The thermal regime of the Gulf of California, rifting processes and the ocean-continent transition

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The Gulf of California formed when continental crust rifted apart and seafloor spreading began. The focus of this project is to obtain a better understanding of the processes involved in the initial rifting of the Gulf and its subsequent evolution. During this project heat flow measurements will be obtained on a research cruise in the Gulf of California. The sea-going expedition is part of a funded Mexican research effort to understand the geothermal regime in this region. Variations in heat flow measurements will be correlated with the observed style of rifting to understand how rifting transitions to seafloor spreading as opening continues, a fundamental process that is still poorly known. The study includes strong collaboration with Mexican colleagues and allows acquisition of and access to a unique new heat flow dataset. The regional tectonic history and the structure of the Gulf of California are well understood from plate reconstructions, geologic relationships, recent swath mapping and seismic data. Less well understood are processes associated with rifting and those that have led to observed variations in rifting style and the ocean-continent transition. A key to this understanding is observational constraints on the thermal structure of the Gulf. The principal science goals of this project are to 1) characterize the background conductive heat flux through the thickly sedimented basins in the northern and central Gulf and thinly sedimented basins in the southern Gulf; 2) determine the pattern and magnitude of hydrothermal circulation and differences between the thickly and thinly sedimented basins of the northern and southern Gulf, respectively, and that associated with magmatic sills intruding sediments; and 3) link these observations to styles of rifting and the ocean-continent transition. These goals will be achieved through the integration of new heat flow data with previously collected data and modeling.