| Abstract: | Acoustically discovered hydrocarbon seeps along a transform fault zone on the Sonoran margin of Guaymas Basin and in the Southern Trough of Guaymas Basin were examined and sampled during dives of DSV Alvin. Seepage of methane and heavier hydrocarbons occurs through shallow pockmarks along the eroding crest of a steep anticline, 1600 m below sea level. Extensive ledges of aragonite crop out around the rims of the pockmarks; isotopic analysis indicates that carbonate precipitation is a result of methane oxidation. Seepage zones within the pockmarks support dense communities of Calyptogena, half buried in the mud; tubeworms (Lamellibracheae sp.) have colonized many of the aragonite outcrops. Though the margin site is only a few kilometers from a high-temperature sulfide-precipitating and petroleum-discharging vent system at a nearby center, its structural setting is more akin to pockmarks described from continental shelves, and its chemosynthetic fauna is more like that around low temperature seeps on other continental slopes and margins (e.g. Oregon, U.S.A., and Japan). The seep in the Southern Trough is a condensate-type petroleum (C1-C40) and rises as a plume from a young vent-mound system about 2000 m below sea level. ?? 1990. |
| Genre: | Article |
| ProdID: | 70016217 |
| Citation Author: | Simoneit, B. R. T.; Lonsdale, P. F.; Edmond, J. M.; Shanks, III, W. C. |
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| Citation End Page: | 49 |
| Citation Issue: | 1-2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Applied Geochemistry |
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| Citation Number Of Pages: | 9 |
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| Citation Search Results Text: | Deep-water hydrocarbon seeps in Guaymas Basin, Gulf of California; 1990; Article; Journal; Applied Geochemistry; Simoneit, B. R. T.; Lonsdale, P. F.; Edmond, J. M.; Shanks, III, W. C. |
| Citation Start Page: | 41 |
| Citation Volume: | 5 |
| Citation Year: | 1990 |
| Type: | citation/reference |
| Text: | Deep-water hydrocarbon seeps in Guaymas Basin, Gulf of California; 1990; Article; Journal; Applied Geochemistry; Simoneit, B. R. T.; Lonsdale, P. F.; Edmond, J. M.; Shanks, III, W. C. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1990 00:00 -0600 |
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