scholarly journals Volcanic origin of the mercury anomalies at the Cretaceous-Paleogene transition of Bidart, France

Geology ◽  
2021 ◽  
Author(s):  
Eric Font ◽  
Jiubin Chen ◽  
Marcel Regelous ◽  
Anette Regelous ◽  
Thierry Adatte
Keyword(s):  
Mass Extinction ◽  
Isotope Composition ◽  
Deccan Traps ◽  
Large Igneous Province ◽  
Volcanic Emissions ◽  
Volcanic Origin ◽  
Asteroid Impact ◽  
Significant Enrichment ◽  
Additional Support ◽  
Mass Dependent Fractionation

The timing and mechanisms of the climatic and environmental perturbations induced by the emplacement of the Deccan Traps large igneous province (India) and their contribution to the Cretaceous-Paleogene (K-Pg) mass extinction are still debated. In many marine sediment archives, mercury (Hg) enrichments straddling the K-Pg boundary have been interpreted as the signature of Deccan Traps volcanism, but Hg may also have been derived from the Chicxulub (Mexico) impact. We investigated the Hg isotope composition, as well as the behavior of iridium (Ir) and other trace elements, in K-Pg sediments from the Bidart section in southwest France. Above the K-Pg boundary, Ir content gradually decreases to background values in the Danian carbonates, which is interpreted to indicate the erosion and redistribution of Ir-rich fallouts. No significant enrichment in Ir and W, or Zn and Cu, is observed just below the K-Pg boundary, excluding the hypothesis of downward remobilization of Hg from the boundary clay layer. Positive Δ199Hg and slightly negative values in the upper Maastrichtian and lower part of the early Danian are consistent with the signature of sediments supplied by atmospheric Hg2+ deposition and volcanic emissions. Up section, large shifts to strongly negative mass-dependent fractionation values (δ202Hg) result from the remobilization of Hg formerly sourced by the impactor or by a mixture of different sources including biomass burning, volcanic eruption, and asteroid impact, requiring further investigation. Our results provide additional support for the interpretation that the largest eruptions of the Deccan Traps began just before, and encompassed, the K-Pg boundary and therefore may have contributed to the K-Pg mass extinction.

Ocean sulfate scarcity as a pre-condition for Large Igneous Province driven mass extinction

2021 ◽  
Author(s):  
Robert J. Newton ◽  
Tianchen He ◽  
Jacopo Dal Corso ◽  
Paul Wignall ◽  
Ben Mills ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Isotope Composition ◽  
Feedback Mechanism ◽  
Large Igneous Province ◽  
Mass Extinctions ◽  
Anoxic Waters ◽  
Igneous Province ◽  
Marine Realm ◽  
Extinction Events ◽  
Increasing Temperature

<p>Records of sulfur cycling during mass extinction events increasingly show that they are associated with rapid shifts in the sulfur isotope composition of seawater indicative of low concentrations of ocean sulfate [1-4]. These events are also often associated with the spread of anoxic conditions in the marine realm. We propose a feedback mechanism whereby the production of methane in marine sediments increases in proportion to decreasing sulfate and consumes bottom water oxygen, thus acting as a positive feedback on spread of anoxic waters. This can be further amplified via increased weathering or recycled fluxes of phosphate enhancing productivity [e.g. 5], the effects of increasing temperature on the rate of methanogenesis and the additional suppression of marine sulfate via increased pyrite burial.</p><p>We propose that sulfate drawdown occurs prior to climate forcing and other extinction drivers imposed by large igneous province (LIP) eruption. The likely mechanism for the drawdown of sulfate prior to these extinction is the removal of sulfate from the oceans as gypsum in evaporite deposits. Several large mid-Phanerozoic mass extinctions have clear evidence of increased evaporite deposition prior to, or approximately coincidental with LIP eruption and extinction.</p><p>If this idea is correct, the biological impact of a LIP will partly depend on the sulfate status of the ocean at the time of its eruption, and may at least partly explain the observation that whilst many mass extinctions are associated temporally with a LIP, not all LIPs seem to cause mass extinctions.</p><p>1. Newton, R.J., et al., Geology, 2011. 39(1): p. 7-10.</p><p>2. Song, H., et al., Geochimica et Cosmochimica Acta, 2014. 128(0): p. 95-113.</p><p>3. Witts, J.D., et al., Geochimica et Cosmochimica Acta, 2018. 230: p. 17-45.</p><p>4. He, T., et al., Science Advances, 2020. 6(37): p. eabb6704.</p><p>5. Schobben, M., et al., Nature Geoscience, 2020. </p>

