Résumé
Integrated Ocean Drilling Program Expedition 313 recovered siliciclastic sediments from three holes cored through a series of Miocene clinoforms offshore New Jersey. The clinoform sequence that lies between seismic reflectors m5.2 and m4.1 has been dated as mid-Miocene within an interval of major climatic change and displays interesting sedimentological and petrophysical features. However, the depth ties between surfaces in the recovered succession and seismic reflectors, correlation across sites, and depositional environments are not all well defined in this interval. Additionally, features observed in the two more proximal boreholes are absent from the most distal borehole. This report presents X-ray fluorescence (XRF) measurements from scanning the split surface of archive sediment cores and from individual core samples from Holes M0027A, M0028A, and M0029A. Major trends are identified and described, aided by statistical analyses (correlation coefficient matrix plots and principal component analyses). Si/Al and Zr/Rb ratios and, to a lesser extent, Th correspond with changes in the ratio of clay minerals to quartz. In the most proximal Hole M0027A, an alternating sequence of dark and light bands in an extended sequence of clays is characterized by distinctive high and variable magnetic susceptibility and equivalently variable Fe/S ratios. A similar sequence is observed in Hole M0028A, with both sequences located above the inferred m4.1 seismic sequence boundary. Redox elements in this interval are highly variable and suggest the influence of postdepositional processes. In Hole M0029A, despite an expanded sequence, similar characteristics are absent from the clay sequences, which are also geochemically more homogeneous. The analyzed geochemical compositions are compared with sedimentological observations and petrophysical analyses before discussing in their wider context.