Validation of empirical source-to-sink scaling relationships in a continental-scale system: The Gulf of Mexico basin Cenozoic record

Abstract

Empirical scaling relationships between known deepwater siliciclastic submarine fan systems and their linked drainage basins have previously been established for modern to submodern depositional systems and in a few ancient, small-scale basins. Comprehensive mapping in the subsurface Gulf of Mexico basin and geological mapping of the North American drainage network facilitates a more rigorous test of scaling relationships in a continental-size system with multiple mountain source terranes, rivers, deltas, slopes, and abyssal plain fan systems formed over 65 m.y. of geologic time. An immense database of drilled wells and high-quality industry seismic data in this prolific hydrocarbon basin provide the independent measure of deepwater fan distribution and dimensions necessary to test source-to-sink system scaling relationships.Analysis of over 40 documented deepwater fan and apron systems in the Gulf of Mexico, ranging in age from Paleocene to Pleistocene, reveals that submarine-fan system scales vary predictably with catchment length and area. All fan system run-out lengths, as measured from shelf margin to mapped fan termination, fall in a range of 10%-50% of the drainage basin length, and most are comparable in scale to large (Mississippi River-scale) systems although some smaller fans are present (e.g., Oligocene Rio Bravo system). For larger systems such as those of the Paleocene Wilcox depositional episodes, fan runout lengths generally fall in the range of 10%-25% of the longest river length. Submarine fan widths, mapped from both seismic reflection data and well control, appear to scale with fan run-out lengths, though with a lower correlation (R 2 = 0.40) probably due to uncertainty in mapping fan width in some subsalt settings. Catchment area has a high correlation (R 2 = 0.85) with river length, suggesting that fluvial discharge and sediment flux may be primary drivers of ancient fan size.Validation of these first-order source-to-sink scaling relationships provides a predictive tool in frontier basins with less data. Application to less-constrained early Eocene fan systems of the southern Gulf of Mexico demonstrates the utility for exploration as well as paleogeographic reconstructions of ancient drainage systems. This approach has considerable utility in estimating dimensions of known but poorly constrained submarine fans in the subsurface or exposed in outcrop.

Detrital-zircon records of Cenomanian, Paleocene, and Oligocene Gulf of Mexico drainage integration and sediment routing: Implications for scales of basin-floor fans

“…21B). We use our DZbased paleodrainage re constructions and estimates of paleodrainage length to estimate lengths of basinfloor fans in the deepwater GoM, and compare these estimates with em pirical measurements (Snedden et al, 2017).…”

“…This research was conducted in par allel with Milliken et al (2015), who independently measured pointbar thick nesses from well logs for these and other stratigraphic intervals as a proxy for paleodrainage area and length. We then used sourcetosink scaling rela tionships to estimate the length scales of basinfloor fans from reconstructed paleodrainage areas and lengths, and compared those estimates to measure ments from a large GoM database (Snedden et al, 2017).…”

“…We use this relationship and our DZbased paleodrainage reconstruc tions to estimate the firstorder lengths of basinfloor fans in the deepwater GoM. We compare estimates of fan length from our DZbased paleodrainage reconstructions with empirical measurements (Snedden et al, 2017), with the important caveat that measurements are minimum values because they are based on the limits of mappable sandy facies and do not include what could be a considerable downdip muddy fringe.…”

Structure and origin of the rifted margin of the northern Gulf of Mexico

“…The vast amount of industry seismic-reflection data and decades of drilling results have created a detailed record of sediment routing and basin stratigraphy (Snedden et al, 2018;Zhang et al, 2018), postrift subsidence (Roure et al, 2009), heat flow (Christie and Nagihara, 2016), and salt tectonics (Fort and Brun, 2012;Dooley et al, 2013). However, a consequence of the thick overburden in the Gulf of Mexico is that it makes imaging of the underlying crust more challenging than at sediment-starved margins Bayrakci et al, 2016).…”

Application of fluvial scaling relationships to reconstruct drainage-basin evolution and sediment routing for the Cretaceous and Paleocene of the Gulf of Mexico

“…This paper applies empirical scaling relationships from modern systems to reconstruct the scales of fluvial systems for Late Cretaceous, Paleoceneearliest Eocene, and Oligocene sediment-dispersal systems of the northern Gulf of Mexico sedimentary basin from subsurface data, in this case well logs. This paper is conceptually linked to those of Blum et al (2017), who recon-structed drainage areas for the same stratigraphic intervals from detrital zircon U-Pb provenance and geochronological data; Snedden et al (2018), who quantified changes in the scale of Gulf of Mexico basin-floor fans through time from subsurface data; and Xu et al (2017), who focused on reconstructing early Miocene fluvial systems from both detrital-zircon and well-log data. Collectively, these papers are designed to use the data-rich northern Gulf of Mexico margin to test the utility of a semiquantitative S2S approach to reconstructing paleodrainage and sediment routing at the continental scale, and prediction of the scales of basin-floor fans in the terminal sink.…”