Carbonate mineralogy and carbonate content were determined on 65 samples from Sites 1244-1252, which were drilled on southern Hydrate Ridge and in an adjacent slope basin at the Cascadia accretionary prism. X-ray diffraction analyses data indicate varying carbonate compositions. Pure calcites are rare but were found at Sites 1246 and 1252. Low- and high-magnesium calcites are the dominant carbonate mineralogies and occur at all sites. The presence of dolomite is characteristic for the slope basin sites. The sampling depth of the carbonates varies from near seafloor to deep within the accretionary complex, suggesting different modes of carbonate formation. The summit, flank, and slope basin sites show characteristic carbonate compositions with different carbonate contents in distinct depth intervals.

Supplement to: Teichert, Barbara M A; Bohrmann, Gerhard (2006): Data report: Composition of authigenic carbonates in sediments of the Cascadia accretionary prism, ODP Leg 204. In: Tréhu, AM; Bohrmann, G; Torres, ME; Colwell, FS (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 204, 1-8