--> Record of Cretaceous Through Paleogene Gulf of Mexico Drainage Integration From Detrital Zircons

AAPG Annual Convention and Exhibition

Datapages, Inc.Print this page

Record of Cretaceous Through Paleogene Gulf of Mexico Drainage Integration From Detrital Zircons

Abstract

Published analysis of scaling relationships between sediment-dispersal system components imply that reconstruction of the length-scales of drainage basins and fluvial systems can assist prediction of the dimensions of basin-floor fans. This paper is the first of three to address this overall goal, and provides a summary reconstruction of mid-Cretaceous to Paleogene Gulf of Mexico (GoM) drainage integration and drainage-basin scales from detrital zircons (DZs). GoM DZ data include >6000 U-Pb and Pb-Pb ages from ~60 samples of Cenomanian Tuscaloosa-Woodbine, Paleocene Wilcox, and Oligocene Frio-Catahoula, fluvial deposits: samples were collected across each outcrop belt, from Alabama to Texas. Complementary DZ data comes from Aptian to Cenomanian fluvial deposits of the Great Plains, the US Rocky Mountain Front Range, and Aptian-Albian deposits of the Alberta foreland. Collectively, these data show that much of early-mid Cretaceous North America was part of a continental-scale drainage that originated in the Appalachian-Ouachitas, and flowed north and west across the Great Plains to the Alberta foreland and Boreal Sea. GoM drainage was restricted to south of the Appalachian-Ouachitas through at least the Cenomanian: Tuscaloosa-Woodbine fluvial deposits contain no DZ signatures from the Western Cordillera, fluvial systems were of regional scale only (<<106 sq. km), and the largest system is interpreted to represent a paleo-Tennessee River that discharged to the eastern Mississippi embayment. By the Paleocene, much of southern North America, from the Appalachians to the Sierra Nevada, was re-routed to the GoM through a series of major fluvial axes that remain extant today. These included the paleo-Tennessee and its Appalachian source terrain, and an ancestral Mississippi-Arkansas system with an estimated drainage area >106 sq. km that encompassed the central and northern Rockies. However, large axes were also located farther west in Texas, and included an ancestral Colorado-Brazos system with headwaters in the Sierra Nevada, Sevier orogen, and Laramide Rockies, and an ancestral Rio Grande with headwaters in the Mexican Cordillera: the paleo-Colorado-Brazos axis had an estimated drainage area >>106 sq. km, and length scales >2000 km. Beginning in the Oligocene, far western sources were tectonically dismembered, and GoM drainage areas extended no farther west than the eastern Laramide Rockies, heralding development of the Neogene to present continental divide.