The elusive character of discontinuous deep-water channels: New insights from Lucia Chica channel system, offshore California

Geology
By: , and 

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Abstract

New high-resolution autonomous underwater vehicle (AUV) seafloor images, with 1 m lateral resolution and 0.3 m vertical resolution, reveal unexpected seafloor rugosity and low-relief (<10 m), discontinuous conduits over ∼70 km2. Continuous channel thalwegs were interpreted originally from lower-resolution images, but newly acquired AUV data indicate that a single sinuous channel fed a series of discontinuous lower-relief channels. These discontinuous channels were created by at least four avulsion events. Channel relief, defined as the height from the thalweg to the levee crest, controls avulsions and overall stratigraphic architecture of the depositional area. Flow-stripped turbidity currents separated into and reactivated multiple channels to create a distributary pattern and developed discontinuous trains of cyclic scours and megaflutes, which may be erosional precursors to continuous channels. The diverse features now imaged in the Lucia Chica channel system (offshore California) are likely common in modern and ancient systems with similar overall morphologies, but have not been previously mapped with lower-resolution detection methods in any of these systems.

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Publication type Article
Publication Subtype Journal Article
Title The elusive character of discontinuous deep-water channels: New insights from Lucia Chica channel system, offshore California
Series title Geology
DOI 10.1130/G31589.1
Volume 39
Issue 4
Year Published 2011
Language English
Publisher Geological Society of America.
Contributing office(s) Pacific Coastal and Marine Science Center
Description 4 p.
First page 327
Last page 330
Country United States
State California
Other Geospatial Lucia Chica channel system
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