Tectonic inferences from oxygen isotopes in volcano‐plutonic complexes of the India‐Asia COllision Zone, NW India
Article
Srimal, N, Basu, AR, Kyser, TK. (1987). Tectonic inferences from oxygen isotopes in volcano‐plutonic complexes of the India‐Asia COllision Zone, NW India
. TECTONICS, 6(3), 261-273. 10.1029/TC006i003p00261
Srimal, N, Basu, AR, Kyser, TK. (1987). Tectonic inferences from oxygen isotopes in volcano‐plutonic complexes of the India‐Asia COllision Zone, NW India
. TECTONICS, 6(3), 261-273. 10.1029/TC006i003p00261
The India‐Asia collision zone in Ladakh, NW India, is characterized by two major granitic batholiths. The northern, Karakoram granitic complex and the southern, Ladakh granitic complex are separated by thrust‐bound belts of ophiolites, flysch, and calc‐alkaline volcanics (Khardung Volcanics) of Late Paleozoic to Tertiary age. Oxygen isotope analyses of whole rock and coexisting mineral separates indicate that (a) The Ladakh granitic complex belongs to an I type suite with δ18O = +5.6‰ to +6.1‰ and (b) The Karakoram granitic complex comprises two contrasting suites of granitoids, an older, predominantly I type with δ18O = +6.2‰ to + 7.7‰ and a younger S type with δ18O = +9.5‰ to +10.7‰. The Khardung volcanics show wide variation in δ18O values, ranging from +0.75‰ to +10.7‰ indicating isotopic exchange with a meteoric‐hydrothermal convective system. We suggest that the older I type suite of the Karakoram batholith represents Jurassic to Early Cretaceous arc magmatism along the Bangong‐Nujiang‐North Saltoro suture. This implies a continental collision between the Lhasa‐Shyok‐Kohistan block and the Asian plate prior to the Tertiary collision between India and Asia. India‐Asia collision resulted in the rejuvenation of the North Saltoro suture with the emplacement of the younger anatectic granite of the Karakoram batholith. Copyright 1987 by the American Geophysical Union.
