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The case for persistent southwest-dipping Cretaceous convergence in the northeast Antilles; geochemistry, melting models, and tectonic implications

Wayne T. Jolly, Edward G. Lidiak and Alan P. Dickin
The case for persistent southwest-dipping Cretaceous convergence in the northeast Antilles; geochemistry, melting models, and tectonic implications
Geological Society of America Bulletin (August 2008) 120 (7-8): 1036-1052

Abstract

Constraints on the polarity of Cretaceous subduction in the Greater Antilles are provided through geochemical comparison between the erupted island arc lavas in central Puerto Rico and potential pelagic sediment reservoirs in the flanking ocean basins. Early Jurassic to mid-Cretaceous (185- to 65-Ma) sediment from the open Pacific on the southwest is dominated by pelagic chert, which is highly refractory and depleted with respect to incompatible elements. In comparison, mid- to Late Cretaceous (ca. 112- to 65-Ma) sediment from the younger Atlantic basin on the northeast was dominated by mixtures of two end members. These include (1) biogenic clay and carbonates with elevated light rare-earth element (LREE) abundances, negative MORB-normalized, high field-strength element (HFSE) anomalies, and low Zr/Sm; and (2) turbiditic detritus of upper continental crust composition with high LREE, comparatively shallow HFSE anomalies, and high Zr/Sm. Compositions of Puerto Rican arc basalts are inconsistent with incorporation of Pacific pelagic chert. Instead, patterns characteristic of high-Fe island arc tholeiites are reproduced by incorporation of up to 4% of a low-Zr/Sm biogenic sediment component of Atlantic origin, whereas patterns of low-Fe lavas require, in addition to biogenic sediment, introduction of up to 2% of a high-Zr/Sm crustal turbidite component. The Atlantic origin of all the subducted sediments indicates the polarity of subduction throughout the Cretaceous in the northeast Antilles was persistently southwest dipping. This conclusion is supported by the presence of a low-Zr/Sm suprasubduction zone component of Atlantic origin in Caribbean plateau basalts (91-88 Ma) from southwest Puerto Rico, which were erupted within the broad back-arc region of the Greater Antilles during intermediate stages of arc development.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 120
Serial Issue: 7-8
Title: The case for persistent southwest-dipping Cretaceous convergence in the northeast Antilles; geochemistry, melting models, and tectonic implications
Affiliation: Brock University, Department of Earth Sciences, St. Catharines, ON, Canada
Pages: 1036-1052
Published: 200808
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 98
Accession Number: 2008-104177
Categories: Solid-earth geophysicsIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2008003
Illustration Description: illus. incl. geol. sketch map
N17°30'00" - N27°30'00", W85°00'00" - W65°00'00"
Secondary Affiliation: University of Pittsburgh, USA, United StatesMcMaster University, CAN, Canada
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200836
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