scholarly journals The Choiyoi magmatism in south western Gondwana: implications for the end-permian mass extinction - a review

2017 ◽  
Vol 44 (3) ◽  
pp. 328 ◽  
Author(s):  
Luis A. Spalletti ◽  
Carlos O. Limarino
Keyword(s):  
Carbon Dioxide ◽  
Mass Extinction ◽  
Atmospheric Carbon Dioxide ◽  
Sedimentary Basins ◽  
Fire Frequency ◽  
Large Igneous Province ◽  
Volcanic Emissions ◽  
Gas Generation ◽  
Study Region ◽  
Carbon Dioxide Co2

The end of the Permian period is marked by global warming and the biggest known mass extinction on Earth. The crisis is commonly attributed to the formation of large igneous provinces because continental volcanic emissions have the potential to control atmospheric carbon dioxide (CO2) levels and climate change. We propose that in southwestern Gondwana the long-term hothouse Permian environmental conditions were associated with the development of the Choiyoi magmatism. This large igneous province was developed between the Cisuralian and the early Triassic. It covers an area estimated at 1,680,000 km2 with an average thickness of 700 m, so that the volume of effusive and consanguineous rocks is estimated at 1,260,000 km3. Towards the western sector of the study region, a major overlap exists between the regional development of the Choiyoi magmatism and the Carboniferous sedimentary basins, which include paralic and continental deposits with intercalations of peat and coal beds. Commonly, these upper Palaeozoic deposits accumulated on a thick substrate composed of Cambro-Ordovician carbonates and Ordovician to Devonian terrigenous sedimentary rocks characterised by a large proportion of dark organic-rich shales and turbidite successions. While extensive volcanism released large masses of carbon dioxide into the Permian atmosphere, the heating of Palaeozoic organic-rich shales, peat and carbonates by ascending magma led to CO2 and CH4 gas generation in sufficient volumes to amplify the major climatic change. The analysis of the almost continuous record of Permian redbeds in the Paganzo basin, where the Choiyoi magmatism is not recorded, allowed us to recognize two main pulses of strong environmental desiccation, one at the Cisuralian and the second around the end-Permian. These two drastic climatic crisis are attributed to peaks of CO2 and CH4 outbursts to the atmosphere and related collateral effects, such as acid rain, impoverishment of soils and increase in forest-fire frequency. We propose that the combination of these multiple mechanisms triggered the decline of biodiversity in southwestern Gondwana and caused the end-Permian extinction of most of the Glossopteridales.

scholarly journals Toxic mercury pulses into late Permian terrestrial and marine environments

Geology ◽  
2020 ◽  
Vol 48 (8) ◽  
pp. 830-833 ◽  
Author(s):  
Stephen E. Grasby ◽  
Xiaojun Liu ◽  
Runsheng Yin ◽  
Richard E. Ernst ◽  
Zhuoheng Chen
Keyword(s):  
Trophic Levels ◽  
Large Igneous Province ◽  
Late Permian ◽  
Volcanic Emissions ◽  
Loading Rates ◽  
Siberian Traps ◽  
Igneous Province ◽  
Permian Extinction ◽  
Potential Impact ◽  
Normal Background

