Data Report: dissolved manganese concentrations in Deep Drill Holes off New Zealand (ODP Leg 181)

Abstract

During Leg 181, seven locations (Sites 1119-1125) were drilled off the eastern coast of New Zealand. Although the sites were primarily targeted to reconstruct the stratigraphy and paleoceanography of the region (Shipboard Scientific Party, 1999), they are particularly interesting from a geochemical perspective because, as clearly evidenced by shipboard pore water and gas analyses, recovered sediment cores span an exceptional range of chemical environments. Pore water alkalinity, NH4+, SO42-, and PO43- concentrations, as well as headspace CH4 concentrations, indicate significant differences in sediment redox conditions across the region (Shipboard Scientific Party, 1999). The distribution of solid and dissolved manganese plays an important role in geochemical interpretations of such sedimentary environments (e.g., Froelich et al., 1979; Thamdrup and Dalsgaard, 2000). Dissolved Mn2+ concentrations of pore waters at four sites (1119, 1122, 1123, and 1125) drilled during Leg 181 are presented in this report.