Micropalaeontology of the hydrothermal region in the Guaymas Basin, Mexico

摘要: Abstract. A micropalaeontological analysis of 40 sedimentary samples from a hydrothermal region in the Guaymas Basin, Gulf California, Mexico, was carried out to describe microenvironments. These microenvironments were defined through Q-mode Factor species abundance data benthic foraminiferal biocoenoses and thanatocoenoses. The results correlated with biogeographic patterns diatoms, radiolarians, planktonic foraminifers ostracods ‘graphic-multivariate analysis’. Although have patchy distribution within region, it is possible define following: (1) ‘hydrothermal environment’, which foraminifera Bulimina mexicana Globocassidulina sp. cf. C. subglobosa coexist mollusc Calyptogena pacifica, even though almost direct influence fluids drastically reduces presence microfauna; (2) ‘bacterial Trochammina Recurvoides are associated bacterial mats; (3) ‘cool further influence. In this microenvironment spinosa, Bolivina seminuda Cibicides common. three assemblages different other live Basin but not influenced by fluids. non-hydrothermal regions, Uvigerina peregrina Buliminella tenuata subsurface shows same as superficial samples.