The conductive and advective heat flow budget across the Gulf of California rift system
A primary control on the geodynamics of rifting is the thermal regime. To better understand the thermal regime of the northern Gulf of California we systematically measured heat-flow across the Wagner Basin, a tectonically active basin that lies at the southern terminus of the Cerro Prieto fault. Se...
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| Format: | doctoral thesis |
| Status: | Published version |
| Publication Date: | 2017 |
| Country: | México |
| Institution: | Centro de Investigación Científica y de Educación Superior de Ensenada |
| Repository: | Repositorio Institucional CICESE |
| Language: | English |
| OAI Identifier: | oai:cicese.repositorioinstitucional.mx:1007/1623 |
| Online Access: | http://cicese.repositorioinstitucional.mx/jspui/handle/1007/1623 |
| Access Level: | Open access |
| Keyword: | info:eu-repo/classification/Autor/Gulf of California Extensional Province info:eu-repo/classification/Autor/Distributed deformation info:eu-repo/classification/Autor/Advective heat transport info:eu-repo/classification/Autor/Golfo de California info:eu-repo/classification/Autor/Deformación distribuida info:eu-repo/classification/Autor/Transporte de calor advectivo info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/25 info:eu-repo/classification/cti/2506 info:eu-repo/classification/cti/250608 |
| Summary: | A primary control on the geodynamics of rifting is the thermal regime. To better understand the thermal regime of the northern Gulf of California we systematically measured heat-flow across the Wagner Basin, a tectonically active basin that lies at the southern terminus of the Cerro Prieto fault. Seismic reflection profiles show sediment in excess of 5 s two-way travel time implying a sediment thickness 5 km. The heat flow profile is 40 km long, has a nominal measurement spacing of ~ 1 km, and is collocated with a seismic reflection profile. Heat flow measurements were made with a 6.5 m Fielax violin-bow probe. Most measurements are of good quality in that the probe fully penetrated sediments and measurements were stable enough to perform reliable inversion for heat flow and thermal properties. We have estimated corrections for environment perturbations due to sedimentation and changes in bottom water temperature. The mean and standard deviation of heat flow across the western, central, and eastern parts of the basin are 220 ± 60, 99 ± 14, 889 ± 419 mW m^-2, respectively. Corrections for sedimentation would increase heat flow across the central part of basin by 40 to 60%. We interpret the relatively high heat flow and large variability on the western and eastern flanks in terms fluid discharge, whereas the more consistent values across the central part of the basin is suggestive of conductive heat transfer. This interpretation is consistent with the seismically imaged pattern of faulting showing faults near the seafloor across the western and eastern flanks of the Basin. Based on an observed fault depth of 1.75 km we estimate the Darcy velocities through the western and eastern flanks at 2 and 8 cm/yr, respectively. |
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