archives@tulane.edu / Salt basins are complex structural systems, showing genetic relationships between salt structures, faults, and variable sediment depositional patterns. The dynamics of salt-fault interaction, the role of shale deformation, and the influence of salt evacuation on surface features have been poorly understood. A link between all these processes is the throw history of faults adjacent to and within a salt basin. In this dissertation, I interpret industry well logs and 3D seismic data from the Terrebonne Salt Withdrawal Basin (TSWB) of southeastern Louisiana, to understand these processes. The methodology includes the use of fault throw maps, throw variations along strike and with depth, and sediment expansion indices to understand fault kinematics adjacent to sediment loads and mobile material, i.e., salt or shale. I address the histories of three faults along the northern margin of the TSWB: the Lake Boudreaux, Montegut, and Isle de Jean Charles faults. Each shows Miocene and Quaternary active phases correlated with sediment loading, separated by relative inactivity during the Pliocene. The pattern of Quaternary activity and the surface projections of these faults are consistent with a fault-controlled pattern of wetland loss, suggesting that faults in southeastern Louisiana are active. Isle de Jean Charles fault and the Lake Boudreaux fault interact with the Bully Camp and Lake Barre Salt stocks, respectively. Each stock is interpreted to have grown by a different diapiric mechanism, consistent with different spatial patterns of throw variation on the two faults, despite similar temporal histories. Throw on the Isle de Jean Charles fault increases towards the Bully Camp stock, suggesting deformation inside and outside the stock. In contrast, a decrease in the throw on the Lake Boudreaux fault and an increase in diameter of the Lake Barre stock indicate that deformation exists only within the stock. Additionally, this dissertation considers throw patterns along the southern margin of the TSWB, showing that faults linking the Dog Lake and Caillou Island salt stocks are affected by shale deformation adjacent to salt. These results show that studies of fault-related subsidence and wetland loss in coastal Louisiana need to include observations from nearby salt structures. / 1 / Akinbobola Akintomide

<p>The modern coastline provides few clues as to the ancient harbour configuration since Kalamianos has been partially submerged by > 6 m of relative sea-level rise since the Early Helladic. In 2009, a detailed marine geophysical survey and underwater diver search was conducted in the inshore waters to identify potential anchorage sites and to examine evidence for coastal subsidence. Single-beam bathymetry and magnetic gradiometer data were acquired and integrated within a detailed digital bathymetric model (DBM).</p> <p>The DBM revealed two submerged beachrock platforms (BR-1, BR-2) paralleling the modern shoreline and a submerged isthmus connecting the mainland with small island 200 m offshore. The BR-1 platform (3.5-3.7 m depth) contained abundant Late Helladic (LH; 1300-1190 BC) pottery sherds (30-50%) and wood charcoal fragments.¹⁴C dating of the extracted charcoal yielded an AMS ¹⁴C uncalibrated age of 3250±40 BP, consistent with the LH ceramics. The BR-2 platform (5.8-5.9 m depth) contained less pottery (<20%) and included well-preserved fragments of Early Helladic (EH) jars.</p> <p>The beachrock elevations and ¹⁴C and pottery ages were used to reconstruct a sea level curve and a series of paleogeographic maps of the EH to LH shorelines. The presence of abundant pottery and wood charcoal in the BR-1 beachrock indicates that shipping activity during the LH was focused at the south end of the site in a western harbour basin. This is supported by magnetic gradiometer results, which identified several magnetic anomalies in the western harbour basin. These were investigated by diver search and found to be concentrations of ship ballast stones (mainly andesite) and clay pottery.</p> / Master of Science (MSc)