scholarly journals Hyperthermal-driven mass extinctions: killing models during the Permian–Triassic mass extinction

2018 ◽  
Vol 376 (2130) ◽  
pp. 20170076 ◽  
Author(s):  
Michael J. Benton
Keyword(s):  
Direct Evidence ◽  
Rapid Heating ◽  
Large Igneous Province ◽  
Mass Extinctions ◽  
Depth Zone ◽  
Ambient Temperatures ◽  
Physical Conditions ◽  
The Past ◽  
Geological Past ◽  
Igneous Province

Many mass extinctions of life in the sea and on land have been attributed to geologically rapid heating, and in the case of the Permian–Triassic and others, driven by large igneous province volcanism. The Siberian Traps eruptions raised ambient temperatures to 35–40°C. A key question is how massive eruptions during these events, and others, could have killed life in the sea and on land; proposed killers are reviewed here. In the oceans, benthos and plankton were killed by anoxia–euxinia and lethal heating, respectively, and the habitable depth zone was massively reduced. On land, the combination of extreme heating and drought reduced the habitable land area, and acid rain stripped forests and soils. Physiological experiments show that some animals can adapt to temperature rises of a few degrees, and that some can survive short episodes of increases of 10°C. However, most plants and animals suffer major physiological damage at temperatures of 35–40°C. Studies of the effects of extreme physical conditions on modern organisms, as well as assumptions about rates of environmental change, give direct evidence of likely killing effects deriving from hyperthermals of the past. This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.

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 Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Menghan Li ◽  
Stephen E. Grasby ◽  
Shui-Jiong Wang ◽  
Xiaolin Zhang ◽  
Laura E. Wasylenki ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Aerosol Particles ◽  
Sedimentary Rocks ◽  
Large Igneous Province ◽  
Siberian Traps ◽  
The Past ◽  
Igneous Province ◽  
Nickel Isotopes ◽  
Extinction Event ◽  
Permian Mass Extinction

AbstractThe end-Permian mass extinction (EPME) was the most severe extinction event in the past 540 million years, and the Siberian Traps large igneous province (STLIP) is widely hypothesized to have been the primary trigger for the environmental catastrophe. The killing mechanisms depend critically on the nature of volatiles ejected during STLIP eruptions, initiating about 300 kyr before the extinction event, because the atmosphere is the primary interface between magmatism and extinction. Here we report Ni isotopes for Permian-Triassic sedimentary rocks from Arctic Canada. The δ60Ni data range from −1.09‰ to 0.35‰, and exhibit the lightest δ60Ni compositions ever reported for sedimentary rocks. Our results provide strong evidence for global dispersion and loading of Ni-rich aerosol particles into the Panthalassic Ocean. Our data demonstrate that environmental degradation had begun well before the extinction event and provide a link between global dispersion of Ni-rich aerosols, ocean chemistry changes, and the EPME.

scholarly journals On the application of the theory of dissociation of Arrhenius electrolyte solutions to electrophysiology

2020 ◽  
Vol VI (1) ◽  
pp. 173-188
Author(s):  
V. Chagovets
Keyword(s):  
Direct Evidence ◽  
Practical Interest ◽  
Electrolyte Solutions ◽  
Past Century ◽  
Living Tissue ◽  
Physical Conditions ◽  
The Past ◽  
Satisfactory Answer ◽  
Living Tissues ◽  
Secondary Results

Some 150 years passed since the time when the idea was first expressed that the source of nervous power is electricity (Gausen, 1743). So much noise was overtaken in the past century by Mesmer's statements, which also explained how the special manifestation of electrical and magnetic forces, even more strengthened the faith, if not into identity, then) at least, into a close kinship of the energetic beginning of electricity. But, apart from abstract considerations, there was no direct evidence in support of these views in science. Only half a century later, after Gausen Galvani made his famous discovery that the muscles of a dissected frog's leg contract if the sciatic nerve and the lower part of it are connected with a metal conducting arc. Galvani, as is known, attributed this phenomenon to the presence of electrical forces generated in itself by the living tissue itself. But soon Volta arose against this view, who believed in this case the source of electricity not in the very tissues of the frog, but in the place of contact of the metal of the conducting arc with the liquid of living tissue. It was here that the beginning of that endless dispute was laid, which has been going on for a whole century and has not yet received a final solution, and which can be formulated as follows: does living protoplasm have independent sources of electric motor force, or does the electric phenomenon observed in living tissues only secondary results of the chemical or physical conditions that this tissue represents at a given moment, and do not have any direct connection with its functional activity? This question of enormous theoretical and practical interest, despite the mass of works of many outstanding scientists, has not yet received a satisfactory answer. Professor Biderman, in his extensive work on electrophysiology, which appeared last year, expresses himself on this matter as follows: the results of individual experiments and an almost complete lack of knowledge of the scope of their significance for the function of the underlying tissues. " (W. Biedermann. Elektrophysiologie. I. Abtheil. S. 273. Jena 1895).

