Research presented herein shows the derivation of a uniquely determined linear inversion model of downhole logging data that accurately predicts lithologies through most Leg 150 logged intervals. Five lithologic end-members, consisting of terrigenous (quartz, albite, and microcline), opaline (opal-A and opal-CT), calcareous (aragonite and calcite), argillaceous (all clay and mica minerals), and "heavies" (siderite and pyrite) compositions, were modeled. Modeling results abide by theoretical constraints, match semiquantitative X-ray diffraction analyses to within 10%, and closely approximate sedimentologist's descriptions of recovered cores. Modeling results complete the lithologic characterization of the sediments drilled during Leg 150 by providing compositional estimates for intervals with incomplete core recovery, as well as additional high-resolution (0.33 m) petrologic estimates and insight to subtle lithologic variations not readily apparent to sedimentological observation.
Modeling results show important stratigraphic information regarding the lithologic nature of sequences on the New Jersey slope. For example, modeling results highlight dissimilar lithologic compositions among coeval sediments from different mid-slope sites as well as the presence of lithologic cycles within previously defined sequences. Results indicate the upper and middle slope is a dynamic system with heterogeneous deposition and differential erosion. Integration of available biostratigraphic data indicates these processes may be influenced by forces operating on frequencies correlative to glacioeustatic forces as far back as the middle Eocene.
Date of initial receipt: 17 February 1995
Date of acceptance: 29 August 1995
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