日本海東縁海域の活構造およびその地震との関係
		K-Ar ages of white micas from pelitic schists of the Bayanhongor area, west Mongolia
		The granitoid series in Bayankhongor area, central Mongolia
		地学関係論文・報告書の英文表記

日本海東縁海域の活構造およびその地震との関係

岡村行信(海洋地質部)・倉本真一(海洋地質部)・佐藤幹夫(海洋地質部)

1998

第49巻 第1号，1-18頁

14図

Keywords:Japan Sea, active fault, earthquake, plate boundary

[ 要　旨 ]
　日本海東縁海域に分布する第四紀に形成された活断層及び活構造の分布と特徴を，今までに得られている主に地質調査所の音波探査データを基に解析し，それらの構造の特徴から南部，中部及び北東部に区分した．南部は佐渡島から男鹿半島周辺までの範囲で，幅100kmに達する断層帯を形成するが，その中で２つの断層帯に顕著な断層が集中している．中部は津軽半島西方から奥尻島を経て留萌西方沖まで達する奥尻海嶺を中心とする長さ約450kmの断層帯を形成し，長さ約100km毎に消長を繰り返す．奥尻島以南では奥尻海嶺の西側の日本海盆にも活断層帯が形成されている．北東部は積丹半島から北西に伸びる南西落ちのリニアメントより北東側を占める．ここでは，奥尻海嶺より東側に北北東方向の規模の小さい数列の断層帯が形成されている．武蔵堆からその西側のタータリートラフには顕著な活構造は確認できない．新潟地震と日本海中部地震は震源断層にほぼ一致する活断層が認められるが，北海道南西沖地震は震源断層と奥尻海嶺の地質構造とは一致しない部分がある．日本海東縁では，多くの逆断層が幅数十km-百km以上に達する領域の中に分布し，その規模や形態は内陸の活断層と大きく異ならないことから，現在の日本海東縁を沈み込みプレート境界と呼ぶことは適当でない．

K-Ar ages of white micas from pelitic schists of the Bayanhongor area, west Mongolia

Chikao KURIMOTO(Geology Department, GSJ), Floragiin TUNGALAG(IGMR Project, Bureau of Geological Survey), Lkhamsuren BAYARMANDAL(IGMR Project, Bureau of Geological Survey) and Niidengiin ICHINNOROV(IGMR Project, Bureau of Geological Survey)

1998

vol. 49 (1) P. 19-23

6figs., 1table

Keywords: Mongolia, Bayanhongor, white mica, K-Ar age, pelitic schist

Abstract: The Bayanhongor area is about 500km west of Ulaanbaatar, and is geotectonically divided into the Baidrag, Burdgol, Bayanhongor, Zag, and Hangai Zones from south to north. K-Ar age determination was made on white micas from two samples of pelitic schists which were collected at the northern extremity of the Bayanhongor Zone. The white micas gave K-Ar ages of 453.9±9.1Ma and 447.4±9.0Ma, indicative of the age of metamorphism.

The granitoid series in Bayankhongor area, central Mongolia

Yuhei Takahashi(IGMR Project, Bureau of Geological Survey), Sambuu Oyungerel(IGMR Project, Bureau of Geological Survey), Kazuki Naito(Mineral and Fuel Resources Department, GSJ) and Baljinnyamiin Delgertsogt(MCS International Co. Ltd.)

1998

vol. 49 (1) P. 25-32

7figs.

Keywords: granitoid, magnetite-series, ilmenite-series, ore deposits, Bayankhongor, Mongolia

Abstract: The granitoid series in Bayankhongor area, central Mongolia, has been investigated using magnetic susceptibility and chemical data. In Riphean, the ilmenite-series granitoids were dominant. In early Paleozoic, the ilmenite-series granitoids were dominant, but the magnetite-series granitoids were also distributed in southwestern part of the study area. In late Paleozoic, the magnetite-series granitoids were predominant. The boundary between magnetite- and ilmenite-series granitoids shifted northeastward in early Paleozoic to late Paleozoic. Shifting of the boundary between the two series may be genetically related to the development of the Khangay Zone, which consists of middle to late Paleozoic strata. Mesozoic granitoids are ilmenite-series granitoids.
　In late Paleozoic, Cu and Au deposits are distributed within the magnetite-series granitoids area. Sn and W deposits occur around the boundary between the two series and in the ilmenite-series dominant area. These distribution patterns indicate that the redox potential decreases from southwest to northeast in late Paleozoic granitoids of the study area.

地学関係論文・報告書の英文表記

吉井守正(資源エネルギー地質部)

1998

第49巻 第1号，33-53頁

3表

Keywords: guide, English, capitalization, italicization, numeral, abbreviation, punctuation