著者

町田 洋 新井 房夫

出版者

日本第四紀学会

雑誌

第四紀研究 (ISSN:04182642)

巻号頁・発行日

vol.17, no.3, pp.143-163, 1978

被引用文献数

56 118

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A Holocene volcanic ash layer comprising abundant glass shards occurs as near-surface, soil-forming parent materials in south to north Kyushu and in Shikoku. This layer has been given several local names such as &ldquo;Akahoya&rdquo;, &ldquo;Imogo&rdquo;, &ldquo;Onji&rdquo;, etc. by farmers and pedologists. Its remarkable characteristics as a parent material of soil stimulated the interest of many pedologists to study its source, pedological features, distribution, etc. However, opinions on its source and proper identification varied considerably from one author to another.<br>Detailed petrographic observation and accurate determinations of the refractive indices of the glass and several phenocryst phases in the tephra, together with extensive field work, have led to the conclusion that the Akahoya ash is the product of a single major eruption of the Kikai caldera.<br>The ash is dacitic in composition and contains abundant bubble-walled glass shards and plagioclase, hypersthene, augite and opaque minerals as phenocrysts. The refractive index of the glass ranges from 1.505 to 1.514, and that of the hypersthene, from 1.705 to 1.714. The thickness contour of the ash layer and its grain-size distribution clearly indicate that this ash represents ejecta from the Kikai caldera, which is one of the largest calderas in Japan with an approximate diameter of 20km and largely submerged beneath the sea.<br>The formation associated with this widespread tephra consists of three members; (1) a pumice-fall deposit as the earliest stage, (2) pyroclastic-flow deposits as the middle to the latest stages, and (3) an ash-fall deposit approximately contemporaneous with the pyroclastic flow. The 3rd member is assigned to the Akahoya ash and has the most extensive lobe with an axis length of over 1, 000km, covering most of southwest to central Japan and northwest Pacific Ocean. The volumes of the Akahoya ash-fall deposits must be greater than those of the pyroclastic flows.<br>More than twenty-seven radiocarbon dates of the ash have been obtained so far, ranging rather widely from ca. 3, 000y.B.P. to ca. 9, 000y.B.P. However, the average value of the carbonated woods and peaty materials containing in the layer and the stratigraphical relationships with human remains give a probable age of the ash between 6, 000y.B.P. and 6, 500y.B.P. This marker-tephra is thus extremely significant for studies of Holocene climatic changes and sea levels, as well as for the correlation of archaeological sites.

著者

町田洋 白尾元理著

出版者

東京大学出版会

巻号頁・発行日

1998

著者

町田 洋 新井 房夫

出版者

特定非営利活動法人 日本火山学会

雑誌

火山.第2集

巻号頁・発行日

vol.28, no.2, 1983

被引用文献数

3

著者

町田 洋 新井 房夫 村田 明美 袴田 和夫

出版者

公益社団法人 東京地学協会

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.83, no.5, pp.302-338, 1974

被引用文献数

25 17

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This paper presents the basic data for tephrochronology of the Middle Pleistocene events of South Kanto, Central Japan. The tephra preceding to the last interglacial age (the Tama tephra) is found in highly dissected terraces (Fig. 1) much thicker than the younger tephra formations (Fig. 2). It is subdivided into five formations from T-A to T-E in order of increasing age (Table 1 and Fig. 2). This classification is based not on the eruptive history of the volcanoes but on the sequence of terraces. The relationship between these two is shown in Fig. 2.<BR>Of the four columnar sections (Fig. 6), section 1, synthesized from many sections in the Ooiso Hill (Fig. 3), 25 km east of the Hakone volcano, provides a standard section for South Kanto. There are so many tephra layers of the Tama stage (about 150 m in thickness) preserved in a relatively fresh state, that they are expected to cover a long time in the Middle Pleistocene. A detailed description is therefore needed for specifying any particular tephra bed. 75 marker beds have been selected, and described in terms of lithological and petrographical characteristics as in Table 2 and Fig. 4. The most valuable for characterizing marker tephras are the refractive indices of orthopyroxene and hornblende.<BR>The distribution and the petrographic character of tephras indicate that the tephras mainly comprising two pyroxene phenocrysts might come chiefly from the Old Somma of the Hakone volcano (Fig. 8-1 and 8-2) and partly from the Ashitaka volcano. Whereas such salic tephras with abundant hornblende, biotite and other phenocrysts as GoPi and TE-5 might originate from distant volcanoes (Fig. 8-3).<BR>As a result of precise examination, tens of the marker beds have been traced eastward to the environs of Tokyo and Yokohama (Fig. 6), where the standard Quaternary sequence had been established. Furthermore, several marker beds have been recognized within the Middle Pleistocene marine sediments in the Boso Peninsula. By use of these the Quaternary stratigraphy already established in South Kanto is significantly revised (Table 3 and 6).

