COLD SEEPS AND HYDROTHERMAL VENTS SYSTEMS ON THE GUAYMAS BASIN, GULF OF CALIFORNIA, MÉXICO

The Gulf of California is an extraordinary laboratory of all geologic knowledge areas, in this place it’s possible to study the structural process that give origin to this new ocean, as well as hydrothermal activities and cold seeps released over the diverse basin on the gulf. The Guaymas Basin is one of the principal place for study those process, it is located on the central part of The Gulf of California in front of the Guaymas Bay, here two long grabens in an overlapping structure produces the continental crust thinning. The NE end of the Northern Rift is the over the south end of The Guaymas Transform Fault (T.F), being this the region covered in our study. In the middle of 80’s a few research cruise where dedicated to study this basin, discovering the emanation of bubble plumes on both rift, as well as on the escarpment of the Guaymas T.F. They determinate the presence of hydrothermal vents over the rift systems and a cold seeps system over the Guaymas F.T.; however at that time there no positioning and navigation systems as precise and accurate as exist today, as well, geophysical equipment used are of low resolution compared to those used today. It represents a big uncertainly for location of those seeps sites, especially because the hole of the seep is not bigger than 30 cm (11 ft). In our investigation we used a new technology on multibeam echo-sound, available on the NO L’Atalant, during BIG10 campaign on 2010; it is multibeam images of water column taking by the EM122. It allows you to know the localization of the seeps and its physical characteristics creating a catalogue of the active plumes raisin on the northern part of the Guaymas Basin. This data was correlated with the bathymetric chart and 19 seismic reflection profiles of high resolution taking during campaign GUAYRIV10 on boar BO El Puma. We found two plumes system on the basin, one of those correspond to the cold seeps on the Guyamas F.T. where it lift the stratigraphy of basin on a big escarpment, where the methane hydrate is exposed liberating the hydrocarbon bubble plumes. And other disperse group not reported before located on the margins of Northern Rift, that seems to be associated to the thermal activities on the rifting process, and the normal faults works as a release mechanism. It was impossible to locate the vents reported on the Northern Rift maybe because it was extinct