Paroxysmal Deccan Eruptions linked to End-Cretaceous Mass Extinction

2021 ◽  
Author(s):  
Thierry Adatte ◽  
Gerta Keller ◽  
Jorge E. Spangenberg ◽  
Paula Mateo ◽  
Jahnavi Punekar ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Mass Extinctions ◽  
Deccan Volcanism ◽  
Time Resolved ◽  
Global Climate Changes ◽  
Chicxulub Impact ◽  
The Impact

<p>The Chicxulub impact in Mexico and Deccan volcanism in India are both linked to the end-Cretaceous mass extinction but the relative timing of the impact, volcanic eruptions, and environmental changes remain controversial, precluding a full assessment of their respective roles. Mercury anomalies within the stratigraphic record have recently been proposed as atmospheric fallout of continental large igneous provinces (LIPs), and these anomalies are associated with all five major mass extinctions in Earth’s history. If this proxy is robust, it could provide a record of volcanism directly correlated to mass extinctions and in the case of the End-extinction, the Chicxulub impact. To test this hypothesis, we analyzed mercury in the late Maastrichtian from the base of C29r to the Cretaceous-Paleogene boundary (KPB) n the astronomically tuned Elles section in Tunisia, and correlate this chemostratigraphic record with recent high-precision U-Pb geochronology of Deccan volcanism. Our results support that Hg is a robust indicator of LIP volcanism, and directly links Deccan volcanism to rapid global climate changes, ocean acidification and increasing environmental stress during the last 320-340 kyr of the Maastrichtian. Furthermore, our time-resolved Hg record and U-Pb resolved eruption volumes reveal paroxysmal volcanic eruptions (~30% by volume) during the final 35 kyr leading up to the KPB mass extinction.</p>

Deccan Volcanism or the Chicxulub Impact: The Chicken or Egg Question

2020 ◽  
Author(s):  
Gerta Keller
Keyword(s):  
Mass Extinction ◽  
Impact Crater ◽  
Global Climate ◽  
Mass Extinctions ◽  
Deccan Volcanism ◽  
Asteroid Impact ◽  
Global Climate Warming ◽  
Chicxulub Impact Crater ◽  
Chicxulub Impact ◽  
The Impact

<p>The Cretaceous–Paleogene boundary (KTB or KPB) mass extinction is primarily known for the<br>demise of the dinosaurs, the Chicxulub impact, and the rancorous forty-year-old controversy<br>over the cause of this mass extinction. For the first 30 years, the controversy primarily revolved<br>around the age of the impact claimed as precisely KTB based on the assumption that it caused<br>the mass extinction. The iridium (Ir) anomaly at the KTB was claimed proof of the asteroid<br>impact, but no Ir was ever associated with impact evidence and recent findings reveal no<br>extraterrestrial component in PGEs or the KTB Ir anomaly. Impact melt rock glass spherules are<br>also claimed as indisputable evidence of the KTB age impact, but such spherule layers are<br>commonly reworked from the primary (oldest) layer in late Maastrichtian, KTB and Danian<br>sediments; thus only the oldest impact spherule layer documented near the base of zone CF1<br>~200 ky below the KTB can approximate the impact’s age. Similarly, the impact breccia in the<br>Chicxulub impact crater predates the KTB. The best age derived from Ar/Ar dating of impact<br>glass spherules is within 200 ky of the KTB and thus no evidence for the KTB age. All evidence<br>strongly suggests the Chicxulub impact most likely predates the mass extinction ~ 200 ky and<br>played no role in it.<br>Deccan volcanism (LIP) was dismissed as potential cause or even contributor to the KTB mass<br>extinction despite the fact that all other mass extinctions are associated with Large Igneous<br>Province (LIP) volcanism but none with an asteroid impact. During the last decade, Deccan<br>volcanism gained credence based on a succession of discoveries: 1) the mass extinction in<br>between the longest Deccan lava flows across India; 2) high-precision dating of the entire<br>sequence of Deccan volcanism based on UPb zircon dating; 3) recognition of four distinct<br>eruption pulses all related to global climate warming with the largest pulse beginning 20 ky prior<br>to and ending at the KTB; 4) Identifying the climate link to Deccan volcanism based on age<br>dating and mercury from Deccan eruptions in marine sediments; and 5) Identifying the KTB<br>mass extinction directly related to the major Deccan eruption pulse, hyperthermal warming and<br>ocean acidification all linked to global mercury fallout from Deccan eruptions in marine<br>sediments. Despite this remarkable culmination of evidence, the controversy continues with<br>impact proponents arguing that Deccan volcanism didn’t exist at the KTB – the impact was the<br>sole cause.</p>

scholarly journals Massive methane fluxing from magma–sediment interaction in the end-Triassic Central Atlantic Magmatic Province

