Chronology of late Quaternary glacial cycles in the Bering Trough, Gulf of Alaska; constraints from core-log-seismic integration across the continental shelf and slope

Author(s): Clary, Wes A.; Worthington, Lindsay Lowe; Daigle, Hugh; Slagle, Angela L.; Gulick, Sean P. S.
Author Affiliation(s): Primary:
University of New Mexico, Albuquerque, NM, United States
Other:
University of Texas at Austin, United States
Lamont-Doherty Earth Observatory, United States
Volume Title: AGU 2016 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2016; American Geophysical Union 2016 fall meeting, San Francisco, CA, Dec. 12-16, 2016. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Sediments offshore Southern Alaska offer a natural laboratory to study glacial erosion, sediment deposition, and orogenesis. A major goal of Integrated Ocean Drilling Program (IODP) Expedition 341 was investigation of interrelationships among tectonic processes, paleoclimate, and glacial activity. Here, we focus on core-log-seismic integration of IODP Sites U1420 and U1421 on the shallow shelf and slope near the Bering Trough, a glacially derived shelf-crossing landform. These sites sample glacial and marine sediments that record a history of sedimentation following the onset of glacial intensification near the mid-Pleistocene transition (1.2 Ma) and Yakutat microplate convergence with North America. Ocean drilling provides important stratigraphic, physical properties, and age data in depth which support development of a stratigraphic model that can be extended across the shelf if carefully calibrated to local and regional seismic surveys. We use high resolution multichannel seismic, core, and logging data to develop a time-depth relationship (TDR) and update the developing chronostratigraphic model based on correlation of seismic sequence boundaries and drilling-related data, including biostratigraphic and paleomagnetic age controls. We calibrate, combine, and interpolate core and logging data at each site to minimize gaps in physical property information and generate synthetic seismic traces. At Site U1421, vertical seismic profiling further constrains the TDR, and provides input for the initial velocity model during the tie. Finally, we match reflectors in the synthetic trace with events in nearby seismic reflection data to establish a TDR at each site. We can use this relationship to better interpret the development of the Bering Trough, a recurring and favored path for ice streams and glacial advance. Initial results suggest late Pleistocene sedimentation rates of at least 1 km/m.y. on average, and variable sedimentation rates which are possibly correlated with paleoenvironmental indicators such as sea ice related species of diatoms.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 20 Geophysics, Applied; 24 Surficial Geology, Quaternary Geology; Bering Trough; Cenozoic; East Pacific; Expedition 341; Geophysical methods; Geophysical surveys; Gulf of Alaska; IODP Site U1420; IODP Site U1421; Integrated Ocean Drilling Program; North Pacific; Northeast Pacific; Pacific Ocean; Quaternary; Seismic methods; Surveys; Upper Quaternary
Coordinates: N593026 N593026 W1440243 W1440244
N594120 N594120 W1431204 W1431204
Record ID: 2017056067
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