• S P Singh

Articles written in Journal of Earth System Science

• N–S crustal shear system in the Bundelkhand massif: A unique crustal evolution signature in the northern Indian peninsula

The Bundelkhand massif, located in the northern part of the Indian shield, is a poly-deformed and poly-metamorphic terrain. This paper reports a new shear system developed throughout the massif in the form of N–S trending quartz veins that are sometimes quartzo-feldspathic and rarely granitic in composition. The veins are vertical and commonly occur in conjugate sets. This tectono-magmatic event appears to represent the youngest shear system of the massif as it cross-cuts all the earlier shear systems (E–W, NE–SE and NW–SE). Emplacement of this N–S vein system may have taken place due to extensional processes that developed some cracks along which siliceous magma was vertically emplaced. The complete absence of signature of the N–S event from the surrounding sedimentary cover of Vindhyan Supergroup, Bijawar and Gwalior Groups suggests that this shear system is pre-tectonic to the nearly E–W trending passive basins developed at the margins of the Bundelkhand craton. Further, several workers have considered the Bundelkhand massif as a part of the Aravalli craton. However, due to the absence of N–S, as well as the other (i.e., E–W, NW–SE and NW–SE), tectonic fabrics of the Bundelkhand massif in other cratons of the Peninsular India, and vice versa, makes the Bundelkhand block a separate and unique craton of its own and is not part of the Aravalli craton.

• A new occurrence of two-pyroxene granulites at Chicholi from Betul supracrustal belt in Central Indian Tectonic Zone (CITZ), MP, India

We report the new occurrence of two-pyroxene granulites from Chicholi, the Betul Group of the Central Indian Tectonic Zone (CITZ). The common mineral assemblage observed within different thin sections is orthopyroxene–clinopyroxene–hornblende–plagioclase–biotite–quartz. The textural relationship of these mineral phases shows the reaction: hornblende + quartz = orthopyroxene + clinopyroxene + plagioclase. The estimated $P–T$ condition of metamorphism of the two-pyroxene granulites is $901 \pm 30^{\circ}\rm{C}$ and $8.68 \pm 1.4$ kbar.

• # Journal of Earth System Science

Current Issue
Volume 128 | Issue 8
December 2019

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019