著者

町田洋

雑誌

科学

巻号頁・発行日

vol.46, pp.339-347, 1976

被引用文献数

61

著者

町田洋

雑誌

地形

巻号頁・発行日

vol.5, pp.155-178, 1984

被引用文献数

5

著者

町田洋

雑誌

「古文化財に関する保存科学と人文 自然科学」-総括報告書-

巻号頁・発行日

pp.865-928, 1984

被引用文献数

1

著者

内山 治樹 池田 英治 吉田 健司 町田 洋介 網野 友雄 柏倉 秀徳

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.63, no.2, pp.605-622, 2018-12-10 (Released:2018-12-20)

参考文献数

66

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The purpose of this study was to clarify the causal relationship between the “flow of a game” in basketball, defined as “the situation in which 4 periods, which consist of a division time of 10 minutes, advance gradually while having an influence on each other”, and its outcome, focusing on the interrelationships of the 4 periods. For this purpose, a hypothesis was established that the “flow of a game,” in which “factors causing changes in conditions” cannot be overlooked, consists of 4 periods, each creating opportunities that finally affect the outcome. In order to test this hypothesis, an analysis was performed of 1044 periods in 261 games in Japan’s strongest university league, the Kanto Men’s First Division League, based on the following 3 perspectives: (1) the importance of each period; (2) the mutual dependency among the periods; and (3) the relationship between the difference in cumulative scoring and outcome. The results were subjected to logistic regression analysis and covariance structure analysis, and the following 3 points were clarified: (1) Periods that influenced the outcome were the first, third and fourth, ranked in importance as third > first > fourth > second. (2) With regard to mutual dependency among the periods, the points difference in the preceding period in the sequence “first → second (cumulative),” “second (cumulative) → third (cumulative), “third (cumulative) →“fourth” created an opportunity in the following period. (3) A cumulative score difference of less than 8 points by the end of the third period was associated with a high potential for coming back to win. These findings should be applicable to coaching in various games under the official rules of the FIBA as new practical guidelines for closely analyzing the causal relationships between the unique “flow of a game” and outcomes in basketball that take place over 4 periods.

著者

町田 洋 新井 房夫 杉原 重夫

出版者

Japan Association for Quaternary Research

雑誌

第四紀研究 (ISSN:04182642)

巻号頁・発行日

vol.19, no.3, pp.233-261, 1980-11-15 (Released:2009-08-21)