Abstract Large spikes in mercury (Hg) concentration are observed globally at the latest Permian extinction (LPE) horizon that are thought to be related to enhanced volcanic emissions of the Siberian Traps large igneous province (LIP). While forming an effective chemostratigraphic marker, it remains unclear whether such enhanced volcanic Hg emissions could have generated toxic conditions that contributed to extinction processes. To address this, we examined the nature of enhanced Hg emissions from the Siberian Traps LIP and the potential impact it may have had on global ecosystems during the LPE. Model results for a LIP eruption predict that pulses of Hg emissions to the atmosphere would have been orders of magnitude greater than normal background conditions. When deposited into world environments, this would have generated a series of toxic shocks, each lasting >1000 yr. Such repeated Hg loading events would have had severe impact across marine trophic levels, as well as been toxic to terrestrial plant and animal life. Such high Hg loading rates may help explain the co-occurrence of marine and terrestrial extinctions.

scholarly journals Mercury linked to Deccan Traps volcanism, climate change and the end-Cretaceous mass extinction

2020 ◽  
Vol 194 ◽  
pp. 103312 ◽  
Author(s):  
Gerta Keller ◽  
Paula Mateo ◽  
Johannes Monkenbusch ◽  
Nicolas Thibault ◽  
Jahnavi Punekar ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Extinction ◽  
Deccan Traps

scholarly journals When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150834 ◽  
Author(s):  
Michael O. Day ◽  
Jahandar Ramezani ◽  
Samuel A. Bowring ◽  
Peter M. Sadler ◽  
Douglas H. Erwin ◽  
...  
Keyword(s):  
South Africa ◽  
Mass Extinction ◽  
Southern China ◽  
Large Igneous Province ◽  
Temporal Association ◽  
Carbonate Platforms ◽  
Biodiversity Crisis ◽  
Karoo Basin ◽  
Extinction Event ◽  
Permian Mass Extinction

A mid-Permian (Guadalupian epoch) extinction event at approximately 260 Ma has been mooted for two decades. This is based primarily on invertebrate biostratigraphy of Guadalupian–Lopingian marine carbonate platforms in southern China, which are temporally constrained by correlation to the associated Emeishan Large Igneous Province (LIP). Despite attempts to identify a similar biodiversity crisis in the terrestrial realm, the low resolution of mid-Permian tetrapod biostratigraphy and a lack of robust geochronological constraints have until now hampered both the correlation and quantification of terrestrial extinctions. Here we present an extensive compilation of tetrapod-stratigraphic data analysed by the constrained optimization (CONOP) algorithm that reveals a significant extinction event among tetrapods within the lower Beaufort Group of the Karoo Basin, South Africa, in the latest Capitanian. Our fossil dataset reveals a 74–80% loss of generic richness between the upper Tapinocephalus Assemblage Zone (AZ) and the mid- Pristerognathus AZ that is temporally constrained by a U–Pb zircon date (CA-TIMS method) of 260.259 ± 0.081 Ma from a tuff near the top of the Tapinocephalus AZ. This strengthens the biochronology of the Permian Beaufort Group and supports the existence of a mid-Permian mass extinction event on land near the end of the Guadalupian. Our results permit a temporal association between the extinction of dinocephalian therapsids and the LIP volcanism at Emeishan, as well as the marine end-Guadalupian extinctions.

scholarly journals Carbon and nitrogen isotope evidence for widespread presence of anoxic intermediate waters before and during the Permian-Triassic mass extinction

2021 ◽  
Author(s):  
Baojin Wu ◽  
Genming Luo ◽  
Michael M. Joachimski ◽  
Paul B. Wignall ◽  
Lidan Lei ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Column ◽  
Water Depth ◽  
Mass Extinction ◽  
Isotope Composition ◽  
Nitrogen Isotope ◽  
Intermediate Water ◽  
Negative Shift ◽  
Intermediate Waters ◽  
Direct Killing

