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Awasthi, Neeraj
- Origin of the Mile Tilek Tuff, South Andaman: Evidence from 40Ar-39Ar Chronology and Geochemistry
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PDF Views:82
Authors
Affiliations
1 Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, IN
2 Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, IN
1 Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, IN
2 Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, IN
Source
Current Science, Vol 108, No 2 (2015), Pagination: 205-210Abstract
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 (~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 40Ar-39Ar method and measured its trace element contents and Sr-Nd isotopic ratios. The 40Ar-39Ar plateau age for the whole rock is 0.73 ± 0.16 (2σ) 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 (87Sr/86Sr = 0.7073 and εNd ≤ 0.9) suggest substantial continental crustal contamination of its source magma, which points to a source volcano in Sumatra. Based on available age information on large-scale volcanic eruptions in Indonesia, we speculate that the Ranau volcano in south Sumatra could have been the source of the Mile Tilek Tuff.Keywords
40Ar–39Ar Dating, Geochemical Fingerprinting, Mile Tilek Tuff, Sumatra.- Tracking Indian Monsoon Variability from Changes in Sediment Provenance
Abstract Views :222 |
PDF Views:67
Authors
Affiliations
1 Department of Earth and Planetary Sciences, Prof. Rajendra Singh (Rajju Bhaiya) Institute of Physical Sciences for Study and Research, VBS Purvanchal University, Jaunpur 222 003, IN
2 Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, IN
1 Department of Earth and Planetary Sciences, Prof. Rajendra Singh (Rajju Bhaiya) Institute of Physical Sciences for Study and Research, VBS Purvanchal University, Jaunpur 222 003, IN
2 Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, IN