Header menu link for other important links
Detrital chromian spinels from beach placers of Andaman Islands, India: A perspective view of petrological characteristics and variations of the Andaman ophiolite
Volume: 21
Issue: 3
Pages: 188 - 201
Along the east coast of the Andaman Islands, abundant detrital chromian spinels frequently occur in black sands at the confluence of streams meeting the Andaman Sea. The mineral chemistry of these detrital chromian spinels has been used in reconstructing the evolutionary history of the Andaman ophiolite. The chromian spinels show wide variation in compositional parameters such as Cr# [=Cr/(Cr+A1) atomic ratio] (0.13-0.91), Mg# [=Mg/(Mg+Fe 2+) atomic ratio] (0.23-0.76), and TiO 2 (<0.05-3.9wt%). The YFe 3+[=100Fe 3+/(Cr+A1+Fe 3+) atomic ratio] is remarkably low (usually <10 except for south Andaman). The ranges of chemical composition of chromian spinels are different in each locality. The spinel compositions show very depleted signatures over the entire island, which suggests that all massifs in the Andaman ophiolite were affected under island-arc conditions. Although the degree of depletion varies in different parts of the island, a directional change in composition of the detrital chromian spinels from south to north is evident. Towards the north the detrital chromian spinels point to less-depleted source rocks in contrast to relatively more depleted towards the south. The possibilities to explain this directional change are critically discussed in the context of the evolution of Andaman ophiolite. © 2012 Wiley Publishing Asia Pty Ltd.
About the journal
JournalData powered by TypesetIsland Arc
PublisherData powered by TypesetWILEY-BLACKWELL
Open AccessNo