Oxygenation of the Archean atmosphere: New paleosol constraints from eastern India: COMMENT
نویسندگان
چکیده
منابع مشابه
Late Archean biospheric oxygenation and atmospheric evolution.
High-resolution geochemical analyses of organic-rich shale and carbonate through the 2500 million-year-old Mount McRae Shale in the Hamersley Basin of northwestern Australia record changes in both the oxidation state of the surface ocean and the atmospheric composition. The Mount McRae record of sulfur isotopes captures the widespread and possibly permanent activation of the oxidative sulfur cy...
متن کاملComment on "Iron isotope constraints on the Archean and Paleoproterozoic ocean redox state".
Rouxel et al. (Reports, 18 February 2005, p. 1088) argued that changes in the iron isotopic composition of sedimentary sulfides reflect changes in the oxidation state of the atmosphere-ocean system between 2.3 and 1.8 million years ago. We show that misinterpretations of the origins of these minerals undermine their conclusions.
متن کاملthe effect of traffic density on the accident externality from driving the case study of tehran
در این پژوهش به بررسی اثر افزایش ترافیک بر روی تعداد تصادفات پرداخته شده است. به این منظور 30 تقاطع در شهر تهران بطور تصادفی انتخاب گردید و تعداد تصادفات ماهیانه در این تقاطعات در طول سالهای 89-90 از سازمان کنترل ترافیک شهر تهران استخراج گردید و با استفاده از مدل داده های تابلویی و نرم افزار eviews مدل خطی و درجه دوم تخمین زده شد و در نهایت این نتیجه حاصل شد که تقاطعات پر ترافیک تر تعداد تصادفا...
15 صفحه اولThe oxygenation of the atmosphere and oceans.
The last 3.85 Gyr of Earth history have been divided into five stages. During stage 1 (3.85-2.45 Gyr ago (Ga)) the atmosphere was largely or entirely anoxic, as were the oceans, with the possible exception of oxygen oases in the shallow oceans. During stage 2 (2.45-1.85 Ga) atmospheric oxygen levels rose to values estimated to have been between 0.02 and 0.04 atm. The shallow oceans became mildl...
متن کاملMass-independent fractionation of sulfur isotopes in Archean sediments: strong evidence for an anoxic Archean atmosphere.
Mass-independent fractionation (MIF) of sulfur isotopes has been reported in sediments of Archean and Early Proterozoic Age (> 2.3 Ga) but not in younger rocks. The only fractionation mechanism that is consistent with the data on all four sulfur isotopes involves atmospheric photochemical reactions such as SO2 photolysis. We have used a one-dimensional photochemical model to investigate how the...
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ژورنال
عنوان ژورنال: Geology
سال: 2015
ISSN: 1943-2682,0091-7613
DOI: 10.1130/g36554c.1