The VML dating of distal Q2c fan surfaces on Hanaupah Canyon alluvial fan in Death Valley, California, yields a minimum-limiting age of 73.55 ka, in accord with cosmogenic ³⁶Cl depth-profile ages of 66 22/−14 ka and 72 24/−20 ka for the same fan deposits.
The close agreement between the VML age estimates and the independently derived radiometric ages for these geomorphic features attests to the validity and reliability of millennial-scale VML dating.
The analysis of new data concerning the properties of desert soils in Central Asia basically confirmed the ideas of I. The micromorphological signs of a solonetzic, or cryptosolonetzic process responsible for fine particles mobilization in the surface horizons of boreal desert soils were revealed.
Aridic Soils, Patterned Ground, and Desert Pavements // Geomorphology of desert environments / Eds.
The VML dating of a prehistoric flaked stone (a primary core) from Ocotillo, southern California, yields a minimum age of 12,500 YBP for the flaking of this stone artifact, suggesting at least a Paleo-Indian human occupation at Ocotillo during the terminal Pleistocene.
These results indicate that, when properly applied, the VML dating technique has the great potential to yield numerical age assignments for surface stone tools, petroglyphs, and geoglyphs of prehistoric age in the drylands of western USA.
In this study, we establish a generalized late Pleistocene (18–74 ka) millennial-scale microlamination sequence in fine-grained, fast-accumulating rock varnish for the drylands of western USA, radiometrically calibrate the sequence and correlate it with the δ¹⁸O record in the GISP2 Greenland ice core.
rock varnish; vml dating; holocene climate; debris flow fan; petroglyph; stone artifact; western USA; desert varnish; mojave desert; cosmogenic he-3; great-basin; radiocarbon ages; climatic-change; death-valley; california; lake; nevada; Analyses of hundreds of rock varnish samples from latest Pleistocene and Holocene geomorphic features in the drylands of western USA reveal a regionally replicable Holocene microlamination sequence.
Among common features, the preservation of the traits of former elevated moistening should be mentioned, which seems to be mitigated or deleted by current active aeolian processes. The fabric of the crusty horizon in different deserts he attributed to their particular nature, primarily to climate.
In the end of the 20th and beginning of the XXI centuries, the application of electron microscopy, tomography, micromorphology and microbiology in pedological research permitted to evaluate the origin and fabric of crusty subhorizon in desert soils and underlying platy one at a micro-level. It became possible to elucidate the natural phenomena affecting the properties of desert soils in Gobi and Turan deserts, as well as to relate the formation of the vesicular desert crust to various microbiological, physical and physicochemical processes.
New aspects in the comparison of macro- and micromorphological, chemical and physicochemical properties of soils studied in the eastern and western deserts of Central Asia, the Gobi and Turan deserts, respectively, are presented in the article.
Common and specific properties of these deserts were revealed, and they were compared with the statements in the paper written by I. Gerasimov in 1954 entitled “Similarity and difference in the nature of deserts”. Gerasimov explained this paradox by the existence of the crusty horizon on the surface of desert soils protecting them from destruction.