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Geomorphology and Geologic Structure: Straits of Florida

1970; Geological Society of America; Volume: 81; Issue: 7 Linguagem: Inglês

10.1130/0016-7606(1970)81[1947

1943-2674

Richard J. Malloy, Robert J. Hurley,

Geological Modeling and Analysis

Research Article| July 01, 1970 Geomorphology and Geologic Structure: Straits of Florida R. J MALLOY; R. J MALLOY Environmental Science Services Administration, Atlantic Oceanographic and Meteorological Laboratories, Miami, Florida 33130 AUTHOR'S PRESENT ADDRESS: U.S. NAVAL CIVIL ENGINEERING LABORATORY, PORT HUENEME, CALIFORNIA 93041 (MALLOY) Search for other works by this author on: GSW Google Scholar R. J HURLEY R. J HURLEY School of Marine and Atmospheric Sciences, Miami, Florida 33149 Search for other works by this author on: GSW Google Scholar Author and Article Information R. J MALLOY AUTHOR'S PRESENT ADDRESS: U.S. NAVAL CIVIL ENGINEERING LABORATORY, PORT HUENEME, CALIFORNIA 93041 (MALLOY) Environmental Science Services Administration, Atlantic Oceanographic and Meteorological Laboratories, Miami, Florida 33130 R. J HURLEY School of Marine and Atmospheric Sciences, Miami, Florida 33149 Publisher: Geological Society of America Received: 17 Sep 1969 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1970, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1970) 81 (7): 1947–1972. https://doi.org/10.1130/0016-7606(1970)81[1947:GAGSSO]2.0.CO;2 Article history Received: 17 Sep 1969 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation R. J MALLOY, R. J HURLEY; Geomorphology and Geologic Structure: Straits of Florida. GSA Bulletin 1970;; 81 (7): 1947–1972. doi: https://doi.org/10.1130/0016-7606(1970)81[1947:GAGSSO]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 A bathymetric map of the Straits of Florida was compiled using a 10-fathom contour interval. Except for coastal areas of Cuba and the Bahamas, depth soundings were collected by systematic surveys between 1951 and 1964, using electronic positioning and recording fathometers. Distances between depth sounding lines were: 1 n. m. below 100 fms north of Miami and below 300 fms elsewhere; ½ n.m. to 20 fms; and ¼ n.m. from 20 to 10 fms. Seismic reflection profiling and previous seismic refraction studies suggest that the main axis of the Northern Straits (west of Little Bahama and Grand Bahama Banks) has formed aseismically, by non-deposition and limited erosion, and that the Southern Straits (north of Cuba) have formed principally by subsidence and normal faults along Cuba to form a half-graben with the down-dropped portion tilted toward the south. Downward flexing and subsidence of the strata which form the southern terminus of the Florida Plateau have probably been accompanied by normal faulting, although of less than regional significance, along the Pourtalès Terrace Escarpment and the Mitchell Escarpment. This subsidence reaches its maximum near Cuba where the Sierra de Jatibonica and the Las Villas normal faults form the major scarps. The thalweg, or axis of greatest depths, of the Southern Straits lies only 17 n.m. north of Cuba in response to the southerly tilted blocks of the Southern Straits.Sediment distribution on the floor of the Straits is strongly influenced by elongate depositional anticlines which occur typically at the base of steep slopes. These anticlines are separated from the scarps by nondepositional troughs which may be formed by contour currents concentrated along the bases of the scarps. The associated sedimentary rises may be formed by periodic spill-over.The surfaces of Pourtalès and Miami Terraces are marked with karst-like topography, probably true solution and collapse features which formed, or at least have been maintained, subaqueously by the corrosive waters of the Floridan aquifer, effluent in the Straits of Florida.Oceanic reefs, largely branching coral with entrapped sediments, have locally reshaped the morphology of the Northern Straits. Areas of the thalweg of the Northern Straits and Little Bahama Bank are mounded or ridged (or both) with reef topography. The length of the outer edge of the Miami Terrace, including buried extensions north and south, may have been elevated by reef growth, but extensive dredging yielded phosphatic nodules, not coral.Eroded strata crop out on the sea floor along the thalweg of the Northern Straits and in places along the bases of scarps. 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.