Petrology and tectonics of Hidaka, Kamuikotan and Tokoto belts in Hokkaido, Japan

日本北海道日高带、神威古丹带和东琴带的岩石学和构造

• 批准号: 60302031
• 负责人: KOMATSU Masayuki
• 金额: $ 7.87万
• 依托单位: Ehime University (1987)Niigata University (1985-1986)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60302031/
• 关键词: Hidaka Metamorphic Belt; Kamuikotan tectonic belt; Tokoro belt; high pressure metamorphism; granulite facies; peraluminaous granite; 蛇紋岩メランジ; 北海道; 日高変成帯; グラニュライト相

1. A clockwise P-T path of metamorphic rocks was analyses for the Hidaka metamorphic belt, in which 4 deformational-metamorphic stages were defined;(1)tectonic thickning of accretional-forearc sediments metamorphosed under high P/T regime, (2) isobaric heating due to gabbro-diorite magmatism, giving rise to formation of an island arc metamorphic crust, (3)subhorizontal displacement of the crustal layer to form duplex structure, resulting in pressure release, and (4)dextral-reverse movement of the duplex with isobaric cooling.2. The Kamuikotan high pressure schists were divided into 3 zones using Ca-A1 minerals;I. lawsonite-pumpellyite z.,II. lawsonite-pumpellyite-epidote z.,III. oumpellyite-epidote z. The Schreinemakers analysis of the parageneses show relatively steep P/T gradient in P-T space.3. Na-amphibole, Na-pyroxene, lawsonite and aragonite were first found in the Tokoro belt, by which the belt was divided into 4 metamorphic zones. The fact supports a thought of two Cretaceous subductions with opposite subduction directions.

1. 分析了Hidaka变质带变质岩的顺时针P-T路径，确定了4个变形变质期；(1)高P/T条件下增生-弧前沉积变质的构造增厚；(2)辉长岩-闪长岩岩浆作用等压加热，形成岛弧变质地壳；(3)地壳层次水平位移形成双相构造，导致压力释放；(4)双相右向逆运动，等压冷却。利用Ca-A1矿物将Kamuikotan高压片岩划分为3个带；lawsonite-pumpellyite z二世。lawsonite-pumpellyite-epidote z,三世。P-T空间的Schreinemakers分析显示出相对陡峭的P/T梯度。在Tokoro带中首次发现了na -角闪洞、na -辉石、钠长石和文石，并将其划分为4个变质带。这一事实支持了白垩纪两次俯冲方向相反的俯冲的观点。

项目成果

渡辺暉夫・前川寛和 N.Nasu;K.Kobayashi;S.Uyeda; I.Kushiro and H.Kagami ,eds.: Formation of active Ocean Margins. 677-699 (1985)

Akio Watanabe 和 Hirokazu Maekawa N.Nasu；K.Kobayashi；S.Uyeda；I.Kushiro 和 H.Kagami，编辑：活跃海洋边缘的形成 677-699 (1985)。

小松正幸・宮下純夫・在田一則: 地団研専報. 31. 189-204 (1986)

小松正之、宫下纯夫、再田和典：Jidanken Senpo。31. 189-204 (1986)

Yasuhito OSANAI: "Geology and metamorphic zoning of the Hidaka metamorphic belt in the Shizunai river region, Hokkaido." Jour. Geol. Soc. Japan. 91. 259-278 (1985)

Yasuhito OSANAI：“北海道静内河地区日高变质带的地质和变质带。”

小松正幸: 地団研専報. 31巻. 441-450 (1986)

小松雅之：《Chidanken Senpo》第 31 卷。441-450 (1986)

前田仁一郎: 地団研専報. 31巻. 223-246 (1986)

前田仁一郎：《Chidanken Senpo》第 31 卷。223-246 (1986)