Luminescence dating of K-feldspar from sediments: A protocol without anomalous fading correction

A protocol for optical dating of potassium-rich feldspar (K-feldspar) is proposed. It utilizes the infrared stimulated luminescence (IRSL) signal measured by progressively increasing the stimulation temperature from 50 to 250 degrees C in step of 50 degrees C, so-called multi-elevated-temperature post-IR IRSL (MET-pIRIR) measurements. Negligible anomalous fading was observed for the MET-pIRIR signals obtained at 200 and 250 degrees C. This was supported by equivalent dose (D(e)) measurements using the IRSL and MET-pIRIR signals. The De values increase progressively from 50 degrees C to 200 degrees C, but similar D(e) values were obtained for the MET-pIRIR signal at 200 and 250 degrees C. Measurement of modern samples and bleached samples indicates that the MET-pIRIR signals have small residual doses less than 5 Gy equivalent to about 1-2 ka. We have tested the protocol using various sedimentary samples with different ages from different regions of China. The MET-pIR IRSL ages obtained at 200 and 250 degrees C are consistent with independent and/or quartz OSL ages. (C) 2011 Elsevier B.V. All rights reserved.