著者

大嶋 和雄

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.100, no.6, pp.967-975, 1991-12-05 (Released:2009-11-12)

参考文献数

12

被引用文献数

36 37

著者

藤原 治 太田 耕輔 青島 晃

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.132, no.4, pp.309-325, 2023-08-25 (Released:2023-09-08)

参考文献数

32

被引用文献数

2

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Array coring survey at the site of Yonezu Pond, which is depicted on a 1680s map, revealed a sand bed deposited by a tsunami caused by the 1498 CE Meio Earthquake occurred in the eastern Nankai Trough. This sand bed consists mainly of medium-grained sand, 10-15 cm thick, forming large ripples or dunes that record the reversal of tsunami inundation and return flows. Our age model based on radiocarbon dating limits the depositional timing of the sand bed to c. 1440-1600 CE. Only a tsunami could have generated a flow fast enough and long enough in duration to deposit a large amount of sand in Yonezu Pond, which at that time was more than 1.2 km inland from the coast and river. The facies change from peat to clay and pollen composition before and after the Meio tsunami suggest that the tsunami had a significant impact on the vegetation around the pond, especially herbaceous vegetation. Plant opal analysis revealed that paddy field devastation occurred with the formation of the Meio tsunami deposit.

著者

柴田 勇

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.72, no.3, pp.131-138, 1963-06-30 (Released:2009-11-12)

参考文献数

28

---

Common geological features of the known kimberlite-occurring regions in the continents are briefly described with special notice to certain tectonic processes that seem to be linked to the eruption of kimberlites.Some investigators suppose that kimberlite magma originated in the peridotite layer just below the Mohorovicic discontinuity. Judging, however, from the tectonic processes prior to the eruption of kimberlites in most regions and the structural model concerning to the crust and the upper mantle supported by the writer, sources of kimberlites might be in more deeper part of the mantle than the peridotite layer.

著者

砂村 倫成 野口 拓郎 山本 啓之 岡村 慶

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.118, no.6, pp.1160-1173, 2009-12-25 (Released:2010-03-23)

参考文献数

59

被引用文献数

3 2

---

Hydrothermal circulations supply a huge amount of chemical species into the deep sea. More than 99% of chemical species emitted from high-temperature hydrothermal fluids flow into the deep sea and construct deep-sea hydrothermal plumes. Observations of hydrothermal plumes have led studies of deep-sea hydrothermal vents, such as locating deep-sea hydrothermal vents, locating deep-sea volcanic eruptions, and calculating geochemical fluxes from sub-seafloor to deep ocean. Hydrothermal plumes affect the microbial community in deep seas by supplying many reduced chemicals, which are possible energy sources of chemolithotrophic microbes. This paper (1) reviews physical, chemical, biological studies of hydrothermal plumes and (2) discusses novel field survey technology and ecological infection of sub-seafloor to the deep-sea environment.

著者

大渡 忠太郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.11, no.5, pp.355-358, 1899-05-25 (Released:2010-10-13)

著者

白岩 孝行 山口 悟

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.111, no.4, pp.476-485, 2002-08-25 (Released:2009-11-12)

参考文献数

28

被引用文献数

13 12

---

More than 400 glaciers exist in the mountains of Kamchatka Peninsula and they constitute the southern boundary of present-day glacierization along the eastern coast of the Eurasian continent. The mass balances of the glaciers are characterized by decadal and interdecadal oscillations, and they are closely related to those observed in the glaciers of Pacific North America. A negative relation was also found for the net accumulation timeseries reconstructed by ice cores from Ushkovsky Volcano, Kamchatka, and Mt. Logan, Canada, for the last 170 years. Because the oscillations of the net accumulation rate and the average annual δ 18O reconstructed from Ushkovsky-ice-core seem to be closely correlated with the so-called Pacific Decadal Oscillation (PDO) Index, it was suggested that the mass balances of the glaciers at both sides of the North Pacific had been affected not only by global warming trends but also by the interdecadal climate variability that had dominantly been occurring over the North Pacific.

著者

安江 恒 久保 典子 赤尾 実紀子 佐野 雅規 中塚 武

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.128, no.1, pp.49-59, 2019-02-25 (Released:2019-04-03)

参考文献数

31

被引用文献数

3 1

---

Ring width, maximum density, and δ18O chronologies of Tsuga diversifolia and Picea jezoensis var. hondoensis growing in a sub-alpine forest at Mt. Senjo in the Akaishi Mountains were developed. Ring width and maximum density were measured with X-ray densitometry. Tree-ring δ18O was measured using a mass spectrometer after cellulose extraction. The chronologies developed have significant positive correlations with monthly temperatures in July, August, and September, with the exception of the ring width of T. diversifolia. The transfer functions for July-September temperature were developed using the four chronologies and were verified statistically. The transfer functions reveal a high coefficient of determination, whereas statistical verifications were not successful with rather low RE, CE, and sign test. The estimated temperatures since 1774 partially agreed with reported climate changes based on historical records. The results indicate that estimated temperature is weak for reconstructing increasing trends and low-frequency variations of temperature, although it is potentially useful for higher frequency temperature changes in local areas.

