Case Studies of Non-Unique Provenance Interpretaions
Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA, USA
To deduce events of exhumation, exposure and erosion of Himalayan tectonic units from the detrital record, we need a strong understanding of the structural evolution and deformed stratigraphy from which the erosion occurred. Most Himalayan detrital studies use a simplistic approach: either considering erosion of three units (LHS, GHC, THS), four units (Outer LHS, Inner LHS, GHC, THS), or in some cases five units (Outer LHS, Inner LHS, GHC, lower THS, upper THS) with simplified models of the structural settings of these units throughout the Cenozoic. Recent investigations of Himalayan bedrock geology suggest that the structural evolution and deformed stratigraphy are more complex than the models considered in most detrital studies. The complexities, for example, repetitions of similar protoliths in different tectonic units, geologically recent removal of sequences that would have provided much detritus in the past but are no longer exposed in bedrock, indicate that many of our interpretations of the detrital record with respect to erosional signals are non-unique or incorrect. We demonstrate the necessary changes in interpretation via three case studies which compare existing detrital and recent structural and stratigraphic data sets. This study will try to understand the thrusting and exhumation history of the Himalaya from both structural and sedimentological perspectives.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects