Stratigraphic controls on a salt-withdrawal intraslope minibasin, north-central Green Canyon, Gulf of Mexico: Implications for misinterpreting sea level change

Abstract

Three-dimensional seismic data from the Fuji basin, a saltcontrolled intraslope minibasin in north-central Green Canyon, Gulf of Mexico, reveal complex interactions between gravity-and suspension-driven sedimentation. Seismic volumes for late Pleistocene (∼470 ka) to Holocene fill within the Fuji basin consist of approximately 45% mass transport complexes (MTCs), 5% channelized sandy turbidites, and 50% hemipelagites and muddy turbidites. At least ten MTCs within the Fuji basin flowed radially toward its depocenter, either from basin flanks (i.e., intrabasinal) or as a result of largerscale salt motion (i.e., extrabasinal). Sediment transport directions are inferred on the basis of elongate basal incisions and smaller-scale scours, head scarps, fold orientation within the complexes, and stratigraphic thinning trends at downdip margins. An amalgamated set of three channelized sandy turbidite complexes less than 350 m (1148 ft) thick and 3 km (1.8 mi) across represents the main sand delivery pathway into the Fuji basin. These deposits are thought to be due to shelf bypass, and possibly, to proximity to the Pleistocene shoreline. Hemipelagites and muddy turbidites are homogeneous, and their thickness is relatively consistent at basin scale. This facies represents background sedimentation.

Bi-modal deformation styles in confined mass-transport deposits: Examples from a salt minibasin in SE Brazil

“…Short remobilisation distances are also supported by the relative position of the studied MTDs, which occur on ridge flanks and in 19 specific locations in the salt-withdrawal basin, in contrast to the remobilised deposits that pond at the centre of the minibasins (Madof et al, 2009). …”

“…Type 2 MTDs are represented in the study area by MTDs C and SF1, which show very similar internal characters i.e., present slabs in a generally convergent, frontally confined flow. Other published examples of Type 2 MTDs have been observed around salt ridges in West Africa (Maia et al, 2015), in the Gulf of Mexico (Posamentier and Martinsen, 2011;Madof et al, 2009), and in lacustrine settings (Moernaut and de Batist, 2011).…”

“…In salt-rich basins, strata deposited over growing salt structures are either thinned or completely removed by erosional processes, and can accumulate as MTDs in peripheral salt-withdrawal basins, or minibasins (Gamboa et al, 2011;Giles and Lawton, 2002;Tripsanas et al, 2004). Detached MTDs thus predominate over far-reaching slope-attached MTDs in distal minibasins of the Gulf of Mexico, Brazil and West Africa, leading to the deposition of heterogeneous strata that can be tied to key periods of salt movement (Beaubouef and Abreu, 2010;Jackson, 2012;Madof et al, 2009;Olafiranye et al, 2013).…”

Disconnected submarine lobes as a record of stepped slope evolution over multiple sea-level cycles

“…templates, such as tortuous corridors (Smith, 2004a;Hay, 2012), mini-basins (Booth et al, 2003;Beaubouef and Abreu, 2006;Madof et al, 2009;Pirmez et al, 2012;Prather et al, 2012b;Oluboyo et al, 2014;Doughty-Jones et al, 2017), and piggy-back basins/foredeep margin slopes , and/or do not span multiple large-scale sea-level cycles (e.g., Beaubouef and Abreu, 2006;Barton, 2012). Moreover, these studies do not investigate the long-term stratigraphic evolution of slopes nor characterize stratigraphic architecture at a scale that resolves relationships between sedimentary processes and seabed topography.…”

Fabric Development and Pore-Throat Reduction in a Mass-Transport Deposit in the Jubilee Gas Field, Eastern Gulf of Mexico: Consequences for the Sealing Capacity of MTDs

“…Although, for obvious industrial reasons, turbidites have received the most attention during the past decades, the more recent acquisition of high-resolution three-dimensional (3-D) seismic data has shown that many slope and abyssal systems comprise a very significant portion of MTCs. In some settings around the world, up to 70-90% of the entire slope and deepwater stratigraphic record is composed of MTCs and associated deposits (Canals et al, 2004;Newton et al, 2004;Moscardelli, 2007;Madof et al, 2009;Beaubouef and Abreu, 2010;Posamentier and Martinsen, 2011). Although numerous geoscientists use the terms MTDs and MTCs interchangeably, in this study we define a MTC as a depositional architectural complex comprised of several coeval or closely chronological-and genetically-related masstransport deposits (MTDs)-i.e.…”