Screen Reader Access  | Skip to main content  | Skip to navigation  |   

English

  Home  |   Contact Us  |   WIHG 

Email: himgeol@wihg.res.in
     
 

Abstract


<< Back

Himalayan Geology, Vol. 41 (1), 2020, pp. 1-10, Printed in India

Characterization of the Detrital Zircon from the Lesser Himalayan Proterozoic siliciclastics

MANJU NEGI1*, SANTOSH K. RAI1, SUMIT K. GHOSH1, UDAY BHAN2, SAURABH SINGHAL1

1Wadia Institute of Himalayan Geology, Dehradun, 248001, India

2University of Petroleum and Energy Studies, Dehradun, 248007, India

*Email (Corresponding author): manjunegi34@gmail.com

Abstract: Zircons are common and a key resistant mineral found in the clastic rocks. These are useful to trace the provenance of sediments in varying basinal set up. The Proterozoic Lesser Himalayan basin largely consists of thick succession of siliciclastic, argillite, and limestone deposited under shallow marine shelf set up.The southern and northern parts of the Lesser Himalaya are divided as the Outer Lesser Himalaya (OLH) and Inner Lesser Himalaya (ILH). The clastic sediments have retained the accessory minerals such as, zircon, monazite and apatite, sourced from the Aravalli and Bundelkhand cratons of the peninsular India.

The present study attempts to categorize the physical features apparent in the zircons of the two prominent lithounits- 1.80 Ga Damtha Group and 0.80 Ga Jaunsar Group of the Lesser Himalaya, in accordance to the processes responsible for their genesis. The zircons are varied in terms of external morphology and internal textures. Zircons from (1.8-0.8 Ga) Lesser Himalayan siliciclastics are euhedral to subhedral in shape with angular to rounded perimeter. The average size of the zircon separates is 112 µm ±24 with length: breadth (L/B) ratio 1.83 ± 0.12. The internal structure shows low-to-high luminescence growth zones, core rim texture, alternate bright and dark rim and fractures. Zircon grains of OLH and ILH show nearly similar morphological and internal features. Dimension wise the OLH zircons are bigger (117 µm) than the ILH (101 µm). Near similar internal morphological characteristics of the zircon separate simplies that the ILH and OLH has been sourced from the similar protolith (Bundelkhand and Aravalli). Zircon grains show zoning pattern of magmatic as well as metamorphic characteristics. However, differences in morphological characteristics of different zircons suggest that each formation (Nagthat, Chandpur and Rautgara) of the Lesser Himalaya are sourced from a protoliths, which underwent different processes of formation, besides different degree of transportation and recycling.

Keywords: Proterozoic, zircons, siliciclastic, Aravalli and Bundelkhand Cratons.

 
 
 
Follow us on:
 
 
Copyright © 2024 Wadia Institute of Himalayan Geology, Dehradun, Uttarakhand. All Rights Reserved.