Recycling sediments between source and sink during a eustatic cycle: Systems of late Quaternary northwestern Gulf of Mexico Basin

Abstract

The Northwestern Gulf of Mexico Basin is an ideal natural laboratory to study and understand source-to-sink systems. An extensive grid of high-resolution seismic data, hundreds of sediment cores and borings and a robust chronostratigraphic framework were used to examine the evolution of late Quaternary depositional systems of the northwestern Gulf of Mexico throughout the last eustatic cycle (~125 ka to Present). The study area includes fluvial systems with a wide range of drainage basin sizes, climate settings and water and sediment discharges. Detailed paleogeographic reconstructions are used to derive volumetric estimates of sediment fluxes (Volume Accumulation Rates). The results show that the response of rivers to sea-level rise and fall varied across the region. Larger rivers, including the former Mississippi, Western Louisiana (presumably the ancestral Red River), Brazos, Colorado and Rio Grande rivers, constructed deltas that advanced across the shelf in step-wise fashion during Marine Isotope Stages (MIS) 5-2. Sediment delivery to these deltas increased during the overall sea-level fall due to increases in drainage basin area and erosion of sediment on the inner shelf, where subsidence is minimal, and transport of that sediment to the more rapidly subsiding outer shelf. The sediment supply from the Brazos River to its delta increased at least 3-fold and the supply of the Colorado River increased at least 6-fold by the late stages of sea-level fall through the lowstand. Repeated filling and purging of fluvial valleys from ~119-22 ka contributed to the episodic growth of falling-stage deltas. During the MIS 2 lowstand (~22-17 ka), the Mississippi River abandoned its fallingstage fluvial-deltaic complex on the western Louisiana shelf and drained to the Mississippi Canyon. Likewise, the Western Louisiana delta was abandoned, presumably due to merger

Geological controls on the geometry of incised‐valley fills: Insights from a global dataset of late‐Quaternary examples

“…The major components of source to sink systems – continent, shelf, slope and basin floor segments – are considered to be genetically related in analytical approaches that use mass‐balance theory (Sømme et al., 2009a). Based on modern and late‐Quaternary fluvial systems from different tectonic and climatic settings, recent work on source to sink systems (Anderson et al., 2004, 2006; Syvitski & Milliman, ; Sømme et al., ,b; Blum et al., ; Sweet & Blum, ; Xu et al., ) has demonstrated scaling relationships between the scale of drainage‐basin area, water discharge, river‐driven sediment flux, channel‐belt dimensions and the corresponding scale of other distal components of sediment‐dispersal systems (for example, submarine canyons and basin‐floor fans). Incised‐valley systems play a key role in transferring sediments from hinterland regions to deep‐marine environments, especially during lowstands (Blum & Törnqvist, ; Blum et al., ).…”

Clinoforms and clinoform systems: Review and dynamic classification scheme for shorelines, subaqueous deltas, shelf edges and continental margins

“…In contrast, regardless of other conditions, whenever incised valleys and submarine canyons are developed, river-dominated shelf-edge deltas are the most efficient agents of coarse-grained sediment delivery to the slope and basin-floor, with significant basin-floor fan development (Short and Stauble, 1967;Suter and Berryhill Jr, 1985;Mayall et al, 1992;Sydow and Roberts, 1994;Steel et al, 2000Steel et al, , 2003Steel et al, , 2008PlinkBjörklund et al, 2001;Mellere et al, 2002;Deibert et al, 2003;Steel, 2003, 2006;Roberts and Sydow, 2003;Sydow et al, 2003;Crabaugh and Steel, 2004;Anderson, 2005;Anderson et al, 2016;Johannessen and Steel, 2005;PlinkBjörklund and Steel, 2006;Burgess et al, 2008;Fig. 21.…”

“…16); Sydow and Roberts, 1994;Deibert et al, 2003;Anderson, 2005;Anderson et al, 2016;Sztanó et al, 2013). Normally, both a proximal active delta-scale clinoform system and a distal shelf edge draping clinoform with rollover-point bathymetries of up to 500 m are present (Fig.…”

“…Existing examples of each of the 12 final classes are also proposed here. The examples shown for each of 12 classes have been modified after: Shor-1: Quaternary Gulf of Lions shorelines (Bassetti et al, 2008); Shor-2: Recent Huanghe Delta (Zhou et al, 2014); Shor-3: Holocene Po Delta (Correggiari et al, 2005); Sub-1: Recent Southern Iberia (Hernández-Molina et al, 2000a); Sub-2: Recent Adriatic shelf (Cattaneo et al, 2007); Sub-3: Intervals in Holocene mud wedges (Huanghe subaqueous delta: Liu et al, 2004); Shelf-1: Quaternary Gulf of Mexico shelf-edge delta (Anderson et al, 2016); Shelf-2: Type C clinothems from the Pleistocene mid-Adriatic shelf-edge Po Delta (Pellegrini et al, 2017); Shelf-3: abandoned shelf-edge deltas from the Quaternary United States Gulf of Mexico (Sydow and Roberts, 1994); Cont-1: Neogene Brazilian continental margin (Viana et al, 1998); Cont-2: Cenozoic-Recent South African margin (Austin and Uchupi, 1982); Cont-3: Cenozoic Baffin Bay continental margin (Rice and Shade, 1982). In each of these images, the clinothems highlighted with grey shading correspond to each given clinothem class.…”

Clinoforms and clinothems: Fundamental elements of basin infill

“…For examples their study can reveal signals from river floods (e.g. Bohacs, Lazar, & Demko, 2014; Milliman & Syvitski, 1992; Wheatcroft et al, 1997); strong tidal currents on deltas (Rossi et al, 2017) or intricately preserved tidal signals in a wave‐dampened shelf setting (Peng et al, 2018), to signals of syn‐orogenic tectonic (Alan et al, 2019) or eustatic change (Anderson et al, 2016; Stanley & Warne, 1994; Trincardi & Correggiari, 2000). Arguably, basinward‐accreting clinoforms represent a dominant architectural style of the succession on many sedimentary margins, and clinothems are one of the fundamental elements of the sedimentary record (Figure 3).…”