Summer Research Fellowship Programme of India's Science Academies

Petrography and Geochemistry of Basic Rocks from the Nagaland-Manipur Ophiolites, NE India

Rajdeep Mondal

M.Sc Applied Geology, Department of Geological Sciences, Jadavpur University, Kolkata-700032

Dr. A. Krishnakanta Singh

Scientist ā€˜Eā€™, Wadia Institute of Himalayan Geology, (An Autonomous Institute of DST, Govt. Of India), 33, General Mahadeo Singh Road, Dehradun - 248001


Ophiolites are considered to be masses of oceanic crust and upper mantle thrust onto the edge of a continent or incorporated in mountain belts, where they are tectonically disrupted and exposed by erosion. This report mainly represents the variation in the geochemistry of basic rocks from Manipur Ophiolitic Complex. The study was carried out using major element analysis and rare earth elemental (REE) characteristics. The mafic volcanics of the MOC are identified as mid oceanic basalt (MORB) and alkaline ocean island basalt (OIB). MORB type is further classified into two groups which are depleted tholeiitic N-MORB/variably enriched MORB as Type-Ia and alkaline plume influenced MORB (P-MORB) as Type-Ib. The OIB type is represented as Type-II. Besides this, thin section preparation technique for petrography and instrumentation, working principle of X-Ray Fluorescence Spectrometry (XRF), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Electron Probe Micro Analyzer (EPMA), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), Raman Spectroscopy are studied during the course.

Keywords:Indo-Myanmar orogenic belt, Ophiolites, Analytical Techniques, MORB, OIB, Basic rocks

Written, reviewed, revised, proofed and published with