INVESTIGATING THE RELATIONSHIP BETWEEN TECTONICS AND LAND LOSS NEAR GOLDEN MEADOW, LOUISIANA BY UTILIZING 3D SEISMIC AND WELL LOG DATA

Land loss is one of the greatest environmental and economic threats in the deltaic plains of the Gulf Coast. Land loss is controlled by subsidence and sediment flux from the Mississippi River delta complex, movement along growth faults, salt tectonics, fluid extraction and compaction related to oil, gas and water exploration. However, the interplay and feedback between these different processes are still poorly understood.

In this study, we investigate the role of active faulting and salt tectonics on land loss by focusing on the Golden Meadow fault zone, an area located in the coastal marshes of southern Louisiana. Using 3D seismic and well log data, we investigate key structural features, such as segments of the Golden Meadow fault zone and the Leeville salt dome, in conjunction with areas of wetland loss and subsidence.

Faults were mapped to a depth of 4,000 ft, and well logs were tied to the upper 600 ft of the seismic data to make accurate projection of the faults to the surface. Preliminary results highlight a graben structure south of a segment of the Golden Meadow fault. Well log data reveals a thicker accumulation at the center of the graben up to 150 ft thicker than the shoulders of the graben. The location of the graben also coincidently correlates with Catfish Lake. Bayou Lafourche, a part of the Lafourche lobe of the Mississippi River delta complex, appears to flow along a major growth fault. Bayou Lafourche shifts direction in conjunction with two radial faults of the Leeville salt dome. These preliminary data indicate that there is a relationship between surface geomorphology and subsurface structures, suggesting that active tectonics exert a control on land loss in southern Louisiana.