Factors affecting the diagenesis of Quaternary sediments at ODP Leg 172 sites in western North Atlantic: evidence from pore water and sediment geochemistry


Cagatay M. N. , BOROWSKI W., TERNOIS Y.

CHEMICAL GEOLOGY, cilt.175, ss.467-484, 2001 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

Pore waters and Quaternary sediments at ODP Leg 172 sites on the Carolina Slope (CS; Site 1054), Blake Outer Ridge (BOR. Sites 1057 and 1060), Bahama Outer Ridge (BAOR; 1062) and Bermuda Rise (BR, Site 1063) were studied. The sediments are mainly clayey and silty mud with intercalations of nannofossil-rich and lutite-rich beds towards the top. Sedimentation rate ranges from 4.2 cm/ky at Site 1054 to 23 cm/ky at Site 1060. Average total organic carbon (TOC) contents of the upper sediment units range from 0.40% to 0.58% at Sites 1057, 1060, 1062 and 1063, and from 0.86% to 1.25% at Site 1054. The organic matter at all the sites is mostly degraded, except at Site 1054. Sediments at Sites 1062 and 1063 have lower total sulfur (TS) (0.00-0.62%; average: 0.06%) than those at the other sites. Site 1054 has the highest TS (0.8-1.4%) and the lowest reactive iron (0.003-0.074%) contents among all the sites.