See more from this Division: Topical Sessions
See more from this Session: Mesozoic Sedimentary Basins as Archives of Mexican Magmatic History and Paleogeography
Abstract:
Chemical composition of the amphibolitic rocks of the Cuicateco terrane is toleitic basalts MORB (SiO2 45-50%), with a depletion in light rare earths and flat high rare earths patterns. Trace elements show a pattern depleted in incompatible elements, a slight enrichment in compatible elements, and negative anomalies of Nb and Th. A contribution of subduction-related magmas is also shown.
U-Pb dating by LA-MC-ICPMS on zircons belonging to the amphibolite, which yielded a maastrichtian age (65.6 ± 0.2 Ma) interpreted as the crystallization age of the basaltic protolith. Detrital U-Pb analyses on zircons of a vulcanoclastic phyllite suggest a maximum depositional maastrichtian age (~ 78 Ma). Zircons belonging to a sandstone of the Todos Santos Formation indicate a maximum depositional age, later to Middle-Upper Triassic (228 Ma).
The data obtained suggest the development of a basic volcanism in an ocean basin environment with a subduction-related influence during the Late Cretaceous,. that suffered the effect of two events, a transpressive and other compressive, during the latest Cretaceous - Paleocene, following by normal-lateral faulting miocenic.
See more from this Division: Topical Sessions
See more from this Session: Mesozoic Sedimentary Basins as Archives of Mexican Magmatic History and Paleogeography