| Summary: | Includes bibliographical references. Includes illustrations and maps. Gravity, and seismic measurements made during Nov.-Dec., 1978, 1979, and 1980, are used in the development of a crustal model of McMurdo Sound. Gravity readings were made at 1 km intervals along a refraction profile between Hut Point Peninsula on Ross Island and the Strand Moraine. Bathymetry was obtained from seismic reflection readings at each gravity station. A 38 mgal gravity minimum is located 15 km west of Soss Island with a maximum 3 km east of the Strand Moraine. A model of the upper crust derived from the refraction profile was used in conjunction with a two-dimensional Talwani gravity modeling program to determine depth to the Mohorovicic Discontinuity of 2h km beneath HcMurdo Sound. The crust thickens westward abruptly to 33 km at a point 15 km east of Strand Moraine. A second gravity profile was made along a line between fit. Barnes and the 1097 meter benchmark near Herbertson Glacier in Ferrar Valley. Ferrar Valley gravity data and three seismic refraction profiles are used to model the shape of the crystalline basement floor. The model indicates normal faulting in the valley. Basement depths from Sew Harbor, Ferrar Valley, Bernacchi Bay, and HcMurdo Sound, derived from reversed seismic refraction profiles, are contoured to generate total sediment isopach and basement configuration maps. The basement dips steeply eastward with a block-faulted or glacially-scoured depression near Sew Harbor. Sedimentary thickness ranges from an average 2 km in western IcMurdo Sound to 3.5 km in eastern McMurdo Sound. M.S. (Master of Science)
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