Productivity and organic carbon loading control uranium isotope behavior in ancient reducing settings: Implications for the paleoredox proxy

Geochimica et Cosmochimica Acta, Journal Year: 2024, Volume and Issue: 368, P. 197 - 213

Published: Jan. 13, 2024

Language: Английский

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Oxygen increase and the pacing of early animal evolution

Global and Planetary Change, Journal Year: 2024, Volume and Issue: 233, P. 104364 - 104364

Published: Jan. 14, 2024

While it is widely accepted that early animals originated and primarily evolved during the Neoproterozoic to Cambrian period, there remains ongoing debate over how fluctuations in marine-atmospheric oxygen levels influenced their evolution diversification. To investigate this, we analyzed pristane/phytane ratios—a redox-proxy based on organic geochemistry—in surface sediments from Cryogenian successions South China, Oman, Australia. The temporal changes this proxy exhibited consistent patterns across all sites, revealing five cycles of anoxic oxic conditions ocean between 660 510 Ma. By examining average ratios, identified three events when increased. This represents a transition anoxic-dysoxic boundary at 630–600 Ma, followed by shift dysoxic 570 Ma (Shuram event), finally reaching 520 (Cambrian explosion). Significantly, these oxygenation align with eumetazoan evolution. An inverse relationship was observed oceanic redox positive/negative shifts δ13Ccarb, occurring first second events, suggesting an increase atmospheric levels. Based findings, propose were global increases levels, least Ediacaran period. These likely played role influencing rate among animals.

Language: Английский

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Linking carbon cycle perturbations to the Late Ordovician glaciation and mass extinction: A modeling approach

Earth and Planetary Science Letters, Journal Year: 2024, Volume and Issue: 631, P. 118635 - 118635

Published: March 2, 2024

Language: Английский

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Rapid marine oxygen variability: Driver of the Late Ordovician mass extinction

Science Advances, Journal Year: 2022, Volume and Issue: 8(46)

Published: Nov. 16, 2022

The timing and connections between global cooling, marine redox conditions, biotic turnover are underconstrained for the Late Ordovician. second most severe mass extinction occurred at end of Ordovician period, resulting in ~85% loss species two pulses. As only "Big 5" that during icehouse this interval is an important modern analog to constrain environmental feedbacks. We present a previously unexplored thallium isotope records from paleobasins record conditions document distinct rapid excursions suggesting vacillating (de)oxygenation. strong temporal link these perturbations extinctions highlights possibility dynamic oxygen fluctuations, rather than persistent, stable anoxia, played major role driving extinction. This evidence changes leading has implications deoxygenation biodiversity declines.

Language: Английский

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Stable ocean redox during the main phase of the Great Ordovician Biodiversification Event

Communications Earth & Environment, Journal Year: 2022, Volume and Issue: 3(1)

Published: Sept. 22, 2022

The Great Ordovician Biodiversification Event (GOBE) represents the greatest increase in marine animal biodiversity ever recorded. What caused this transformation is heavily debated. One hypothesis states that rising atmospheric oxygen levels drove biodiversification based on premise animals require for their metabolism. Here, we present uranium isotope data from a Middle carbonate succession shows steepest rise generic richness occurred with global redox stability. Ocean oxygenation ensued later and could not have driven biodiversification. Stable anoxic zones prevailed during maximum (Dapingian-early Darriwilian) when life expectancy of evolving genera greatly increased. Subsequently, unstable ocean conditions together carbon cycle disturbance decrease relative diversification rates. Therefore, propose oceanic stability was factor facilitating establishment more resilient ecosystems allowing to radiate.

Language: Английский

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Uranium isotope systematics of a low-productivity ferruginous ocean analog: Implications for the uranium isotope record of early Earth

Geochimica et Cosmochimica Acta, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Language: Английский

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Geochemical signatures and chemostratigraphic framework for the Early-Middle Permian sedimentary successions of Alborz, Iran

Journal of Asian Earth Sciences, Journal Year: 2025, Volume and Issue: unknown, P. 106607 - 106607

Published: April 1, 2025

Language: Английский

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Salinity variations of the inner Yangtze Sea during the Ordovician-Silurian transition and its influences on marginal marine euxinia

Global and Planetary Change, Journal Year: 2023, Volume and Issue: 225, P. 104129 - 104129

Published: April 28, 2023

Language: Английский

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Nitrogen isotope evidence for oxygenated upper ocean during the Cryogenian interglacial period

Chemical Geology, Journal Year: 2022, Volume and Issue: 604, P. 120929 - 120929

Published: May 20, 2022

Language: Английский

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Roller-coaster atmospheric-terrestrial-oceanic-climatic system during Ordovician-Silurian transition: Consequences of large igneous provinces

Geoscience Frontiers, Journal Year: 2023, Volume and Issue: 14(3), P. 101537 - 101537

Published: Jan. 18, 2023

The Ordovician-Silurian transition (OST) hosted profound and frequent changes in the atmospheric-terrestrial-oceanic-climatic system (ATOCS). Previous studies have found contrasting stages for such changes, primarily based on hiatus-interrupted sections. However, dominant driving factors mechanisms reconciling remain controversial. Mercury isotopes, which undergo both mass-dependent mass-independent fractionation, can provide critical insights into deep-time ATOCSs, especially those impacted by large igneous provinces (LIPs) events. Here, we build a high-resolution multi-proxy record of Hg (concentrations isotopic compositions) combined with organic carbon isotopes (δ13Corg) whole-rock geochemical data (including trace elements phosphorus) from continuous cores Yangtze Platform, South China. Our data, reported ones, indicate occurrence LIP eruptions against localized volcanism, four successive, yet ATOCSs during OST. Moreover, identified coupling between two-pulse magmatism extreme each special pCO2, weathering rate, primary productivity, redox condition, climatic mode, biotic evolution. For stage I, first pulse triggered global warming, enhanced terrestrial weathering, oceanic acidification, eutrophication, anoxia, P recycling, thereby widespread deposition black shales. During II, Hirnantian glaciation oxygenation arose intense chemical shale I; slashed facilitated CO2 accumulation. In III, another de-glaciation, ATOCS was largely similar to that I. This led round positive δ13Corg excursion IV. Compared environmental pressure peculiar stage, their transitions might been more devastating triggering prolonged Late Ordovician Mass Extinction (LOME). limited recovery possible later portion I III. study strata OST provides an excellent framework better illuminating LIPs' essential role "roller-coaster" behavior thus crisis pivotal period

Language: Английский

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