Pelagic erosion and sedimentation north of Carnegie Ridge, eastern Equatorial Pacific

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Author(s): Brooks, Caroline K.; Lyle, Mitchell W.; Marcantonio, Franco; Lewis, Danl M.; Paul, Chris
Author Affiliation(s): Primary:
Texas A&M University, Department of Oceanography, College Station, TX, United States
Volume Title: AGU 2011 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2011; American Geophysical Union 2011 fall meeting, San Francisco, CA, Dec. 5-9, 2011. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The Carnegie Ridge is one of three bathymetric highs bounding the Panama Basin and is known to exhibit erosion and redeposition of pelagic sediments. The extent of erosion and redeposition was studied during the R/V Melville cruise MV1014 in November 2010 to compare with geochemical estimates of sediment focusing. The MV1014 cruise acquired geochemical, geological and geophysical data using multichannel 2-D seismic and 3.5 kHz sub-bottom profiler, swathmap bathymetry, coring, and water casts. The seismic reflection, digital sub-bottom profiler and swathmap bathymetry data were used to investigate biogenic sedimentary deposition in the Panama Basin and erosion from Carnegie Ridge. We compare the new geophysical results with drilling on ODP Leg 202, the NEMO-03 site survey cruise for Leg 202, an early survey from 1969 and other data compiled by Ecuadorian surveys. Areas of non-deposition and/or erosion include the bathymetric highs along the ridge, seamounts, and an area of interest, a valley located on the northwestern flank of the ridge. The valley encompasses 183 km2 and exhibits large scale erosion, cutting down through sediments deposited over the 10-million year life of this segment of the Carnegie Ridge. All other valleys located within the Carnegie Ridge study area demonstrate ample deposition with sedimentary packages ranging from 200-800m with an average value trending around 400m. Higher sediment deposition is found in basins to the north of the erosional valley but similar sedimentation is also found even further north, beyond intervening high topography. The thickest sediment deposit near the Carnegie Ridge is actually found on the southern flank of the ridge, more than 100 km to the south of the survey area. Digital chirp sub-bottom profiler data combined with high-resolution seismic illustrate changes in sedimentation and erosion on the Carnegie Ridge, highlighting the dynamic sedimentary environment.
Year of Publication: 2011
Research Program: ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 20 Geophysics, Applied; Acoustical methods; Bathymetry; Carnegie Ridge; Deposition; East Pacific; Equatorial Pacific; Erosion; Geophysical methods; Geophysical surveys; Leg 202; Marine sedimentation; Marine sediments; Ocean Drilling Program; Pacific Ocean; Panama Basin; Sedimentation; Sediments; Seismic methods; Surveys
Coordinates: S030000 N010000 W0810000 W0920000
Record ID: 2012049860
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