کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5779912 | 1634692 | 2017 | 15 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Multiple sulfur isotope geochemistry of Dharwar Supergroup, Southern India: Late Archean record of changing atmospheric chemistry
ترجمه فارسی عنوان
ژئوشیمی ایزوتوپ گوگرد چندگانه از تیمارار برتر، جنوب هندوستان: ضبط تغییرات جوی شیمیایی در اواخر اردیبهشت
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی
Earth's tectonic and climatic systems may have changed fundamentally before the Great Oxidation Event (GOE) at about 2.3 Ga. Sulfur Mass Independent Fractionation (S-MIF) has demonstrated that Earth's atmosphere was virtually oxygen-free before the GOE. During 3.0 to 2.4 Ga, the change in Î33S and Î36S signals may reflect the perturbation of atmospheric chemistry, though the mechanisms of the change are uncertain. Here, we reported multiple sulfur isotopic studies of Archean volcano-sedimentary sequences of the Dharwar Supergroup, distributed in the Chitradurga Schist Belt (CSB), Southern India. New field mapping and zircon U-Pb dating allows us to reconstruct detailed lithostratigraphy of the Dharwar Supergroup. The lower unit consists of post-3.0 Ga conglomerate, stromatolitic carbonate, siliciclastics with diamictite, chert/BIF and pillowed basalt in ascending order, all of which are older than the 2676 Ma dacite dyke that had intruded into the lower unit. The upper unit unconformably overlies the pillow basalts at the top of the lower unit, and consists of conglomerate/sandstone with â¼2600 Ma detrital zircons, komatiitic basalt, BIF and siliciclastic sequence with mafic volcanics. Sulfur isotope analysis of extracted sulfides shows MIF signals (ÎS33>+1â°) with clear ÎS33-ÎS36 correlations. The lower group of the Dharwar Supergroup shows a ÎS36/ÎS33 slope of â1.48, the middle group shows â1.16 and â1.07, and the upper group shows â0.94. Reassessment of all the Archean S-MIF records from sedimentary rocks indicates that the ÎS36/ÎS33 slope systematically changed during the Archean period. The observed trend in the Indian section is similar to those of its Pilbara-Kaapvaal equivalents, thus it could reflect a global atmospheric signature. Moreover, the isotopic trend seems to correlate with mid-Archean glaciation. Thus, the ÎS36/ÎS33 slope could be a useful tracer for atmospheric chemistry and its link with climate change before the GOE.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 464, 15 April 2017, Pages 69-83
Journal: Earth and Planetary Science Letters - Volume 464, 15 April 2017, Pages 69-83
نویسندگان
Kaoru Mishima, Rie Yamazaki, Madhusoodhan Satish-Kumar, Yuichiro Ueno, Tomokazu Hokada, Tsuyoshi Toyoshima,