参考文献数

63

被引用文献数

34 41

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The middle Pleistocene time range is defined here the period before the last interglacial in the Brunhes epoch. In Japan, the Shimosa-Kazusa Groups around the Tokyo Bay in Kanto and the upper part of the Osaka Group in Kinki both represent the standard middle Pleistocene sequences and have been studied in detail. These groups are characterized by the cyclic sedimentation caused by transgression and regression corresponding to climatic changes.The purpose of this paper is to attempt the correlation of the Kazusa Group and the Osaka Group by identification of widespread marker-tephras. Accurate determinations of the refractive indices of volcanic glass, orthopyroxene and hornblende, together with other determinations, have enabled successful characterization for correlation to be made for several tephra layers in southern Kanto and Kinki. The following marker-tephras are found over two districts, resulting in the establishment of several important datum planes in the middle Pleistocene sequences.The vitric tephra called Ks 11, which is sandwiched in the Kasamori Formation and its correlatives in southern Kanto, can be identified as a marker tephra of the Osaka Group called Sakura ash, in the vicinity of Osaka and Kyoto. The estimated age of this tephra, about 450, 000 years, is based on its stratigraphic relationship with the underlying dated tephra, Kinukawa ash (460, 000-470, 000 years). Stratigraphically, it is included in the deposits immediately below the transgressive horizon (Tama-f and Ma 7) and also occurrs in the biozone of Stegodon orientalis in both districts. The vitric tephra called Ku 1, sandwiched in the Kokumoto Formation, is identified and correlated with a tephra called Imakuma I ash. It is included in the deposits immediately above the Brunhes-Matuyama boundary. The very important dated tephra, Azuki ash (870, 000 years), in the Osaka Group, can be correlated with Ku 6C tephra in the lower part of the Kokumoto Formation by their peculiar petrographic properties. Both are sandwiched in the deposits below the Brunhes-Matuyama boundary.From the relationship between the identified tephras and marine sequences, it is concluded that during the period from 700, 000 years to 450, 000 years at least three interglacial-glacial cycles are recorded, and that after 450, 000 years the following major interglacial episodes are indicated; 450, 000YBP, 370, 000YBP, 300, 000YBP, 230, 000YBP, and 130, 000YBP.

著者

山県 耕太郎 町田 洋 新井 房夫

出版者

特定非営利活動法人日本火山学会

雑誌

日本火山学会講演予稿集

巻号頁・発行日

vol.1986, 1986

著者

森脇 広 松島 義章 町田 洋 岩井 雅夫 新井 房夫 藤原 治

出版者

Japan Association for Quaternary Research

雑誌

第四紀研究 (ISSN:04182642)

巻号頁・発行日

vol.41, no.4, pp.253-268, 2002-08-01

被引用文献数

2 7

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姶良カルデラ北西縁の平野を対象に,完新世の地形発達および相対的海水準変動,地殻変動を,地形と堆積物の観察,¹⁴C年代測定,テフラ分析,考古遺跡,貝化石と珪藻化石の分析結果にもとづいて検討した.3面に区分される完新世海成段丘は,それぞれ7,300cal BP(6,500yrs BP)~3,500yrs BP,3,000~2,000BP,古墳時代(1,500cal BP)以降に形成された.姶良カルデラ周縁では,カルデラ中心部へ向かって傾き上がる傾動隆起が生じ,その隆起量は7,300cal BP(6,500yrs BP)以降,最大10m以上に達する.この地域の海面高度は8,700cal BP(8,000yrs BP)頃には現海面高度にあり,現海面上4~5m(8,500~8,400cal BP:7,700yrs BP頃),現海面上6m(8,100cal BP:7,300yrs BP頃)を経て,7,300cal BP(6,500yrs BP)頃に現在の海抜12mの高さに達した.その後,海面は次第に低下し,現海面上5~7m(3,000~2,000yrs BP),現海面上2~3m(1,500cal BP)を経て現在に至った.この特異な相対的海水準変動は,姶良カルデラの火山活動に伴う地殻変動が影響しているとみられる.8,100~8,000cal BP(7,200~7,300yrs BP)には,海進は内陸深く及び,溺れ谷が形成された.この時期,米丸マールを形成したベースサージは,別府川流域の内湾を大きく埋積した.その後,汀線は段階的に前進し,縄文時代後期(3,500yrs BP頃)には現在の海岸に近い位置にまで達した.約8,000~7,000cal BP(約7,300~6,000yrs BP)の時期に,池田カルデラ,桜島,鬼界カルデラでも大規模な噴火が起こり,縄文海進最盛期に形成された南九州のリアス式海岸は急激に変化した.

