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INFLUENCE OF SALT TECTONICS ON SEAFLOOR MORPHOLOGY FROM ALGERIA TO SARDINIA
Yeakley, Julia A

2018, MS, Kent State University, College of Arts and Sciences / Department of Geology.
This study uses previously obtained marine geophysical data for the proposed Galsi pipeline route from Algeria to Sardinia to analyze the buried salt distribution and calculate the amounts of fault displacements associated with halokinesis. Crossing the convergent African/Nubian–European plate boundary, the southern section of the proposed pipeline route traverses’ continental shelves and slopes of Algeria and Sardinia, as well as the Algerian abyssal plain of the Western Mediterranean. Deeply buried Messinian-age salt is present throughout this area. With its low compressibility, salt is less dense and, therefore, more buoyant than the clastic overburden sediment, and thus tends to flow and form diapiric structures. Salt diapirs rise and push on overlying sediments, steepening slopes and causing faults to form.
Fault displacements above diapiric structures were compared near the compressive plate boundary with those within passive margin environments. Measured offsets from seismic profiles of different resolutions are associated in this study with predicted sediment age at depth of each offset. The offsets were then used to calculate an average rate of movement along faults of 1.5 cm/ky. The highest rates along faults associated with halokinesis are along the Cagliari slope near Sardinia (2.5 to 2.7 cm/ky) and near the convergent plate boundary (2.3 cm/ky).
In addition to faulting, one of the major threats to underwater pipelines can be submarine landslides. Due to decreased frictional resistance to sliding because of pore pressure, submarine landslides can occur at very low slope angles and can spread for much greater distances than terrestrial slope failures. Utilizing the same marine geophysical surveys and geotechnical data, analysis of the frequency and aerial extent of underwater failure events in this area can be linked, partially, to the distribution and nature of Messinian-age evaporites and the influence of salt tectonics (halokinesis). Turbidity currents and hyperpycnal flows are present within the Algerian Basin, whereas local debris flows, landslide runouts, and channelized debris flows are present along the Sardinian slope. Several mass wasting events affecting the slope off the coast of Sardinia can be observed using ultra high resolution 2D seismic data as well as geomorphic features in bathymetric images. Many small slides can be connected to the upward movement of salt diapirs pushing on the overlying sedimentary drape. However, low sedimentation rates, determined during this study, suggest slope failures related to such salt occurred more than 12,000 years ago with an overall average of greater than 20,000 years between events.
Abdul Shakoor, Dr. (Advisor)
Daniel Holm, Dr. (Committee Member)
Christopher Rowan, Dr. (Committee Member)
William Johnson (Committee Member)
121 p.

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Yeakley, J. (2018). INFLUENCE OF SALT TECTONICS ON SEAFLOOR MORPHOLOGY FROM ALGERIA TO SARDINIA . (Electronic Thesis or Dissertation). Retrieved from https://etd.ohiolink.edu/

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Yeakley, Julia. "INFLUENCE OF SALT TECTONICS ON SEAFLOOR MORPHOLOGY FROM ALGERIA TO SARDINIA ." Electronic Thesis or Dissertation. Kent State University, 2018. OhioLINK Electronic Theses and Dissertations Center. 15 Nov 2018.

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Yeakley, Julia "INFLUENCE OF SALT TECTONICS ON SEAFLOOR MORPHOLOGY FROM ALGERIA TO SARDINIA ." Electronic Thesis or Dissertation. Kent State University, 2018. https://etd.ohiolink.edu/

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