Seabed Fluid Flow

Abstract

Seabed fluid flow involves the flow of gases and liquids through the seabed. Such fluids have been found to leak through the seabed into the marine environment in seas and oceans around the world - from the coasts to deep ocean trenches. This geological phenomenon has widespread implications for the sub-seabed, seabed, and marine environments. Seabed fluid flow affects seabed morphology, mineralization, and benthic ecology. Natural fluid emissions also have a significant impact on the composition of the oceans and atmosphere; and gas hydrates and hydrothermal minerals are potential future resources. This book describes seabed fluid flow features and processes, and demonstrates their importance to human activities and natural environments. It is targeted at research scientists and professionals with interests in the marine environment. Colour versions of many of the illustrations, and additional material - most notably feature location maps - can be found at www.cambridge.org/9780521819503.

Gas escape features off New Zealand: Evidence of massive release of methane from hydrates

“…To our knowledge these are over twice the size of any known pockmarks [Judd and Hovland, 2007]. Two such giant features are observed in swath bathymetry (Figure 1).…”

Distribution of hydrocarbon leakage indicators in the Malvinas Basin, offshore Argentine continental margin

“…Biogenic gas generation from organic 581 rich shales is favoured in shelves and deepwater settings, where it can be generated at very 582 shallow sediment depths in the range of centimetres up to more than 1000 m depth (Rice, 583 1993). Generation of biogenic methane can be summarized as the reduction of CO 2 into 584 methane (Judd and Hovland, 2007). This process requires both high sedimentation rates of at 585 least 200 m/Ma, and a minimum of 0.5% total organic carbon (TOC) in the sediments 586 (Clayton, 1992).…”

Late Cretaceous (Maastrichtian) shallow water hydrocarbon seeps from Snow Hill and Seymour Islands, James Ross Basin, Antarctica

“…Judd and Hovland, 2009, and 47 references therein). Much of the seeping hydrocarbons comprises methane, both of thermogenic and 48 biogenic origin, deriving from underlying thick, organic-rich sedimentary sequences.…”