著者

町田 洋 早川 由紀夫 森脇 広 Blong Russell Talai Benjamin

出版者

特定非営利活動法人日本火山学会

雑誌

日本火山学会講演予稿集

巻号頁・発行日

vol.1989, no.2, 1989-10-08

著者

森脇 広 松島 義章 町田 洋 岩井 雅夫 新井 房夫 藤原 治

出版者

日本第四紀学会

雑誌

第四紀研究 (ISSN:04182642)

巻号頁・発行日

vol.41, no.4, pp.253-268, 2002-08-01 (Released:2009-08-21)

参考文献数

39

被引用文献数

3 7

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姶良カルデラ北西縁の平野を対象に,完新世の地形発達および相対的海水準変動,地殻変動を,地形と堆積物の観察,14C年代測定,テフラ分析,考古遺跡,貝化石と珪藻化石の分析結果にもとづいて検討した.3面に区分される完新世海成段丘は,それぞれ7,300cal BP(6,500yrs BP)~3,500yrs BP,3,000~2,000BP,古墳時代(1,500cal BP)以降に形成された.姶良カルデラ周縁では,カルデラ中心部へ向かって傾き上がる傾動隆起が生じ,その隆起量は7,300cal BP(6,500yrs BP)以降,最大10m以上に達する.この地域の海面高度は8,700cal BP(8,000yrs BP)頃には現海面高度にあり,現海面上4~5m(8,500~8,400cal BP:7,700yrs BP頃),現海面上6m(8,100cal BP:7,300yrs BP頃)を経て,7,300cal BP(6,500yrs BP)頃に現在の海抜12mの高さに達した.その後,海面は次第に低下し,現海面上5~7m(3,000~2,000yrs BP),現海面上2~3m(1,500cal BP)を経て現在に至った.この特異な相対的海水準変動は,姶良カルデラの火山活動に伴う地殻変動が影響しているとみられる.8,100~8,000cal BP(7,200~7,300yrs BP)には,海進は内陸深く及び,溺れ谷が形成された.この時期,米丸マールを形成したベースサージは,別府川流域の内湾を大きく埋積した.その後,汀線は段階的に前進し,縄文時代後期(3,500yrs BP頃)には現在の海岸に近い位置にまで達した.約8,000~7,000cal BP(約7,300~6,000yrs BP)の時期に,池田カルデラ,桜島,鬼界カルデラでも大規模な噴火が起こり,縄文海進最盛期に形成された南九州のリアス式海岸は急激に変化した.

著者

福澤 仁之 安田 喜憲 町田 洋 岩田 修二

出版者

東京都立大学

雑誌

重点領域研究

巻号頁・発行日

1995

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すでに入手済みの福井県三方五湖水月湖における過去15万年間の年稿堆積物コアおよび鳥取県東郷池における過去5万年間の年稿堆積物の観察および記載を行った.その結果、1年毎に形成される年稿葉理(ラミナ)と、地震による津波や乱泥流によって形成される厚い葉理を分離し識別することが可能となった.地震による葉理はその前後の年稿に比べて、層厚が厚く粒子比重が大きいことが特徴であり、分級化構造も認められる.また、水月湖の場合には、氷期の葉理は1年に2枚の暗灰色葉理が認められることがあり、この暗灰色薄層は夏期と冬期の菱鉄鉱濃集層である.すなわち、氷期における水月湖は冬期に氷結して垂直循環が停止した可能性がある.一方、東郷池にはこのような冬期の暗灰色葉理が認められず、冬期に氷結しなかった可能性が高い.これらの事実は、湖沼の年稿堆積物を用いて編年を行なう際の留意点を示しており、今後、放射性炭素年代の測定を行なって、これらの仮定を裏付ることが是非必要である.一方、これらの年稿堆積物に含まれる風成塵鉱物の同定および定量を行って、次のことが明らかになった.1)中国大陸起源の風成塵鉱物の一つであるイライト(雲母鉱物の一種)の結晶度は、最終氷期の最寒期(ステージ2およびステージ4)において最も良好になるが、最終間氷期(エ-ミアンすなわちステージ5)においては最も不良になる.ただし、エ-ミアンの中ではほとんど結晶度の変動は認められなかった.2)イライト堆積量の変動についてみると、氷期には多いが間氷期には少ない.しかも、年稿との対比から、その変動は数年単位で急激に変動していることが明らかになった.これらの事実は、氷期から間氷期へあるいはその反対の移行期に、中国大陸へ湿潤な空気をもたらすモンスーンと、日本列島周辺に風成塵をもたらす偏西風の強度が数年間で急激に変動したことを示しており、その変動現象は注目される.