Testing the use of an OSL Standardised Growth Curve (SGC) for D-e determination on quartz from the Chinese Loess Plateau

摘要

In the Standardised Growth Curve (SGC) method of De determination, once a SGC has been constructed, a De can be determined by measuring the natural OSL and the OSL response to a test dose only, instead of constructing a growth curve for each aliquot. This is a major advantage when a large number of samples from the same section, or the same geographical area, have to be dated, and the samples are well bleached before deposition. In the present study, the use of a SGC for De determination is tested using quartz extracted from loess samples from the Chinese Loess Plateau. It is demonstrated that: (a) A common growth curve exists for samples collected from four different sections in the Chinese Loess Plateau; (b) The scatter in De for samples younger than about 270ka is dominated by the scatter of the natural signal levels, not that of the growth curve; (c) There is a slight difference between the shape of the growth curves of young samples (< 270 ka) and those from old samples (c. 0.65-2.5 Ma). The cause is not known, but may be due to the difference in ages (total natural irradiation dose) or in the dust sources (origins of quartz); (d) Up to a De of c. 200 Gy, the single aliquot regenerative-dose (SAR) De and the SGC De are in agreement. The ratio of the sum of SAR Des to the sum of SGC Des is 1.01, close to unity. It is therefore concluded that SGC is an alternative procedure for De determination for loess samples from the Chinese Loess Plateau. (c) 2005 Elsevier Ltd. All rights reserved.