The Carboniferous Baralacha La basaltic dykes (Upper Lahul, Ladakh) : remnants of an early rifting event along the Indian northern plate.

François Chauvet (1) , Henriette Lapierre (1) , Delphine Bosch , Alain Demant , François Bussy , Jean-Claude Vannay , Georges Mascle (1) , Pierre Brunet , Joseph Cotten (2) , Francine Keller (1)

1 LGCA - Laboratoire de Géodynamique des Chaines Alpines
2 LDO - Domaines Océaniques

The Lower Carboniferous Baralacha La basaltic dykes were emplaced along transtensional faults. The basalts exhibit tholeiitic and alkaline affinities. The tholeiites are TiO2-poor, moderately enriched in light rare earth (LREE), and display Nb and Ta negative and Th positive anomalies. The alkali basalts, compared to the tholeiites, have higher TiO2, rare earth and highly incompatible trace element contents and greater LREE enrichments. The Nd and Pb isotope compositions of the Baralacha La basalts suggest that they derive from the partial melting of an enriched OIB mantle source, characterized by a HIMU component, and contaminated by the lower continental crust. The Baralacha La dyke swarm represent the remnants of an early rifting event on the northern Indian passive margin.

Domaines: Pétrographie

François Chauvet, Henriette Lapierre, Delphine Bosch, Alain Demant, François Bussy, et al.. The Carboniferous Baralacha La basaltic dykes (Upper Lahul, Ladakh) : remnants of an early rifting event along the Indian northern plate.. Bulletin de la Société Géologique de France, 2005, 176(6), pp.499-511. ⟨10.2113/176.6.499⟩. ⟨hal-00101900⟩