Abstract: Interior Structure of Oak Grove Ridge Chenier, Louisiana

Ricky P. Gremillion, Michele Matthews, William R. Paine

A chenier is an elongate sand body representing the remains of a stranded beach that grades both landward and seaward into bottom sand and silt and marsh deposits.

The Holocene Oak Grove Ridge cheniers are composed of, from top to bottom: (1) highly organic silt or clay; (2) an oxidized, limonitic, fine to medium sand with irregular patches of organic material composed primarily of decayed roots; (3) markedly oxidized, limonitic sand and shelly sand with ripple marks, cross-bedding, cut-and-fill structure, and thin clay laminae; and (4) a unit composed of shell beds alternating with silty sand. The units are separated vertically by diastemic breaks and probably would form separate reservoirs within each sandy unit. Both along trend and transversely, these units grade into highly organic silty clay and massive clay. Because of these facies changes, the sand bodies have the potential of becoming excellent stratigraphic traps for hydrocarbons.

Effective porosity and permeability are basically parallel with the trend of the chenier rather than its dip, which would be the normal dip direction in the Gulf Coast.

AAPG Search and Discovery Article #90967©1977 GCAGS and GC Section SEPM 27th Annual Meeting, Austin, Texas