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doi:10.2204/iodp.proc.311.205.2009

Results

Analysis of grain size distributions

All results are shown in Table T1. Mean grain size is ~10 µm and ranges from ~5 to ~20 µm. Figure F3 represents the relationships of mean grain size for each sample at each site with depth and porosity. There is no relationship between them.

Kurtosis is ~16 on average and ranges from ~4 to ~44 (Table T1). Skewness is ~3.2 on average and ranges from ~1.8 to ~5.4 (Table T1). Figures F4 and F5 show their relationships with depth and porosity. It is difficult to find a trend in the relationships.

Exponential-R is ~0.957 on average and ranges from 0.83 to 0.996. Power-R is ~0.939 on average and ranges from 0.816 to 0.999. Figures F6 and F7 show their relationships with depth and porosity. There are not any relationships between them. However, there is a relationship between exponential-R and power-R (Fig. F8). Samples with higher exponential-R values have lower power-R values. The opposite is also true.

Those statistical parameters should indicate the characteristics of grain size distribution. They have, however, no relationships with depth and porosity on the whole.

Occurrences of grains in thin sections

Samples can be classified by exponential-R or power-R because they represent the opposite values in each sample. Therefore, samples were classified into three types: high exponential-R, high power-R, and others. After reexamination of the occurrences of grains on the basis of this classification, some different characteristics in the occurrences are found with the classification.

Figure F9 shows the occurrences of grains in samples with higher exponential-R values and lower power-R values. Grain size is homogeneous. This homogeneous grain size can make the exponential distribution. The grains are relatively isolated with larger areas of matrix. The grains are relatively rounded. Cracks in the grains are very rare.

Figure F10 represents the occurrences of grains in samples with lower exponential-R values and higher power-R values. The grains show variations in their sizes. The shape of grains is relatively angular to subangular. Spaces between grains are smaller than those of the samples with higher exponential-R values, which indicates denser packing. Cracks within the grains are found in some places. Higher power-R values indicate that the grain size distribution is fractal. The distribution is the same as that within the web structure reported by Hashimoto et al. (2006).

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