The VML dating of a giant ejecta block on the rim of Meteor Crater in northern Arizona yields a minimum-limiting age of 49.15 ka, closely matching a thermoluminescence (TL) age of 49 ± 3 ka and slightly younger than a recently updated cosmogenic Cl age of 56.0 ± 2.4 ka for the meteor impact event.
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 14 ka and 72 24/− 20 ka for the same fan deposits.
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 δO record in the GISP2 Greenland ice core.
Because fan aggradation is ultimately controlled by the intensity and frequency of precipitation events — which in turn are modulated by major climatic oscillations such as Heinrich events, Dansgaard/Oeschger (DO) events, and glacial/interglacial shifts — these major climatic changes could be the pacemaker of regionally contemporaneous large-area fan segmentation.► Rock varnish record of millennial-scale wetness variations in western USA deserts.
► Age calibration and climatic correlation of the varnish record with the GISP2 record.
Varnish microlamination (VML) dating is a correlative age determination technique that can be used to date and correlate various geomorphic features in deserts.
In this study, we establish a generalized late Quaternary (i.e., 0–300 ka) varnish layering sequence for the drylands of western USA and tentatively correlate it with the SPECMAP oxygen isotope record.