Sediment cores depth-time profiles

The Cd/Ca quotient of benthic Foraminifera sampled from core tops (diamonds) and from the sediment depth of the last glacial maximum (circles) of eight cores from the North Atlantic at different vs ter depths. The difference in depth dependence illustrates the different profiles of dissolved cadmium in the North Atlantic at these times. Reproduced from Broecker (2002) as derived from the data in Boyle and Keigwin (1987). 

From the 137Cs profile of the core (Fig. 3 A), three time markers can be derived The beginning of the nuclear weapon tests (1952) in the depth interval from 92-96 cm, the culmination of the nuclear weapon tests (1963-64) in the depth interval from 52-56 cm and the Tschemobyl reactor accident (1986) in the top four cm. This implies, however, that the last 16 years are missing in the core. This may be due to either partial erosion of the sediment or infrequent occurrence or absence of flooding events during the past decade. From the three time markers a mean sedimentation... 

We evaluated the ages of every layer by virtue of the depth and sediment rate. From bottom to surface, the core sample was deposited from 1914 to 2004 with about 6 years interval at every layer. Fig. 3.74 showed the vertical profile of EPAHs varying with depth and time. In general, EPAHs decreased with depth... 

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