Petrography and Geochemistry (Trace, Ree and Pge) of Pedda Cherlo Palle Gabbro-Diorite Pluton, Prakasam Igneous Province, Andhra Pradesh, India

• Published in: Open Geosciences Vol. 7; no. 1
• Main Authors: Subramanyam, K.S.V., Reddy, U.V.B., Balaram, V., Roy, Parijat
• Format: Journal Article
• Language: English
• Published: Warsaw De Gruyter Open 01.01.2015; De Gruyter Poland; De Gruyter
• Subjects: Fractional Crystalisation; Gabbros; Geochemistry; IAT; Island arcs; Isotopes; Petrography; PGE; Platinum; Prakasam Igneous Province; Titanium dioxide; India
• ISSN: 2391-5447; 2391-5447
• DOI: 10.1515/geo-2015-0014

Prakasam Igneous Province (PIP) is an important geological domain in the Eastern Dharwar Craton (EDC), found in the junction zone between the EDC and Eastern Ghat Mobile Belt (EGMB). The Pedda Cherlo Palle (PCP) gabbros are massive, leucocratic-mesocractic, and show cumulus textures with minerals plagioclase, cpx, and amphiboles. Compositionally, plagioclase is a labradorite-bytownite, cpx is diopside to augite, olivines are hyalosiderites and amphiboles are magnesiohornblendes. PCP gabbros have normal SiO , high Al , moderate to high TiO , Na O and medium Fe , so, classified as subalkaline tholeiitic gabbros. Fractionated rare earth element (REE) patterns, high abundance of large ion lithofile elements (LILE) and transitional metals coupled with light REE (LREE) relative enrichment over heavy REE (HREE) and Nb are characteristics of partial melting of depleted mantle and melts that have undergone fractional crystalisation. These partial melts are enriched in LREE and LILE, due to the addition of slab derived sediment and fluids. PCP gabbros contain low abundance (5.1 to 24.6 ng/g) of platinum group elements (PGE), and show an increase in the order Ir>Os>Pt>Ru»Pd>Rh. We propose that the subduction related intraoceanic island arc might have accreted to the southeastern margin of India to the east of Cuddapah basin in a collisional regime that took place during Ur to Rodinia amalgamations.