Late Cenozoic cooling favored glacial over tectonic controls on sediment supply to the western Gulf of Mexico

Abstract

Terrigenous marine sediment records the landscape response to climate and tectonic perturbations. Here, we determined the source of Miocene-Pleistocene debris in the western Gulf of Mexico (WGOM) to understand changes in sediment supply during a greenhouse-glacial transition. Sediment composition at Deep Sea Drilling Project (DSDP) Sites 3, 87, and 89-91 shows a reversal in provenance following the onset of Pleistocene glaciation. During Miocene time, sediment was supplied to the deep WGOM from tectonically active, tropical highlands of southern Mexico, accumulating as sediment-gravity-flow deposits across broad deep-water fan systems. Then, following the mid-Pleistocene transition (ca. 0.7 Ma), the WGOM saw sustained (10 5 yr) influx of sediment from the north due to glacial erosion, high discharge, and expanded drainages across the Mississippi catchment. This major provenance shift points to the importance of glacial controls on marine sediment supply during late Cenozoic cooling.

Detrital zircons reveal sea-level and hydroclimate controls on Amazon River to deep-sea fan sediment transfer

“…New data from the Pleistocene Amazon Fan yield similar results to studies in the Indus River source-to-sink system, where variable monsoonal intensity since the LGM has resulted in measurable changes in provenance of sediment from cores along the delta and in the submarine canyon (Clift et al, 2008;Clift and Giosan, 2014;Li et al, 2019). In North America, continental ice-sheet dynamics modulated the Pleistocene Mississippi River-Missouri River drainage system and resulted in major variation of provenance signatures and overall sediment delivery to the Mississippi submarine fan (Fildani et al, 2018;Hessler et al, 2018). Here we note the relatively surprising result that the Amazon Fan appears to archive a consistent record of glacial sea levels and terrestrial hydroclimate of South America, rather than the expected sediment mixture present in the lower Amazon today.…”

“…The Amazon River and deep-sea fan represent a globally important end-member system for understanding land-to-sea sediment dynamics. Submarine fans have been shown to archive histories of output fluxes and onshore environmental change (Normark and Reid, 2003;Fildani et al, 2016;Hessler et al, 2018), and have been used to invert up-system climate forcings in glaciated continent-scale rivers (Clift et al, 2008;Fildani et al, 2016Fildani et al, , 2018Mason et al, 2017;Li et al, 2019). The Amazon catchment straddles equatorial latitudes and has dis-tinct sediment and detrital zircon (DZ) source terranes and physiography ( Fig.…”

Age and provenance of upland gravels in Missouri, USA, and their relationship to Early Pleistocene glaciation

“…The fact that this gravel contains typical clasts present within the Meramec till, and that it forms a distinct finingupward sequence originally >7 m thick suggest that this deposit is or includes outwash deposited in front of a retreating ice margin. The age also corresponds closely to an increase in the rate of sediment delivery and accumulation in the Gulf of Mexico (Hessler et al 2018), further suggesting that this depositional event marks a widespread geomorphic re-organization to a glacial-dominated sedimentary system. In any case, the Grenville-age which proved to be an Early Pleistocene deposit.…”

“…The age also corresponds closely to an increase in the rate of sediment delivery and accumulation in the Gulf of Mexico (Hessler et al . ), further suggesting that this depositional event marks a widespread geomorphic re‐organization to a glacial‐dominated sedimentary system. In any case, the Grenville‐age granitic erratics within this gravel prove that at least one glacial advance from east of Hudson Bay reached the Mississippi River basin during the earliest Pleistocene.…”

“…A Pleistocene age, however, would imply that such cooling initially suppressed erosion in North America so that enhanced sediment transport to the Gulf of Mexico only began with the onset of widespread glacial erosion (e.g. Hessler et al 2018).…”