Nature of the Salt-Clastic Sediment Interface Over Weeks Island Salt Dome, Louisiana Using Shallow Imaging 2-D Seismic Data and Well Log Data <p> HR: <span class="hr"> 09:30h<br></span> AN: <span class="an"> NS21A-05 <a href="../absbook/sm05_NS21A.html">[Abstracts]</a><br></span> TI: <span class="ti"> Nature of the Salt-Clastic Sediment Interface Over Weeks Island Salt Dome, Louisiana Using Shallow Imaging 2-D Seismic Data and Well Log Data <br></span> AU: <span class="au"> * Kinsland, G L<br></span> EM: <span class="em"> glkinsland@louisiana.edu<br></span> AF: <span class="af"> Energy Institute, University of Louisiana at Lafayette, 635 Cajundome Blvd., Lafayette, LA 70506 United States <br></span> AU: <span class="au"> Rutter, B W<br></span> EM: <span class="em"> grindog@aol.com<br></span> AF: <span class="af"> Rutter and Wilbanks, 301 S. Main St., Midland, TX 79701-5211 United States <br></span> AB: <span class="ab"> Shallow-imaging surface-sourced 2-D seismic data on the flank of Weeks Island, Louisiana yielded what has been termed a 7000 ft/s refraction layer 50 to 100 ft below the surface and a strong 100 ms (too shallow to be top of salt) locally continuous reflection as well as areas with no strong reflector. A geophysical well-log near the line of the seismic data indicates that there is another density discontinuity about 130 ft above the salt and the driller's log reported increased chlorides at this level. Near the apex of the dome a shallow-imaging survey performed by a crew from the Kansas Geological Survey and the University of Kansas located a well-defined top of salt reflector. Model calculations and geological arguments indicate that the 7000 ft/s refractor and the strong reflector result from a layer of salt cemented clastic sediments above the top of salt. Dissolution of the salt by groundwater flowing down the flank of Weeks Island disrupts the salt sediment interface creating rugosity that destroys coherent reflections, leads to karstic collapse on the island which breaks up the reflector, has led to the topography of the island and has at times and in places led to deposition of salt within the clastic sediments which has created the reflector. At the top of the dome these processes are not as active, because of the lesser flow of water, and the salt clastic sediment interface remains much better defined. We were not able to image the top of salt in our area of interest. Therefore, Morton Salt Co., for whom we performed this study, remained uncertain of the safety of mining a zone shallower than their existing workings within the dome and did not develop the proposed level. <br></span> DE: <span class="de"> 1219 Local gravity anomalies and crustal structure<br></span> DE: <span class="de"> 8105 Continental margins and sedimentary basins<br></span> SC: <span class="sc"> Near-Surface Geophysics [NS]<br></span> MN: <span class="mn"> 2005 Joint Assembly<br></span></p></body></html>