Research Highlights
Several models have been proposed to understand the spatio-temporal evolution of the Himalayan orogen. However, our field observations from the Himachal Himalaya question their validity. Observations discover a regional scale back-fold in the Himalaya that refolded both the GHC and the THS rocks, for the first time in Himalaya.
The Singhbhum Craton (SC) is one of the thinnest craton in the world. However, the consequence of the thickness of the creation, and when the craton attended stability were not explored. To address this, we have conducted a detailed structural analysis and stress inversion in the SC to understand the past stress condition. The analysis reveals that the far-field stress from the Singhbhum Mobile Belt imprints the SC in the form of brittlely deformed dykes and the Singhbhum granites. Moreover, geological evidence suggests the craton was capable of accommodating internal deformation at least as early as 1.6 billion years ago, challenging the prevailing notion of cratonic stability established after their formation at ca. 3.0 Ga.
Several lines of evidence suggest the role of fluid in earthquakes. For example, the 1999 Chamoli earthquake (6.6 Mw) is attributed to be a result of fluid present in the MCT. However, there is no such geological evidence available that can be directly linked to present-day natural earthquakes. To solve this issue, we have analyzed samples from a shear zone that has been exhumed more than 10 km with numerous veins and faults, indicative of fluids activity and earthquakes. Our result strongly suggests that the fluid trapped in the vein is indicative of the earthquake cycle.
This is the first-ever evidence that strongly implies the role of different structures such as foliations, faults, and fractures in weathered zone thickness and hence directly controls the groundwater conditions and critical zones in hard-rock terrain.
Fry method has been widely used as a robust strain estimation technique in the field of Geology. However, the effect of packing density of the sample on the results of the Fry method was not known. To find this we have tasted the effect of packing density both in simulated and natural samples and demonstrably argue that the packing density should be greater than 30% to minimize the error in the results related to the packing density.