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.

Deep CO2 from the Central Atlantic Magmatic Province during the end-Triassic mass extinction

2021 ◽  
Author(s):  
Manfredo Capriolo ◽  
Andrea Marzoli ◽  
László E Aradi ◽  
Sara Callegaro ◽  
Jacopo Dal Corso ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Melt Inclusions ◽  
Environmental Changes ◽  
Analytical Techniques ◽  
Global Scale ◽  
Large Igneous Province ◽  
Mass Extinctions ◽  
Basaltic Rocks ◽  
Central Atlantic Magmatic Province ◽  
Central Atlantic

<p>Throughout Earth’s history, the coincidence in time between Large Igneous Province eruptions and mass extinctions points out a potential causality, where volcanic degassing may drive the global-scale climatic and environmental changes leading to biotic crises. The volcanic activity of the Central Atlantic Magmatic Province (CAMP, ca. 201 Ma), one of Earth’s most voluminous Large Igneous Provinces, is synchronous with the end-Triassic mass extinction event, among the most severe extinctions during the Phanerozoic. Combining different in situ analytical techniques (optical microscopy, confocal Raman microspectroscopy, EMP, SEM-EDS, and NanoSIMS analyses), bubble-bearing melt inclusions within basaltic rocks revealed the abundance of CO<sub>2</sub> (up to 1.0 wt.%) in CAMP magmas [1]. Gaseous CO<sub>2 </sub>and solid elemental C, alternatively preserved by gas exsolution bubbles within melt inclusions mainly hosted in clinopyroxene crystal clots, represent direct evidence for large amounts of volcanic CO<sub>2</sub> (up to 10<sup>5</sup> Gt) emitted into Earth’s surface during the entire CAMP activity [1]. The entrapment conditions of these melt inclusions within clinopyroxene aggregates constrain the degassed CO<sub>2</sub> to a mantle and/or lower-middle crustal origin, indicating a deep source of carbon which may favour rapid and intense CAMP eruption pulses. Each magmatic pulse may have injected CO<sub>2</sub> into the end-Triassic atmosphere in amounts similar to those projected for the anthropogenic emissions during the 21<sup>st</sup> century [1]. Therefore, volcanic CO<sub>2</sub> degassed during CAMP eruptions likely contributed to end-Triassic global warming and ocean acidification with catastrophic consequences for the biosphere.</p><p> </p><p>[1] Capriolo et al. (2020), Nat. Commun. <strong>11</strong>, 1670.</p>

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>

Land plants and terrestrial environmental changes during the onset of the end-Triassic event

2020 ◽  
Author(s):  
Sofie Lindström ◽  
Hans Peter Nytoft ◽  
Gunver K. Pedersen ◽  
Grzegorz Niedzwiedzki ◽  
Karen Dybkjær ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Magmatic Activity ◽  
Central Atlantic Magmatic Province ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
Geochronological Dating ◽  
Ecosystem Changes ◽  
Central Atlantic ◽  
Insight Into

<p>The end-Triassic mass extinction is considered to have been caused by voluminous and repeated emissions of CO<sub>2</sub> and/or methane and other gases from magmatic activity in the Central Atlantic Magmatic Province. Despite improved geochronological dating and correlation between the magmatic activity and the extinctions, exactly how the biotic crisis commenced remains poorly understood. Here, we compile palynological and palaeobotanical data, bulk organic δ<sup>13</sup>C, biomarkers, mercury and other geochemical proxies, charcoal, and sedimentology, from a Rhaetian terrestrial succession in southern Sweden. Our results provide an insight into the climatic, environmental and ecosystem changes that took place at the onset of the mass extinction event.</p>

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>

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.

scholarly journals The Central Atlantic Magmatic Province (CAMP) in Morocco

2019 ◽  
Vol 60 (5) ◽  
pp. 945-996 ◽  
Author(s):  
Andrea Marzoli ◽  
Hervé Bertrand ◽  
Nasrrddine Youbi ◽  
Sara Callegaro ◽  
Renaud Merle ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Major And Trace Elements ◽  
Large Igneous Province ◽  
Published Data ◽  
Crustal Assimilation ◽  
The North ◽  
Pan African ◽  
Central Atlantic Magmatic Province ◽  
Intermediate Unit ◽  
Central Atlantic

