Publication Date:
2014-12-13
Description:
Publication date: Available online 11 December 2014 Source: Quaternary Geochronology Author(s): Christina M. Neudorf , Olav B. Lian , Ian J. Walker , Dan H. Shugar , Jordan B.R. Eamer , Libby C.M. Griffin The Quaternary geology of British Columbia’s central coast contains a rich and complex record of glacial activity, post-glacial sea level and landscape change, and early human occupation spanning the last ∼10,000 years. At present, however, this region remains a largely understudied portion of coastal North America. This study describes the luminescence characteristics of quartz and K-feldspar from coastal dune and beach sands on Calvert Island and develops a suitable luminescence dating protocol that will allow for a more rigorous chronology for post-glacial landscape evolution and human occupation on BC’s central coast. Luminescence signals from Calvert Island quartz are dim, and appear to lack the so-called “fast” component that is most desirable for optical dating. K-feldspar signals are sufficiently bright for optical dating. We test and refine a single-aliquot regenerative-dose (SAR) protocol for K-feldspar specific to Calvert Island samples through a series of dose recovery and preheat plateau tests. Two approaches for correcting a sample age for anomalous fading are compared and a correction for phototransfer is introduced and applied. Measured fading rates vary from sample to sample implying that, in this region, it is not sufficient to rely on two or three representative fading rates as has sometimes been done elsewhere. Refined age estimates show consistency with independent radiocarbon dating control and help identify radiocarbon-dated organic-rich sediments that have been reworked.
Print ISSN:
1871-1014
Electronic ISSN:
1878-0350
Topics:
Geosciences