This study describes molecular organic geochemical investigations of 14 samples from Site 903 off New Jersey, as well as bulk analysis of a great number of sediments from Sites 903 and 905. Detailed lipid analysis of the solvent-extractable organic matter exhibits a complex assemblage of marine, terrigenous, and bacterial compounds. rc-Alkanes and n-alcohols are the most abundant compounds in extracts of sediments from Site 903, followed by steroidal alcohols in considerably smaller concentrations that decrease with depth. Analysis of long-chain unsaturated ketones for reconstruction of paleo-sea surface temperature results in an average water temperature estimate of 25°C since the middle Miocene. The results indicate continuous supply of terrigenous organic material to the region with occasional conditions of better marine organic matter preservation, particularly in Oligocene to middle Miocene times. Some variations in organic matter composition may be caused by sea-level changes. A warm current analogous to the present Gulf Stream appears to have existed off New Jersey at least since the Oligocene.

This paper reports the genetic links among the depth distribution, mineralogy, and stable isotopic composition of diagenetic carbonates with sedimentation rates and types and preservation of organic matter in the terrigenous and biogenic sediments of Oligocene and Miocene age on the New Jersey slope. Calcites formed close to the sediment surface at sequence boundaries and maximum flooding surfaces, when the profile of early-diagenetic reactions was stabilized in the sediment column for extended periods. Dolomites precipitated in the sulfate reduction zone when diagenetic profiles stabilized during truncation, sequence boundary formation, and the deposition of lowstand sediments that overlie the sequence boundaries. Most dolomites occur in distal slope sediments that were deposited before the shelf had prograded into the study area. Siderites formed during a later stage of burial in the methanogenic zone; they are not directly genetically related to the sequence stratigraphy of the New Jersey slope. The diagenetic dolomites and siderites occur in widely separated depth intervals below the present sea floor. The distribution of the diagenetic carbonates and their preferential occurrence in separated depth intervals resulted from different combinations of sedimentation rates and organic matter types and preservation. Fig. 8 Large calcite nodule or thin layer from glaucony-rich mudstone right above the Pliocene/Upper Miocene boundary (unconformity p6). Large burrows and surrounding sediment were differentially impregnated by carbonate. 356.55-356.725 mbsf (Hole 903 A, Core 41, Section 01, 85-102.5 cm)

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