Late Quaternary sedimentology and geochronology of small playas on the Southern High Plains, Texas and New Mexico, U.S.A.

Abstract

Playas are small, circular basins forming a ubiquitous component of the southern High Plains landscape. They are filled with carbonaceous mud deposited since the terminal Pleistocene. The stratigraphy and geochronology of 30 playas was investigated to better understand the paleoenvironmental record of basin filling. At the base of the fill in some playas is a well sorted eolian sand dated between ~ 13,000 and ~ 11,000 14C yr BP. The beginning of mud deposition, representing aggradation of eolian dust on a moist, vegetated playa floor was largely between ~ 12,000 and ~ 10,500 14C yr BP. Playa filling slowed ~ 9000 to ~ 4000 14C yr BP, probably due to dry conditions, increased ~ 4000 to ~ 2000 14C yr BP, then slowed again. Eolian sand and loam, likely representing regional aridity, accumulated in some basins episodically just prior to ~ 10,700 14C yr BP, between ~ 8600 and ~ 4700 14C yr BP, and at ~ 1300 14C yr BP. Stable C isotopes from one basin indicate that the playa was inundated only seasonally throughout the record beginning ~ 11,500 14C yr BP. The phytolith record in that basin indicates an abrupt shift toward cooling ~ 11,400 to ~ 11,200 14C yr BP and then increasing importance of xeric-adapted C4 grasses through the Holocene.

Late Quaternary environmental reconstructions of playa-lunette system evolution on the central High Plains of Kansas, United States

“…Within playas, C 3 plant species dominate when the fl oors become fl ooded, whereas upland C 4 plant species expand onto the playa fl oors as they dry out (Haukos and Smith, 1997;Smith, 2003). Accordingly, Holliday et al (2008) proposed that δ 13 C data from playas indicate the frequency and duration of standing water in the basin.…”

“…10 and 20 ka, though some playas have existed on the surface for >30 k.y. (Holliday, 1997;Holliday et al, 2008). Playa-like basins >30 k.y.…”

Isotope paleoecology of episodic mid-to-late Holocene bison population expansions in the Southern Plains, U.S.A.

“…For example, isotope data from the Aubrey site indicate very dry conditions~6800e4500 cal BP (Humphrey and Ferring, 1994). Holliday et al (2008) suggest a prolonged period of limited playa filling from~10,200 to 4500 cal BP indicating uninterrupted mid-Holocene aridity. Hall (1990) recognizes a period of entrenching in eight Texas river systems between~7800 and 5700 cal BP, and Lintz (1993) similarly summarizes a variety of geomorphic evidence to suggest severely dry conditions between~7800 and 4500 cal BP.…”

Geomorphic and hydrologic controls of dust emissions during drought from Yellow Lake playa, West Texas, USA

“…Lunette dunes are deposited on the downwind margins of deflating playas on the Southern High Plains, USA during arid episodes (Holliday, 1997;Holliday et al, 2008;Rich, 2013;Wood and Sanford, 1995). In general, playa sediments deflate to the capillary zone (Wood and Sanford, 1995), yielding quartz-rich sand (low calcareous sand of Holliday, 1997) and aggregates of sand, silt and clay (carbonate sandy loam of Holliday, 1997) to the growing lunettes (Holliday, 1997).…”