第四紀研究
Online ISSN : 1881-8129
Print ISSN : 0418-2642
ISSN-L : 0418-2642
24 巻 , 2 号
選択された号の論文の6件中1~6を表示しています
  • ブルーム アーサー, 朴 龍安
    1985 年 24 巻 2 号 p. 77-84
    発行日: 1985/07/31
    公開日: 2009/08/21
    ジャーナル フリー
    韓国の黄海沿岸に位置するたくさんの小さい入江 (三角江) は, 20世紀初期以来, 干拓が行なわれてきた. これらの入江では, 薄い水田土壌及び河成の堆積物の下に, 有機質に富む河口成堆積物が風化した基盤の砕屑物を覆っている. 河口成堆積物の基部約15cmは, とくにたくさんの流木の破片を含み, これは完新世海面上昇期の高潮位に形成された泥炭質泥層と混ざっている. これらの基底付近の河口成泥層のうち, 8試料の14C年代が得られた. その年代と深度に基づいて韓半島黄海沿岸における完新世海水準変化曲線が復元された.
    8,600y.B.P.から4,800y.B.P.の間, 韓国の黄海海岸は約1.6mm/年の平均速度で沈水した. その後, 沈水速度は約0.4mm/年に減少した. 韓国南東部の浦項-梁山地塊は, その東岸を一連の海成段丘で縁取られている. これらの海成段丘の年代はまだわからないが, おそらく少くとも最終間氷期 (約125,000年前) にさかのぼると考えられる. 後期更新世のこの地塊の隆起速度は約0.1m/1,000年と推定される.
  • 寒川 旭, 衣笠 善博, 奥村 晃史, 八木 浩司
    1985 年 24 巻 2 号 p. 85-97
    発行日: 1985/07/31
    公開日: 2009/08/21
    ジャーナル フリー
    The Nara Basin, the eastern rim of which is bordered by N-S trending faults and flexures, is located in the central part of the Kinki Triangle.
    The writers have investigated displaced topographies and deformed strata to understand the nature of neotectonics of the area. The findings are summarized as follows.
    1) Several river terraces distribute widely along the eastern rim of the Nara Basin. They are classified into five according to their age: namely Kokuzoyama, Narasaka, Rokuyaon, Wani and Ichinomoto surfaces in descending order. The deposits of the Ichinomoto surface are dated 18, 410±920y.B.P. (GaK-9709) by 14C method.
    2) Terraces have been deformed along the Tenri and Narasaka flexures. These flexures are surface expressions of the reverse faults in bed rocks. The average rate of the vertical component of the deformation is calculated 0.07-0.30m/103y. for the Tenri flexure and 0.13-0.17m/103y. for the Narasaka flexure.
    3) The Tenri flexure occurred after the formation of the Kokuzoyama surface, and simultaneously the Sanbyaku fault, which borders the basin in the west and the mountains in the east, became inactive. This implies that the fault movement migrated from the mountain foot toward the basin in middle Pleistocene.
  • 五十嵐 八枝子, 高橋 伸幸
    1985 年 24 巻 2 号 p. 99-109
    発行日: 1985/07/31
    公開日: 2009/08/21
    ジャーナル フリー
    Two different types of upland bogs in the Daisetsu Mountains, central Hokkaido, were studied in order to examine their origin and vegetational succession.
    The Numano-hara bog (1, 424m, a.s.l.) which is located on a lava plateau in the southeastern part of the Mountains, formed around 4, 000y.B.P. in a cool and moist climate. The result of pollen analysis suggests the following 3 pollen assemblage zones. During the period of Zone Nu-III (ca. 4, 000-2, 000y.B.P.), Betula ermanii was most dominant. Zone Nu-II (ca. 2, 000-400y.B.P.) is characterized by the decrease of Betula ermanii and the dominance of Picea glehnii as a rerult of the expansion of the bog in a cooler and moister climate. Also, a needle-leaved forest composed of Picea glehnii and/or Picea jezoensis and Abies sacharinensis spread to the lower areas. Finally, the bog decreased in size under a slightly drier condition, and Betula ermanii invaded again at the period of Zone Nu-I (ca. 400y.B.P.-present).
