In this paper, we summarize our recent studies using the high-resolution 14C dating analysis on Holocene wave-dominated coastal sequences in the Kujukuri and Sendai coastal plains, eastern Japan. Results of high-resolution 14C dating, depositional facies, grain-size and depositional-depth analyses reconstruct temporal and spatial developments of the sequences in relation to the Holocene relative sea-level change and regional sediment supplies in detail. From the comparison between the sequences, we discuss (1) how the nature and developments of the sequences were affected by the differences in style and amount of sediment supply, (2) relationship between relative sea-level change and grain-size characteristics, and (3) controls on preservation potential of wave-dominated sequence.
The Nara basin, located in the central part of the Kinki triangle in central Japan, mainly consists of Plio-Pleistocene sediments (Osaka group), Pleistocene terrace deposits, and Holocene alluvial deposits. The upper most part of the Osaka group extending in this area consist of fluvial deposits, and is correlated with the Ma3, which is includes the Azuki tephra. The terrace surfaces have developed along the eastern foot of the Kongo-katsuragi Range, in the southwestern part of the basin. Based on the distribution of surface heights and stratigraphies, these terraces are classified into the H, Ml, M2, M3, Li, and L2 surfaces in descending order. The Kongo fault system striking in the north-south direction extends along the eastern foot of the Kongo-katsuragi Range. This fault system consists of the Yamaguchi, Kongo, Nakato, and Yamada faults. These faults have displaced fluvial terrace surfaces, and the slip rates of the vertical component are about 0.03-0.3 m/ky. The Median Tectonic Line striking in the west-east direction and extending southward of the Nara basin, separates the Izumi Range and the Kinokawa lowland. The Shobudani fault, one of the fault systems of the Median Tectonic Line, had a tendency of reverse faulting activity in the former half of the Quaternary. On the contrary, right lateral faulting activity of the Gojodani fault started from the middle Pleistocene, and this tectonic movement has continued to the present along the Median Tectonic Line. Based on the stratigraphy of the Osaka group and fault activity around the study area, the fact that the Nara basin was divided from the Kinokawa lowland by reverse faulting of the Shoubudani fault at least the early Pleistocene, was, clarified. This faulting also formed the, present drainage pattern and the watershed located in the southwestern part of the Nara basin. Fault activity of the Kongo fault system started after the middle Pleistocene. The central part of the fault system shows the highest slip rate. On the contrary, the slip rate at the tips of fault system show a small value compared with the slip rate in the central part of the fault system. Both the height distribution of the terraces and that of the Kongo-katsuragi range, extending to the southwestern part of the Nara basin, have same trend in comparison with the distribution of slip rate along the Kongo fault system. In conclusion, tectonic movement with faulting of the Kongo fault system has affected the formation of landforms in the southwestern margin of the Nara basin.
This study shows the revised stratigraphy and correlations of the middle Pleistocene tephras in and around the Aizu area, Northeast Japan. Significant marker tephras in this area are as follows, in descending order of stratigraphy : Nm-SB, TG, Hu-TK, and Kn-KD from volcanoes adjacent to Oze, So-OT, and APm. Stratigraphic positions of Sn-MT and Sn-SK are not clear, but they seem to be positioned near Kn-KD. Nm-SB (110 ka) from Numazawa caldera is mainly a plinian pumice fall deposit distributed in the central to western part of Fukushima Prefecture and northern part of Tochigi Prefecture. Eruption producing Nm-SB associated with ash fall, plinian eruption, and pyroclastic flow or pyroclastic surge. TG (125-135 ka), which is characterized by volcanic glass shards with a low index, was probably derived from the Sunagohara caldera. The distribution of fall-out tephra of TG is similar to that of Nm-SB, and pyroclastic flow deposit of TG is recognized southwest to west of the Numazawa caldera and along the western margin of the Aizu basin. The eruption process of TG comprises plinian eruption, pyroclastic flow, and plinian eruption. So-OT (300-330 ka) is composed of an ignimbrite and a fall-out tephra derived from the Shiobara caldera. This ignimbrite is known as Otahara pyroclastic flow deposit. On the other hand, fall-out tephra of So-OT has been newly identified. APm tephra beds are significant widespread tephras derived from volcano in the Hida mountains at 330-400 ka. This study corrects a correlation of APm in this area, which was shown by Suzuki (1993). Tephras identified as APm in this study are Nm-13, -14, -16 tephras below So-OT. Sn-MT (180-260 ka : FT ages) is composed of an ignimbrite and a fall-out tephra derived from the Sunagohara caldera. The former is part of the Sunagohara-Kubota tephra reported by Yamamoto and Sudo (1996) and the Pyroclastic Flow Deposit I reported by Mizugaki (1993). The latter is the Sunagohara-Kachikata tephra along the western margin of Aizu basin reported by Yamamoto and Sudo (1996), and the Okayaji Volcanic Ash Layer at the eastern foot of Adatara volcano reported by Soda and Saijo (1987). Sn-SK (220 ± 50 ka : FT age), originating from the Sunagohara caldera, was defined by Yamamoto and Sudo (1996). Sn-SK is composed of an ignimbrite and a fall-out tephra characterized by abundant accretionary lapilli. The latter is correlative to the Minowa Volcanic Ash Layer (Soda and Saijo, 1987) distributed at the eastern foot of Adatara volcano. All pyroclastic deposits derived from the Numazawa caldera are Nm-NM (5 ka), Nm-KN (50-55 ka), and Nm-SB (110 ka), and those from the Sunagohara caldera are TG (125-135 ka), Sn-MT (180-260 ka), and Sn-SK (220 ka). This means that, at both caldera, explosive eruptions occurred three times over 260, 000 years, and it appears that the active period of explosive eruptions moved from the Sunagohara caldera to the Numazawa caldera. This resulted in the preservation of volcanic landforms with more dissected caldera landforms at the Sunagohara caldera. Intervals between eruptions at the Numazawa caldera range from 50, 000 to 60, 000 years, and the volumes of the three products are similar, indicating periodic and regular activities with a discharge rate of 0.02-0.06 DRE km3/1, 000 years. On the other hand, the mean interval of eruptions at the Sunagohara caldera is 70, 000 to 40, 000 years, and the discharge rate is estimated to be 0.05-0.08 DRE km3/1, 000 years : the latter is equivalent to or a little larger than that of the Numazawa caldera.
This paper analyzes regional differences in the development of the wine industry in Spain through a comparative study of five wine-making regions : Jerez, Rioja, Penedès, La Mancha, and Ribeiro. Initially, in this study, the author pays attention to the fact that the market structure for wine is very fragmented. Concerning quality, there is a wide diversity of consumer preferences for wine on the other hand, the market scale varies with the product from local to international. This implies that the strategy of what type of wine they produce or on which market they put their products should influence the development process that one wine-making region would pursue. In this study, the quality of wine and its market scale are adopted as criteria to argue the different patterns of development of wine-making regions. After a brief review of the history of the Spanish wine industry from the beginning of the 19th century to the present, 56 wine-making regions certified as Denomination of Origin (DenominaciOn de Origen) are classified into six types by the quality of wine and its market scale. Subsequently, the development of the wine industry in the selected regions, which represent six types, is examined in terms of physical environment, accessibility to market, and vinification technique, as well as some changes of circumstances such as evolution of the transportation system or shifts of preference for wine among consumers. The comparison of five wine-making regions shows that regional differences in the development of the wine industry are generated by a complicated interaction among such regional factors as physical environment, geographical location, and role of entrepreneurs.
To reveal environmental changes across the Permo-Triassic boundary (PTB), detailed lithostratigraphy was analyzed of the PTB interval at Chaotian in northern Sichuan, China. The study interval is composed mainly of shelf carbonates that are lithologically divided into 7 units, i.e., Units A to G in ascending order. Units A-E (8.5 m) correspond to the uppermost Permian, and Units F-G (3.5 m) to the lowermost Triassic. On the basis of a field study and microscopic observations of more than 200 thin sections, the main extinction horizon is recognized at the Unit DIE boundary. Various fossils, such as ammonoid, brachiopod, bivalve, radiolaria, and conodont occur abundantly in Units A-D, while they are absent (or nearly absent) in Units E-G. Radiolarians in particular, show a clear contrasting mode of occurrence : abundant in Unit D to its top, while barren in Unit E and above. The Unit D/E boundary is thus identified as the event PTB horizon with major extinction. The PTB extinction terminated various Late Permian organisms, particularly radiolarians, which are representative planktons in open ocean, suggesting a sharp decline in total marine productivity. On the other hand, the Griesbachian (Early Triassic) index conodont Hindeodus parvus first appears at the base of Unit F, thus the Unit E/F boundary is recognized as the biostratigraphically-defined PTB horizon. The marl of Unit E represents the interval of strong environmental stress that appeared around the PTB. The population of the latest Permian radiolarians decreased remarkably across the Unit B/C boundary, while their mean shell size stayed constant, and even increased rapidly within Unit D. As large-shelled radiolarians often predominate in the cool waters of modern oceans, the radiolarian size increase in Unit D may indicate that the depositional site may have been invaded by a cooler water mass at the end of Permian period.
