Mineralogical and geochemical study of mud volcanoes in north Moroccan atlantic margin

Abstract

The gulf of Cadiz is one of the most interesting areas to study mud volcanoes and structures related to cold fluid seeps since their discovery in 1999. In this study, we present results from gravity cores collected from Ginsburg and Meknes mud volcanoes and from circular structure located in the gulf of Cadiz (North Atlantic Moroccan margin) during the cruise TTR14 in 2004 on board of the R/V Logachev. The clay mineralogical analysis by XRD shows a difference in clay mineral amounts mainly in smectite between the different studied structures. Ginsburg MV shows high percentage of smectite with an average of 44% whereas Meknes MV displays illite rich clay association, smectite average percentage is about 16%. In circular structure, amount of smectite is about 13%. This variation in clay mineralogy association between the mud volcanoes suggests different nature and depth of parent layers and fluids feeding the mud volcanoes in gulf of Cadiz.

Key word: Mud volcano, clay mineralogy, geochemistry, mud breccias, North Moroccan Atlantic margin.