JaLCDOI 10.18926/ESR/13870
Title Alternative Paleoenvironmental Analyses of the Buried Peat Deposit during the mid-Holocene at the Desaki Coast in Tamano City, Okayama Prefecture, Weatern Japan
FullText URL earth_science_reports_011_1_39.pdf
Author Matsushita, Mariko| Sato, Hiroshi| Suzuki, Shigeyuki| Yukumoto, Koichi| Momohara, Arata| Ueda, Yayoi| Katoh, Shigehiro| Maeda, Yasuo|
Abstract The buried peat deposit was foud in the sand beach on the Desaki coast (Tamano City, Okayama Prefecture), the northeastern coast of Seto Inland Sea. In this study, we performed sulfur and diatom analyses of the deposit. The results were used along with 14C dates and the eruption age (7300 cal BP) of Kikai-Akahoya tephra (K-Ab) to derive sedimentary environments of the deposit. K-Ah was detected just below the peat deposit. At the culmination of the Jomon transgression, the peat deposit had been formed in brackish environments of salt marsh for about 300 years. In order to reconstruct local paleovegetation, we analyzed pollen, wood and plant fossils in the deposit. The results show vegetational transition from a deciduous broadleaved forest mainly of Ouercus subgen. Lepidobalanus to Pinus forest. In spite of the Holocene thermal optimum, the vegetation dominated by Ouercus subgen. Cyclobanopsis was not recognized at the Desaki site, as has been shown in many other regions of regions of western Japan. Ouercus sect. Prinus was replaced by Ouercus sect. Aegilops as the dominant section of Ouercus subgen. Lepidobalanus, suggesting early establishment of traditional rural vegetation of 'Satoyama' in Japan. However, no evidence for human agency has been obtained from the mid-Holocene archaeological sites around the Desaki site. Thus it is more likely that this vegetational transition resulted from the succession caused by natural forces such as ecological disturbance and climatic and/or endemic situations rather than by cultural deforestation.
Keywords Desaki coast diatom remains Jomon transgression Kikai-Akahoya tephra mid-Holocene Paleoenvironment peat deposit plant fossils
Publication Title Okayama University Earth Science Report
Published Date 2004-12-31
Volume volume11
Issue issue1
Start Page 39
End Page 47
ISSN 1340-7414
language 日本語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310603
JaLCDOI 10.18926/ESR/13869
Title Alternative Relative sea-level changes of the Okayama Plain Area during the Holocene, Southwest Japan
FullText URL earth_science_reports_011_1_33.pdf
Author Suzuki, Shigeyuki|
Abstract Postglacial relative sea-level change of the Okayama Plain Area has been analyzed. Former sea-levels were recognized by using peat beds and marine organisms which are also available for 14C dating. Peat beds were rhought to be formed under a stable sea-level condition. 14C ages of the analyzed peat beds were seprated by 4 groups ; 30~18 ka BP, 11~8 ka BP, 6~4 ka BP and 3~2.5 ka BP, indicate 4 stable sea-level periods. 2 transgressive events (18~11 ka BP and 8~6 ka BP) and one regressive event (3.5?~3 ka BP) were also inferred.
Keywords sea-level change peat bed Holocene Okayama Plain
Publication Title Okayama University Earth Science Report
Published Date 2004-12-31
Volume volume11
Issue issue1
Start Page 33
End Page 37
ISSN 1340-7414
language 日本語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310268
JaLCDOI 10.18926/ESR/13847
Title Alternative Geology of Holocene deposits in Mizushima Area, Okayama Prefecture, Japan
FullText URL EAR_13_1_15.pdf
Author Suzuki, Shigeyuki|
Abstract The study srea, Mizushima is occupied by polder and reclaimed land. The ground of this area is composed of the Holocene deposits below the surface. The deposits are mostly 10 to 20m in thickness and composed of 2 units, the B Unit and C&D Unit. The B Unit is composed of muddy sand with 2 to 3m in thickness. This unit is thought to be deposited in the mouth of paleoriver. The C&D Unit is composed of marine mud and sand with 10 to 15m in thickness. This unit is especially soft and will expand ground oscillations during an earthquake.
Keywords Holocene deposits Mizushima Area Ground oscillation
Publication Title Okayama University Earth Science Report
Published Date 2006-03-31
Volume volume13
Issue issue1
Start Page 15
End Page 18
ISSN 1340-7414
language 日本語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310562
JaLCDOI 10.18926/ESR/13844
Title Alternative バングラディシュの更新世台地の地形と地質
FullText URL EAR_13_1_1.pdf
Author Towhida Rashid| Md. hossain Monsur| Suzuki, Shigeyuki|
Abstract With regards to the origin and evolution of the Pleistocene tracts (Lalmai, Madhupur and Barind tracts) of Bangladesh, two trends of thoughts are common. Most of the authors believed that the Madhupur, Barind and Lalmai tracts represent tectonically uplifted surface. Some researchers have different opinion and they believed that the Lalmai hills and the Madhupur locality represent tectonically uplifted blocks but the whole Barind tract and the major portion of the Madhuput tracts are not tectonically uplifted, rather these are originated by erossional-depositional processes. In order to solve the problems associated with origin and evolution of Pleistocene tracts of Bangladesh, further study is needed. Borehole data may be collected and fusion images can be prepared from aerial photographs and setellite images to detect netectonic imprins and geomorphological signatures of the areas. Elaborate laboratory analysis of sediment deposits, radiocarbon dating my indicate a new dimension about the origin and evolution of these tracts.
Keywords Bangladesh Lalmai Hill Barind Tract Madhupur Tract Neotectonices Aerial photographs Satellite Image Fusion Image
Publication Title Okayama University Earth Science Report
Published Date 2006-03-31
Volume volume13
Issue issue1
Start Page 1
End Page 13
ISSN 1340-7414
language 英語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310445