کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4731231 1640401 2013 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Geochemistry of pillow basalts from Bompoka, Andaman–Nicobar islands, Bay of Bengal, India
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Geochemistry of pillow basalts from Bompoka, Andaman–Nicobar islands, Bay of Bengal, India
چکیده انگلیسی

Pillow lavas in Bompoka island of the Andaman–Nicobar islands, forming a part of Sunda–Burmese forearc, are composed of plagioclase and clinopyroxene microphenocrysts in a fine-grained ferruginous groundmass along with glass. They are also characterized by several quench plagioclase and clinopyroxene morphologies. Zr/TiO2 versus Nb/Y relationship of these pillow lavas show that these are tholeiitic basalts in composition. These basalts have low MgO (5.19–6.12 wt%), Ni (84–118 ppm), and Cr (144–175 ppm) abundance and high FeO(T)/MgO (1.71–1.92) ratios, reflecting their fractionated nature. In Th/Yb versus Nb/Yb and Ti/Yb versus Nb/Yb binary diagrams, they show N-MORB affinity. However, La/Nb–Y and Ce/Nb–Th/Nb relationships along with a slight LREE depleted (LaN/YbN = 0.75–0.82) pattern and high Ba/Zr (0.28–0.40) ratios and LILE (K, Rb, Ba, Sr and Th) enrichment relative to N-MORB, suggest their back-arc basin basalt affinity. It is inferred that these pillow basalts have been derived from a metasomatised N-MORB-like mantle source in a trench-distal (wider) back-arc basin, probably near the leading edge of the Eurasian continent during Early to Late Cretaceous times, prior to the currently active Andaman–Java subduction system.


► Petrography of the pillow basalts show several quench morphologies of plagioclases.
► Geochemistry of these basalts show tholeiitic back-arc basin basalt affinity.
► They have been derived from a metasomatised N-MORB-like mantle source.
► It is suggested that these basalts have formed in a trench-distal back-arc basin.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Asian Earth Sciences - Volume 64, 5 March 2013, Pages 27–37
نویسندگان
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