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Interactions between the Earth sphere and its constraint on the progress of anoxic-oxic in the Cretaceous ocean

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doi: 10.12029/gc20170405
Authors:Zhang Zhenguo; Huo Shaochuan; Leng Chunpeng; Gao Lianfeng; Zhang Ying; Fu Haifeng
Author Affiliations:Primary:
North China University of Science and Technology, College of Mining Engineering, Tangshan, China
Volume Title:Zhongguo Dizhi Geology in China
Source:Zhongguo Dizhi = Geology in China, 44(4), p.707-721. Publisher: Science Press, Beijing, China. ISSN: 1000-3657
Publication Date:2017
Note:In Chinese with English summary. 170 refs.; illus., incl. sects., sketch maps
Summary:The Cretaceous is an important period in which occurred many geological events, especially the OAEs (Oceanic Anoxic Events) characterized by black shales, and the oxic process characterized by CORBs (Cretaceous Oceanic Red Beds). This paper describes the causative mechanism which explains how the oceanic environment changed from anoxic to oxic in Cretaceous. Two typical events show different results that caused by interactions of the Earth Spheres. Here we propose that the rise of atmospheric CO2 occurred because the enhanced submarine volcanism-was abruptly and permanently diminished during the Cretaceous. The Cretaceous large-scale submarine volcanism caused the concentration of CO2. The releasing of the inner energy of the lithosphere and the distribution of land which caused the increasing of atmospheric temperature. This change presented the same trend as the oceanic water temperature, and caused the decreasing of O2 concentration in the Cretaceous ocean, and then the OAEs occurred. The lithosphere produced volume of lava in the upper oceanic crust which contained Fe in the seafloor. When the hydrothermal fluids alteration of oceanic crust and the seawater/basalt interactions (including microbes alteration of submarine basaltic glass), the element Fe dissolved in seawater. Iron is a micronutrient essential for the synthesis of enzymes required for photosynthesis in oceanic environment, it could spur phytoplankton growth rapidly. The photosynthesis of phytoplankton which can consume carbon dioxide is in much of the world's oceans, wherever they are in atmosphere or in ocean. This process could produce equal oxygen. And then, the oxic environment characterized by red sediment which is rich in Fe3+ appeared. The data show rhythm of the anoxic and oxic from south Tibet and DSDP/ODP section, which the anoxic is often accompanied by the occurrence of oxygen rich environment. Undoubtedly, the anoxic and oxic in the Cretaceous Ocean were controlled by the mutually dependent processes of the Earth system which included lithosphere, hydrosphere, atmosphere and biosphere. An important conclusion of this study is that the black shales and the oceanic red beds are caused by the same reason, but led different results. The anoxic and oxic in the Cretaceous ocean were caused by volcanic activities, but they were of different causative mechanisms. The former was based on physical and chemical process, while the latter involved more complicated bio-oceanic-geochemistry process.
Subjects:Anaerobic environment; Black shale; Carbon dioxide; Chemical composition; Clastic rocks; Cretaceous; Deep Sea Drilling Project; Earth; Geochemistry; Iron; Marine environment; Mesozoic; Metals; Ocean Drilling Program; Oceanic anoxic events; Paleo-oceanography; Sedimentary rocks; Submarine volcanoes; Volcanism; Volcanoes; Atlantic Ocean; Cape Verde Basin; DSDP Site 105; DSDP Site 305; DSDP Site 306; DSDP Site 367; DSDP Site 370; Leg 11; Leg 198; Leg 32; Leg 41; North Atlantic; North Pacific; Northwest Pacific; ODP Site 1207; ODP Site 1213; ODP Site 1214; Pacific Ocean; Shatsky Rise; West Pacific
Coordinates:N200000 N410000 E1800000 E1540000
N234000 N385000 W0690000 W0772000
N050000 N330000 W0100000 W0220000
N313400 N374800 E1624600 E1571500
Record ID:843327-5
Copyright Information:GeoRef, Copyright 2021 American Geosciences Institute.
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