PETROGENESIS OF SANUKITOIDS FROM JHANSI AREA: IMPLICATIONS FOR ARCHEAN SUBDUCTION

Mahanti, Antarip (2025) PETROGENESIS OF SANUKITOIDS FROM JHANSI AREA: IMPLICATIONS FOR ARCHEAN SUBDUCTION. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Antarip Mahanti (Roll No. 20MS069)) 20MS069_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (9MB)

Abstract

The Mesoarchean to Neoarchean is considered a crucial period in the transition of plate tectonic style. However, in many of the Archean cratons, key markers of subduction are absent. Sanukitoids are considered a unique indicator of subduction, emplaced mainly across the Mesoarchean to Neoarchean. Many sanukitoid bodies have been reported in the Bundelkhand Craton of central India, making it a crucial place to study Archean tectonics. The study aims at the petrogenesis of sanukitoids from the Jhansi region of Bundelkhand Craton, expecting from it the possibility of understanding their formation and implications in the evolution of the Archean crust. The samples collected from the field bear hornblende and biotite as mafic minerals and plagioclase, K-feldspar, and quartz as felsic minerals. Provided with moderate SiO2, the samples have a higher value of Mg#, Cr, Ni, and FMMT (ferromagnesian: FeOt+MgO+MnO+TiO2, from mantle wedge), as well as enrichment of Ba and Sr (from the subducting crust). They show high Th/Nb, Ce/Pb, and La/Nb ratios, suggesting mixed source signatures indicating enriched mantle and continental crust. The evidences suggest that the mantle was enriched through interaction with the fluids and melts released from the subducted Archean oceanic slab and sediments, suggesting initiation of a modern-style of subduction in Bundelkhand Craton. The geochemical characteristics show affinity towards both mantle and crust-like sources for the generation of Bundelkhand sanukitoids, akin to the typical Archean sanukitoids.

Actions (login required)

View Item