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Manfredo Capriolo ◽  
Andrea Marzoli ◽  
László E. Aradi ◽  
Michael R. Ackerson ◽  
Omar Bartoli ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Global Climate ◽  
Large Igneous Province ◽  
Mass Extinctions ◽  
Quartz Crystals ◽  
Global Climate Changes ◽  
Central Atlantic Magmatic Province ◽  
Basaltic Magmas ◽  
Central Atlantic

AbstractExceptional magmatic events coincided with the largest mass extinctions throughout Earth’s history. Extensive degassing from organic-rich sediments intruded by magmas is a possible driver of the catastrophic environmental changes, which triggered the biotic crises. One of Earth’s largest magmatic events is represented by the Central Atlantic Magmatic Province, which was synchronous with the end-Triassic mass extinction. Here, we show direct evidence for the presence in basaltic magmas of methane, generated or remobilized from the host sedimentary sequence during the emplacement of this Large Igneous Province. Abundant methane-rich fluid inclusions were entrapped within quartz at the end of magmatic crystallization in voluminous (about 1.0 × 106 km3) intrusions in Brazilian Amazonia, indicating a massive (about 7.2 × 103 Gt) fluxing of methane. These micrometre-sized imperfections in quartz crystals attest an extensive release of methane from magma–sediment interaction, which likely contributed to the global climate changes responsible for the end-Triassic mass extinction.

Biogeochemical disruptions across the Cretaceous-Paleogene boundary : insights from sulfur isotopes

2021 ◽  
Author(s):  
Arbia Jouini
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Sea Water ◽  
Sulfur Isotopes ◽  
Deep Understanding ◽  
Sulfur Cycle ◽  
Mass Extinctions ◽  
Deccan Volcanism ◽  
Organic Carbon Burial ◽  
Early Paleocene

<p><strong>Biogeochemical disruptions across the Cretaceous-Paleogene boundary : insights from sulfur isotopes</strong></p><p> </p><p>Arbia JOUINI<sup>1*</sup>, Guillaume PARIS<sup>1</sup>, Guillaume CARO<sup>1</sup>, Annachiara BARTOLINI<sup>2</sup></p><p><sup>1 </sup>Centre de Recherches Pétrographiques et Géochimiques, CRPG-CNRS, UMR7358, ,15 rue Notre Dame des Pauvres, BP20, 54501Vandoeuvre-lès-Nancy, France, email:[email protected]</p><p><sup>2</sup> Muséum National D’Histoire Naturelle, Département Origines & Evolution, CR2P MNHN, CNRS, Sorbonne Université, 8 rue Buffon CP38, 75005 Paris, France</p><p> </p><p>The Cretaceous–Paleogene (KPg) mass extinction event 66 million years ago witnessed one of the ‘Big Five’ mass extinctions of the Phanerozoic. Two major catastrophic events, the Chicxulub asteroid impact and the Deccan trap eruptions, were involved in complex climatic and environmental changes that culminated in the mass extinction including oceanic biogenic carbonate crisis, sea water chemistry and ocean oxygen level changes. Deep understanding of the coeval sulfur biogeochemical cycle may help to better constrain and quantify these parameters.</p><p>Here we present the first stratigraphic high resolution isotopic compositions of carbonate associated sulfate (CAS) based on monospecific planktic and benthic foraminifers' samples during the Maastrichtian-Danian transition from IODP pacific site 1209C. Primary δ34SCAS data suggests that there was a major perturbation of sulfur cycle around the KPg transition with rapid fluctuations (100-200kyr) of about 2-4‰ (±0.54‰, 2SD) during the late Maastrichtian followed by a negative excursion in δ34SCAS of 2-3‰ during the early Paleocene.</p><p>An increase in oxygen levels associated with a decline in organic carbon burial, related to a collapse in primary productivity, may have led to the early Paleocene δ34SCAS negative shift via a significant drop in microbial sulfate reduction. Alternatively, Deccan volcanism could also have played a role and impacted the sulfur cycle via direct input of isotopically light sulfur to the ocean. A revised correlation between δ34SCAS data reported in this study and a precise dating of the Deccan volcanism phases would allow us to explore this hypothesis.</p><p>Keywords : KPg boundary, Sulphur cycle, cycle du calcium, Planktic and benthic foraminifera</p><p> </p>

