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doi:10.2204/iodp.proc.308.205.2008

Results

We conducted particle size distribution curves for 340 samples at Penn State and MIT. Sand, silt, and clay percentages are given in Table T1 for Site U1322 and in Table T2 for Site U1324. Data sheets and curves similar to Figures F4 and F5 for each sample are available in Excel format in “Supplementary material.”

We plot the downcore profile of percent sand, silt, and clay against gamma ray and resistivity logs for Sites U1322 and U1324 in Figures F6 and F7, respectively.

We plot sand, silt, and clay percentages for all samples from both sites on a single classification chart in Figure F8. In Figure F9, we plot results for Sites U1322 and U1324 separately. Nearly all samples from Site U1322 plot as silty clay, whereas samples from Site U1324 are scattered in a wide range in both silty clay and clayey silt fields. The four sand samples are from Site U1324 (~305 mbsf) (Fig. F7).

From our particle size analyses of the Ursa Basin samples, we define two characteristic lithologies: silty clay and clayey silt. Silty clays are generally composed of ~60% (±10%) clay-sized particles by weight, ~40% silt-sized particles by weight, and <1% sand-sized particles by weight. Ursa Basin clayey silts are generally composed of ~65%–70% silt-sized particles by weight, 30% clay-sized particles by weight, and 0%–5% sand-sized particles by weight.

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