Sub-bottom navigation data (ASCII format) acquired offshore Galveston, Texas, during the 2020 OCS2020 survey of Sabine, Heald and Shepard Banks

This data set presents processed navigation data files that were collected during a sub-bottom survey using an EdgeTech SB-512i (0.7-12 kHz) chirp towfish. These navigation files are stored in the ASCII format with column headers and include the GPS antenna lat/lon and the layback-corrected towfish lat/lon. The sub-bottom survey was performed on a Bordelon work boat in Oct-Nov 2020 by APTIM Inc. under a joint effort between the Bureau of Ocean and Energy Management (BOEM), coop# M21AC00005, and the Texas General Land Office (GL0), CEPRA (Coastal Erosion Planning and Response Act) project 1706, to explore the stratigraphy of Sabine, Heald and Shepard Banks, as well as the outer Trinity River Paleovalley and its confluence with the Sabine River Paleovalley, with the broad goals of investigating the setting for the potential for sand resources, and for understanding the history of sedimentary deposition in this coastal/estuarine/marine setting in response to sea level rise in the Holocene. The University of Texas Institute for Geophysics was contracted on this project to apply UTIG-developed advanced chirp processing techniques (Saustrup et al., 2019) to this OCS chirp data set, to produce a level of image quality that will enable detailed stratigraphic interpretations, and to interpret the processed data within the regional context. Study collaboration and funding were provided by the GLO (Contract #20-164-000-C216) and BOEM (Coop #M16AC00020) funded projects covering the Trinity River Paleovalley, offshore Galveston, Texas, out to the confluence with the Sabine River Paleovalley.