    The bogs around the Midorino-numa and the Basho-numa (1, 365m, a.s.l.) located near the eastern margin of Takanega-hara in the central part of the Mountains were observed in some places around the depressions formed by landslide. According to tephrochronology of 5 thin volcanic ash layers, the beginning of the Midorino-numa bog is a little prior to 1, 300y.B.P., whereas the Basho-numa bog is considered to have originated between 1, 300 and 5, 000y.B.P. Although Betula ermanii invaded into the landslide area in an early stage, Picea glehnii increased after the bog formed (Zone Mi-II). At about 1, 300y.B.P. the forest around the bog reached the climax Picea glehnii forest just like the present one (Zone Mi-I).
    Four other upland bogs developed in Hokkaido are classified into 2 types in the same way as the bogs in the Daisetsu Mountains. The Pankenai bog in the Teshio Mountains and the Ukishima bog in the Takinoue Plateau on flat plains like Numanohara formed in a cool and moist climate (Zone Nu-II). On the other hand, the bogs developed around the depression by landslide such as the Midorino-numa and the Basho-numa belong to different ages. The age is Orochiga-hara bog on Mt. Muine is estimated to be approximately 6, 000y.B.P. and the age of a small bog located on the southeastern slope of Mt. Onnebetsu-dake is approximately 300y.B.P.. Therefore, their difference in age probably depends on the formation of the depressions.
  • 野尻湖発掘調査団人類考古グループ , 野尻湖発掘調査団哺乳類グループ
    1985 年 24 巻 2 号 p. 111-124
    発行日: 1985/07/31
    公開日: 2009/08/21
    ジャーナル フリー
    Since 1962, excavations at Tategahana site which is located on the west coast of Lake Nojiri, Central Japan, have been carried out by the Nojiri-ko Excavation Research Group. On the occasion of the 8th excavation in 1981, 1, 064 materials were excavated in total. They include 234 stone artifacts, 19 wooden tools or man-made wooden flakes and 13 bone artifacts which were mainly made of Naumann elephant (Palaeoloxodon naumanni) and Yabe giant deer (Sinomegaceros yabei).
    Palaeolithic bone tools are, presently, available only in a few archaeological sites such as Hanaizumi, Iwate Pref., the First Cave of Yamashita-cho and Gohezu Cave, Okinawa Pref.; but the bone materials from the latter two caves are in controversy whether they belong to man-made tools or materials made by non-human agencies. In any case, there is not a single artifact in Japan comparable to the bone scraper from Tategahana. A portion of the bone scraper which is flaked off by a single side-blow percussion is identified with a left tibia of Naumann elephant. The shape is oval and it measures 18.5×6.2×1.7cm, and the scraper-edge is retouched from dorsal surface along the sharp margin of the primary flaking. Use-wear and abrasion on the edge surface have also been examined with a binocular microscope.
    The stratigraphic units of the Lower Nojiri-ko Member are divided into Members I, II and III in ascending order, and the bone scraper has been discovered on the bottom of Section IIIBl. A radiocarbon date of Section IIIA formed right under Section IIIBl indicates 36, 320±1, 130y.B.P. (GaK7792). This suggests that the age of the bone scraper belongs to a little bit younger range than this date.
    Berelekh is an archaeological site in the U.S.S.R. which reveals some bone scrapers morphologically related to that of Tategahana. But they represent a later stage of Upper Palaeolithic. The Section III of the Lower Nojiri-ko Member includes both stone and bone tools, and the stone industry is less developed than the bone industry.
    The age of the bone scraper, beyond dispute, coincides with the transitional phase from Neanderthal Man to Modern Man. The present paper focuses on a description of the bone scraper and its related problems. But this will provide some fundamental information for the elucidation of the bone tool manufacturing technology in the East Asian later Pleistocene.
