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Volume 107, Issue 1
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Norikazu MATSUOKA1998 Volume 107 Issue 1 Pages 1-24
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSRecent progress in rock glacier studies is reviewed with some emphases on the competition between the glacial and periglacial hypotheses. Rock glaciers are tongue-shaped or lobate bodies composed of angular boulders that resembles a small glacier, usually accompanied by multiple transverse ridges resulting from a compressive flow. Rock glaciers are classified, in terms of the origin of surface materials, into talus and morainic rock glaciers, and in the light of the activity status, into active, inactive and fossil ones. The distribution of active rock glaciers are delimited by the regional glacier equilibrium line and lower limit of mountain permafrost.
The internal structure of rock glaciers has been approached by direct observations and indirect geophysical soundings. In some rock glaciers, natural outcrops exhibit a massive ice body with debris bands beneath the surface boulder layer, which has encouraged the glacial hypothesis. Massive ice was also found in boreholes penetrating through a rock glacier permafrost in the Swiss Alps, despite being considered to originate from snow avalanche or refrozen meltwater. In fact, deformation occurred mostly in the frozen debris layer beneath the massive ice, indicating the periglacial origin of the rock glacier due to permafrost creep. Geophysical soundings, including seismic, geoelectric and gravimetric measurements, have provided useful information on the three-dimensional structure, stratigraphy and ice contents of rock glacier bodies, although authors preferring the glacial hypothesis tend to reject such indirect results. The origin of any rock glacier is thus equivocal without detailed analyses of internal stratigraphy and ice composition.
Most of the active rock glaciers are moving at a speed of 101 cm yr-1, two orders of magnitude slower than 'ice' glaciers. The periglacial model attributes such a slow movement to permafrost creep. A possible consequence of this is that active rock glaciers usually have ages of several thousand years ; that inactive ones were activated repeatedly during the colder periods of the Holocene; and that fossil ones moved during the Late Glacial. In contrast, the glacial model explains that many rock glaciers originated from a debris-covered glacier during the Little Ice Age and have been loosing their ice content and speed rapidly with the 20th-Century warming.
Only a few rock glaciers have been identified from Japanese mountains. Although locations favorable for active rock glaciers are restricted to the northern side of some high mountains, the mountain permafrost belt must have been wide enough to form a number of rock glaciers during some past cold periods. Subsequent permafrost melting would have fossilized these rock glaciers, some of which may have been misinterpreted as glacial moraines or protalus ramparts.View full abstractDownload PDF (4658K) -
A case study of Nabeta Reclaimed Land in the suburbs of Nagoya CityAkio YAMANO1998 Volume 107 Issue 1 Pages 25-48
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThis research examines the changing process of farming on reclaimed land, as seen from the changing farming conditions of each settler, in the context of national land reclamation, which took place after the Second World War when agricultural production was increasing.
As a case study, I researched the background of 136 settlers who started farming in 1962 on Nabeta Reclaimed Land, Aichi Prefecture, situated at the mouth of Kiso River. I examined the following 3 points : (1) settlement conditions of Nabeta Reclaimed Land, (2) the influence of Typhoon hazards from Ise Bay on the farming behavior of settlers and (3) the influence of urbanization from the metropolitan area Nagoya. The results are as follows :
1) There occurred some differences in farming among settlers, depending upon the time of settlement, their native places, the land condition of their farm and their successors. The difference in farming was most greatly influenced by land conditions based on the time of settlement.
2) The changing process of farming in Nabeta Reclaimed Land can be divided into 3 periods : 1 st period (commencement of farming), 2nd period (change in farming) and 3 rd period (settlement of farming).
3) The farming conditions of settlers diversified gradually over 3 periods : 1 st period→2 nd period→ 3 rd period (Fig. 11). In the 1 st period, conditions were classified into thetype, mainly composed of field husbandry and animal husbandry. In the 3rd period, conditions could be classified into 4 patterns : field husbandry, animal husbandry, part-time farming and abandonment of farming. These were farming patterns that had been already started during the 2 nd period.
4) In comparison with other reclaimed lands in Japan, the following can be considered as regional characteristics of Nabeta Reclaimed Land.
First, about 20 percent of all settlers were close relatives of those people who were killed by Typhoon Ise Bay. They were less interested in farming, compared to normal settlers, and quite a few of them gave up farming when farming became diversified.