State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact

Science ◽  
2015 ◽  
Vol 350 (6256) ◽  
pp. 76-78 ◽  
Author(s):  
Paul R. Renne ◽  
Courtney J. Sprain ◽  
Mark A. Richards ◽  
Stephen Self ◽  
Loÿc Vanderkluysen ◽  
...  
Keyword(s):  
High Precision ◽  
Seismic Energy ◽  
Marine Ecosystems ◽  
Deccan Traps ◽  
Mass Extinctions ◽  
Transient Effects ◽  
Magmatic System ◽  
Deccan Volcanism ◽  
Chicxulub Impact ◽  
The Impact

Bolide impact and flood volcanism compete as leading candidates for the cause of terminal-Cretaceous mass extinctions. High-precision 40Ar/39Ar data indicate that these two mechanisms may be genetically related, and neither can be considered in isolation. The existing Deccan Traps magmatic system underwent a state shift approximately coincident with the Chicxulub impact and the terminal-Cretaceous mass extinctions, after which ~70% of the Traps' total volume was extruded in more massive and more episodic eruptions. Initiation of this new regime occurred within ~50,000 years of the impact, which is consistent with transient effects of impact-induced seismic energy. Postextinction recovery of marine ecosystems was probably suppressed until after the accelerated volcanism waned.

scholarly journals Graptolite community responses to global climate change and the Late Ordovician mass extinction

2016 ◽  
Vol 113 (30) ◽  
pp. 8380-8385 ◽  
Author(s):  
H. David Sheets ◽  
Charles E. Mitchell ◽  
Michael J. Melchin ◽  
Jason Loxton ◽  
Petr Štorch ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Mass Extinction ◽  
Climate Changes ◽  
Global Climate ◽  
Extinction Risk ◽  
Late Ordovician ◽  
Ecological Communities ◽  
Mass Extinctions ◽  
The Impact

Mass extinctions disrupt ecological communities. Although climate changes produce stress in ecological communities, few paleobiological studies have systematically addressed the impact of global climate changes on the fine details of community structure with a view to understanding how changes in community structure presage, or even cause, biodiversity decline during mass extinctions. Based on a novel Bayesian approach to biotope assessment, we present a study of changes in species abundance distribution patterns of macroplanktonic graptolite faunas (∼447–444 Ma) leading into the Late Ordovician mass extinction. Communities at two contrasting sites exhibit significant decreases in complexity and evenness as a consequence of the preferential decline in abundance of dysaerobic zone specialist species. The observed changes in community complexity and evenness commenced well before the dramatic population depletions that mark the tipping point of the extinction event. Initially, community changes tracked changes in the oceanic water masses, but these relations broke down during the onset of mass extinction. Environmental isotope and biomarker data suggest that sea surface temperature and nutrient cycling in the paleotropical oceans changed sharply during the latest Katian time, with consequent changes in the extent of the oxygen minimum zone and phytoplankton community composition. Although many impacted species persisted in ephemeral populations, increased extinction risk selectively depleted the diversity of paleotropical graptolite species during the latest Katian and early Hirnantian. The effects of long-term climate change on habitats can thus degrade populations in ways that cascade through communities, with effects that culminate in mass extinction.

