Liu, H.; Takagawa, T., and Sato, S., 2014. Sand transport and sedimentary features based on feldspar thermoluminescence: a synthesis of the Tenryu–Enshunada fluvial system, Japan.
On the basis of the feldspar thermoluminescence (TL) measurement, sediment transport features were investigated in the entire Tenryu River watershed and the corresponding littoral sediment zone of the Enshunada coast. Subsequently, the sedimentary configuration and sand provenance in the river mouth area were studied using subsurface samples. In the Tenryu River watershed, TL intensities of the riverine samples fluctuated with respect to the local geological characteristics. Comparing with samples collected from the main river route, branch samples generally present larger TL intensities. Nevertheless, sediment supply from branches is considered to be rather limited in terms of their small discharges. Increase in the riverine TL property can be detected in the immediate dam downstream area, as well as the region with mass sand movements. Taking into account the Enshunada coastal samples, measured sediment TL intensities present a local peak value around the river mouth and a decreasing trend with the increasing distance away from the river mouth. This is attributed to the river sand supply and the gradual sunlight exposure during the longshore sediment transport. In general, riverine samples present much larger TL intensities than coastal samples, and a criterion on the basis of a TL intensity value of 5 was recognized to distinguish these two types of sands in the study area. Applying this criterion to the subsurface samples collected in the river mouth sand spit, a sedimentary interface at Tokyo Peil −1 m was confirmed with coastal sands (small TL intensity with wave experience) located on the top and riverine sands (large TL intensity without wave experience) deposited at the bottom, which is in agreement with estimations from other physical and geomorphological approaches.