T19 New Insights into Controls on the Behavior of Orogenic Systems and their Associated Basins

Sunday, 15 October 2023
8:00 AM - 12:00 PM
326

GOT SALT? RECOGNIZING THE FORMER PRESENCE OF DIAPIRIC SALT BODIES IN OROGENIC BELTS

Paper number: T19-2
Program: Technical Sessions
Time: 8:05 AM – 8:20 AM

Authors

Abstract

Orogenic belts may invert, overprint, and deform former rift basins and overlying passive margin successions that often contain long-lived mobile salt systems. Orogenic shortening can effectively “squeeze” the salt completely out of the system leaving behind apparent faults and folds that may be mistakenly interpreted as reflecting only orogenic tectonic processes and not the precursor salt tectonics. In addition, diapiric salt may carry sedimentary, igneous, and/or metamorphic inclusions that can be recycled into higher stratigraphic levels leading to erroneous sediment source exhumation level interpretations in the associated sedimentary basin. Understanding the contribution, location, and timing of salt diapirism is critical to structural restoration, burial history, thermal history, and reconstruction of the tectonic evolution of orogenic systems.

Presented here are a series of sedimentologic, stratigraphic, and mineralogic tools that can be applied to recognize the former presence of diapiric salt bodies that have been removed or overprinted by orogenic processes. Salt welds and fault welds will display halokinetic sequences in their wall rocks. Wall rocks may contain recycled sedimentary facies from the diapir with unusual lithoclasts/grains (for example doubly-terminated quartz) or display zircon populations derived from non-evaporite diapiric inclusions (diapir-derived detritus). Orogenic igneous and metamorphic bodies that contain unusually high Na, Cl, K, Al, and/or B bearing mineral assemblages may reflect the incorporation of evaporite-concentrated elements from assimilation or metamorphism of salt bodies. Other features that are not exclusive to, but that hint at possible salt diapirism, are polygonal structural patterns and unusual thrust map traces. Scrutinizing structures for a potential precursor mobile salt history is especially important when working orogenic belts that deform former basins associated with the two major periods of continental break-up and salt deposition in Earth’s history (i.e. late Neoproterozoic breakup of Rodinia and early Mesozoic breakup of Pangea).

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-394517

© Copyright 2023 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.