著者

日本地学史編纂委員会 (東京地学協会)

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.103, no.2, pp.166-185, 1994-04-25 (Released:2010-12-22)

参考文献数

109

被引用文献数

1 1

著者

日本地学史編纂委員会 東京地学協会

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.102, no.7, pp.878-889, 1993-12-25 (Released:2010-04-23)

参考文献数

19

被引用文献数

2

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.132, no.3, pp.Cover03_01-Cover03_02, 2023-06-25 (Released:2023-07-07)

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紀伊半島南部に分布する古第三系~新第三系の牟婁(むろ)層群佐本川(さもとがわ)層は,四万十帯南帯の付加体を構成する砂岩・泥岩互層である.そのなかには堆積物がまだ未固結時に形成されたさまざまな規模の褶曲構造が見られる.写真は和歌山県西牟婁郡すさみ町口和深(くちわぶか)付近の海岸で観察される褶曲の好例である.かつて重力性のスランプ褶曲と考えられていたが,場所によって褶曲軸の倒れる方向が正反対のものもあることから,現在では付加体形成時の高間隙水圧下で形成された構造と判断されている.とくに目を引くこの褶曲露頭は,付近の小字(こあざ)の地名である天鳥(あまどり)にちなむ「フェニックス褶曲」という愛称をもつ.中央の「>」状褶曲上部の水平部分の長さは約5 mあり,迫力のある景観を提供している.ちなみに,この露頭を観察するためには,事前に南紀熊野ジオパークセンターを通じてガイドツアーに申し込む必要がある.(写真・説明:小松原純子 2023年3月28日撮影)

著者

李 盛源 田瀬 則雄

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.132, no.3, pp.231-246, 2023-06-25 (Released:2023-07-07)

参考文献数

41

---

The remediation effects of a permeable reactive barrier (PRB) using sulfur-limestone are investigated. The results show that highly concentrated NO3− (133-180 mg/L) in shallow groundwater decreased below the detection limit within the PRB. This phenomenon was maintained for approximately 300 days; therefore, the remediation effects within the PRB and its durability are demonstrated. It is suggested that the remediation effects due to the PRB are not solely restricted to the area within the barrier, because the decrease in NO3− extended 4.0 m downstream. Furthermore, the results of ORPSHE, δ15N, and isotopic fractionation factor (ɛ) indicate that a reductive condition forms within the PRB, where sulfur-oxidizing denitrifying bacterium preferentially exists. Before installing the PRB, three-dimensional (3-D) groundwater flow systems around the study site and detailed hydrogeological setting should be investigated first.

著者

西沢 邦和

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.87, no.4, pp.222-226, 1978-08-25 (Released:2009-11-12)

参考文献数

7

著者

中村 高志 尾坂 兼一 CHAPAGAIN Saroj Kumar 西田 継

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.132, no.2, pp.183-196, 2023-04-25 (Released:2023-05-15)

参考文献数

47

被引用文献数

2 2

---

ネパール・カトマンズ盆地における硝酸イオン(NO3−)およびアンモニウム(NH4+)による高濃度の地下水汚染について,窒素の起源とその分布の要因について調査を行なった。2009年と2010年の雨季(8月)に,丸井戸と掘り抜き井戸から計36の浅層地下水の試料を採取した結果,高濃度のNO3−(最大:63.9 mg/L)ならびにNH4+(最大:36.7 mg/L)が検出された。多くの丸井戸から採取した地下水については全溶存無機窒素に対するNO3−の含有量が多く,不飽和帯から流入するNO3−または酸素の供給により井戸内部で硝化が生じている可能性が示唆された。NO3−の窒素および酸素の安定同位体比(δ15Nとδ18O)の観測の結果,浅層地下水の主要な窒素汚染源は下水の漏水による窒素負荷であることが示された。また,NO3−濃度の減少に伴うNO3−-δ15N値の指数関数的な増加がみられたことや,δ18O値とδ15N値の間に得られる相関の近似式の傾きがおよそ0.5を示したことから,浅層地下水中において脱窒反応が生じでいることが考えられた。加えて,NO3−濃度と溶存有機炭素の間には負の相関関係がみられ,溶存有機炭素が脱窒反応の進行に強く寄与していることを示した。

