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doi:10.2204/iodp.proc.339.201.2016

Methods and materials

Sites U1385 (37°34.285′N, 10°7.562′W; 2578 meters below sea level [mbsl]) and U1391 (37°21.5322′N, 9°24.6558′W; 1080 mbsl) were drilled on the West Iberian margin as part of Integrated Ocean Drilling Program Expedition 339 (see the “Expedition 339 summary” chapter [Expedition 339 Scientists, 2013]). CaCO3 and TOC contents were determined for a total of 195 levels between 75 and 100 mcd at Site U1385 and 225 levels between 160 and 220 mcd at Site U1391 (Tables T1, T2).

The 2 cm3 sediment samples from each level were dried and then powdered and homogenized on a Fritsch Pulverizette 7 rotary mortar. Three replicates of 2 mg subsamples per level were then analyzed for total carbon using a CHNS-932 LECO elemental analyzer. The same set of samples was later subject to combustion for 8 h through a predefined stepwise increase in temperature up to 400°C and reanalyzed for inorganic carbon. The organic carbon content was determined by the difference between total carbon and inorganic carbon (TOC = TC – IC). Data are presented in weight percent. The relative precision of repeated measurements of both samples and standards was 0.03 wt%. Analyses were done in the sedimentology and micropaleontology laboratory of the Marine Geology Division at the Portuguese Institute for the Ocean and Atmosphere (IPMA).