Subsidence history of the Bahama Escarpment and the nature of the crust underlying the Bahamas

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doi: 10.1016/0012-821X(87)90010-0
Authors:Freeman-Lynde, R. P.; Ryan, W. B. F.
Author Affiliations:Primary:
Univ. Ga., Dep. Geol., Athens, GA, United States
Lamont-Doherty Geol. Obs., United States
Volume Title:Earth and Planetary Science Letters
Source:Earth and Planetary Science Letters, 84(4), p.457-470. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X
Publication Date:1987
Note:In English. 49 refs.; illus. incl. 2 tables, geol. sketch map, sketch maps
Summary:Subsidence of this escarpment, determined from deep-diving submersible and dredge samples, is used to constrain the nature of crust underlying the Bahamas. Horizontal disposition of the Hauterivian/Barremian (125 m.y.) age boundary along the escarpment is inconsistent with the underlying oceanic crust (either normal or thickened) here, and suggests that thinned continental crust underlies the Bahamas. Subsidence curves are then fitted based on a stretched lithosphere model to a stratigraphic section (2000-4000 m) off Cat Island. This analysis indicates crustal thinning by a factor (beta) of 2.0-2.5, resulting in present crustal thicknesses of 10-12 km. It is proposed that rifting beneath the Bahamas occurred from middle (175-180 m.y.) to late (160 m.y.) Jurassic time. The pre-extension Bahamas fit between N and S America and Africa in early Jurassic time, eliminating overlap of the present Bahamas onto Africa in reconstructions of the N Atlantic. Age data for Cat Island and the Bahama escarpment are presented. [P.Br.]
Subjects:Anomalies; Continental crust; Cretaceous; Crust; Equations; Extension tectonics; Jurassic; Mesozoic; Models; Paleogeography; Plate tectonics; Stratigraphy; Submersibles; Subsidence; Tectonics; Tectonophysics; Thickness; Atlantic Ocean; Bahamas; Blake Plateau; Caribbean region; North Atlantic; West Indies; Cat Island; Sections
Abstract Numbers:88M/3179
Record ID:1987081321
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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