Chronology of Last Glacial Maximum sediments in the coast of Fujian, South China

Abstract

The coast in South China is an important area for the coupling of terrestrial, marine, and atmospheric processes. Widespread loose sediments in the area likely recorded regional climatic and geomorphic processes since the Late Pleistocene, and these that can be deciphered through geochronology. In the present study, eighteen samples prepared from the FN1 core retrieved from the Funing Bay in the coast of Fujian were used for OSL dating. The single-aliquot regenerative-dose (SAR) approach was employed for dating using three grain-size fractions of quartz, while coarse-grained K-feldspars were used for post-infrared infrared stimulated luminescence (pIRIR) dating of the core. Seven samples were also dated using the AMS 14C dating technique to establish the reliable chronology. The results reveal the following: 1) Minerals and grain size variations directly affect the accuracy of the luminescence dating. The present study demonstrates that cross-validation of the OSL dating data is an effective way to enhance their reliability. 2) Dating results from the three grain-size fractions of quartz in the upper section of the core are consistent within the error range, and these agree with ages from the AMS 14C method for the corresponding horizon. However, the OSL ages based on the three grain-size fractions of quartz and the coarse-grain K-feldspar differed for the lower section of the core (10.6–14.7 m). 3) Samples produced ages ranging from 25.4 to 0.8 ka based on the OSL dating method. According to a chronological framework starting from the Last Glacial Maximum and a palaeoenvironmental index, the sedimentation rate is partitioned into three main periods. Sedimentation rates during the periods between 25 and 21 ka and < 7 ka are higher than those for the period between 21 and 7 ka. These results suggest that the sedimentation rate was probably linked to the regional transgression events.