The largest mass extinction since the advent of animals occurred during the Permian-Triassic (P-Tr) transition, ca. 252 Ma, and is commonly attributed to the eruption of the Siberian Traps large igneous province. However, the direct killing mechanism is still debated. In this study, we investigated marine redox conditions of the intermediate water column that most organisms inhabit with special attention to the time interval before the onset of the mass extinction. The carbon isotope composition of carbonate and organic carbon (δ13Ccarb and δ13Corg) as well as the nitrogen isotope composition of bulk nitrogen (δ15N) were analyzed in four P-Tr boundary sequences (Zhongli, Jianshi, Ganxi, and Chaotian sections), which record a transect from a shallow water carbonate platform to a deep water, lower ramp slope in South China. δ13Ccarb shows a distinct negative shift in all sections and displays a clear, 2−4‰, decreasing gradient accompanying an increase in water depth both before and after the mass extinction. A distinct negative shift in δ15N is observed in the shallow water Zhongli section, whereas a minor negative shift is present in the three deeper water sections. Before the mass extinction, the δ15N values from shallow water sections are higher than those from deeper waters. The low δ15N values close to 0‰ in deeper water sections suggest that microbial nitrogen fixation was the predominant source of biologically available nitrogen before the onset of the mass extinction. Thus, the water depth- dependent gradient in δ13Ccarb and δ15N suggests that an oxygen-deficient intermediate water column was already present before the mass extinction. The uniform δ15N values around 0‰ accompanying the onset of the mass extinction reveal that anoxic intermediate waters expanded into shallow waters. Meanwhile, the distinct positive shift in δ13Corg observed in upper ramp slope sections, i.e., the Jianshi and Ganxi sections, suggests that a euxinic photic zone was at least episodically present in the earliest Triassic. The temporal coincidence between the expansion of intermediate water column anoxia and the onset of the P-Tr mass extinction supports the hypothesis that marine anoxia was a direct killing mechanism.

scholarly journals Archosauriform footprints in the Lower Triassic of Western Alps and their role in understanding the effects of the Permian-Triassic hyperthermal

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10522
Author(s):  
Fabio Massimo Petti ◽  
Heinz Furrer ◽  
Enrico Collo ◽  
Edoardo Martinetto ◽  
Massimo Bernardi ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Lower Triassic ◽  
Western Alps ◽  
Large Igneous Province ◽  
Early Triassic ◽  
Triassic Boundary ◽  
Habitable Zones ◽  
Single Well ◽  
Permian Mass Extinction ◽  
Permian Triassic Boundary

The most accepted killing model for the Permian-Triassic mass extinction (PTME) postulates that massive volcanic eruption (i.e., the Siberian Traps Large Igneous Province) led to geologically rapid global warming, acid rain and ocean anoxia. On land, habitable zones were drastically reduced, due to the combined effects of heating, drought and acid rains. This hyperthermal had severe effects also on the paleobiogeography of several groups of organisms. Among those, the tetrapods, whose geographical distribution across the end-Permian mass extinction (EPME) was the subject of controversy in a number of recent papers. We here describe and interpret a new Early Triassic (?Olenekian) archosauriform track assemblage from the Gardetta Plateau (Briançonnais, Western Alps, Italy) which, at the Permian-Triassic boundary, was placed at about 11° North. The tracks, both arranged in trackways and documented by single, well-preserved imprints, are assigned to Isochirotherium gardettensis ichnosp. nov., and are here interpreted as produced by a non-archosaurian archosauriform (erytrosuchid?) trackmaker. This new discovery provides further evidence for the presence of archosauriformes at low latitudes during the Early Triassic epoch, supporting a model in which the PTME did not completely vacate low-latitude lands from tetrapods that therefore would have been able to cope with the extreme hot temperatures of Pangaea mainland.

scholarly journals Supplemental Material: Volcanic origin of the mercury anomalies at the Cretaceous-Paleogene transition of Bidart, France

2021 ◽  
Author(s):  
Eric Font ◽  
et al.
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Analytical Methods ◽  
Isotope Composition ◽  
Volcanic Origin

Detailed analytical methods, Table S1 (Hg concentration, total organic carbon, and Ir concentration of the Bidart samples), Table S2 (Hg isotope composition of the Bidart samples), and methods.<br>

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