Research Paper GEOSPHERE Detrital-zircon records of Cenomanian, Paleocene, and Oligocene Gulf of Mexico drainage integration and sediment routing: GEOSPHERE; v. 13, no. 6 Implications for scales of basin-floor fans doi:10.1130/GES01410.1 Michael D. Blum1, Kristy T. Milliken1,*, Mark A. Pecha2,*, John W. Snedden3,*, Bruce C. Frederick1,*, and William E. Galloway3,* 25 figures; 3 tables; 1 supplemental file 1Department of Geology, University of Kansas, Lawrence, Kansas 66047, USA 2Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA 3Institute for Geophysics, The University of Texas at Austin, Austin, Texas 78758, USA CORRESPONDENCE: mblum@ ku .edu CITATION: Blum, M.D., Milliken, K.T., Pecha, M.A., ABSTRACT paleo-Mississippi. With the notable exception of the Oligocene, measured fans Snedden, J.W., Frederick, B.C., and Galloway, W.E., 2017, Detrital-zircon records of Cenomanian, Paleo- reside within the range of our predictions, indicating that this approach can be cene, and Oligocene Gulf of Mexico drainage inte- This paper uses detrital zircon (DZ) provenance and geochronological exported to other basins that are less data rich. gration and sediment routing: Implications for scales data to reconstruct paleodrainage areas and lengths for sediment-routing of basin-floor fans: Geosphere, v. 13, no. 6, p. 2169– 2205, doi:10.1130/GES01410.1. systems that fed the Cenomanian Tuscaloosa-Woodbine, Paleocene Wilcox, and Oligo cene Vicksburg-Frio clastic wedges of the northern Gulf of Mex- INTRODUCTION Received 9 August 2016 ico (GoM) margin. During the Cenomanian, an ancestral Tennessee-Alabama Revision received 19 December 2016 River system with a distinctive Appalachian DZ signature was the largest sys- The northern Gulf of Mexico (hereafter GoM) continental margin is domi­ Accepted 19 May 2017 tem contributing water and sediment to the GoM, with a series of smaller nated by the Mississippi River sediment­dispersal system. The Mississippi Published online 2 October 2017 systems draining the Ouachita Mountains and discharging sediment to the drainage stretches from the Rocky Mountains in the western U.S. to the Appa­ western GoM. By early Paleocene Wilcox deposition, drainage of the south- lachian cordillera in the east, and feeds the alluvial­deltaic plain of south Loui­ ern half of North America had reorganized such that GoM contributing areas siana as well as its linked basin­floor fan in the deepwater GoM (Fig. 1; Bentley stretched from the Western Cordillera to the Appalachians, and sediment was et al., 2015). Regional­scale fluvial systems drain basin­margin terrain of the delivered to a primary depocenter in the northwestern GoM, the Rockdale south­central U.S. to the west of the Mississippi, and the southern Appala­ depocenter fed by a paleo–Brazos-Colorado River system, as well as to the chians to the east. More than 90% of the sediment load delivered to the north­ paleo–Mississippi River in southern Louisiana. By the Oligocene, the western ern GoM margin during the late Quaternary period comes from the Missis­ drainage divide for the GoM had migrated east to the Laramide Rockies, with sippi drainage (calculated from Syvitski and Milliman, 2007), a load reflected much of the Rockies now draining through the paleo–Red River and paleo– in the enormous scale of the Mississippi basin­floor fan. However, integration Arkansas River systems to join the paleo–Mississippi River in the southern of a continental­scale Mississippi drainage is a Neogene phenomenon, and Mississippi embayment. The paleo–Tennessee River had diverted to the north paleodrainage and sediment routing have changed over time (Galloway et al., toward its present-day junction with the Ohio River by this time, thus be- 2011; Blum and Pecha, 2014). coming a tributary to the paleo-Mississippi within the northern Mississippi This paper presents a detrital zircon (DZ) record of mid­Cretaceous to OLD G embayment. Hence, the paleo-Mississippi was the largest Oligocene system Paleo gene GoM paleodrainage and sediment routing, focusing on Ceno­ of the northern GoM margin. manian, Paleo cene, and Oligocene sediment­dispersal systems. Our research Drainage basin organization has had a profound impact on sediment de- uses DZs to reconstruct basin­scale paleodrainage, then uses reconstructions livery to the northern GoM margin. We use paleodrainage reconstructions to to predict sediment routing to basin­floor fans. This is one of several ongoing OPEN ACCESS predict scales of associated basin-floor fans and test our predictions against parallel efforts that follow a GoM source­to­sink (S2S) theme, which quan­ measurements made from an extensive GoM database. We predict large fan tify the scale of GoM basin­floor fans through time from subsurface data systems