Research Article| August 01, 1992 Megabreccia shedding from modern, low-relief carbonate platforms, Nicaraguan Rise ALBERT C. HINE; ALBERT C. HINE 1Department of Marine Science, University of South Florida, St. Petersburg, Florida 33701 Search for other works by this author on: GSW Google Scholar STANLEY D. LOCKER; STANLEY D. LOCKER 1Department of Marine Science, University of South Florida, St. Petersburg, Florida 33701 Search for other works by this author on: GSW Google Scholar LENORE P. TEDESCO; LENORE P. TEDESCO 2Rosentiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149 Search for other works by this author on: GSW Google Scholar HENRY T. MULLINS; HENRY T. MULLINS 3Department of Geology, Syracuse University, Syracuse, New York 13210 Search for other works by this author on: GSW Google Scholar PAMELA HALLOCK; PAMELA HALLOCK 1Department of Marine Science, University of South Florida, St. Petersburg, Florida 33701 Search for other works by this author on: GSW Google Scholar DANIEL F. BELKNAP; DANIEL F. BELKNAP 4Department of Geological Sciences, University of Maine, Orono, Maine 04469 Search for other works by this author on: GSW Google Scholar JUAN LUIS GONZALES; JUAN LUIS GONZALES 5INGEOMINAS, Direccion Regional Cali, Cali, Colombia Search for other works by this author on: GSW Google Scholar A. C. NEUMANN; A. C. NEUMANN 6Marine Sciences Program, University of North Carolina, Chapel Hill, North Carolina 27514 Search for other works by this author on: GSW Google Scholar STEPHEN W. SNYDER STEPHEN W. SNYDER 7Department of Earth, Marine, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27594 Search for other works by this author on: GSW Google Scholar Author and Article Information ALBERT C. HINE 1Department of Marine Science, University of South Florida, St. Petersburg, Florida 33701 STANLEY D. LOCKER 1Department of Marine Science, University of South Florida, St. Petersburg, Florida 33701 LENORE P. TEDESCO 2Rosentiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149 HENRY T. MULLINS 3Department of Geology, Syracuse University, Syracuse, New York 13210 PAMELA HALLOCK 1Department of Marine Science, University of South Florida, St. Petersburg, Florida 33701 DANIEL F. BELKNAP 4Department of Geological Sciences, University of Maine, Orono, Maine 04469 JUAN LUIS GONZALES 5INGEOMINAS, Direccion Regional Cali, Cali, Colombia A. C. NEUMANN 6Marine Sciences Program, University of North Carolina, Chapel Hill, North Carolina 27514 STEPHEN W. SNYDER 7Department of Earth, Marine, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27594 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1992) 104 (8): 928–943. https://doi.org/10.1130/0016-7606(1992)104<0928:MSFMLR>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation ALBERT C. HINE, STANLEY D. LOCKER, LENORE P. TEDESCO, HENRY T. MULLINS, PAMELA HALLOCK, DANIEL F. BELKNAP, JUAN LUIS GONZALES, A. C. NEUMANN, STEPHEN W. SNYDER; Megabreccia shedding from modern, low-relief carbonate platforms, Nicaraguan Rise. GSA Bulletin 1992;; 104 (8): 928–943. doi: https://doi.org/10.1130/0016-7606(1992)104<0928:MSFMLR>2.3.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 Single-channel seismic reflection data from the margins of lowrelief (150-250 m, measured from edge of bank to basin) carbonate platforms on the northern Nicaraguan Rise reveal complex seismic intervals consisting of mounded, chaotic seismic facies interspersed with discontinuous, parallel/laminated seismic facies. We interpret that these intervals contain megabreccias (chaotic facies) and sandy turbidites (parallel/laminated facies). One megabreccia is exposed on the sea floor displaying an overall fan shape having individual blocks measuring nearly 300 m across and >110 m high. The source area consists of a scalloped embayment with a headwall scarp 180 m high. Reflections within the platform are sharply truncated by this escarpment. This single megabreccia is ∼120 m thick and extends ∼27 km along slope and ∼16 km out into the basin. Other megabreccias within the basin have individual blocks measuring >400 m across.Rocks from dredge hauls are a mixture of shallow- and deep-water facies. Shallow-water facies consist of mixed, skeletal grain-stones and Halimeda packstones. Deep-water facies are massive chalks, chalks with shallow-water skeletal grains, and chalk-block breccias. This indicates that the megabreccias formed as a result of bank-margin collapse, during which the ensuing debris flow eroded into slope and basin facies, mixing rock types together. We speculate that bank-margin-collapse events, resulting in megabreccia formation, may have been seismically triggered, and we emphasize that these large-scale, mass-wasting events occurred along margins of low-relief carbonate platforms. 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.