Existence of the DHArwar-BAstar-SInghbhum (DHABASI) megacraton since 3.35 Ga: Constraints from the Precambrian Large Igneous Province record

2021 ◽  
pp. SP518-2021-53
Author(s):  
Rajesh K. Srivastava ◽  
Richard E. Ernst ◽  
Ulf Söderlund ◽  
Amiya K. Samal ◽  
Om Prakash Pandey ◽  
...  
Keyword(s):  
Building Block ◽  
Large Igneous Province ◽  
Indian Shield ◽  
Large Igneous Provinces ◽  
The Past ◽  
Igneous Provinces ◽  
Igneous Province ◽  
The Individual ◽  
Age Range

AbstractWe propose a Precambrian megacraton (consisting of two or more ancient cratons) ‘DHABASI’ in the Indian Shield that includes the Dharwar, Bastar and Singhbhum cratons. This interpretation is mainly based on seven large igneous provinces (LIPs) that are identified in these three cratons over the age range of ca. 3.35-1.77 Ga, a period of at least 1.6 Gyr. The absence of any subsequent breakup of ‘DHABASI’ since 1.77 Ga suggests that this megacraton has existed for the past 3.35 Gyr.In addition to their use in recognizing this megacraton, these LIP events may also provide likely targets for Cu-Ni-Cr-Co-PGE deposits. We suggest that the megacraton ‘DHABASI’ was an integral part of supercontinents/supercratons through Earth's history, and that it should be utilized as a distinct building block for paleocontinental reconstructions rather than using the individual Dharwar, Bastar and Singhbhum cratons.

Lithostratigraphy of the Palaeoproterozoic Hekpoort Formation (Pretoria Group, Transvaal Supergroup), South Africa

2020 ◽  
Vol 123 (4) ◽  
pp. 655-668
Author(s):  
N. Lenhardt ◽  
W. Altermann ◽  
F. Humbert ◽  
M. de Kock
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Sedimentary Rocks ◽  
Type Locality ◽  
Large Igneous Province ◽  
Braided River ◽  
River Systems ◽  
The West ◽  
Igneous Province ◽  
Transvaal Supergroup

Abstract The Palaeoproterozoic Hekpoort Formation of the Pretoria Group is a lava-dominated unit that has a basin-wide extent throughout the Transvaal sub-basin of South Africa. Additional correlative units may be present in the Kanye sub-basin of Botswana. The key characteristic of the formation is its general geochemical uniformity. Volcaniclastic and other sedimentary rocks are relatively rare throughout the succession but may be dominant in some locations. Hekpoort Formation outcrops are sporadic throughout the basin and mostly occur in the form of gentle hills and valleys, mainly encircling Archaean domes and the Palaeoproterozoic Bushveld Complex (BC). The unit is exposed in the western Pretoria Group basin, sitting unconformably either on the Timeball Hill Formation or Boshoek Formation, which is lenticular there, and on top of the Boshoek Formation in the east of the basin. The unit is unconformably overlain by the Dwaalheuwel Formation. The type-locality for the Hekpoort Formation is the Hekpoort farm (504 IQ Hekpoort), ca. 60 km to the west-southwest of Pretoria. However, no stratotype has ever been proposed. A lectostratotype, i.e., the Mooikloof area in Pretoria East, that can be enhanced by two reference stratotypes are proposed herein. The Hekpoort Formation was deposited in a cratonic subaerial setting, forming a large igneous province (LIP) in which short-termed localised ponds and small braided river systems existed. It therefore forms one of the major Palaeoproterozoic magmatic events on the Kaapvaal Craton.

Ultramafic-alkaline-carbonatite complexes as a result of two-stage melting of mantle plume: evidence from the mid-paleoproterozoic Tiksheozero intrusion, Northern Karelia, Russia

2019 ◽  
Vol 486 (4) ◽  
pp. 460-465
Author(s):  
E. V. Sharkov ◽  
A. V. Chistyakov ◽  
M. M. Bogina ◽  
O. A. Bogatikov ◽  
V. V. Shchiptsov ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Mantle Plume ◽  
Large Igneous Province ◽  
Intrusive Complex ◽  
Incongruent Melting ◽  
Isotopic Data ◽  
Two Stage ◽  
Similar Composition ◽  
Igneous Province ◽  
Alkaline Magmas

Tiksheozero ultramafic-alkaline-carbonatite intrusive complex, like numerous carbonatite-bearing complexes of similar composition, is a part of large igneous province, related to the ascent of thermochemical mantle plume. Our geochemical and isotopic data evidence that ultramafites and alkaline rocks are joined by fractional crystallization, whereas carbonatitic magmas has independent origin. We suggest that origin of parental magmas of the Tiksheozero complex, as well as other ultramafic-alkaline-carbonatite complexes, was provided by two-stage melting of the mantle-plume head: 1) adiabatic melting of its inner part, which produced moderately-alkaline picrites, which fractional crystallization led to appearance of alkaline magmas, and 2) incongruent melting of the upper cooled margin of the plume head under the influence of CO2-rich fluids  that arrived from underlying zone of adiabatic melting gave rise to carbonatite magmas.

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