We investigated solar-cycle and semiannual variations of magnetic storms based on data observed at the Kakioka Magnetic Observatory since 1924. First, we show that magnetic storms with a peak value of ≥ 100 nT are considered to have been almost completely recorded for both types of storm, i.e., those with sudden commencement (Ssc) and those with gradual commencement (Sg). Using data for storms larger than 100 nT, we found that the variation of numbers of Ssc correlates well with that of the sunspot Wolf numbers, but that of Sg does not. The number of storms decreases linearly with the peak value in the semi-logarithmic plot. The inclination is steeper for Sg storms than for Ssc storms. The semiannual variation, that is, more storms are observed in spring and fall than in summer and winter, is clearly seen for storms with a peak value ≥ 100 nT for Sg, but it is recognized only for larger storms with a peak value ≥. 150 nT for Ssc. Concordant with the difference between Ssc and Sg in the semiannual variation, the decrease in the number of large storms in the semi-logarithmic plot is less in spring and fall than that in summer and winter for Ssc. Although such a difference is not apparently seen for Sg, the ratio of the number of storms with a peak value ≥ 150 nT to that of storms with a peak value between 100 nT and 150 nT is larger for spring and fall. We propose the hypothesis that the efficiency of magnetic reconnection depends on the three dimensional direction of the magnetic field in the solar wind relative to the geomagnetic field, and on the north-south symmetry of the geomagnetosphere when it is seen from the stream of the solar wind. We think these “equinoctial effects” are the main causes of the semiannual variation in the number of large magnetic storms. As for the Sudden Commencement (SC), the semiannual variation is not seen, but an annual variation with the number of SC being larger in summer is observed. The reason may be that the shock wave in the solar wind hits against the northern part of the geomagnetosphere in summer, and the southern part in winter.
This study provides a micro-level analysis of the relationship between land-ownership change and the growth process of Sapporo city. In this paper the author focused on the importance of land-ownership change as a good indicator for analyzing the urban growth. The most important questions addressed by this paper are : Why the process occurred?, When did it occur?, Where did it take place?, Who was responsible?, and How was it conducted? The author analyzed the long-term process of building supply and revealed how many renovation cases were identified that brought by newly advanced land purchasers, while other renovation cases were brought by original land-owners without land-ownership change. The result of this paper was summarized : As for the building supply in Sapporo city, two peaks were identified. The first period was in the years around 1972, which was the year of the Winter Olympics, held in Sapporo city. The transportation bureau of the city built a subway (Nanboku line) by 1972, which created the high urban land demand along the subway line. Along it many old and large-lot buildings were found which were mainly provided by major financial groups in Tokyo and Osaka by 1972. The second peak was during the year after 1985. Several high-rise buildings (over 16 stories) were built in the Central Business District (CBD), but their locations tended to be away from the subway line for two reasons : higher land price; and no space for new buildings along the subway line where already occupied by 1972. This is a significant characteristic of Sapporo compared to other major cities where we can find high-rise buildings in the highest priced district along the main streets of the cities. To investigate the process of land-ownership change, the data housed in the Bureau of Legal Affairs in Sapporo were used. According to the data, four major patterns of building supply were identified. Among them, 'Type A' and 'Type D' provided typical examples. 'Type A' included 28 cases out of a total of 63 and was mainly brought about by companies from Tokyo and Osaka who actively purchased some lots so that they could build their own buildings. On the other hand, distribution of 'Type D' was quite different compared to that of 'Type A'. The lot size of 'Type D' was relatively larger. 'Type D' also included 28 cases and was brought about by the same land-owners who continued to keep their land and have renovated the original old buildings (mostly low-rise single use) to larger ones by themselves. Since the number of cases of 'Type B' and 'Type C' were a very few, 'Type A' and 'Type D' could be considered as 'Driving Forces' for the growth of the city.
Miono Formation consisting of Pleistocene marine silty sands occurs from -72.5 to -75.7 m a.s.l. at the base of Onidake volocanics. The K-Ar dating for basaltic lavas overlaying and underlying the Miono Formation indicates that its age is ca. 0.4 Ma. The molluscan fossils of the formation show that it deposited on inner-bay muddy bottom with 5 to 10 m depth. The sediments include pollen and dinoflagellate cyst assemblages showing cool-environment. Assuming the Quaternary tectonics has probably been stable around the Goto Islands, the Miono Formation was deposited in a glacial stage around ca. 0.4 Ma with a sea-level 60 to 70 m below that in the present and cool environment.