Glauconite at the New Jersey margin was studied by Harris and Whiting (2000) and by Hesselbo and Huggett (2001). Glauconite is generally inferred to correspond to shelf to upper slope settings characterized by low rates of sediment accumulation and times of marine flooding. This is borne out by Leg 174A data, although glauconization ceased in the Pliocene-Pleistocene at slope Site 1973 (Harris and Whiting, 2000). In deepwater settings, the concentration of glauconite pellets in burrows indicates in situ formation (Hesselbo and Huggett, 2001). Glauconite is associated with quartz sand only in proximal deepwater strata. The high degree of fragmentation and presence of ooidal glauconite around mature pellets or pellet fragments in shallow-water settings suggests reworking or transportation after deposition. The relative roles of physical and biogenic processes in this reworking is unknown.
The clay fraction of shelf sediments at Sites 1071 and 1072 is composed of variable proportions of chlorite, smectite, kaolinite, vermiculite, and mixed-layer clays (Vanderaveroet, 2000). Miocene and Pliocene climates permitted the development of vermiculite and kaolinite, whereas Pleistocene clays are characterized by abundant chlorite and illite from glacial erosion of crystalline crustal rocks at least during the past 550 k.y.