Interpretation of magnetic fabrics in the Dalma volcanic rocks and associated meta-sediments of the Singhbhum Mobile Belt

Journal of earth system science

Saurodeep Chatterjee^1¹  Supriya Mondal^1² 

[1] Department of Geological Sciences, Jadavpur University, 188, Raja S.C. Mullick Road, Kolkata 700 032, India.^1;Geology Department, Asutosh College, Kolkata 700 026, India.^2

关键词: Anisotropy of Magnetic Susceptibility (AMS);    Dalma;    East Indian Shield;    Fe–Ti oxide;    magnetic fabric;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

The present work deals with the generations of Fe–Ti oxides and the variation in magnetic fabrics of the Dalma lavas and associated meta-sediments of the Singhbhum Mobile Belt (SMB) in relation to tectonics. Generations of the Fe–Ti oxides are different in meta-sediments and volcanics, the former preserving upliftment related oxidised grains, whereas the latter contains fresh grains prompting towards their upliftment due to plume upwelling before the volcanic eruption. In the meta-sediments, the magnetic fabric has close accordance with $\rm{D_{2}/F_{2}}$ event revealing synchronous development with $\rm{D_{2}}$. The Dalma thrust developed a sudden break in the homogeneity of the magnetic fabrics of the rocks where the magnetic foliations are all parallel to the Dalma thrust. This also causes P_{j} to be highest in this sector. The magnetic fabrics of volcanic rocks are different from the meta-sediments and record no signature of deformation. The pattern of distribution of susceptibility axes are in accordance with the subaerial lava flows. However, their $\rm{K_{1}}$ and $\rm{K_{2}}$ dispersed throughout the periphery with$\rm{K_{3}}$ clustering at the centre. This infers towards the fact that although the volcanism took place in a subaerial environment, calm aqueous environment was locally present where the oblate grains settled on the eruption surface with their$\rm{K_{3}}$ vertical.

【 授权许可】

CC BY