Last ~1,300 years environmental change at Lake Koyama-ike inferred from diatom fossil assemblages and electric conductivity analyses, Tottori Prefecture, Japan
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- Sato Yoshiki
- National Institute of Advanced Industrial Science and Technology
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- Kodama Yoshinori
- Tottori University
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- Kashima Kaoru
- Kyushu University
Bibliographic Information
- Other Title
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- 珪藻化石群集および電気伝導度から推定される過去約 1,300 年間における湖山池の環境変化
Abstract
Using a 150-cm lake bed core sample, the paleoenvironmental change during the past ~1,300 years in Lake Koyama-ike, Tottori Prefecture, western Japan, was reconstructed based on diatom fossil assemblages, electric conductivity, and radiocarbon ages. Consequently, the following points were clarified:<br> 1) During the past 1,300 years, the surface water of Lake Koyama-ike has been a freshwater environment—freshwater pond or lake—because freshwater diatom species were dominant in the entire core. In contrast, due to salinity stratification, a brackish-to-marine environment has remained immediately above the lake bed.<br> 2) The diatom fossil assemblages indicated the decrease in water salinity and depth after ~1,000 cal BP. Because a similar transition has been previously reported in studies conducted at other sites in Lake Koyama-ike, this environmental change is a common phenomenon in this lake.<br> 3) A decrease in water salinity around 1,000 cal BP indicated that the channel connecting the Japan Sea and Lake Koyama-ike was filled by the blown sand. The shallowing of the lake around the same period was probably caused due to rapid deposition of riverine sediments and relative sea-level fall, which presumably induced the sand to actively blow in the coastal area.
Journal
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- Laguna
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Laguna 24 (0), 27-37, 2017
Japanese Association for Estuarine Science
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Keywords
Details 詳細情報について
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- CRID
- 1390862623772024960
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- ISSN
- 21852995
- 13403834
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- Text Lang
- ja
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- Data Source
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- JaLC
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- Abstract License Flag
- Allowed