Accretion-Collision Tectonics of Sakhalin and Circum-Pacific Orogeny

萨哈林岛的增生碰撞构造和环太平洋造山运动

• 批准号: 03041059
• 负责人: MIYASHITA Sumio
• 金额: $ 2.24万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Overseas Scientific Survey.
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03041059/
• 关键词: Accretionary complex; Cretaceous; Blueschists; Susunai; Aniba; Sakhalin

The results obtained from this project are summarized as follows. 1) The Cretaceous accretionary complexes, called the Aniba complex, are composed of two tectonic units. The upper unit consisting of basalts, bedded cherts, hemipelagec siliceous shale, Melange, and terrigenous sediments in ascending order, thrust over thd lower the unit which is composed of dominant basalts and melanges characterized by abundant limestone blocks. The lower unit composing of five thrust sheets verging eastward, seems to be an underplating complex beneath the upper unit. 2) The Susunai complexes, high pressure metamorphic ones extending to the Kamuikotan metamorphic belt in Hokkaido, reveal a complete sequence of the tectonic pile composed of tens of thrust sheets which are stacked by low angle thrusts verging southward. The complexes consist mainly of greenschists, metachert, silicious shist, and metapelites associated with metagreywackes. The complex is divided into five domains based on lithologic assemblages. For example, Domain 4 is characterized by dominant basalts to dolerites overlain by basaltic sediments with pelagic limestones capped by a thin sequence of black shale. Three phases of deformation, D1 to D3 are discriminated. The rocks subjected the highest strain of D2, strongest deformation among them, show NE trending asymmetric folds, NW trending sheath folds and lineation of both the stretching and micro folding. Two metamorphic zones are defined in the surveyed areas, i. e. pumpellyite-actionlite zone in southern part and pumpellyite-epidote-actionlite zone in northern part. The P-T conditions at the peak of metamorphism are estimated to have been 200-300ﾟC and 4-5Kbar. The metamorphism coincides with D2 phase of deformation. 3) Major and minor element compositions of basaltic rocks exhibit that those from the Aniba complex represent oceanic island tholeiites features and alkaline affinity, whereas those from the Susunai complex reveal N-MORB to T-MORB features

该项目取得的成果总结如下。1)白垩纪增生杂岩，称为阿尼巴杂岩，由两个构造单元组成。上部单元由玄武岩、层状硅质岩、半深海硅质页岩、混杂岩和陆源沉积物组成，自下而上逆冲于下部单元之上，下部单元由玄武岩和混杂岩组成，以丰富的灰岩块为特征。下单元由5个向东延伸的逆冲岩席组成，似为上单元之下的底侵复合体。2)延伸至北海道Kamuikotan变质带的高压变质杂岩Susunai揭示了一个由数十个逆冲岩片组成的完整的构造堆序列，这些逆冲岩片由向南的低角度逆冲断层叠加而成。杂岩主要由绿片岩、变黑岩、硅质片岩和与变灰岩共生的变岩组成。根据岩性组合将该杂岩划分为五个域。例如，域4的特征是主要的玄武岩到粗玄岩，其上覆有玄武岩沉积物和远洋石灰岩，其上覆有薄的黑色页岩序列。区分了变形的三个阶段，D1至D3。岩石应变最大，变形最强，为D2应变，表现出NE向不对称褶皱、NW向鞘状褶皱、拉伸线理和微褶皱线理。在测区划分出两个变质带，即：第一变质带和第二变质带。e.南部为绿帘石-绿帘石带，北方为绿帘石-绿帘石带。变质作用高峰期的P-T条件估计为200-300 ℃和4- 5 Kbar。变质作用与D_2变形阶段一致。3)玄武质岩石的主、微量元素组成显示Aniba杂岩具有洋岛拉斑玄武岩的特征和亲碱性，而Susunai杂岩具有N-MORB到T-MORB的特征

项目成果

宮下 純夫: "下川オフィオライトにおける鉱物の異常構造に関する予察的研究" 新潟大学理学部地質学鉱物学教室研究報告. 7. 85-101 (1992)

Sumio Miyashita：“下川蛇绿岩矿物异常结构的初步研究”研究报告，新泻大学理学院地质矿物学系 7. 85-101 (1992)。

Miyashita, S.: "A preliminary study on the zonings of plagioclase and clinopyroxene from the Shimokawa ophiolite, northen Hidaka zone, Hokkaido" Contrib. Dept. Geol. Min., Niigata Univ.7. 85-101 (1992)

Miyashita, S.：“北海道日高地区北部下川蛇绿岩斜长石和单斜辉石分区的初步研究”Contrib。

田中 久雄: "ソ連カムチャッカ半島東北部オリュ-トル地域の深成岩類" 岩鉱. 87. 1-11 (1992)

Hisao Tanaka：“苏联堪察加半岛东北部奥柳托尔地区的深成岩”《岩石矿山》，87. 1-11 (1992)。

Kimura,G.: "Mode of Mixture of oceanic fragments and terrigencus trench fill in an accretionary complex:example from southeum Sakhalin" Tectonophysics. 201. (1992)

Kimura,G.：“海洋碎片和陆源海沟填充在增生复合体中的混合模式：萨哈林岛南部的例子”构造物理学。

Kimura,G.: "Huge Jurassic oceanic plateau-the Sorachi Pleateau-accreted to the northwestern Pacific margin" Tictonics.

Kimura,G.：“巨大的侏罗纪海洋高原——Sorachi Pleateau——增生到西北太平洋边缘”，构造运动。