Late Quaternary eolian sand depositional record for southwestern Kansas: Landscape sensitivity to droughts

Modern and late Holocene wind regimes over the Great Plains (central U.S.A.)

“…The oldest dates from the Arkansas River dune field range from 16 to 12 ka, while there is evidence for small, more recent events at 430, 380-320, 180, and 70 yrs ago. No evidence of dune reactivation during the Medieval Climatic Anomaly has been found, likely due to an incomplete record (Forman et al, 2008). Paleowinds are recognized as northerly to northwesterly (Forman et al, 2008) as indicated by loess distribution as well as the weak trend of dunes in the area (south-southwest to north-northeast).…”

“…This extended drought has been documented within North America using several types of proxies including lake levels and salinity, tree ring records (Cook et al, 2004), and timing of dune activity (Mason et al, , 2007. Smaller, more recent droughts are recognized in some dune fields in the Great Plains (Clarke and Rendell, 2003;Forman et al, 2005Forman et al, , 2008, although these events were not extensive enough to promote complete dune reactivation across the area (Muhs and Holliday, 1995;Wolfe et al, 2001). These small periods of dune activity are recognized in single dune fields, suggesting localized drought (rather than regional drought, as in the Medieval Climatic Anomaly).…”

“…These dates provide limiting ages for sand layers present above or below the organic material. More recently, luminescence geochronology, typically optically stimulated luminescence, has been used to date the eolian sands themselves (Forman and Maat, 1990;Goble et al, 2004;Lepper and Scott, 2005;Miao et al, 2007;Forman et al, 2008), providing specific information about periods of dune movement.…”

A regional-scale climate reconstruction of the last 4000 years from lakes in the Nebraska Sand Hills, USA

“…The number of vertical gray bars is based on time equivalent events of both lake-level fall and increased sand input across multiple sites. OSL ages from Goble et al (2004) and Forman et al (2008) are shown with error bars, while droughts inferred from OSL ages from Miao et al (2007) are represented by horizontal bars identical to those from wetland studies (Dean, 1974 andNicholson andSwinehart, 2005). The bottom graph compares results of this paper with the PDSI record of the north-central Sand Hills and the ostracode-derived Mg/Ca data from South Dakota for the last 1200 cal yr BP.…”

Centennial eolian cyclicity in the Great Plains, USA: a dominant climate pattern of wind transport over the past 4000 years?

“…In the Great Plains of the U.S., which is a major agricultural region, most of the published records of droughts span the past 1000e2000 years (e.g., Muhs et al, 1997;Woodhouse and Overpeck, 1998;Fritz et al, 2000;Laird et al, 1996aLaird et al, , 2003Fye et al, 2003;Cook et al, 2004;Graham et al, 2007;Forman et al, 2008;Seifert et al, 2009), although a few high-resolution records extend to earlier periods of the Holocene, such as the those published by Brown et al (2005), Clark et al (2002), and Donovan and Grimm (2007).…”