ABSTRACT

Mineralogical studies of continental shelf sediments have been made off the northeast coast of the United States between Hudson and Veatch Canyons. Mineral data of the sand fraction of 36 grab samples indicate that a garnet heavy mineral association and soda-lime feldspar light mineral association lie west of Block Channel; a mixed garnet-amphibole association is identified with this Channel; and an opaque heavy minerals association, an amphibole association, and a potash feldspar light mineral association occur east of Block Channel. Further, the garnet and soda-lime feldspar associations and the opaques and potash feldspar associations may portray two sedimentary petrological provinces for the region.

The character of these petrological provinces is believed to be the result of a change in composition of the coastal rocks from Massachusetts to the Hudson River, but the genesis of the amphibole association remains in doubt. Opaque minerals association sediments appear to have been dispersed toward the south from southeastern Massachusetts and there is evidence of an eastward-moving longshore drift near the shelf edge at a time when sea level was lower.

The depositional sequence of the heavy mineral associations indicates that the amphibole-garnet (mixed) association is younger than the basal garnet and opaque minerals associations. However, the amphibole association, is also younger than the opaques association, but more recently reworked sands of opaques association derivation have migrated over both amphibole association and basal opaques association sands.