| Abstract: | Considerable crustal thickness variations are inferred along Cayman Trough, a slow-spreading ocean basin in the Caribbean Sea, from modeling of the gravity field. The crust to a distance of 50 km from the spreading center is only 2-3 km thick in agreement with dredge and dive results. Crustal thickness increases to ???5.5 km at distances between 100 and 430 km west of the spreading center and to 3.5-6 km at distances between 60 and 370 km east of the spreading center. The increase in thickness is interpreted to represent serpentinization of the uppermost mantle lithosphere, rather than a true increase in the volume of accreted ocean crust. Serpentinized peridotite rocks have indeed been dredged from the base of escarpments of oceanic crust rocks in Cayman Trough. Laboratory-measured density and P-wave speed of peridotite with 40-50% serpentine are similar to the observed speed in published refraction results and to the inferred density from the model. Crustal thickness gradually increases to 7-8 at the far ends of the trough partially in areas where sea floor magnetic anomalies were identified. Basement depth becomes gradually shallower starting 250 km west of the rise and 340 km east of the rise, in contrast to the predicted trend of increasing depth to basement from cooling models of the oceanic lithosphere. The gradual increase in apparent crustal thickness and the shallowing trend of basement depth are interpreted to indicate that the deep distal parts of Cayman Trough are underlain by highly attenuated crust, not by a continuously accreted oceanic crust. Published by Elsevier Science Ltd. |
| Genre: | Article |
| ProdID: | 70024402 |
| Citation Author: | ten, Brink, U. S.; Coleman, D. F.; Dillon, William, P. |
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| Citation End Page: | 987 |
| Citation Issue: | 8 |
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| Citation Language: | English |
| Citation Larger Work Title: | Marine and Petroleum Geology |
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| Citation Number Of Pages: | 17 |
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| Citation Search Results Text: | The nature of the crust under Cayman Trough from gravity; 2002; Article; Journal; Marine and Petroleum Geology; ten, Brink, U. S.; Coleman, D. F.; Dillon, William, P. |
| Citation Start Page: | 971 |
| Citation Volume: | 19 |
| Citation Year: | 2002 |
| Type: | citation/reference |
| Text: | The nature of the crust under Cayman Trough from gravity; 2002; Article; Journal; Marine and Petroleum Geology; ten, Brink, U. S.; Coleman, D. F.; Dillon, William, P. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/S0264-8172(02)00132-0 |
| Date Other: | Tue, 1 Jan 2002 00:00 -0600 |
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