Geochronology and Depositional History of the Sandy Springs Aeolian Landscape in the Unglaciated Upper Ohio River Valley, United States

Abstract

The study of active and stabilized late Quaternary aeolian landforms provides important proxies for past climate events and environmental transitions. Despite an overall increase in the study of aeolian landforms in previously glaciated and coastal settings in eastern North America, the history of aeolian sedimentation in many unglaciated inland alluvial settings remain poorly understood. This study reports on the geochronology and depositional history of aeolian landforms and sediments in the unglaciated upper Ohio Valley at the Sandy Springs site. Aeolian landforms and sediments include complex, linear, barchan-like, and climbing dunes; an interdune sand sheet; and sandy loess that blankets high valley surfaces. At Sandy Springs, aeolian dune sands and sandy loess are restricted to intermediate (S2) and higher (S3) geomorphic surfaces. Eight optically stimulated luminescence age estimates constrain the initiation of aeolian processes on the S2 surface to sometime after 17 ka and episodic deposition on the S2 and S3 surfaces between 11 and 1.4 ka. The distribution of aeolian sediments at Sandy Springs is influenced by several past factors including local wind fetch potential, sediment availability, and underlying alluvial topography. Sediment availability is interpreted as the primary factor controlling aeolian processes and appear linked to several pan-regional paleoclimate events. Sandy loess deposition at ca. 8.2 ka on the S3 surface may reflect hydrologic variability and cooling, associated with the final pulse of meltwater into the North Atlantic from the Laurentide Ice Sheet. Dune reactivation and erosion at ca. 4.5 ka on the S2 surface indicate enhanced sediment availability possibly associated with drought conditions. These results illustrate that the deciphering the coupled fluvialaeolian records in this catchment of the Ohio River provides new insight into the nature of changing surface processes against the backdrop of climate variability over the past ca. 20 ka.

Origin and Paleoenvironmental Significance of the Old Red Sand Along the Southeast Coast of China

“…Grain size characteristics of sediments are mainly controlled by the transportation mode and sedimentary environment. Therefore, grain size analysis is often used to identify sedimentation process and depositional environment (Yang et al, 2017;Purtill et al, 2019). The classification scheme used in this study is: Clay (0-4 μm), silt (4-63 μm), very fine sand (63-125 μm), fine sand (125-250 μm), medium sand (250-500 μm), coarse sand (500-1,000 μm) and extremely coarse sand (1,000-2,000 μm).…”

The Road Not Taken: How Early Landscape Learning and Adoption of a Risk-Averse Strategy Influenced Paleoindian Travel Route Decision Making in the Upper Ohio Valley

“…The presence of sandy loess sediments on adjacent, easterly alluvial surfaces and uplands in the valley (Rutledge et al 1975) suggests eolian deflation of newly created braid bars and alluvial plains. Although undated in the Scioto Valley, sandy loess deposition on high alluvial surfaces at Sandy Springs date to the late Pleistocene–early Holocene (Purtill et al 2019). Contemporary eolian deflation and subsequent transport likely occurred in the Scioto Valley, perhaps increasing air dustiness and deposition of fine sediment in rivers.…”

Provenance and Climatic Implications of the Middle-Pleistocene Loess Deposit, Southern China

“…Global climate changes and their regional responses are receiving considerable research attention, with Quaternary climate evolution providing an important focus (Liu, 1985;Pye, 1987;Li et al, 2001a;Li et al, 2018a;Purtill et al, 2019;Westerhold et al, 2020). China is a typical monsooninfluenced country, the summer monsoon brings abundant water vapor to the continent, and the winter monsoon entrains and transports large volumes of dust, carrying it to the middle, east and south of China (Ding et al, 2019;Li et al, 2021a;Li et al, 2021b).…”