Subhajit GHOSH
Institute: University of Calcutta
Title: PhD Research Scholar
Country: India
Period: 2019/02/01 ~ 2020/01/31
Theme: Role of melting in controlling the rheology of the crust: insights from experimental investigation
Host: Takehiko HIRAGA
Introduction: I pursued my PhD from the Department of Geology, University of Calcutta, India. By training, I am a structural geologist and a modeller. Mostly I prefer to work on experimental modelling of different geodynamic and geological processes and rock deformation. In course of my PhD thesis, I started working on Himalayan tectonics, the modern-day archetype for continent-continent collision. My fundamental goal was to understand the kinematics of orogenic wedge development during plate-convergence. However, one significant problem that caught my attention at that time was the lack of clarity about how the deformation behaviour of an orogenic wedge and the processes of strain localization change from the mountain interior to the mountain front, which were strongly evident from my field experiences. In my research, I integrated detailed geological mapping and field observations with the experimental models (both analogue and numerical modelling of ductile and brittle deformation) to acquire comprehensive insight into the mechanism of mountain building processes.

Although, this theoretical (and/or philosophical) approach is really important in enhancing our scientific knowledge about continental deformation, I have also tried to include a robust practical aspect to my research, simultaneously. For example, the hypocentre of the recent 2015 Mw 7.8 Nepal earthquake in the eastern Himalaya concurs with the mid-crustal ramp on the Main Himalayan Thrust (MHT), which behaves as an asperity by focusing stress and strain build up. As a corollary to my thesis work, I am also trying to understand the origin of such mid-crustal ramping in continental setting using the numerical-sandbox approach.

During, my stay at ERI, I will work with Prof. Takehiko Hiraga to explore the role of initial grain alignment (Shape Preferred Orientation; SPO), Crystallographic Preferred Orientation (CPO) and melts on mantle rheology and strain localization. Potentially, my project will focus on yielding some new insights in the rheology of the crust and/or lithospheric mantle rocks by integrating high-T rock deformation experiments in contention with the observations from natural rocks.
Fiscal Year: 2018