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Volume 66 (2012)
- Issue 6 Pages 205-
- Issue 5 Pages 157-
- Issue 4 Pages 117-
- Issue 3 Pages 69-
- Issue 2 Pages 43-
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Volume 66, Issue 5
Displaying 1-5 of 5 articles from this issue
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Shigeki CHIBAArticle type: Article
2012 Volume 66 Issue 5 Pages 157-159
Published: September 25, 2012
Released on J-STAGE: May 16, 2017
JOURNAL OPEN ACCESSDownload PDF (10670K) -
Akihiko SUZUKI, Takafumi ENYAArticle type: Article
2012 Volume 66 Issue 5 Pages 161-162
Published: September 25, 2012
Released on J-STAGE: May 16, 2017
JOURNAL OPEN ACCESSDownload PDF (6925K) -
Dalai BANZRAGCH, Hiroaki ISHIGAArticle type: Article
2012 Volume 66 Issue 5 Pages 163-176
Published: September 25, 2012
Released on J-STAGE: May 16, 2017
JOURNAL OPEN ACCESSRecent archaeological excavations at the Yamasaki site, Hikimi River, in Shimane prefecture of SW Japan discovered Earliest to Late Jomon pottery fragments. Based on the ages of the unearthed artifacts, sediment samples were collected from three trenches to examine their geochemical composition in relation to source composition, and to interpret past human activity and heavy metal accumulation. X-ray fluorescence analyses of 68 samples showed different concentrations of elements due to source rock type, sediment grain size fractionation, and past human activity. However, all trenches had low abundances of Cr, Ni, V and Sc relative to UCC, indicating that the sediments at the Yamasaki site were derived from highly felsic source rocks. Contents of As, Pb, Zn, Cu, Fe2O3 and P2O5 were considerably greater than UCC, and are likely to be associated with past human habitation. The northern trench (NST-1) which contained the oldest past human settlement exhibited the lowest abundances of heavy metals. Highest abundances of heavy metals occur in the eastern and western trenches, which also contained the most artifacts. Peak concentrations of phosphate and zinc were detected in the Guro-1 black layer. The geochemical and archaeological evidence indicates that people were living and producing pottery at the Yamasaki site at about 3500-3000 BP. Past human life style, activities such as cooking, heating, and firing pottery, and human wastes were probably significant contributors to the distributions of elements in the soils.View full abstractDownload PDF (21626K) -
Gen'ichi ASANO, Takao YANO, Kazuyuki HIRAO, Yuichi TANAKAArticle type: Article
2012 Volume 66 Issue 5 Pages 177-191
Published: September 25, 2012
Released on J-STAGE: May 16, 2017
JOURNAL OPEN ACCESSMid-Miocene transgressive sediments at Miyanoshita, Tottori City, yield abundant fossils of shallow marine fishes. As a part of investigation on the taphonomy of the fish fossils, this paper aims to analyze the sedimentary facies of the lower and middle Miocene Tottori Group, and to clarify the formative process of the fossiliferous unit. The major conclusions are as follows: 1) Facies analysis of the Tottori Group depicts the diachronous change of sedimentary environments: alluvial fan to meandering river environment for the Entsuji Conglomerate, Sandstone and Mudstone Member, lacustrine delta for the Shozan Sandstone and Mudstone Member, meandering river and flood plain for the Fuganji Mudstone and Sandstone Member, and outer shelf to deeper marine for the Tochimoto Shale Member. 2) The fish-fossil stratigraphic unit at the base of the Tochimoto Member comprises alternation of very fine-grained sandstone and siltstone in millimeter to sub-millimeter thickness. It contains abundant remains of shallow marine fish fossils, but no body- and trace-fossils of benthos. These facts indicate that the fossiliferous unit has accumulated in a coastal low-energy environment, i.e., in a lagoon, and that the hypersaline bottom water of the lagoon basin has been steadily anoxic due to strong density stratification, which is characteristic of deep and choked lagoons. 3) Although shoreface erosion frequently removes coastal lagoon sediments in transgressive stages, the fish-fossil unit at Miyanoshita was preserved through a rapid increase in accommodation. The increase was due to tectonic subsidence (0.45 mm/y on the average), eustatic rising (TB2.3) during the mid-Miocene climatic optimum, and sediment starvation resulted from extensive submergence of hinterland. 4) The fish-fossil unit appears to have formed through the following processes: (a) at a stormy high tide, sea water with shallow-marine fishes invaded into the coastal lagoon, (b) the fishes soon became feeble and dead through exhaustion of dissolved oxygen in the bottom seawater, and (c) very-fine sand grains and silt particles suspended in river floodwater settled down to envelope the fish remains at the lagoon bottom.View full abstractDownload PDF (3285K) -
Sadako TAKEUCHI, Akihiro YOSHIDAArticle type: Article
2012 Volume 66 Issue 5 Pages 193-197
Published: September 25, 2012
Released on J-STAGE: May 16, 2017
JOURNAL OPEN ACCESSThe Sendai Group consists of the Kameoka, Tatsunokuchi, Mukaiyama, and Dainenji Formations in ascending order. Among them, the Tatsunokuchi, Mukaiyama and Dainenji Formations are distributed in the Mukaiyama area, Sendai City, Miyagi Prefecture. Pollen analysis was made on the sediment samples of these Formations. The uppermost part of the Tatsunokuchi Formation is characterized by a dominance of Sequoia type pollen including Sequoia and Metasequoia, and they are accompanied by Taxodium and Fagus. The Mukaiyama Formation has a high percentage of Fagus pollen. The frequencies of Sequoia type pollen are higher in the upper part than those in the lower part. In the lower part of the Dainenji Formation, Allnus pollen are dominant, followed by Fagus and Sequoia type. Palaeoclimatic condition in Pliocene time is inferred to have been mild and maritime during deposition of the uppermost part of the Tatsunokuchi Formation up to the lower part of the Dainenji Formation.View full abstractDownload PDF (786K)
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