Proceedings of the Mizoram Science Congress 2018 (MSC 2018) - Perspective and Trends in the Development of Science Education and Research

Geochemistry and nature of protolith of quartz sillimanite schist from Sonapahar area, West Khasi Hills district of Meghalaya

Authors
V. Vanthangliana, Jimmy Lalnunmawia, Laldinpuia, Lalhmingsangi
Corresponding Author
V. Vanthangliana
Available Online December 2018.
DOI
10.2991/msc-18.2018.19How to use a DOI?
Keywords
Quartz sillimanite schists, Sonapahar, geochemistry, sediment, rock
Abstract

The Precambrian terrain of the Sonapahar area is characterised by the presence of a thin, long, discontinuous band of quartz-sillimanite schist which hosts the massive sillimanite-corundum deposits. The quartz sillimanite schists are generally siliceous, SiO2 (60.59-76.82 wt %) and are characterized by high Al2O3 content with average value (27.22 wt %), low P2O5, Fe2O3 and MgO, MnO Na2O, K2O and TiO2. Average MgO, CaO, K2O and Na2O values are generally less than 0.15 wt %. TiO2 values range from 0.13-0.35 wt %. Compared with the post-Archean metasediments, the Sonapahar schists are richer in SiO2 and Al2O3 but depleted in other oxides. In Harkers variation diagram, SiO2 shows a linear inverse correlation with Al2O3 and TiO2, but there are no significant correlations observed with other oxides. In general, Al2O3 and SiO2 constitute more than 97 wt % in most of the samples. Among trace elements, Zr, Hf and Pb are characterized by high concentration and low La/Th and Th/U. The schistose rocks are generally low in Sr/Ba ratios (< 0.88 %) and relatively high content of Rb in contrast to Ba. Chondrite normalize REE patterns of the schists reveals a strongly fractionated patterns with enriched LREE and low HREE values [(La/Yb)N = 27.38-43.98] with prominent negative Eu-anomaly. The concentration of V (10.28-51.49) shows the apparent mobility in these quartz sillimanite schists and the oxidizing conditions prevailed during weathering. Geochemical characteristics suggested that quartz sillimanite schists from Sonapahar area are derived from post-Archean recycled upper crust sources and the precursor sediments are possibly derived from felsic rocks and probably not mafic rocks.

Copyright
© 2018, the Authors. Published by Atlantis Press.
Open Access
This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

Download article (PDF)

Volume Title
Proceedings of the Mizoram Science Congress 2018 (MSC 2018) - Perspective and Trends in the Development of Science Education and Research
Series
Advances in Engineering Research
Publication Date
December 2018
ISBN
10.2991/msc-18.2018.19
ISSN
2352-5401
DOI
10.2991/msc-18.2018.19How to use a DOI?
Copyright
© 2018, the Authors. Published by Atlantis Press.
Open Access
This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

Cite this article

TY  - CONF
AU  - V. Vanthangliana
AU  - Jimmy Lalnunmawia
AU  - Laldinpuia
AU  - Lalhmingsangi
PY  - 2018/12
DA  - 2018/12
TI  - Geochemistry and nature of protolith of quartz sillimanite schist from Sonapahar area, West Khasi Hills district of Meghalaya
BT  - Proceedings of the Mizoram Science Congress 2018 (MSC 2018) - Perspective and Trends in the Development of Science Education and Research
PB  - Atlantis Press
SP  - 116
EP  - 122
SN  - 2352-5401
UR  - https://doi.org/10.2991/msc-18.2018.19
DO  - 10.2991/msc-18.2018.19
ID  - Vanthangliana2018/12
ER  -