Sonobuoy seismic studies at ODP drill sites in Prydz Bay, Antarctica

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Five sonobuoy seismic-refraction records were collected along the Leg 119 geophysical transect across the Prydz Bay shelf. Velocity-depth profiles are computed from the sonobuoy data and are used to produce a depth section for the principal acoustic unit boundaries observed in the seismic-reflection data along the transect. Traveltime curves generated by ray-tracing for models constructed from downhole velocity logs are compared to curves generated for models based solely on the sonobuoy data. This comparison reveals that sonobuoy data are less reliable for analysis of lithostratigraphy in vertically and laterally complex areas; however, the sonobuoy data can be used to accurately estimate the depth to a specific horizon in the reflection data to within 10 m. Near-surface velocities exceed 2.0 km/s at all sites, indicating likely overconsolidation of sediments due to glacial loading and erosion during periods of grounded ice sheets on the shelf. Sedimentary rock velocities exclusively were observed beneath the shelf to depths of 3 km. At the landward site a deep refraction is observed with a velocity and vertical gradient indicative of basement rock.

Publication type Conference Paper
Publication Subtype Conference Paper
Title Sonobuoy seismic studies at ODP drill sites in Prydz Bay, Antarctica
DOI 10.2973/
Volume 119
Year Published 1991
Language English
Publisher Texas A&M University, Ocean Drilling Program
Contributing office(s) Coastal and Marine Geology Program, Pacific Coastal and Marine Science Center
Description 17 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings of the Ocean Drilling Program, Scientific Results
First page 27
Last page 43
Other Geospatial Prydz Bay, Antarctica
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