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Origin of the Mile Tilek Tuff, South Andaman: evidence from Ar-40-Ar-39 chronology and geochemistry

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Title Origin of the Mile Tilek Tuff, South Andaman: evidence from Ar-40-Ar-39 chronology and geochemistry
 
Creator AWASTHI, N
RAY, JS
PANDE, K
 
Subject BARREN ISLAND VOLCANO
JAVA SUBDUCTION COMPLEX
INDIAN-OCEAN
TRACE-ELEMENT
MIO-PLIOCENE
AGE
ISOTOPE
SEA
ARC
EVOLUTION
Ar-40-Ar-39 dating
geochemical fingerprinting
Mile Tilek Tuff
Sumatra
 
Description The Mile Tilek Tuff is one of several consolidated volcanic ash deposits in the Andaman and Nicobar Islands that has preserved evidence of a large-scale volcanic eruption in Southeast Asia. Assumed to be of Mio-Pliocene age (similar to 25-2 Ma), the tuff was thought to have been generated by the Andaman-Indonesia volcanic arc. Little was known about its source volcano because of absence of critical isotope data. To provide accurate age information and determine its source, we dated the tuff by Ar-40-Ar-39 method and measured its trace element contents and Sr-Nd isotopic ratios. The Ar-40-Ar-39 plateau age for the whole rock is 0.73 +/- 0.16 (2 sigma) Ma, which suggests that the tuff got deposited much later than previously believed. Chemically, the tuff possesses typical characteristics of subduction zone magmatism. Its Sr-Nd isotopic compositions (Sr-87/Sr-86 = 0.7073 and epsilon(Nd)
 
Publisher INDIAN ACAD SCIENCES
 
Date 2016-01-15T10:53:52Z
2016-01-15T10:53:52Z
2015
 
Type Article
 
Identifier CURRENT SCIENCE, 108(2)205-210
0011-3891
http://dspace.library.iitb.ac.in/jspui/handle/100/18397
 
Language en