Figure 34. Interpretative summary diagram for Site 1139 showing 19 igneous units, which range from basalt to rhyolite, together with rudstone and volcaniclastic breccia. All units are highly altered, which obscures the primary vesicularity of the lava flows and marginal breccias. Sanidine xenocrysts are distributed throughout the more mafic flows. Although changes in potassium concentration from downhole natural gamma measurements correlate generally with the defined igneous units, the logging data show more complexity, indicating unrecovered changes in lithology.