New structural and geochemical observations from the Pacific-Antarctic Ridge between 52°45′S and 41°15′S

We investigated the morphology and structure of the Pacific-Antarctic Ridge between 52 degrees 45'S and 41 degrees 15'S during the Pacantarctic2 cruise using multibeam echosounder together with gravity measurements and dredges. Analysis of the bathymetric, gravity and geochemical data reveal three ridge segments separated by overlapping spreading centers south of the Menard transform fault (MTF) and five segments north of it. Calculation of the cross-sectional area allows quantification of the variation in size of the axial bathymetric high. Together with the calculation of the mantle Bouguer anomaly, these data provide information about variations in the temperature of the underlying mantle or in crustal thickness. Areas with hotter mantle are found north and south of the MTF. Geochemical analyses of samples dredged during the survey show a correlation of high cross-sectional area values and negative mantle Bouguer anomalies in the middle of segments with relatively less depleted basalts.