Revisiting the Krakatau 1883 Volcanic Aerosol Dispersal 

2021 ◽  
Author(s):  
Rafael Castro ◽  
Tushar Mittal ◽  
Stephen Self
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Volcanic Eruptions ◽  
Climate Impact ◽  
Volcanic Plume ◽  
Quasi Biennial Oscillation ◽  
Aerosol Cloud ◽  
Pinatubo Eruption ◽  
The Impact

<p>The 1883 Krakatau eruption is one of the most well-known historical volcanic eruptions due to its significant global climate impact as well as first recorded observations of various aerosol associated optical and physical phenomena. Although much work has been done on the former by comparison of global climate model predictions/ simulations with instrumental and proxy climate records, the latter has surprisingly not been studied in similar detail. In particular, there is a wealth of observations of vivid red sunsets, blue suns, and other similar features, that can be used to analyze the spatio-temporal dispersal of volcanic aerosols in summer to winter 1883. Thus, aerosol cloud dispersal after the Krakatau eruption can be estimated, bolstered by aerosol cloud behavior as monitored by satellite-based instrument observations after the 1991 Pinatubo eruption. This is one of a handful of large historic eruptions where this analysis can be done (using non-climate proxy methods). In this study, we model particle trajectories of the Krakatau eruption cloud using the Hysplit trajectory model and compare our results with our compiled observational dataset (principally using Verbeek 1884, the Royal Society report, and Kiessling 1884).</p><p>In particular, we explore the effect of different atmospheric states - the quasi-biennial oscillation (QBO) which impacts zonal movement of the stratospheric volcanic plume - to estimate the phase of the QBO in 1883 required for a fast-moving westward cloud. Since this alone is unable to match the observed latitudinal spread of the aerosols, we then explore the impact of an  umbrella cloud (2000 km diameter) that almost certainly formed during such a large eruption. A large umbrella cloud, spreading over ~18 degrees within the duration of the climax of the eruption (6-8 hours), can lead to much quicker latitudinal spread than a point source (vent). We will discuss the results of the combined model (umbrella cloud and correct QBO phase) with historical accounts and observations, as well as previous work on the 1991 Pinatubo eruption. We also consider the likely impacts of water on aerosol concentrations and the relevance of this process for eruptions with possible significant seawater interactions, like Krakatau. We posit that the role of umbrella clouds is an under-appreciated, but significant, process for beginning to model the climatic impacts of large volcanic eruptions.</p>

HUMAN MOBILITY UNDER THE IMPACT OF ENVIRONMENTAL CHANGES

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Mariana BĂLAN ◽  
Simona Maria STĂNESCU
Keyword(s):  
Environmental Changes ◽  
Global Climate ◽  
Human Mobility ◽  
Human Beings ◽  
Joint Effort ◽  
Sustainable Resources ◽  
International Regulations ◽  
Droughts And Floods ◽  
And Migration ◽  
The Impact

The movement of people due to environment changes is not a new phenomenon. Despite this, only in the most recent 20 years, the international community has begun to acknowledge it as an unprecedented challenge in terms of sustainable resources involved. All over the world, the number of storms, droughts and floods has tripled in the last 30 years, with devastating effects on communities. The paper presents a brief analysis of global climate change in recent years and human mobility due to this phenomenon. The research is based on international regulations addressing the interdependencies between environmental change and migration. The climate risk management with impact on human mobility involves economic, political, cultural, and demographic factors. It also shows how a devastating natural disaster shapes people's mobility towards a more friendly environment protected shelter. The development of resilience community strategies implies a joint effort of communities and stakeholders in protecting human beings against effects of natural disasters.

scholarly journals Paleotemperature and paleosalinity evolution across Eocene-Oligocene Transition in North Atlantic Ocean: Insights from geochemical analysis of bivalve shells.

2020 ◽  
Author(s):  
Justine Briard ◽  
Marc de Rafélis ◽  
Emmanuelle Vennin ◽  
Mathieu Daëron ◽  
Valérie Chavagnac ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Sea Level ◽  
Environmental Changes ◽  
North Atlantic Ocean ◽  
Global Climate ◽  
Ice Sheet ◽  
Major Step ◽  
Mode Identification ◽  
Global Climate Changes ◽  
Bivalve Shells

