Site 1044

Abstract

Principal results: Drilling at Site 1044 penetrated through 685 m of sediment to basaltic basement of the North American Plate at 6 km east of the frontal thrust of the northern Barbados accretionary prism. LWD acquired gamma-ray, resistivity, density, caliper, photoelectric effect, and neutron porosity logs in the hole ( Fig. 1; also see Fig. 2 [back-pocket foldout, this volume]). Excluding neutron porosity, all logs are of good quality because of an in-gauge hole. Ninety-nine percent of the hole had differential caliper measurements of <1 in, and 94% measured <0.5 in. The density log mimics both the character and values of density measurements made from cores, further indicating log reliability (Fig. 12). Both traditional visual and multivariate statistical analyses of the logs define six log units that account for the majority of the lithologic variation observed in the cores (Fig. 9). This profile of log properties specifies the nature of the incoming sedimentary section and correlates well with the 3-D seismic survey and with Site 672, which is located ~35 m from Site 1044. This core-log-seismic data suite provides an unparalleled reference for analysis of the evolution of the accretionary prism to the west.A decrease in density, resistivity, and gamma ray on the logs from 169 to 189 m below seafloor (mbsf) defines log Unit 2, which correlates well with a structurally defined proto-décollement zone (Fig.