  • 鹿島 薫
    1985 年 24 巻 2 号 p. 125-138
    発行日: 1985/07/31
    公開日: 2009/08/21
    ジャーナル フリー
    The author observed fossil diatom assemblages of 138 samples of Holocene deposits in Takagami Lowland, central part of the Choshi Peninsula. The Holocene deposits in Takagami Lowland can be divided into 5 zones of diatom assmeblages (Fig. 8). The character of each zone can be described as follows.
    Zone I (-15m--10m)
    Fresh-water species are dominant and comprise more than 60%. But fresh-brackish species and marine species can be observed together. A ratio of marine species increases toward upper horizon. Dominant species are Achannthes lanceolata, Cocconeis placentula, Navicularadiosa, all of which live in fresh-water pond, lake and river.
    Zone II (-10m--2.5m)
    Marine species are dominant and comprise more than 90%. Dominant species are Thalassiosira excentrica, Cyclotella striata, Actinoptychus undulatus, all of which are planktonic and live in inner bay and ocean.
    Zone III (-2.5m-3.5m)
    Marine species are dominant and comprise more than 90%, too. But Cocconeis scutellum, which lives in polyhaline lagoon, is dominant.
    TR Zone (3.5m-4.7m)
    TR Zone can be observed in Loc. 1 and Loc. 6. This zone is a transitive zone from Zone III to Zone IV. Rhopalodia gibberula, which lives in oligohaline lagoon, is dominant.
    Zone IV (3.5m-10m)
    Fresh-water species are dominant and comprise more than 90%. Marine species cannot be observed. Dominant speceis are Achnanthes minutissima, Fragilaria construens, Fragilaria brevistriata, Melosira granulata, all of which live in fresh-water pond and lake.
    The paleo-environmental succession in Takagami lowland is shown in Fig. 9. About 8, 000-10, 000y.B.P., marine transgression started and a drowned valley began to be formed (I). Due to rapid transgression, the drowned valley was spread widely till 6, 000y.B.P. (II). About 5, 500-6, 000y.B.P., the beach ridge was formed in the eastern part of this drowned valley, so that the depositional environment of this area was changed from inner bay to polyhaline lagoon (III). About 5, 000y.B.P., in the middle and eastern part of Takagami lowland fresh-water marsh was formed, and a second transgression did not happen (IV-1). In the northwestern part, marine sand with shell fragments and diatom valves of marine species were deposited frequently on the freshwater marsh by storm surges till about 3, 000y.B.P. (IV-2).
  • 小杉 正人
    1985 年 24 巻 2 号 p. 139-147
    発行日: 1985/07/31
    公開日: 2009/08/21
    ジャーナル フリー
    It is an important and fundamental study in paleoecology to examine accurately the distribution and ecology of living assemblages. In the case of diatoms, however, living assemblages have been unalbe to be selected from the total assemblages including dead cells.
    Hematoxylin and Eosin stain which is in general use to observe cell contents of organisms anatomically is used in this study to distinguish between living and dead cells of diatoms. Moreover, characteristics in the distribution of diatoms obtained from the lower reach of the Obitsu river, Chiba Prefecture, central Japan, are investigated by this method.
    The results are as follows;
    1. The images of nucleus dyed by Hematoxylin and the part of cytoplasm, considered to be chromatophore, dyed by Eosin show patterns peculiar to some groups of species. The dyed images are classified into four types on the basis of characteristics in their shape, position (nucleus and cytoplasm) and number (cytoplasm). Only completely dyed cells are identified as living, and partly-dyed cells and undyed cells as dead.
    2. In the Obitsu river, living assemblages peculiar to such environments as tidal flat, tidal inlet, salt pond and estuary were recognized as shown in Fig. 2a. These environments are characterized by differences in salinity, bottom sediment, accumulation of organic matter and current of water. On the other hand, dead cells were diffused to the outside of the living area (Fig. 2b). In order to analyze fossil assemblages, it is necessary to make use of the data obtained from present environments.
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