Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Current/Gulf Stream circulation

Abstract

Research Article| June 01, 1987 Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Current/Gulf Stream circulation HENRY T. MULLINS; HENRY T. MULLINS 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244 Search for other works by this author on: GSW Google Scholar ANNE F. GARDULSKI; ANNE F. GARDULSKI 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244 Search for other works by this author on: GSW Google Scholar SHERWOOD W. WISE, Jr.; SHERWOOD W. WISE, Jr. 2Department of Geology, Florida State University, Tallahassee, Florida 32306 Search for other works by this author on: GSW Google Scholar JOE APPLEGATE JOE APPLEGATE 2Department of Geology, Florida State University, Tallahassee, Florida 32306 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1987) 98 (6): 702–713. https://doi.org/10.1130/0016-7606(1987)98<702:MMOEIT>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation HENRY T. MULLINS, ANNE F. GARDULSKI, SHERWOOD W. WISE, JOE APPLEGATE; Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Current/Gulf Stream circulation. GSA Bulletin 1987;; 98 (6): 702–713. doi: https://doi.org/10.1130/0016-7606(1987)98<702:MMOEIT>2.0.CO;2 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 Analysis of ∼1,500 km of high-resolution, single-channel air-gun seismic-reflection profiles, correlated with two drill cores, demonstrates that the central west Florida carbonate-ramp slope experienced an oceanographic event in the middle Miocene that resulted in a major stratigraphic break or succession of depositional sequences. During the long-term eustatic sea-level rise in the early to middle Miocene, carbonate shelf-margin deposition was characterized by seaward-prograding, sigmoidal clinoforms that built both laterally and vertically. Shelf-margin sediments were relatively fine grained and rich in dolomite, total organics, and clay minerals.Approximately 12–15 m.y. ago, tectonically controlled oceanographic closure of the Isthmus of Panama, and/or increased climatic gradients, resulted in an intensification of oceanic circulation. Increased flow velocity of the Loop Current truncated antecedant clinoforms along the mid-Miocene shelf margin as the Loop Current, for the first time, became a dynamic oceanographic barrier to off-shelf sediment transport. Carbonate deposition along the west Florida slope changed dramatically from a series of prograding clinoforms to a pelagic slope-front-fill system bounded on its landward margin by contour-current flow of an invigorated Loop Current. Shelf-margin sediments, presently represented as a condensed sequence, became more carbonate rich, coarser grained, lower in organic content, and depleted in dolomite.Our results suggest that oceanographic events can generate major seismic stratigraphic breaks that result in the succession of depositional sequences and systems along continental margins and that they may be as important as eustatic oscillations. Our data also suggest that “modern” Loop Current/Gulf Stream circulation was initiated in the middle Miocene, controlled by tectono-oceanographic and/or climatic processes. The challenge now is to identify seismic stratigraphic-scale oceanographic events in the rock record, differentiate them from eustatic responses, and evaluate their paleoenvironmental significance. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.