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総合地質 4巻 1号 2020年10月20日発行 [full-issue PDF link]
General Geology, Vol. 4 No. 1, October 20, 2020


[論説]

古倶知安湖の検証:北海道倶知安町の後期更新世堆積物の微化石分析 [PDF link]

嵯峨山 積・関根達夫・星野フサ
総合地質, 4巻, 1–7 頁
Investigation of the Paleo-Lake Kutchan: Diatom and pollen analyses of the late Pleistocene sediments in the Kutchan, Hokkaido, Japan [PDF link]
Tsumoru Sagayama,Tatsuo Sekine and Fusa Hoshino
General Geology, Vol. 4, Page 1–7.

要旨

後志地域の羊蹄山北域に広がる倶知安町周辺には湖(古倶知安湖)が存在していたとされている.湖の形成時代や広がりなどを検証するために縞状堆積物を含む後期更新世の地層について珪藻と花粉の分析を行った.珪藻分析では浮遊性淡水生種の多産から湖沼性の堆積環境が推定された.花粉分析ではPiceaや CYPERACEA などが優勢で,現在よりも冷涼な環境が想定された.分析用試料の採取層は真狩別層と考えられるものの,より詳細な地質年代を明らかにする必要がある.

Abstract

It has been suggested that the Paleo-Lake Kutchan spread in the Kutchan area at the late Pleistocene. In order to investigate the detail geologic time and areas of lake deposits, diatom and pollen analyses of geologic samples picked from the late Pleistocene sediments, which outcrops to the south of the Kutchan downtown, were carried out. Diatom analysis yielded a lot of planktonic freshwater species reconfirmed the existence of the Paleo-Lake Kutchan. Results of pollen analysis show some lower temperature compared with present day. The lake deposits may be assigned to the Makkaribetsu Formation, although further dating studies are necessary to confirm the surmise.


[論説]

北海道札幌市北区の上部更新統~完新統ボーリング層序;札幌扇状地堆積物の基底年代とMIS 5aの海面高 [PDF link]

嵯峨山 積・井島行夫・岡村 聡・阪田義隆
総合地質, 4巻, 9–18 頁
Stratigraphy of the upper Pleistocene to Holocene boring in the Kita Ward, Sapporo, Japan; Geologic time of the Sapporo fan deposits, and sea level of the MIS 5a [PDF link]
Tsumoru Sagayama, Yukio Izima, Satoshi Okamura and Yoshitaka Sakata
General Geology, Vol. 4, Page 9–18.

要旨

札幌市北区で長さ44.00 m のN 8・1 コア(後期更新世~完新世堆積物)が採取され,同堆積物の層序や堆積環境の解明のために火山灰分析と珪藻分析を行った.火山灰分析で深度43.58 m 前後で約10.6 万年前降灰の洞爺火山灰(Toya)を,深度19.42 m 前後で約4.1 万年前噴出の支笏軽石流堆積物(Spfl)の挟在層準を認定し,珪藻分析で深度24.35 m 前後のシルトの堆積環境は淡水域であったことを明らかにした.札幌扇状地堆積物の堆積開始は後期更新世のMIS 5e,またはそれ以前と考えられる.N 8・1 と北大地盤観測井(HU),地質研究所井(GSH)に挟在する泥質物の堆積環境から,MIS 5aの最高海面は標高- 13 m 前後と推定した.

Abstract

In order to elucidate stratigraphy and sedimentary environments of the Pleistocene and Holocene in the Ishikari Lowland, we carried out analyses of volcanic ash and diatom for a boring core (N8・1) of 44 meters long obtained from the Kita Ward, Sapporo, central Hokkaido. Results of volcanic ash analysis show the geologic horizons of following two late Pleistocene ash layers: the Shikotsu Pumice Flow deposits (Spfl) of ca 41 ka in ca 19.42 m depth and the Toya volcanic ash (Toya) of ca 106 ka in ca 43.58 m depth. Diatom analysis indicates that silt bed in ca 24.35 m depth of the core deposited in fresh water environments. Meanwhile the analysis of clay beds, being correlated with the silt bed in neighboring two cores, HU and GSH, shows sedimentary environments brackish. It is inferred that geologic age of those muddy beds is MIS 5a by two ash layers, Spfl and Toya, and maximum sea level of MIS 5a stage was ca 13 m below the present sea level.


[報告・資料]

インド・デカン高原をたずねてー2020 年3 月インド訪問報告 [PDF link]

山岸宏光
総合地質, 4巻, 19–26 頁
Visiting Deccan Trap -Report of travelling in India in March, 2020 [PDF link]
Hiromtsu Yamagishi
General Geology, Vol. 4, Page 19–26.

