Neogene to recent evolution of the Southern Gulf of Mexico basin: Tectonic controls on deep‐water sediment dispersal systems

Abstract

Newly available two-dimensional (2D) and limited three-dimensional (3D) reflection seismic data coupled with publicly available well and core data were used to generate the first comprehensive regional basin evolution model for the deep-water Neogene to recent southern Gulf of Mexico (GoM). This evolution is presented in the context of contemporaneous onshore tectonic drivers and predecessor basin tectonic history. Dynamic uplift to the west in North America, transpression to the south and tectonically influenced salt tectonics to the east served to collapse the margins of the southern Gulf of Mexico Basin throughout the late Neogene and into the modern. This collapse and salt inflation served to shut off efficient sediment transport into the axial deep basin. Newly developed nearshore extensional accommodation along both the western margin of the basin and salt-rooted orogenic structures to the south and east appear to have baffled coarser-caliber sediment input from southern (Mexican) sediment sources into the deep Gulf of Mexico Basin beginning in the late Miocene. This sequence is recorded in the southern GoM basin by a transition from large early-mid Miocene submarine channel belts to late Miocene-recent sediment wave fields and mass transport deposits. Improved resolution of new 2D and 3D subsurface seismic reflection data shows that sediment waves of the southern Gulf of Mexico are supercritical bedforms, long wavelength antidunes and cyclic steps, not contourites. These supercritical bedforms are among the most spatially expansive and morphologically largest documented globally. The location and evolution of these bedforms appears closely tied to the tectonically driven history of margin collapse, salt inflation and the starving of the deep basin of coarse-grained sediment. Cumulatively, the tectonic drivers that intuitively should have increased sediment flux into the deep southern Gulf of Mexico acted to 'pinch off' the basin, starving it of sediment supplied from southern sediment sources. Highlights

Giant meandering channel evolution, Campos deep-water salt basin, Brazil

“…8 and 9). More recently, hydrocarbon exploration efforts in the deep-water western Gulf of Mexico have uncovered a series of Miocene channel systems similar in scale to the Campos Basin channel system of this study (Winter et al, 2017;Winter, 2018;Clark et al, 2019;Sickmann and Snedden, 2021). Cenozoic uplift of the North American Cordillera and accelerated uplift of southern Mexico during the late Miocene (Witt et al, 2012;Molina-Garza et al, 2015; Research Paper Villagómez and Pindell, 2021) increased sediment supply to the western Gulf of Mexico and promoted the development of this large deep-water depositional system, called the Veracruz Fan (Hessler et al, 2018).…”

Reconstructing the Zama (Mexico) discovery source to sink palaeogeography, Part II: Sediment routing from the Late Miocene shelf‐margin to deepwater basin

“…Several prior studies of the Mexico Neogene section penetrated by offshore wells document the presence of a diverse array of sediment gravity flows, mass transport complexes, redistributed volcanic ash, volcaniclastics and deepwater bedforms (Hernández, 2013; Sickmann & Snedden, 2020; Stanbrook et al., 2020). Winter (2018) and Clark et al.…”

“…The Miocene section of the southern Gulf of Mexico is punctuated by significant volumes of terrigenous sediment generated by the Middle Miocene Chiapanecan orogeny (Davison, 2020; Shann et al., 2020; Villagómez et al., 2022). Sediment progradational loading and attendant extensional collapse provided sites to sequester sediment extending from the US/Mexico border to the southern Yucatan margin (Rowan, 2019; Sickmann & Snedden, 2020). In spite of the extensive nearshore accommodation space, sand‐sized material clearly entered the deepwater Campeche salt basin, as observed in industry boreholes and seismic mapping (Davison, 2020; Hernández, 2013; Kosmitis et al., 2021; Snedden et al., 2021).…”

“…Our palaeogeographic reconstruction and empirical scaling relationships invoke a model of sediment gravity flows entering the upper slope near the Cibix‐1 well location and following pathways trending generally to the northwest across the Sureste salt basin (Figure 4). We would classify these as transverse flows on a regional scale with palaeotransport orientations substantially different than channels more aligned with the axis of the north‐trending Veracruz Trough located to the west, as documented from seismic mapping by Winter (2018) and Sickmann and Snedden (2020). The difference in the transport capacity of transverse and axial deepwater systems may explain observed sandstone textural trends in wells drilled in each of these sediment dispersal systems, as discussed in the next section.…”

“…2.1 | Regional occurrence of deepwater channels and channel complexes Several prior studies of the Mexico Neogene section penetrated by offshore wells document the presence of a diverse array of sediment gravity flows, mass transport complexes, redistributed volcanic ash, volcaniclastics and deepwater bedforms (Hernández, 2013;Sickmann & Snedden, 2020;Stanbrook et al, 2020). Winter (2018) and Clark et al (2019) report seismic evidence of large submarine channels and channel complexes of the Early and Middle Miocene that are widespread in the axial Veracruz Trough extending as far north as DSDP sites 1-3 (Hessler et al, 2018; Figure 3).…”