INTENSITY OF CONTINENTAL WEATHERING AND NEARSHORE MARINE CARBONATE SEDIMENTATION DURING AND AFTER THE END-PERMIAN MASS EXTINCTION: KHARTAM MEMBER, KHUFF FORMATION, SAUDI ARABIA

Lithium (Li) isotope analyses of sedimentary rocks from the Meishan section in South China reveal extremely light seawater Li isotopic signatures at the Permian–Triassic boundary (PTB), which coincide with the most severe mass extinction in the history of animal life. Using a dynamic seawater lithium box model, we show that the light seawater Li isotopic signatures can be best explained by a significant influx of riverine [Li] with light δ7Li to the ocean realm. The seawater Li isotope excursion started ≥300 Ky before and persisted up to the main extinction event, which is consistent with the eruption time of the Siberian Traps. The eruption of the Siberian Traps exposed an enormous amount of fresh basalt and triggered CO2 release, rapid global warming, and acid rains, which in turn led to a rapid enhancement of continental weathering. The enhanced continental weathering delivered excessive nutrients to the oceans that could lead to marine eutrophication, anoxia, acidification, and ecological perturbation, ultimately resulting in the end-Permian mass extinction.

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Multiple episodes of extensive marine anoxia linked to global warming and continental weathering following the latest Permian mass extinction

Science Advances ◽

10.1126/sciadv.1602921 ◽

2018 ◽

Vol 4 (4) ◽

pp. e1602921 ◽

Cited By ~ 61

Author(s):

Feifei Zhang ◽

Stephen J. Romaniello ◽

Thomas J. Algeo ◽

Kimberly V. Lau ◽

Matthew E. Clapham ◽

...

Keyword(s):

Global Warming ◽

Mass Extinction ◽

Continental Weathering ◽

Permian Mass Extinction ◽

Multiple Episodes

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A New Bioevent Stratigraphy of Late Jurassic Arab-D Carbonates of Saudi Arabia

GeoArabia ◽

10.2113/geoarabia0103417 ◽

1996 ◽

Vol 1 (3) ◽

pp. 417-434

Author(s):

Geraint Wyn Hughes

Keyword(s):

Saudi Arabia ◽

High Frequency ◽

Late Jurassic ◽

Carbonate Platform ◽

Abu Dhabi ◽

Fine Scale ◽

Shallow Marine ◽

Carbonate Sedimentation ◽

Marine Carbonate ◽

Productivity Rate

ABSTRACT A series of fine-scale biofacies cycles are recognised by the application of semiquantitative micropalaeontological analysis of cores in eight wells from the reservoir carbonates from the Arab-D and upper Jubaila formations in Saudi Arabia. They are of Kimmeridgian - Tithonian age, and form the primary producing reservoir of the world’s largest single continuous reservoir located in the Ghawar field of Saudi Arabia. Three new composite biozones are identified that include a basal, deep marine Biozone D3 with fining-upwards cycles which equate, in part, with the Jubaila Formation. Biozone D2 was deposited in shallower conditions of the lower Arab-D carbonate, and Biozone D1 deposited in a very shallow marine environment of the upper Arab-D carbonate; both zones contain multiple coarsening-upwards cycles. Numerous additional bio-events, of potential subzonal value, are detected within these broad zones, and are considered to be related to discrete shoaling-upwards responses to transgressive episodes. The proposed scheme differs significantly from that erected for the Arab-D Formation in offshore Abu Dhabi. Carbonates of the Arab-D member are concluded to be composed of a series of high frequency palaeobathymetric changes which were superimposed upon an extensive carbonate platform. Gradual shallowing of the platform resulted possibly from a reduction in subsidence rate, a fall in sea level, rise in carbonate productivity rate or a combination of these. The latest episode of very shallow marine carbonate sedimentation terminated with the deposition of the Arab-D evaporites.

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