Figure F5. Comparison of downhole variations of abundances of lithologic components by smear-slide (% area), coulometry (calcium carbonate), and XRD (opal) estimates. Percent terrigenous sediment is estimated by difference. Frames from left to right: coulometric and smear-slide estimates of carbonate abundance (nannofossils + foraminifers on smear slides); opal and diatom abundance; mud and terrigenous sediment content; quartz/feldspar; clay minerals/(quartz+feldspar); and stratigraphy. Qz = quartz, Fsp = feldspar, CM = clay minerals.