著者

高波 紳太郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.131, no.3, pp.317-338, 2022-06-25 (Released:2022-07-08)

参考文献数

59

被引用文献数

2

---

Ata welded ignimbrite (110 ka) lies beneath Ito non-welded ignimbrite and Osumi pumice fall deposit (30 ka) in the Kimotsuki Plain, southern Kyushu. Previous geomorphological studies of the Kimotsuki Plain focused on landform development after deposition of Ito ignimbrite. Landform development of Kimotsuki Plain since the last interglacial, especially until just before deposition of the Osumi pumice fall, is reconstructed using geological data collected from outcrop observations and borehole records. The basal-surface of the Osumi pumice fall deposit obtained shows that Ata welded ignimbrite had been dissected by the Kimotsuki River and its tributaries in response to the last glacial sea-level drop before the Osumi pumice fall was deposited. Longitudinal profiles along the Kushira River in 110 ka and 30 ka indicate recession of the Tanida waterfall, which formed at the edge of the Ata welded ignimbrite plateau. These profile changes imply that the Tanida waterfall retreated 2.4-6.0 km upstream between 110 ka and 30 ka. The Kushira formation, Marine oxygen Isotope Stages (MIS) 5e marine deposits under Ata welded ignimbrite, was found below the present sea-level at multiple locations in the Kimotsuki Plain. This vertical distribution of the Kushira formation indicates that the Kimotsuki Plain has been in a tectonically stable or subsidence area since the MIS 5e, in contrast with the Onejime and Natsui areas, which have been tectonically uplifting. The depositions of the two ignimbrites had significant impacts on filling the Paleo-Shibushi Bay (Sea) and the development of the Kimotsuki Plain under sea-level lowering during the last glacial period. The top-surface of basement rocks is more than −120 m below sea level at the floors of paleo valleys, even though it is adjacent to mountains composed of the basement. Further investigation of lower alluvium and its basal-surface is required for an understanding of valley incision and delta evolution of the Kimotsuki Lowland after deposition of the Ito pyroclastic flow.

著者

中井 達郎

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.116, no.2, pp.223-242, 2007-04-25 (Released:2009-11-12)

参考文献数

43

被引用文献数

4 1

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The spatial structures of a 101-103 m scale on coral reefs were understood by reading aerial photographs and investigating the topography of the fringing reef at the eastern part of Yoron Island, Ryukyu Islands. This study set a new physiographic unit (PGU) at the coral reefs as well as studied zonation. PGU has the following characteristics. (1) In an aerial photo, a linear pattern comprising micro-landform arrangements is recognized on the reef flat; (2) Seawater flowing beyond the reef crest from the open sea and entering the moat before returning to the open sea through a breakout in the reef crest or a channel flowing parallel to the shoreline constitute a very common pattern in the research area; (3) The series of currents observed in the area constitute a water system resembling a drainage water system on land and 4 systems were arranged at the eastern part of Yoron Island ; (4) The movement of seawater is controlled by landforms such as reef crests, channels and lands (a cape), which might qualify as borders of PGUs ; (5) Movements controlled by such landforms are dominant, and tend to be longer in terms of time. In this study, a physiographic unit is defined as follows. (1) A unit that is distinguishable from other adjacent areas by its geomorphological borders ; (2) And, a unit that is distinguishable from other adjacent areas when referring to the movement systems of seawater and materials.The notion of spatial structures of coral reefs of a 101-103 meter scale was substantiated by this research using the overlapping zonation approach known here as PGU on reef flats. The spatial structure makes a frame of the coral reef ecosystem. Therefore, setting a PGU is thought to be effective for application to coral reef conservation.

著者

宮縁 育夫 星住 英夫

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.126, no.5, pp.581-593, 2017-10-25 (Released:2017-11-10)

参考文献数

34

被引用文献数

2 1

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Several volcaniclastic deposits discovered at the foot of the eastern wall of Aso caldera, central Kyushu, southwestern Japan, are divided into two types: lahar deposits (Lh1-Lh5 in descending order), which contain abundant subangular to subrounded lithic clasts ( 3.5 m in diameter) set in a sandy to silty matrix, and debris avalanche deposits (DA1 and DA2), which include numerous plastically deformed fragments of tephra (ash and scoria) and soil layers in a homogenous silty to clay matrix. DA2, which underlies a paleosol dated at 5.4 ka (calibrated 14C age), is the largest volcaniclastic deposit observed in the section (more than 2.5 m thick and about 70 m wide). Because the debris avalanche deposits display no evidence that they were transported by water, they are likely to have originated from landslides triggered by intense earthquakes. Tephra chronology and 14C-dating on paleosols along the succession suggest that lahars occurred once over 900 years (6.3-5.4 ka), three times over 1400 years (5.4-4 ka), once over 400 years (4-3.6 ka) and twice (including the 2012 lahar) in the last 3600 years. This evidence indicates that the lahars occurred at an interval of 400-1800 years. In contrast, two debris avalanche deposits exist in the same succession spanning the last 6300 years. Including landslides and associated debris avalanches triggered by the 2016 Kumamoto earthquake (Mj 7.3), landslides generating debris avalanches in the Aso caldera occurred at least three times in the last 6300 years. This may suggest the frequency of large earthquakes triggering debris avalanches in the central Kyushu region, which has many active faults.

