A Significantly High He Isotopic Signature from the End-Paleozoic (250 Ma) Extinction-related Interval: For Detecting Ancient Extraterrestrial Fluxes through the Earth's History since the Hadean

Takahata, Naoto; Onoue, Tetsuji; Sano, Yuji; Isozaki, Yukio

doi:10.5026/jgeography.128.667

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…200 kyrs prior to the EPME. The causes of this climatic change are debated, and hypotheses include an extraterrestrial influence on the influx of interplanetary dust particles (Onoue et al, 2019;Takahata et al, 2019); however, large-scale eruption of the Siberian Traps is commonly favored to explain the global warming and rapid enhancement of continental weathering (Wignall, 2007;Algeo et al, 2011a;Schobben et al, 2020). Two-thirds of the total lava volume of the Siberian Traps was deposited ca.…”

Section: Enhanced Hydrological Cycle and Ocean Anoxiamentioning

confidence: 99%

Development of Deep-Sea Anoxia in Panthalassa During the Lopingian (Late Permian): Insights From Redox-Sensitive Elements and Multivariate Analysis

Onoue¹,

Soda

Isozaki

2021

Front. Earth Sci.

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The end-Permian mass extinction (EPME) was the most severe mass extinction event of the Phanerozoic, and was associated with the development of global oceanic anoxia. The intensification of ocean anoxia preceded the EPME, but the degree of intensity and timing of oceanic redox changes in the mid-Panthalassa Ocean remain debated. Here we present the results of geochemical and multivariate statistical analyses of a late Guadalupian to Lopingian (middle–late Permian) bedded chert succession from the Iwaidani section, Japan, which preserves pelagic deep-sea facies from the ocean floor to the lower flank of a mid-Panthalassan seamount. The entire section yields a low manganese-enrichment factor (MnEF <1), suggesting that suboxic conditions has appeared in the depositional environment already in the late Guadalupian. Enrichment factors of other redox-sensitive trace-elements (e.g., vanadium and uranium) and principle component analysis (PCA) of major element data show the development of suboxic to weakly anoxic conditions across the Guadalupian/Lopingian boundary. Subsequently, anoxic conditions, as inferred from enrichments in U, Mo, Ni, Cu, Zn, and Tl, were developed during the middle Lopingian. Extremely high concentrations of U and Mo (enrichment factors of ∼6 and ∼5,500, respectively) indicate that H2S-rich euxinic conditions developed during the latest Lopingian and around the time of the EPME. The cause of the shift toward more reducing conditions in the early–middle Lopingian is unknown, but PCA results suggest that the euxinic conditions occurred in association with intensified continental weathering in response to a temperature rise during the ca. 200 kyr before the EPME.

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Section: Enhanced Hydrological Cycle and Ocean Anoxiamentioning

confidence: 99%

Development of Deep-Sea Anoxia in Panthalassa During the Lopingian (Late Permian): Insights From Redox-Sensitive Elements and Multivariate Analysis

Onoue¹,

Soda

Isozaki

2021

Front. Earth Sci.

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“…From now, new theories of the evolution of life will be discussed in an interdisciplinary way and develop among researchers of the Earth's history and molecular biologists. Takahata et al (2019) focus on the discovery of evidence that the mass extinction at the end of Permian was caused by an influx of extraterrestrial matter. The grounds for this were found in organic carbon-rich black mudstone collected from the P/T boundary in Japan.…”

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confidence: 99%

Overview of the Special Issue “The Hadean World (Part II): Preparing a Site for the First Life“

Maruyama

Isozaki²,

Kurokawa

et al. 2019

Journal of Geography(Chigaku Zasshi)

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The special issue "The Hadean World (Part I) : The Birth of a Habitable Trinity Planet" focused on the Tandem model, which is a new planetary formation theory explaining the formation of a habitable trinity planet that enables the birth of life, and the ABEL model, which describes the formation process of the Earth. It went on to introduce the latest research on the origins of life. In the special issue Part II, we mainly focus on the birthplace of life, in order to unravel where and how primordial life emerged. Part II addresses the initial requisites for the birth of life and its early evolution, which will be discussed in the special issue Part III.It is assumed that the Hadean atmosphere had almost no free oxygen, and a large amount of carbon dioxide (a few bars) was present. Ueda and Sawaki (2019) quantitatively evaluate water-rock interactions under the Hadean surface environment with hydrothermal experiments. On the Hadean continent, komatiite was exposed ubiquitously and reacted with surface water to advance serpentinization. Komatiite is a volcanic rock, which mainly comprises olivine and is stable at temperatures above 1,000°C, while liquid water is stable between 0 and 100°C under a pressure of 1 bar. There-fore, when komatiite and liquid water exist simultaneously, serpentinization (olivine turn to serpentinite) proceeds as a non-equilibrium reaction. Serpentinization produces hydrogen due to the decomposition of Fe 2 SiO 4 (olivine) , which produces two hydrogenic atoms as H 2 through the chemical reaction Fe 2+ = Fe 0 + Fe 3+ to produce magnetite (FeO, Fe 2 O 3 ) . In the Hadean atmosphere, however, there should have been a large amount of carbon dioxide, which would have produced carbonate minerals through reactions with CO 2 by consuming Mg and Fe 2+ . Therefore, a reaction that converts Fe 2+ into Fe 3+ does not occur, thus inhibiting the production of hydrogen. This excellent example shows how chemical reactions under the Hadean environment are quite different from those in the present Earth's environment.It has been generally considered, since an experiment performed by Miller (1953) , that a strong input of external energy is necessary for the birthplace of life. In the case of life on the present Earth, the necessary external energy is provided by the Sun as solar energy. What was the energy source when life was born? Was Hadean solar a sufficient external source of energy for life? This problem has not been discussed quantitatively.

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Paleozoic Extinctions in Cosmoclimatological Context: ‘Non-Bolide’ Extraterrestrial Causes for Global Chilling

Isozaki

2022

Paleontological Research

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A Significantly High He Isotopic Signature from the End-Paleozoic (250 Ma) Extinction-related Interval: For Detecting Ancient Extraterrestrial Fluxes through the Earth's History since the Hadean

Cited by 5 publications

References 24 publications

Development of Deep-Sea Anoxia in Panthalassa During the Lopingian (Late Permian): Insights From Redox-Sensitive Elements and Multivariate Analysis

Development of Deep-Sea Anoxia in Panthalassa During the Lopingian (Late Permian): Insights From Redox-Sensitive Elements and Multivariate Analysis

Overview of the Special Issue “The Hadean World (Part II): Preparing a Site for the First Life“

Paleozoic Extinctions in Cosmoclimatological Context: ‘Non-Bolide’ Extraterrestrial Causes for Global Chilling

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