Radiocarbon Dating of Cored Sediments from Oonohara and Naganoyama Moorlands at Tsukude-mura, Shitara-gun, Aichi Prefecture
- Other Title
Several moorlands with thick peaty sediments are existing on an inland valley plain of 500-600m altitude in Mikawa Plateau, at Tsukude-mura, Shitara-gun, an eastern part of Aichi Prefecture. Sediment columns of several-meter long, drilled at Oonohara and Naganoyama moorlands in January 1991,are analyzed for sedimentary structure, organic and inorganic contents, polen contents, plant contents, tephra stratigraphy, and ^<14>C dates. Columnar sections of the cored sediments are shown in Fig.3. The ^<14>C dating is performed on plant fragments in the sediments at 11 horizons for Oonohara sediments (9101-B3) and 6 horizons for Naganoyama sediments (9101-B4), by using a Tandetron accelerator mass spectrometer of the Dating and Materials Research Center, Nagoya University. Seven ^<14>C dates of the 9101-B3 core, ranged from 3,000 to 31,550y.B.P., are consistent in stratigraphy with the AT tephra horizon of 21,000-25,000y.B.P., except for three ^<14>C dates, which are about 10,000 years younger than those expected by the AT tephra(Fig.3). For the Naganoyama 9101-B4 core, only one date is consistent with the K-Ah tephra horizon (ca. 6,300y.B.P.), and other 5 dates are younger than expectation (the Kg tephra horizon of 2,800-2,900y.B.P. in Fig.3). The reason for obtaining such younger dates is being studied. The younger dates may be attributed to vegetation of plants, extending their long roots and stems to the deeper horizons of the sediments, as well as to a vertical mixing of the sediments as the result of periglacial environment and/or earthquakes, rather than to the modern carbon contamination during the sample preparation processes.
タンデトロン加速器質量分析計業境報告 Summaries of Researches Using AMS
名古屋大学加速器質量分析計業績報告書 4 61-72, 1993-03