Second, about 10 percent of cultivated land (an area of 302 ha) in Nabeta Reclaimed Land turned out to be owned by residents in Nagoya City. Further, settlers have been unable to make the most of accessibility to big markets, because of the lack of community integration in reclaimed land villages and because of the poor performance of specializing in one farm product.View full abstractDownload PDF (5041K) -
Raphia taedigera in the estuaryJudith CARNEY, Mario HIRAOKA, Noboru HIDA1998 Volume 107 Issue 1 Pages 49-60
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThis paper presents a biogeographical and socio-economic study of the significance of jupatí (Raphia taedigera) for peasant livelihood strategies in the Amazon esutuary. It engages current research interest in indigenous agroforestry systems as an alternative to deforestation in Amazonia and especially, the role of palms for providing marketable products and sustainable land use systems. While several studies illuminate the economic importance of marketing açaí (Euterpe oleracea) fruits, there is very little attention to other wetland palms, like Raphia, which provide valuable products to rural people but are less visible in the cash economy. Such is the case with Raphia taedigera, which attains its broadest areal extension in the Amazon estuary and whose petioles are used to fashion shrimp traps. Shrimp sales constitute an important income source for ribeirinho (ribereño) families in the estuary. This study presents an overview of the biogeographical range of Raphia taedigera in the lower Amazon, the hydrological conditions that favor its establishment, and the depth of indigenous knowledge of its use within ribeirinho livelihood systems.View full abstractDownload PDF (2777K) -
Makoto NISHIDA, Yoichi KAGEYAMA, Noboru HIDA1998 Volume 107 Issue 1 Pages 61-76
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThis paper presents the result of estimating water areas in the Amazon from the optical remote sensing data by using a new fuzzy estimation method and edge data. Conventionally, multi-temporal image data with different water heights are used to estimate the flooded areas. Optical sensors such as Landsat-TM may be limited by their inability to penetrate cloudcover in the Amazon regions. However, they have been well stocked in comparison with SAR (Synthetic Aperture Radar) image data and are useful to classify landcovers. Thus, this paper proposes a method that uses only one optical image data to estimate the flooded area, called várzea. Distinction between a pure pixel and a mixel (mixed pixel) is computed, and the occupancy of landcover classes in the study area is estimated by a fuzzy estimation method. In addition, estimation maps of the water areas at high and low levels are drawn from the occupancy of landcover classes and the situation of water areas is estimated. It is observed that the estimation results using the occupancy can match the local situation in the study area. As a result of this work, the estimation ratio indicates that water areas around Parintins-city, Brazil, at high level is an increase of about 58 % compared with water areas at low levels. The proposed method is applied to this particular regions, but this approach can also be applied to larger water areas considering varzea areas. Therefore, it is confirmed that the proposed method is very useful to estimate water areas in the Amazon from the optical remote sensing images.View full abstractDownload PDF (12172K) -
Masakazu NARA1998 Volume 107 Issue 1 Pages 77-91
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSSequence stratigraphic analysis of the Middle Pleistocene Kongochi Formation (Kazusa Group) and the bottom part of the overlying Jizodo Formation (Shimosa Group) distributed in the Boso Peninsula, Japan was made, based on the recognition of the facies stacking pattern and stratigraphic discontinuity. The Kongochi Formation consists of three shallowing-upward facies successions. The lower, middle and upper successions are made up of, respectively, outer shelf to upper shoreface, inner shelf to lower shoreface, and inner shelf to salt marsh sediments. The lower succession is interpreted to be an upper segment of a depositional sequence (maximum thickness 270 m), of which lower one is the underlying outer shelf deposits of the upper part of the Kasamori Formation, and to represent highstand systems tract. The others constitute two depositional sequences whose maximum thickness are 43 m and more than 23 m, in ascending order. As the upper part of the Kazusa, and Shimosa Groups were said to be formed under the strong influence of 5th to 6th order glacio-eustatic sea-level changes, the overall upward-shallowing and thinning pattern among the sequences may reflect decreasing of accomodation spaces possibly induced by longer-term (i.e. 4th or 5th order) sea-level falling.View full abstractDownload PDF (6307K) -
Yoshihiko KARIYA, Akihiko SASAKI, Fusao ARAI1998 Volume 107 Issue 1 Pages 92-103
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSSum of eleven tephras occur in Mount Tairappyo (36° 48' N, 138° 49' E, 1, 984 m asl) ofthe Mikuni Mountains, central Honshu Island, Japan. Although these tephras are thought to be useful for Quaternary studies in this area, they have not been described systematically. We investigated stratigraphy, lithofacies, petrographic properties, and refractive indices of volcanic glass shards and phenocrysts of these tephras in order to correlate them with the known ones. We also estimated the calendric ages of the tephras based on their stratigraphy and the radiocarbon ages in the previous references.
