Formation microscanner imagery of Lower Cretaceous and Jurassic sediments from the western Pacific (Site 801)

Abstract

Ocean Drilling Program Leg 129 recovered Jurassic and Lower Cretaceous clayey radiolarite in Hole 801B in the Pigafetta Basin of the western equatorial Pacific. Two runs of the formation MicroScanner logging tool provided high-resolution downhole imagery of relative resistivity at this site. The processed images enabled continuous observation at approximately 1-cm vertical resolution of variations in clay and radiolarian content, of discontinuities in sedimentation, of the degree of silicification, of nodularity of porcellanite and chert, of bedding thickness and spacing, of cyclic sedimentation exhibiting Milankovitch climatic periodicities, and of the dip of structures. -from Authors