Geochemistry of Miocene \"blue tuff\" samples

Distinctive, massive to stratified, pale blue volcaniclastics, initially referred to as the \"blue tuff,\" were encountered at all four sites drilled during ODP Leg 127 in the Japan Sea. Detailed vertical sequence analysis, plagioclase chemistry, plagioclase 87Sr/86Sr isotopic composition, and 40Ar/39Ar age dating indicate that thick sequences of the blue tuff are not genetically related. […]