要旨

2020 年3 月初旬に,インド西部のムンバイの近くのプネ大学から招聘され,同大学の概要を視察したことと,広大なデカン高原玄武岩の地質の概要を見ることができた。報告では,その景観,溶岩・岩脈,火山砕屑岩の産状やそれに関わる地すべり・崩落,岩石に彫られた仏教遺跡,溶岩の空隙に発達する貴重な鉱物などを紹介する.

Abstract

In the beginning of March, 2020, I was visiting Savitribai Phule Pune University, Pune, India, because of invited by the university , and going to the many geological sites of the Deccan Basalt. In this report, I introduce the landscape, variable occurrences such as lava flows, dykes, pyroclastic rocks, and related landsides, and Buda heritages. In addition, the precious minerals formed in the cavities in the basalts are introduced.


[報告・資料]

韓国Jeju 島のジオパークを訪ねて-2019 年第12 回アジア地域応用地質学会(12th_ARC of IAEG, 2019)に参加 [PDF link]

山岸宏光・Dou Jie
総合地質, 4巻, 27–34 頁
Visiting Geoparks on Jeju Island, Korea-Participating the 12th Asian Regional Conference of IAEG, 2019 [PDF link]
Hiromitsu Yamagishi and Dou Ji
General Geology, Vol. 4, Page 27–34.

要旨

2020 年3 月初旬に,インド西部のムンバイの近くのプネ大学から招聘され,同大学の概要を視察したことと,広大なデカン高原玄武岩の地質の概要を見ることができた。報告では,その景観,溶岩・岩脈,火山砕屑岩の産状やそれに関わる地すべり・崩落,岩石に彫られた仏教遺跡,溶岩の空隙に発達する貴重な鉱物などを紹介する.

Abstract

The 12th Asian Regional Conference of International Association of Engineering Geology was held at Jeju Island, Korea, during 23 to 27 September Jeju island. It is relatively new volcanic island and was registered as UNESCO Global Geopark in 2014, and many local geoparks are existing mostly along the coastline. In this report, we introduce the outline of Jeju Island based on the references and guidebooks, and show the volcanic geology of the our visiting geopark, including our remarks.


[自由投稿]

樽前山1874年噴火を見た人たち [PDF link]
宮坂省吾
総合地質, 4巻, 35–42 頁
People who saw the 1874 eruption of Mt. Tarumae [PDF link]
Seigo Miyasaka
General Geology, Vol. 4, Page 35–42.


[論文紹介]

総合地質, 4巻, 43–49 頁 [PDF link]
General Geology, Vol. 4, Page 43–49. [PDF link]

England, P.C. and Katz, R.F., 2010, Melting above the anhydrous solidus controls the location of volcanic arcs. Nature, 467, doi:10.1038/nature 09417.

Ribeiro, J.M., Ishizuka, O., Lee, C.-T.A. and Girard, G., 2020, Evolution and maturation of the nascent Mariana arc. Earth Planet. Sci. Lett., 530, doi. org/10.1016/j.epsl.2019.115912.

Liu, J., Sun, H., Wang, Z., Xia, Q. and Li, W., 2020, Continuous water supply from the subducted pacific plate to the Eastern Asian big mantle wedge: New insights from the water content of late Cretaceous OIB-like basalts. Lithos, 352-353, doi.org/10.1016/j.lithos.2019.105249.

Lin, Y., Zhang, C., Li, C. and Deng, H., 2020, CFrom dextral contraction to sinistral extension of intracontinental transform structures in the Yanshan and northern Taihang Mountain belts during Early Cretaceous: Implications to the destruction of the North China Craton. Jour. Asian Earth Sci., 189, doi. org/10.1016/j.jseaes.2019.104139.

Koulakov, I., Kukarina, E., Fathi, I.H., Khrepy, S.E. and Al-Arifi, N., 2015, Anisotropic tomography of Hokkaido reveals delamination-induced flow above a subducting slab. Jour. Geophys. Res.: Solid Earth, 120, 3219−3239.


総合地質 について

総合地質 (General Geology) は北海道総合地質学研究センターから発行されるアクセスフリーの学術雑誌 (オンライン版 ISSN 2433-7161, プリント版 ISSN 2435-2187) です. 会員以外の方からの投稿も積極的に歓迎いたします. 投稿を希望される方は 総合地質 の投稿規則 [PDF link] と原稿整理カード [PDF link] [Microsoft Word docx version] をご覧ください.


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