by many as providing the quintessential example of kilometre-scale pre-eruption domal uplift associated with mantle plume impingement on the base of the lithosphere. The key line of evidence for this has been the purported deep erosion profile of the Maokou Formation platform...
The evolution of Earth's biota is intimately linked to the oxygenation of the oceans and atmosphere. We use the isotopic composition and concentration of molybdenum (Mo) in sedimentary rocks to explore this relationship. Our results indicate two episodes of global ocean oxygenation. The first coincides with the emergence of the Ediacaran fauna, inc...
The Middle Permian Emeishan large igneous province of SW China has provided the quintessential example of the phenomenon of kilometre-scale pre-eruption domal uplift associated with mantle plume impingement on the base of the lithosphere. One key line of evidence is an interpreted zone of truncation of the platform carbonates belonging to the Maoko...
The Upper Famennian Annulata Black Shales are exposed in the deep-shelf successions of the famous Kowala Quarry and the Ściegnia outcrop in the Holy Cross Mountains, Southern Poland. At Kowala, the twin Annulata anoxic events are manifest as two organic-rich (TOC up to 23 wt.%), finely laminated, fossiliferous black shales, each up to 0.6 m thick,...
Conodont, C isotope and fossil and facies data are presented for the Capitanian (Middle Permian) mass extinction record seen in platform carbonates (Maokou and Wuchiaping formations) of South China, where limestones interdigitate with the volcanic succession of the Emeishan large igneous province. The Maokou Formation provides an extinction record...
Size analysis of pyrite framboids has been undertaken on epicontinental Permian- Triassic boundary sections throughout the world in order to evaluate the intensity and duration of anoxia. Mid-paleolatitude sections from the margins of the Boreal (Spitsbergen, Greenland) and Neotethyan oceans (Western Australia) reveal intense anoxia throughout the...
Fabric and pyrite framboid size analysis of Permian to Jurassic samples from the Mino-Tamba terrane of Japan provide an 80 myr redox history from the Panthalassa Ocean. Fully oxygenated conditions dominated but were punctuated by three phases of anoxia (euxinia) during the Permo-Triassic boundary, the late Early Triassic (Spathian Stage) and the la...
A Middle Permian mass extinction, first discovered in 1994, has become known as the “end-Guadalupian event” in the literature. However, recent studies of foraminifera- and brachiopod-range truncations in conodont-dated sections on the South China Block have shown that the losses occur below this level, in the middle of the Capitanian Stage. Extinct...
A global database of middle–upper Permian foraminiferal genera has been compiled from the literature for 75 Guadalupian and 62 Lopingian localities, grouped into 32 and 19 operational geographical units respectively. Cluster analysis reveals that five distinct Guadalupian provinces were reduced to four in the Lopingian, following the disappearance...
The close association of Pd with Au has been previously reported in highly oxidized chloride hydrothermal systems from several regions, including Australia, Brazil, Poland, and the United Kingdom. The distinctive mineralization precipitated usually as a consequence of contact with reducing environments is characterized by Au alloys containing low A...
The Guadalupian-Lopingian boundary stratotype at Penglaitan, and the nearby Tieqiao section, near Laibin, South China, record a series of major environmental changes within the Jiangnan Basin during a Mid-Permian biotic crisis. The sequence-stratigraphic, petrographic and palaeontological record of these sections has been studied and the associated...
Fabric and pyrite framboid size analysis of Permian to Jurassic samples from the Mino-Tamba terrane of Japan provide an 80 myr redox history from the Panthalassa Ocean. Fully oxygenated conditions dominated but were punctuated by three phases of anoxia (euxinia) during the Permo-Triassic boundary, the late Early Triassic (Spathian Stage) and the la...
The 260-million-year-old Emeishan volcanic province of southwest China overlies and is interbedded with Middle Permian carbonates
that contain a record of the Guadalupian mass extinction. Sections in the region thus provide an opportunity to directly monitor
the relative timing of extinction and volcanism within the same locations. These show that...
Johnson et al. (Johnson, J.G., Klapper, G., Sandberg, C.A., 1985. Devonian eustatic fluctuations in Euramerica. Geological Society of America Bulletin 96, 567–587) proposed one of the first explicit links between marine anoxia, transgression and mass extinction for the Frasnian–Famennian (F–F, Late Devonian) mass extinction. This cause-and-effect n...
Depositional redox conditions of the uppermost Bajocian–Bathonian (Middle Jurassic) ore-bearing clays of the Gnaszyn/Kawodrza
area in the Polish Jura have been determined using an integrated geochemical (Th/U and U/Th ratios, degree of pyritisation
(DOP), sulphur stable isotopes, biomarker analysis) and petrographic approach (measurements of pyrite...
2008. The end-Triassic and Early Jurassic mass extinction records in the British Isles. Proceedings of the Geologists' Association, 119, 73–84. The complex crises of the end-Triassic and Early Jurassic (Toarcian) mass extinctions are well recorded in the British Isles where they coincide with major palaeoenvironmental changes. The end-Triassic exti...
Chemical signatures of enrichment of highly reactive iron, and fram-boid size distributions, are reported in turbidite sediments that host soft tissue pyritization (Beecher's Trilobite Bed, Upper Ordovician, and the Hunsruck Slate, Lower Devonian). These signatures demonstrate that the sediment of Beecher's Trilobite Bed was enriched in highly reac...
The end-Guadalupian mass extinction has been investigated in Sichuan province, SW China. In the south of the province the platform carbonates of the Maokou Formation are overlain by the Emeishan flood basalts, a possible factor in the extinction event, and in the north of the province the formation is succeeded by shallow-marine carbonates of the W...
Bond, D.P.G. and Chapman, R.J., 2007. Evaluation of the origins of gold hosted by the conglomerates of the Indian River formation, Yukon, using a combined sedimentological and mineralogical approach. In: Yukon Exploration and Geology 2006, D.S. Emond, L.L. Lewis and L.H. Weston (eds.), Yukon Geological Survey, p. 93-103. abstract Conglomerates belo...
The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals that are among the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian–Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Dev...
The Frasnian-Famennian (Late Devonian) mass extinction has often been related to the development of the Kellwasser anoxic events in Europe and North Africa but the synchronous development of the anoxia has not been reported from the Great Basin of the western United States. An integrated sedimentological, palaeoecological, and pyrite petrographic s...
The intensity and extent of anoxia during the two Kellwasser anoxic events has been
investigated in a range of European localities using amultidisciplinary approach (pyrite framboid assay,
gamma-ray spectrometry and sediment fabric analysis). The results reveal that the development of the
Lower Kellwasser Horizon in the early Late rhenana Zone (Fra...
The lower Frasnian (transitans Zone with Ancyrodella priamosica = MN 4 Zone) rhythmic basin succession of marly limestones and shales (upper Szydlówek Beds) at Kostomloty, western Holy Cross Mts., Central Poland, contains a record of the transgressive-hypoxic Timan Event in this drowned part of southern Laurussian shelf. The unique facies consists...
The Upper Devonian sequence at Kowala in the Holy Cross Mountains was logged using gamma-ray spectrometry,
for investigating the changes of oxygenation level in the Late Devonian basin. The Th/U ratio indicates that oxygen
levels were low throughout the Late Frasnian interval, with low peaks during the Kellwasser Events showing anoxic
conditions in...
Thesis (Ph. D.)--University of Leeds (School of Earth Sciences), 2004.
