Grain shape, surface texture, and mineralogic analyses were conducted on the Pleistocene and Holocene sands of the northeast Gulf of Mexico shelf and the Mississippi fan to determine their sources. Two distinct petrologic provinces of sand are present in this area: the Mississippi province, characterized by spherical quartz grains derived from older strata in the drainage basin of the Mississippi River, and the eastern Gulf province, characterized by a mixture of spherical and elongate quartz grains. The former is derived from Cretaceous and Tertiary coastal plain strata; the latter is derived from sedimentary and crystalline rocks of the southern Appalachian Mountains.

Sand distribution patterns of these two provinces on the northeast shelf are distinct; Mississippi province sands are found in the western part of the shelf near the Mississippi delta, while Eastern Gulf province sands are found throughout the remaining parts of the shelf. However, sands of the Mississippi fan are a mixture of Mississippi and Eastern Gulf province sand. Glacial sand is uncommon in both the Holocene and Pleistocene deposits of the Mississippi province.

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