کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4730756 1640384 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A common parentage for Deccan Continental Flood Basalt and Central Indian Ocean Ridge Basalt? A geochemical and isotopic approach
ترجمه فارسی عنوان
یک منبع مشترک برای رودخانه دکل قنات سیلاب بازالت و اقیانوس آرام هندوستان ریال بازالت؟ یک روش ژئوشیمیایی و ایزوتوپ
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
چکیده انگلیسی


• Deccan CFB and CIR MORB are geochemically dissimilar.
• CIR MORB evolved through partial melting.
• Fractional crystallization is important for Deccan CFB.
• CIR MORB mantle depleted and contaminated with upper continental crustal component.
• Deccan CFB mantle enriched and contaminated with lower continental crustal component.

A comparison of geochemical and Sr–Nd–Pb isotopic compositions for Deccan Continental Flood Basalts (CFBs) and Central Indian Ridge (CIR) Basalts is presented: these data permit assessment of possible parental linkages between the two regions, and comparison of their respective magmatic evolutionary trends in relation to rift-related tectonic events during Gondwana break-up. The present study reveals that Mid-Ocean Ridge Basalt (MORB) from the northern CIR and basalts of Deccan CFB are geochemically dissimilar because of: (1) the Deccan CFB basalts typically show a greater iron-enrichment as compared to the northern CIR MORB, (2) a multi-element spiderdiagram reveals that the Deccan CFBs reveal a more fractionated slope (Ba/YbN > 1), as compared to relatively flat northern CIR MORB (Ba/YbN < 1), (3) there is greater REE fractionation for Deccan CFB than for the northern CIR MORB (i.e., La/YbN ∼ 2.3 and 1 respectively) and (4) substantial variation of compatible–incompatible trace elements and their ratios among the two basalt groups suggests that partial melting is a dominant process for northern CIR MORB, while fractional crystallization was a more important control to the geochemical variation for Deccan CFB. Further, incompatible trace element ratios (Nb/U and Nb/Pb) and radiogenic isotopic data (Sr–Pb–Nd) indicate that the northern CIR MORBs are similar to depleted mantle [and/or normal (N)-MORB], and often lie on a mixing line between depleted mantle and upper continental crust. By contrast, Deccan CFB compositions lie between the lower continental crust and Ocean island basalt. Accordingly, we conclude that the basaltic suites of the northern CIR MORB and Deccan CFB do not share common parentage, and are therefore genetically unrelated to each other. Instead, we infer that the northern CIR MORB were derived from a depleted mantle source contaminated by upper continental crust, probably during the break up of Gondwanaland; the Deccan CFB are more similar to Ocean island basalt (Reunion-like) composition, and perhaps contaminated by lower continental crust during their evolution.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Asian Earth Sciences - Volume 84, 15 April 2014, Pages 188–200
نویسندگان
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