著者

水野 一晴 中村 俊夫

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.108, no.1, pp.18-30, 1999-02-25 (Released:2009-11-12)

参考文献数

47

被引用文献数

2 2

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Leopard's remains were discovered at Tyndall Glacier on Mt. Kenya in 1997. The radiocarbon dates of ca. 900 ± 100 yrs BP correspond to the shift from a warm period to a cool period and the age of the Tyndall Moraine. The leopard was probably not exposed from the ice of the Tyndall Glacier judging from the condition of the remains. The discovery of the leopard's remains in 1997 is consistent with the climatic change from a cool period which continued until the 19th century to warm period in the 20 century.The succession of alpine vegetation around Tyndall Glacier can be clarified from the conditions of glacial margins and moraines (Lewis Moraine : ca. 100 yrs BP, Tyndall Moraine : ca. 900-500 yrs BP). The Tyndall Glacier on Mt. Kenya retreated at a steady rate from the late 1950 s to 1996. The first colonist species over the new till, Senecio keniophytum, advanced at a rate similar to the retreat of the glacier. The species growing near the ice-front of Tyndall Glacier colonized in tandem with the retreat of the glacier. Till age and stability of land surface are important environmental factors controlling the vegetation pattern around Tyndall Glacier. The pioneer species make humus which results in an improved soil condition. About 70 to 100 yrs elapse from the glacial release before such large woody plants as Senecio keniodendron and Lobelia telekii grow on the glacier foreland.

著者

木内 信蔵

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.69, no.3, pp.119-125, 1960-07-30 (Released:2009-11-12)

参考文献数

9

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Professor Hartshorne's 'The Nature of Geography ' has been widely read among Japanese professional geographers, since Professor I. Matsui had reviewed and then Dr. S. Nomura had translated it into Japanese. Its contribution was too much to write here, but he felt it necessary to supply deeper considerations.The writer generally agrees with the “Perspective” view and would like to express his concept here. Geography is a highly synthesized science, and its study is based on the active regions which have been formed through times and with intimately related human and physical phenomena. But complete synthesis is almost impossible. It should be strived for, with analyzing, comparing actual regions assisted by topical studies.But there remains several questions, for instance valuation of Fr. Ratzel's work with relation to prerent ecological study. And how we could get a proper seat of geography, as chorological science, among traditionaly divied natural and human or social sciences ?

著者

松田 亀三

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.88, no.4, pp.230-245, 1979-08-25 (Released:2009-11-12)

参考文献数

107

被引用文献数

14

著者

宮崎 真由美 石村 大輔

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.127, no.6, pp.735-757, 2018-12-25 (Released:2019-01-30)

参考文献数

37

被引用文献数

5 6

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Marine terraces on the northern Sanriku Coast are mapped, verifying their emergent times with a tephra analysis to provide accurate information on long-term coastal uplift along the Sanriku Coast. The results contradict the conventional view of century-long subsidence and coseismic subsidence associated with the 2011 Tohoku-oki earthquake. Eight visible tephra layers are found to cover the Taneichi surfaces reported as Marine Isotope Stage (MIS) 5 marine terraces in previous research on the northern Sanriku Coast, and these correlate with To-H, To-Of, To-G, To-Ok2, To-AP, To-CP, Toya, and ZP2 tephra layers previously identified at the Kamikita Plain based on petrographic properties. Consequently, because the Toya tephra (ca. 112-115 ka) covers marine sand and/or gravel beds composing the terraces, they are confirmed to be MIS 5e marine terraces. The paleo-shoreline of the MIS 5e marine terraces is inferred, considering topographic profiles and aeolian deposits covering terrace surfaces, and their heights are measured with high-resolution digital elevation models to be ca. 40 m above the present sea level at the Kamikita Plain and ca. 20-30 m at the northern Sanriku Coast. In addition, uplift rates from the Kamikita Plain to the northern Sanriku Coast are estimated to be 0.3 mm/yr and 0.1-0.2 mm/yr, respectively, tending to gradually decrease toward the south, and may be subject to subsidence further south along the southern Sanriku Coast.