2010 Fiscal Year Final Research Report
Surface pollen investigation in the warm-temperate to subtropical regions of Japan : an attempt for quantitative palaeoclimate reconstruction on Quaternary interglacials
| Project/Area Number |
19684018
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| Research Category |
Grant-in-Aid for Young Scientists (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Natural History Museum and Institute, Chiba |
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Principal Investigator |
OKUDA Masaaki Natural History Museum and Institute, Chiba, 生態環境研究部, 上席研究員 (10311383)
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| Co-Investigator(Renkei-kenkyūsha) |
TAKEMURA Keiji 千葉県立中央博物館 (00201608)
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| Project Period (FY) |
2007 – 2010
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| Keywords | 表層花粉 / モダンアナログ法 / 日本列島 / 第四紀 / 暖温帯 / 亜熱帯 / 温暖化 |
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| Research Abstract |
The pollen-based modern analogue technique (MAT) can provide constraints for climate projections for the next decades (IPCC, etc) by reconstructing quantitative palaeotemperature of human habitation areas during the late Quaternary. However, a so-called fade-out problem of reconstructed temperature in >16℃ regime has prevented the MAT from providing analogues for the >2℃ warmer world than present. To reduce this problem, we perform surface pollen investigation for warm-temperate to subtropical regions of Japan, of which annual mean temperature exceeds 16℃.
In geographical context, southern Kii peninsula, SW Shikoku, Kyusyu and islands of Tanega-shima, Amami-Oshima, Okinawa, Hachijo-jima, etc are selected for hot region up to 23℃. The collected samples (surface pollen materials composed of living moss polster) are analyzed in the standard palynological procedure to fill the gaps in the >16℃ regime of Japan. Results provide a complete temperature curve without lack in extreme temperature
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zones (5-7℃ warmer than the present in the Kinki-Kanto districts).
In palynological context, almost all the lower warm-temperate to subtropical zones, located to the south of Shikoku, are dominated by abundant Castanopsis pollen. High values of evergreen oak (Cyclobalanopsis) are restricted in the upper warm-temperate zone (<16℃ in annual mean temperature). In addition, an attempt of palaeoclimate reconstruction using previous surface pollen is also performed on the fossil pollen record from Lake Biwa. These results have been summarized into two English manuscripts for international journals (Okuda et al., Tarasov et al.).
We note that this project also deal with the surface pollen investigation for ocean floors around the Japanese archipelago. The NW Pacific has had a lot of ocean coring points. Since the cored materials from the marine realm are preserved in JAMSTEC, San-So-Ken, etc, sabsampling and analyzing muddy sediments from the core tops can provide surface pollen dataset beneath the ocean, which is in the same manner as those in terrestrial regions.
Unfortunately, surface pollen samples themselves cannot be collected in current urban areas around e.g. the Tokyo Bay. To reduce this problem, we performed a borehole core project in central Chiba city. Results show that fossil pollen of 1500-2500 yr BP age, with little vegetation disturbance by early humans, can serve as a substitute for modern surface pollen. Less
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Research Products
(16 results)
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[Remarks] 受賞歴:2007年日本第四紀学会論文賞奥田昌明ほか(2006)下総層群清川層堆積期間(MIS7)の古気候状態-花粉ほか代理指標からの考察-
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[Remarks] 受賞者の言葉:奥田昌明ほか(2007)第四紀通信14(5),3-4に掲載。
