کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9535750 | 1356899 | 2005 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Crystallization history of a massif anorthosite in the eastern Indian shield margin based on borehole lithology
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Deep drilling, attaining a maximum depth of 622.85 m, reveals a cyclic order of grey, white and mottled anorthosites of variable thickness. The possibility of anorthosite extending further below contradicts the 200 m thickness of anorthosite previously estimated from gravity modeling. Chemical data also indicate a cyclic variation of elemental concentrations and their ratios with depth. In each chemical cycle, the grey plagioclase megacrysts apparently floated over a relatively denser white granular plagioclase with higher anorthite contents. The base of a chemical cycle also contains higher concentrations of transition elements-a feature arising plausibly by sinking of Fe-Ti oxides. The chemical cyclicity possibly indicates derivation of melt in batches and emplacement of the crystal laden-melt by impulses. Minor presence of orthopyroxene in the anorthosite suggests a tholeiitic source.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Asian Earth Sciences - Volume 25, Issue 1, April 2005, Pages 77-94
Journal: Journal of Asian Earth Sciences - Volume 25, Issue 1, April 2005, Pages 77-94
نویسندگان
Dipankar Mukherjee, Naresh C. Ghose, Nilanjan Chatterjee,