A Brief Review of Heat-Flow Studies in the Guaymas Basin, Gulf of California
K. Becker, A. T. Fisher, 1991. "A Brief Review of Heat-Flow Studies in the Guaymas Basin, Gulf of California", The Gulf and Peninsular Province of the Californias, J. Paul Dauphin, Bernd R. T. Simoneit
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The Guaymas Basin in the central Gulf of California is a young spreading center about 1.6-2.1 km deep, which is covered with a thick sequence of sediments. It provides an excellent location to investigate geothermal processes at a sedimented rift using conventional oceanographic heat-flow equipment. Rapid sediment accumulation at this site precludes the formation of “normal” oceanic crust by extrusion; instead, basaltic sills intrude semiconsolidated and unconsolidated sediments, expelling pore water and driving vigorous hydrothermal circulation. Deep-seated heat sources also drive longer-lived convection within and beneath the sediment cover.
The continuous sediment cover has allowed detailed and extensive mapping of the distribution of surface heat flow throughout the Guaymas Basin; more than 400 heat-flow measurements have been collected since 1959 in crust ranging in age from 0 to about 3 Ma. Away from the sites of crustal accretion, the background heat flow throughout the Guaymas Basin is about 180 ± 10 mW/m2. Within the two spreading centers of the basin, known as the northern and southern troughs, heat-flow values range from 0 to nearly 9 W/m2, and variations of two orders of magnitude occur over distances as short as a few hundred meters. Heat-flow patterns generally follow the northeast-southwest structural trend of the central troughs but are locally controlled by recent intrusive activity and associated hydrothermal circulation.
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The Gulf of California is an excellent laboratory for studying sedimentary processes on time scales that are not resolvable in the open ocean. The high biological productivity and the unique physical character of the gulf combine to produce sedimentological processes that preserve annual phenomena. This volume is organized into six sections. Part 1 covers historical exploration of the area. Part 2 includes 5 chapters detailing information contained on the 5 fold-out maps that accompany the volume. Part 3 consists of chapters on regional geophysics and geology. Part 4 covers satellite geodesy. Part 5's seven chapters discuss physical oceanograpy, primary productivity, and sedimentology. Part 6 covers hydrothermal processes.