<p>The Cenozoic period encompasses the last transition from the “greenhouse” climate of the late Early Eocene (~50 Ma) to our modern “icehouse” climate with its much lower CO<sub>2</sub> levels, significant polar glaciation and major sea level drop. The Eocene-Oligocene transition (EOT), that marks the first major ice-sheet build-up on Antarctica, has been extensively studied as it represents the entrance into an icehouse mode. Identification of this major step of Antarctic ice-sheet build-up strongly relies on δ<sup>18</sup>O and Mg/Ca benthic foraminifera records from ODP / DSDP sites. By contrast, few records currently exist from coastal environments despite the presence of abundant fossil archives, like bivalve shells. Yet palaeoenvironmental records from these peculiar coastal sites could bring information on how they react to global climate changes and help to further understand the behavior of our climate system. In this study, we applied a multi-proxy strategy coupling δ<sup>18</sup>O, δ<sup>13</sup>C, clumped isotopes (Δ<sub>47</sub>), strontium isotopes (<sup>87</sup>Sr/<sup>86</sup>Sr) analyses on aragonitic and calcitic bivalves and sediments recovered from the Isle of Wight (London-Paris Basin, Northeastern Atlantic Ocean) to provide additional constrain on environmental changes in this region across the Eocene-Oligocene Transition (~37.8–33 Ma).</p><p>Our new coupled δ<sup>18</sup>O and Δ<sub>47 </sub>dataset highlights a marked decrease in local seawater temperatures (~ 8°C) coupled to a drop in local seawater δ<sup>18</sup>O, likely linked to the sea level drop associated with ice-cap formation and an evolution toward more proximal, brackish environment in this region (that is apparent from sediment facies evolution). We estimate the salinity decrease recorded at the local scale from the Eocene to the Oligocene as reaching about 6 PSU, from 31 to 25 PSU. Strontium isotope analyses of the bivalves support this interpretation, showing values close to that of seawater up to the EOT but a marked deviation from contemporaneous global seawater <sup>87</sup>Sr/<sup>86</sup>Sr values toward more radiogenic values afterward. This positive deviation is in agreement with an evolution toward more proximal environments, subjected to larger freshwater inputs.</p>

scholarly journals Hominin responses to environmental changes during the Middle Pleistocene in central and southern Italy

2013 ◽  
Vol 9 (2) ◽  
pp. 687-697 ◽  
Author(s):  
R. Orain ◽  
V. Lebreton ◽  
E. Russo Ermolli ◽  
A.-M. Sémah ◽  
S. Nomade ◽  
...  
Keyword(s):  
Western Europe ◽  
Southern Italy ◽  
Environmental Changes ◽  
Global Climate ◽  
Middle Pleistocene ◽  
Faunal Remains ◽  
Vegetation Dynamic ◽  
Local Climate ◽  
Global Climate Changes

Abstract. The palaeobotanical record of early Palaeolithic sites from Western Europe indicates that hominins settled in different kinds of environments. During the "mid-Pleistocene transition (MPT)", from about 1 to 0.6 Ma, the transition from 41- to 100-ka dominant climatic oscillations, occurring within a long-term cooling trend, was associated with an aridity crisis which strongly modified the ecosystems. Starting from the MPT the more favourable climate of central and southern Italy provided propitious environmental conditions for long-term human occupations even during the glacial times. In fact, the human strategy of territory occupation was certainly driven by the availabilities of resources. Prehistoric sites such as Notarchirico (ca. 680–600 ka), La Pineta (ca. 600–620 ka), Guado San Nicola (ca. 380–350 ka) or Ceprano (ca. 345–355 ka) testify to a preferential occupation of the central and southern Apennines valleys during interglacial phases, while later interglacial occupations were oriented towards the coastal plains, as attested by the numerous settlements of the Roma Basin (ca. 300 ka). Faunal remains indicate that human subsistence behaviours benefited from a diversity of exploitable ecosystems, from semi-open to closed environments. In central and southern Italy, several palynological records have already illustrated the regional- and local-scale vegetation dynamic trends. During the Middle Pleistocene climate cycles, mixed mesophytic forests developed during the interglacial periods and withdrew in response to increasing aridity during the glacial episodes. New pollen data from the Boiano Basin (Molise, Italy) attest to the evolution of vegetation and climate between MIS 13 and 9 (ca. 500 to 300 ka). In this basin the persistence of high edaphic humidity, even during the glacial phases, could have favoured the establishment of a refuge area for the arboreal flora and provided subsistence resources for the animal and hominin communities during the Middle Pleistocene. This could have constrained human groups to migrate into such a propitious area. Regarding the local climate evolution during the glacial episodes, the supposed displacement from these sites could be linked to the environmental dynamics solely due to the aridity increase, rather than directly to the global climate changes.

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