The paradox of minibasin subsidence into salt: Clues to the evolution of crustal basins

Research Article| January 01, 2009 The paradox of minibasin subsidence into salt: Clues to the evolution of crustal basins Michael R. Hudec; Michael R. Hudec † 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-8924, USA †E-mail: michael.hudec@beg.utexas.edu. Search for other works by this author on: GSW Google Scholar Martin P.A. Jackson; Martin P.A. Jackson 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-8924, USA Search for other works by this author on: GSW Google Scholar Daniel D. Schultz-Ela Daniel D. Schultz-Ela 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-8924, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Michael R. Hudec † 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-8924, USA Martin P.A. Jackson 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-8924, USA Daniel D. Schultz-Ela 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713-8924, USA †E-mail: michael.hudec@beg.utexas.edu. Publisher: Geological Society of America Received: 15 Jun 2007 Revision Received: 28 Feb 2008 Accepted: 22 Apr 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2008 Geological Society of America GSA Bulletin (2009) 121 (1-2): 201–221. https://doi.org/10.1130/B26275.1 Article history Received: 15 Jun 2007 Revision Received: 28 Feb 2008 Accepted: 22 Apr 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Michael R. Hudec, Martin P.A. Jackson, Daniel D. Schultz-Ela; The paradox of minibasin subsidence into salt: Clues to the evolution of crustal basins. GSA Bulletin 2009;; 121 (1-2): 201–221. doi: https://doi.org/10.1130/B26275.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Why do salt-floored minibasins subside? An almost universal explanation is that salt is forced from beneath the sinking basin by the weight of its sedimentary fill. This explanation is valid if the average density of the basin fill exceeds that of salt, which in the Gulf of Mexico needs at least 2300 m of siliciclastic fill to ensure enough compaction. However, most minibasins start sinking when they are much thinner than this. Some mechanism other than density inversion must explain the early history of these minibasins. Conventional understanding of minibasin subsidence is thus incomplete. Here, we identify five alternatives to density-driven subsidence of minibasins. (1) During diapir shortening, the squeezed diapirs inflate, leaving the intervening minibasins as bathymetric depressions. (2) In extensional diapir fall, stretching of a diapir causes it to sag, producing a minibasin above its subsiding crest. (3) During decay of salt topography, a dynamic salt bulge subsides as upward flow of salt slows, which lowers the salt surface below the regional sediment surface. (4) During sedimentary topographic loading, sediments accumulate as a bathymetric high above salt. (5) Finally, subsalt deformation affecting the base of salt may produce relief at the top of salt. Each mechanism (including density-driven subsidence) produces a different bathymetry, which interacts with sediment transport to produce different facies patterns in each type of minibasin. The particular mechanism for minibasin subsidence depends on the tectonic environment, regional bathymetry, and sedimentation rate. Their spatial variation on a continental margin creates provinces in which a given minibasin style is dominant. An appreciation of subsidence mechanisms should thus improve our understanding of minibasin fill patterns and allow genetic comparisons between minibasins.The mechanics of a minibasin sinking into fluid salt is in many ways analogous to a crustal basin sinking into a fluid asthenosphere. However, minibasins lack the complex rheologies, thermal histories, and compositional variations that make study of crustal basins so challenging. Minibasins are thus natural analogs and have the potential to elucidate fundamentals of subsidence mechanics. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.