RESULTS

Analytical results for salt (% Cl), and salt-corrected minor and trace element concentrations are listed in Table 1. To clarify the origin of each element, the enrichment factors relative to "average crust" (Taylor and McLennan, 1985; Fig. 2) and the relationships between element depth profiles and lithofacies (Fig. 3, Fig. 4, Fig. 5) are examined. Enrichment factor is defined as

.

Re and U are highly and moderately enriched, respectively, relative to "average crust" (Fig. 2). Concentrations vary by up to a factor of 7 over the sampled section, with the highest values occurring between 40 and 170 cmbsf and 220 and 240 cmbsf during MIS 1, and between 340 and 390 cmbsf during MIS 2 (Fig. 3A). The U distribution is similar to that of Re, and concentrations vary by up to a factor of 3 (Fig. 3A). Mo and As are moderately and highly enriched, respectively (Fig. 2). Mo maxima occur between 150 and 300 cmbsf during MIS 1, and at 390, 450, and 500 cmbsf during MIS 2. Concentrations vary by as much as a factor of 8 (Fig. 3B). Arsenic shows a similar fluctuation, missing only the distinct maximum at 150 cmbsf (Fig. 3B), which is more closely related to fluctuations in pyrite abundance (Fig. 3C; Tada et al., Chap. 25, this volume), and values vary by up to a factor of 7. Profiles of all four of these elements tend to show maxima where C_carb and/or C_org (Tada et al., Chap. 25, this volume) are relatively enriched (Fig. 3C, D).

The depth profile of Sr resembles that of C_carb (Fig. 3D). Although the element is not significantly enriched relative to average crust (Fig. 2), it does exhibit a clear maximum of ~400 ppm at 220 cmbsf (Fig. 3D). The Sr content varies by a factor of only 1.5 over the course of the section.

Zr, Nb, Ba, Y, and Cr are equal to or are enriched relative to "average crust" (Fig. 2). All sand patches and layers are associated with the maxima of some or all of these elements (Fig. 4). These elements also show minima at 220 cmbsf where carbonate carbon shows a maximum (Tada et al., Chap. 25, this volume). Zr and Nb contents vary downcore by a maximum factor of 4, whereas Ba, Y, and Cr vary by up to a factor of 1.5. The average concentration of Cr during MIS 1 is slightly lower than that during MIS 2.

V, Ni, Cu, and Zn are enriched relative to "average crust" (Fig. 2). Concentration minima occur in sand patches and layers, and concentrations overall vary over a two-fold range (Fig. 5A, B). Average contents of V and Ni during MIS 1 are approximately the same as those during MIS 2, whereas average levels of Cu and Zn during MIS 1 are higher than those during MIS 2. Mn and Rb are slightly depleted and enriched, respectively, relative to "average crust" (Fig. 2). Mn, Rb, and Ti also show minimum concentrations within sand patches and layers (Fig. 5C, D). The average Mn content during MIS 1 is lower than that during MIS 2. Each of these seven elements shows a minimum at 220 cmbsf corresponding to the carbonate carbon maximum.

Co and Pb contents are approximately equal to those in "average crust" (Fig. 2). Because the amplitudes of variations in these elements are comparable to analytical error, characteristics of their profiles are hard to describe. Thus, these elements will not be mentioned further in this report.