Skip to Main Content
GEOREF RECORD

Western Caribbean intraplate deformation; defining a continuous and active microplate boundary along the San Andres rift and Hess Escarpment fault zone, Colombian Caribbean Sea

Luis Carlos Carvajal-Arenas and Paul Mann
Western Caribbean intraplate deformation; defining a continuous and active microplate boundary along the San Andres rift and Hess Escarpment fault zone, Colombian Caribbean Sea
AAPG Bulletin (August 2018) 102 (8): 1523-1563

Abstract

The San Andres rift (SAR), located on the lower Nicaraguan Rise, is a previously poorly studied, active, 015 degrees -trending, bathymetric, and structural rift basin that is 11-27 km (7-17 mi) wide and extends for 346 km (215 mi) across the western flank of the Caribbean plate. In this study, we integrate bathymetric maps, potential field data, and high-resolution, two-dimensional (2-D) seismic lines to understand the crustal structure, tectonic history, and tectonic origin of the SAR, which is one of the active areas within the otherwise stable Caribbean plate. We compiled regional gravity and magnetic data that revealed a negative gravity anomaly and positive magnetic anomaly that we interpret as a result of crustal thinning and an elevated Moho along the main rift axis of the SAR. Forward models of gravity data show four possible interpretations for the origin of the crust underlying and surrounding the SAR. Interpretations of 2-D seismic reflection data show structural features within the upper crust and sedimentary sections typical of other active rift systems including a SAR-parallel, north-south alignment of earthquakes with the larger events showing normal and strike-slip focal mechanisms. Sequential kinematic restorations based on 2-D seismic profiles reveal three major phases of SAR opening: (1) the initial early Eocene rifting stage; (2) middle Eocene extension; and (3) a rapid middle Miocene to early Pliocene extension accompanied by emergence of the San Andres Island as a rift shoulder. We propose slab rollback and intraplate extension as main tectonic mechanisms to explain all rift phases and Neogene volcanism found in the western Caribbean region.


ISSN: 0149-1423
EISSN: 1558-9153
Coden: AABUD2
Serial Title: AAPG Bulletin
Serial Volume: 102
Serial Issue: 8
Title: Western Caribbean intraplate deformation; defining a continuous and active microplate boundary along the San Andres rift and Hess Escarpment fault zone, Colombian Caribbean Sea
Affiliation: University of Houston, Department of Earth and Atmospheric Sciences, Houston, TX, United States
Pages: 1523-1563
Published: 201808
Text Language: English
Publisher: American Association of Petroleum Geologists, Tulsa, OK, United States
References: 124
Accession Number: 2018-077696
Categories: Economic geology, geology of energy sourcesSolid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. block diags., sects., 1 table, geol. sketch maps
N11°00'00" - N15°00'00", W83°00'00" - W79°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States
Update Code: 2018
Close Modal

or Create an Account

Close Modal
Close Modal