for the Cenomanian paleo–Tennessee-Alabama, and especially for the ( Snedden et al., 2017) and reconstruct fluvial system scales through time from two major depocenters of the early Paleocene paleo–Brazos-Colorado and late empirical scaling relationships between drainage­basin size and length, and Paleocene–earliest Eocene paleo-Mississippi systems, and for the Oligocene point­bar thicknesses measured from well logs (Milliken et al., 2015). Finally, papers by Xu et al. (2016, 2017) focus specifically on reconstructing fluvial sys­ This paper is published under the terms of the *E­mail: milliken@ku .edu; mpecha@email .arizona .edu; jsnedden@ig .utexas .edu; bfrederick@ku tems of the early Miocene. Collectively, these papers illustrate a relatively effi­ CC-BY license. .edu; galloway@austin .utexas .edu. cient, semiquantitative approach to reconstructing continental­scale paleo­ © 2017 The Authors Downloaded from https://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/13/6/2169/3991301/2169.pdf by UniversityGEOSPHERE of Kansas user| Volume 13 | Number 6 Blum et al. | Gulf of Mexico drainage integration and sediment routing from detrital zircons on 26 October 2018 2169 Research Paper ARCTIC Figure 1. Modern drainage patterns in North America, illustrating the signifi- cance of the Mississippi River system to the Gulf of Mexico and the Mississippi deep-water fan system. A majority of PACIFIC the water flux for the Mississippi sys- HUDSON BAY tem comes from the Ohio River tributary and eastern North America (blue arrow), whereas the majority of sediment is de- rived from the Missouri River tributary and the Rocky Mountains and Great Plains regions (brown arrow). “WGoM” stands for western Gulf of Mexico drain- age, including the Brazos and Colorado Rivers, whereas “EGoM” stands for east- internal ern Gulf of Mexico drainage and includes the Apalachicola and Alabama Rivers (see MISSISSIPPI Fig. 5). PACIFIC EGoM WGoM Kilometers Mississippi an System 0 250 500 1000 F drainage and sediment routing and predicting basin­floor fan systems in a segments, delivery rate to sediment sinks, and how the unsteadiness of sedi­ well­known basin, an approach that can be exported to other basins that are ment production and transfer through system segments is preserved in the an­ less well known. cient stratigraphic record (NSF MARGINS Program, 2004). Romans et al. (2016) illustrated how the tools required for S2S analyses vary with the time scale of BACKGROUND investigation. Our goals require empirical data on modern sediment flux and scales of sediment­dispersal system segments, and tools that measure scales Source-to-Sink Concepts of terrestrial to marginal­marine components in ancient systems, so as to pre­ dict the scales and properties of linked deepwater components. The S2S approach emerged in association with the National Science Foun­ Our approach assumes that sediment­dispersal system segments develop dation (NSF) MARGINS program and is grounded on understanding sediment self­similar geometries over 104–106 yr, regardless of absolute scale (equilib­ production rates, transport and storage through sediment­dispersal system rium time of Paola and Mohrig, 1996). We assume that, at the first order, the Downloaded from https://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/13/6/2169/3991301/2169.pdf by UniversityGEOSPHERE of Kansas user| Volume 13 | Number 6 Blum et al. | Gulf of Mexico drainage integration and sediment routing from detrital zircons on 26 October 2018 2170 Research Paper scales and properties of each segment within a sediment­dispersal system cor­ Gulf of Mexico Basin Fill relate to water and sediment flux, and the scales and properties of one segment are inherently related to, and can be predicted from, the scales and properties The GoM is a well­understood sedimentary basin: first­order paleogeogra­ of another in the same system. Syvitski and Milliman (2007) showed that, on a phy, patterns of sediment input, key elements of the stratigraphic record, and global scale, sediment flux scales to drainage area and relief at the first order, the overall basin­fill architecture and environments of deposition are known and at the second order, to hydrology and temperature. Somme et al. (2009) from generations of industry activity and academic research (summarized in quantified scaling relationships between drainage area and the different seg­ Galloway, 2008; Galloway et al., 2011; Fig. 3). ments of modern sediment­dispersal systems, a relationship further illustrated The oldest unit of interest here is the Late Cretaceous (Cenomanian) by Helland­Hansen et al. (2016), whereas Blum et al. (2013) focused more spe­ Tuscaloosa­Woodbine trend, which represents the first major episode of cifically on fluvial