The followings were identified :
1) the Haruna-Futatsudake-Ikaho as 1.44 ka, 2) the Haruna-Futatsudake-Shibukawa as 1.47 ka,
3) the Myoko-Otagirigawa as 4.7 ka, 4) the Asama-Tairappyosan 1 as 4.9 ka, 5) the Asama-Tairappyosan 2 as 6.3 ka, 6 and 7) the Myoko-Akakura and the Asama-Tairappyosan 3 as 6.6 ka, 8) the Asama-Tairappyosan 4 as 6.8 ka, 9) the Kikai-Akahoya as 7.2 ka, 10) the Asama-Tairappyosan 5 as 7.5 ka, and 11) the Asama-Kusatsu as 16 ka.
Among them, the Myoko-Akakura and the Asama-Tairappyosan 3 are very unique. The former overlies the latter without intercalation of soil layers, and these two tephras form a thin layer. A set of the two can be correlated with the tephra X found from the Ozegahara bog about 60 km east of Tairappyo. Depositional conditions of these tephras imply that the eruption of Myoko volcano followed that of Asama without long interval, possibly less than few years, in the mid Holocene. A thin layer composed of the Myoko-Akakura and the Asama-Tairappyosan 3 is important as a key bed, as well as the Haruna-Futatsudake-Ikaho, the Kikai-Akahoya, and the Asama-Kusatsu all of which have been described as wide spread tephras. All the tephras provide Quaternary studies in this area with datum planes.View full abstractDownload PDF (1999K) -
Shigeru OTOH, Takenori KATO, Takashi UENO, Naomi KAWAI, Yoshiro HIRAI1998 Volume 107 Issue 1 Pages 104-118
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSGeological outline of the Tianshan Mountains is described along the Dushanzi-Kuqa Highway, Xinjiang-Uygur Automonous Region, west China. The area is mainly occupied by Paleozoic sediments. On the basis of the lithology of the sediments and left-lateral shear zones, the area is divided into three belts : Erenhabirga-Borohoro-Yining, Narat-Erbeng-Harke, and Tarim belts from north to south. The Erenhabirga-Borohoro-Yining Belt is characterized by intermediate to felsic volcaniclastic rocks of Devonian to Carboniferous time, and has an affinity of continental arc or island arc. The Erenhabirga-Borohoro-Yining Belt is bounded from the Narat-Erbeng-Harke Belt by an E-trending, sinistral mega shear zone : the Narat Mountain shear zone. The Narat-Erbeng-Harke Belt has an affinity of carbonate shelf, and mainly comprises Silurian to Carboniferous limestone sequence with mafic volcanic layers in Lower Devonian horizon. The Narat-Erbeng-Harke Belt is bounded from the Tarim Belt by the Tarim northern margin shear zone. The Tarim Belt is characterized by Devonian red sandstone showing a continental 'depositional environment. We interpret that these three belts, formed under different Paleozoic sedimentary environments, were tectonically rearranged by huge sinistral strike-slip faults at the end of Paleozoic time.View full abstractDownload PDF (2914K) -
[in Japanese]1998 Volume 107 Issue 1 Pages 119
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 120-121
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 121-122
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 122-124
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 125-126
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 127-131
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 132-133
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 134-136
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 137-141
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages 142-143
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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[in Japanese]1998 Volume 107 Issue 1 Pages Plate1-Plate2
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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Norikazu MATSUOKA1998 Volume 107 Issue 1 Pages Plate3-Plate6
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
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Shigeru OTOH, Takenori KATO, Takashi UENO, Naomi KAWAI, Yoshiro HIRAI1998 Volume 107 Issue 1 Pages Plate7-Plate10
Published: February 25, 1998
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSDownload PDF (16509K)
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