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Pockmarks: Self-scouring seep features?

July 21, 2011

Pockmarks, or seafloor craters, occur worldwide in a variety of geologic settings and are often associated with fluid discharge. The mechanisms responsible for pockmark preservation, and pockmarks? relation to active methane venting are not well constrained. Simple numerical simulations run in 2-and 3-dimensions, and corroborated by flume tank experiments, indicate turbulence may play a role in pockmark maintenance, and, potentially, in pockmark excavation. Morphological analysis of the pockmarks indicates an abundance of flat-bottomed and/or elongated pockmarks. Pockmarks transition into furrows as the bay narrows and tidal flow is enhanced, providing unmistakable evidence of post-formation evolution. We hypothesize that some pockmarks formed from seafloor perturbations (e.g., gas or methane discharge), are1 maintained and gradually modified by vortical flow. This hypothesis provides a mechanism for pockmark preservation and enlargement without active fluid venting, which has implications for the interpretation of seafloor seep features in gas hydrates areas.

Publication Year 2011
Title Pockmarks: Self-scouring seep features?
Authors Laura L. Brothers, Joseph T. Kelley, Daniel F. Belknap, Walter A. Barnhardt, Peter O. Koons
Publication Type Conference Paper
Publication Subtype Conference Paper
Index ID 70159030
Record Source USGS Publications Warehouse
USGS Organization Woods Hole Coastal and Marine Science Center