کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5782879 | 1637528 | 2016 | 90 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Cenozoic lateritic weathering and erosion history of Peninsular India from 40Ar/39Ar dating of supergene K-Mn oxides
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
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چکیده انگلیسی
Since Deccan Traps extrusion ~Â 65Â Ma ago, thick weathering mantles have developed over Peninsular India on both the western coastal lowland and adjacent eastern plateau separated by the Western Ghats Escarpment. Manganiferous lateritic profiles formed by supergene weathering of Late Archean manganiferous protores are exposed on paleolandsurface remnants on both sides of the escarpment. Petrological and geochemical characterizations of samples from those Mn lateritic profiles allowed identifying cryptomelane (K-Mn oxide) dated by 40Ar/39Ar geochronology. The ages obtained document major weathering periods, ca. 53-50Â Ma, and ca. 37-23Â Ma in the highland, and ca. 47-45Â Ma, ca. 24-19Â Ma and discrete weathering pulses at ~Â 9Â Ma and ~Â 2.5Â Ma in the lowland. Old ages of the highland (53-50Â Ma) and the lowland (47-45Â Ma) indicate synchronous lateritic weathering across the escarpment at a time the peninsula started to drift across the equatorial belt. Intense weathering periods at ca. 53-45 and ca. 37-23Â Ma are interpreted to reflect the Early Eocene climatic optimum and the onset of Asian monsoon regimes, respectively. The ages further indicate that most of the dissection of the highland must have taken place after ~Â 23Â Ma, whereas the lowland was weakly incised essentially after ~Â 19Â Ma. Our results also document divergent erosion and weathering histories of the lowland and the highland after the Eocene, suggesting installation of a dual climatic regime across the Western Ghats escarpment.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 446, 23 December 2016, Pages 33-53
Journal: Chemical Geology - Volume 446, 23 December 2016, Pages 33-53
نویسندگان
Nicolas J. Bonnet, Anicet Beauvais, Nicolas Arnaud, Dominique Chardon, Mudlappa Jayananda,