The evolution of the surveyor fan and channel system, Gulf of Alaska based on core-log-seismic integration at IODP Site U1417

Author(s): Morey, Susannah; Gulick, Sean P. S.; Walton, Maureen A. L.; Swartz, J. Marshall; Worthington, L. L.; Reece, R.; Somchat, K.; Wagner, P. F.; Jaeger, J. M.; Mix, A. C.
Author Affiliation(s): Primary:
University of Texas at Austin, Institute for Geophysics, Austin, TX, United States
University of New Mexico, United States
Texas A&M University, United States
University of Florida, United States
Oregon State University, United States
Volume Title: AGU 2015 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2015; American Geophysical Union 2015 fall meeting, San Francisco, CA, Dec. 14-18, 2015. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The transition to quasi-periodic ∼100-kyr glacial cycles during the mid-Pleistocene transition (MPT, ∼1.2 Ma) saw an acceleration of sediment delivery from the St. Elias orogen. Eroded sediment from the St. Elias Mountains is transferred to the deep sea via glacially carved shelf troughs and eventually to the Aleutian Trench via the Surveyor Channel and Fan system. By analyzing the submarine sediments in this Fan, we can evaluate the source-to-sink relationship between the erosion of an orogen and deep-sea deposition and inform our understanding of the impact of climate on local tectonics. Our work seeks to update depositional models of the unique sedimentary sequences, architecture, and origins of the glacially-fed Surveyor Fan using well-log-seismic correlation and new data from Integrated Ocean Drilling Program (IODP) Expedition 341. Exp. 341 results question proposed ages of major fan stratigraphic packages, necessitating this update. We created an integrated velocity model using discrete core-based p-wave velocities acquired at site U1417 from 100-152 m, down-hole sonic log velocities from 152 m-476 m, and then projected the trend of the sonic log velocity from 476 m to the base of the borehole. Previous work has interpreted the Sequence I/II boundary (∼300 mbsf at U1417) to correspond with the start of the Surveyor Fan and the onset of tidewater glaciation in the late Miocene and the Sequence II/III boundary (∼160 mbsf at U1417) to coincide with the intensification of glaciation and subsequent increase in sediment flux at the MPT. Our updated velocity model places these major sequence boundaries at the correct depths in borehole site U1417. We can use the revised velocity model to correlate lithologic, biostratigraphic, paleomagnetic, and logging data from the borehole/cores to seismic data, allowing for construction of a temporal model for the evolution of the Surveyor fan. We can then examine the relationship between glacial-interglacial cycle duration and intensity with distal sediment flux. Integration with provenance studies can address potential changes in orogen response to deformation and erosion patterns and changes in fan evolution to changing sediment flux.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Cores; East Pacific; Expedition 341; Geophysical methods; Geophysical surveys; Gulf of Alaska; IODP Site U1417; Integrated Ocean Drilling Program; Marine sediments; North Pacific; Northeast Pacific; Pacific Ocean; Sediments; Seismic methods; Submarine fans; Surveys
Coordinates: N565735 N565736 W1470635 W1473600
Record ID: 2016053524
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