Abstract The Central Atlantic Magmatic Province (CAMP) is a large igneous province (LIP) composed of basic dykes, sills, layered intrusions and lava flows emplaced before Pangea break-up and currently distributed on the four continents surrounding the Atlantic Ocean. One of the oldest, best preserved and most complete sub-provinces of the CAMP is located in Morocco. Geochemical, geochronologic, petrographic and magnetostratigraphic data obtained in previous studies allowed identification of four strato-chemical magmatic units, i.e. the Lower, Intermediate, Upper and Recurrent units. For this study, we completed a detailed sampling of the CAMP in Morocco, from the Anti Atlas in the south to the Meseta in the north. We provide a complete mineralogical, petrologic (major and trace elements on whole-rocks and minerals), geochronologic (40Ar/39Ar and U–Pb ages) and geochemical set of data (including Sr–Nd–Pb–Os isotope systematics) for basaltic and basaltic–andesitic lava flow piles and for their presumed feeder dykes and sills. Combined with field observations, these data suggest a very rapid (<0·3 Ma) emplacement of over 95% of the preserved magmatic rocks. In particular, new and previously published data for the Lower to Upper unit samples yielded indistinguishable 40Ar/39Ar (mean age = 201·2 ± 0·8 Ma) and U–Pb ages (201·57 ± 0·04 Ma), suggesting emplacement coincident with the main phase of the end-Triassic biotic turnover (c.201·5 to 201·3 Ma). Eruptions are suggested to have been pulsed with rates in excess of 10 km3/year during five main volcanic pulses, each pulse possibly lasting only a few centuries. Such high eruption rates reinforce the likelihood that CAMP magmatism triggered the end-Triassic climate change and mass extinction. Only the Recurrent unit may have been younger but by no more than 1 Ma. Whole-rock and mineral geochemistry constrain the petrogenesis of the CAMP basalts. The Moroccan magmas evolved in mid-crustal reservoirs (7–20 km deep) where most of the differentiation occurred. However, a previous stage of crystallization probably occurred at even greater depths. The four units cannot be linked by closed-system fractional crystallization processes, but require distinct parental magmas and/or distinct crustal assimilation processes. EC-AFC modeling shows that limited crustal assimilation (maximum c.5–8% assimilation of e.g. Eburnean or Pan-African granites) could explain some, but not all the observed geochemical variations. Intermediate unit magmas are apparently the most contaminated and may have been derived from parental magmas similar to the Upper basalts (as attested by indistinguishable trace element contents in the augites analysed for these units). Chemical differences between Central High Atlas and Middle Atlas samples in the Intermediate unit could be explained by distinct crustal contaminants (lower crustal rocks or Pan-African granites for the former and Eburnean granites for the latter). The CAMP units in Morocco are likely derived from 5–10% melting of enriched peridotite sources. The differences observed in REE ratios for the four units are attributed to variations in both source mineralogy and melting degree. In particular, the Lower basalts require a garnet peridotite source, while the Upper basalts were probably formed from a shallower melting region straddling the garnet–spinel transition. Recurrent basalts instead are relatively shallow-level melts generated mainly from spinel peridotites. Sr–Nd–Pb–Os isotopic ratios in the CAMP units from Morocco are similar to those of other CAMP sub-provinces and suggest a significant enrichment of the mantle-source regions by subducted crustal components. The enriched signature is attributed to involvement of about 5–10% recycled crustal materials introduced into an ambient depleted or PREMA-type mantle, while involvement of mantle-plume components like those sampled by present-day Central Atlantic Ocean Island Basalts (OIB, e.g. Cape Verde and Canary Islands) is not supported by the observed compositions. Only Recurrent basalts may possibly reflect a Central Atlantic plume-like signature similar to the Common or FOZO components.

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