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The Noshiro coastal dune in Akita Prefecture, northeastern Japan, is classifiedas a superpositioning coastal dune and consists of five basic units composed of threeaeolian sand units bounded by layers of humic soil. Topographical map survey on studyarea situated south of the Yoneshiro River revealed differences in topographical characteristicsbetween the northern part of the dune and the southern part. In addition, field surveyrevealed differences in the number of humic soil layers in both the northern and southernparts of the dune. These differences cannot be entirely explained by the commonly acceptedinterpretation that crustal movement caused a dipping to the northeast in the vicinity of theresearch area. Another possible interpretation for the differences is explored here; that a shortage inthe sedimentary supply from the beach to the southern coastal dune, which decreases southwardfrom the Yoneshiro river mouth, promoted the formation of barchans. These are recognizable intopographic maps of the study area, and their accumulation has given the southern coastal dune acomplex structure. |
