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Geophysical Study of the Venezuelan Borderland

1975; Geological Society of America; Volume: 86; Issue: 2 Linguagem: Inglês

10.1130/0016-7606(1975)86 2.0.co;2

1943-2674

Eli A. Silver, James E. Case, H. J. MACGILLAVRY,

Geophysical and Geoelectrical Methods

Research Article| February 01, 1975 Geophysical Study of the Venezuelan Borderland ELI A. SILVER; ELI A. SILVER 1U.S. Geological Survey, Menlo Park, California 940254Present address: (Silver) Board of Earth Science, University of California, Santa Cruz, California 95064; (Case) U.S. Geological Survey, Menlo Park, California 94025. Search for other works by this author on: GSW Google Scholar JAMES E. CASE; JAMES E. CASE 2U.S. Geological Survey, Corpus Christi, Texas 789114Present address: (Silver) Board of Earth Science, University of California, Santa Cruz, California 95064; (Case) U.S. Geological Survey, Menlo Park, California 94025. Search for other works by this author on: GSW Google Scholar H. J. MACGILLAVRY H. J. MACGILLAVRY 3Geologisch Instituut, Universiteit Amsterdam, The Netherlands Search for other works by this author on: GSW Google Scholar Author and Article Information ELI A. SILVER 1U.S. Geological Survey, Menlo Park, California 940254Present address: (Silver) Board of Earth Science, University of California, Santa Cruz, California 95064; (Case) U.S. Geological Survey, Menlo Park, California 94025. JAMES E. CASE 2U.S. Geological Survey, Corpus Christi, Texas 789114Present address: (Silver) Board of Earth Science, University of California, Santa Cruz, California 95064; (Case) U.S. Geological Survey, Menlo Park, California 94025. H. J. MACGILLAVRY 3Geologisch Instituut, Universiteit Amsterdam, The Netherlands Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1975) 86 (2): 213–226. https://doi.org/10.1130/0016-7606(1975)86 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 ELI A. SILVER, JAMES E. CASE, H. J. MACGILLAVRY; Geophysical Study of the Venezuelan Borderland. GSA Bulletin 1975;; 86 (2): 213–226. doi: https://doi.org/10.1130/0016-7606(1975)86 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 The Venezuelan Borderland is composed of several large depositional basins, a linear chain of islands, and a broad outer ridge. It is cut by a nearshore zone of east-trending faults. Geophysical profiles show that the basins have different structural styles, but these features and the large faults and ridges are related to each other and to the Caribbean Coast Range by a complex history of relative movement between the Caribbean and South American plates since Late Cretaceous time.The east-trending Curaçao Ridge is a thick pile of deformed low-density strata (Vc ⩽4.1 km/sec) that apparently formed by compression of Venezuela Basin strata on its north side and by deposition and compression of strata in Los Roques Trough on the south. The basement rock of the Netherlands Antilles is composed of diabase, pillow basalt, and marine sediment that are weakly metamorphosed and cut by quartz dioritic intrusives. Gravity models suggest a thick (32 km) root beneath the islands and a thinned (18 km) crust beneath the Bonaire Trough. The Bonaire Trough probably formed by movement of the island chain away from the mainland in middle Tertiary time but shows little sign of present-day tectonic activity. The Cariaco Trench is an extensional basin between the San Sebastian and El Pilar faults.The Curaçao Ridge is widest and thickest in the west (70° W.), where sediment to the north in the Venezuela Basin is thin. The ridge is narrow in the east (66° W.), where sediment of the Venezuela Basin is thick (up to 4 km). No compressional deformation of the basin sediment is seen east of Los Roques Canyon. This structure may be explained by clockwise rotation of a small crustal block — the Bonaire block — about a pole near Caracas. The rotation of the Bonaire block probably results from dextral movement between the much larger Caribbean and South American plates. The very low seismicity recorded near the Curaçao Ridge may result from a combination of low rate of deformation and low elastic strain release involved in deforming a large sediment body. 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.