Geochronological and petrological studies of the northwestern Indian Himalayas: Understanding the early processes of continental collision zone

• Project/Area Number: 18K03788
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: Okayama University of Science
• Principal Investigator: Imayama Takeshi 岡山理科大学, フロンティア理工学研究所, 准教授 (90551961)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
• Keywords: 大陸衝突帯初期プロセス / ヒマラヤ造山帯 / 北西インド / 変成岩上昇過程 / 北西インドヒマラヤ / 大陸衝突帯初期 / 地質年代学 / 大陸衝突帯 / 超高圧変成岩 / 部分溶融 / 圧力－温度―時間経路 / 沈み込み帯 / 超高圧－中圧型変成岩類 / 変成作用 / 変成圧力－温度―時間経路 / 岩石学

Outline of Final Research Achievements

We clarified the timing of subduction and onset of exhumation for the High Himalayan Crystalline Sequences in the Uttarakhand region of northwestern India. In Nepal, Oligocene thrusts and partial melting via biotite dehydration reaction within the High Himalayan Crystalline Sequences play a major role in the exhumation of metamorphic rocks, whereas these Oligocene thrusts and high-temperature partial melting were not recognized in northwestern India. Instead, the early Miocene normal faulting and fluid-saturated partial melting occurred within the High Himalayan Crystalline Sequences in northwestern India, distinguished from the exhumation mechanism of metamorphic rocks in Nepal. In addition, a geological survey and petrological study of ultrahigh-pressure metamorphic rocks in the northwestern India, Ladakh region revealed ultrahigh-pressure eclogites were accompanied with leucocratic melt, showing direct evidence that the eclogite was partially melted.

Academic Significance and Societal Importance of the Research Achievements

本研究によって、中央～西ヒマラヤ地域（ネパール、北東インド、ブータン）と東ヒマラヤ地域（北西インド）の地域的な地質や変成岩上昇テクトニクスの違いが明確になった。ヒマラヤ造山帯は、北から南へ向かって大きく地質構造が異なるため、南北方向の変成作用の違い（逆転温度構造）や部分溶融の影響について多くの研究がなされてきた。一方で、東西方向の変成作用や部分溶融の相違についての研究例は多くなく、本研究における学術的意義は高い。部分溶融やそれに伴う花崗岩形成に伴ってレアメタルやペグマタイト鉱床が生成される場合があり、その成因論の解明は社会的にも意義がある。

Research Products

• [Int'l Joint Research] インド工科大学ボンベイ校/インド工科大学カーンプル校/インド工科大学カラグプル校(インド)
• [Int'l Joint Research] 全北大学校/韓国基礎科学研究所(韓国)
• [Int'l Joint Research] 名古屋大学/新潟大学/秋田大学(日本)
• [Int'l Joint Research] インド工科大学ボンベイ校/インド工科大学カラグプル校(インド)
• [Int'l Joint Research] 韓国基礎科学研究所/全北大学(韓国)
• [Int'l Joint Research] 韓国基礎科学研究所(韓国)
• [Int'l Joint Research] インド工科大学(インド)
• [Int'l Joint Research] 韓国基礎科学研究所(韓国)
• [Int'l Joint Research] インド工科大学ボンベイ校(インド)
• [Journal Article] Intra-channel detachment in a collisional orogen: The Jhala Normal Fault in the Bhagirathi river section, Garhwal Higher Himalaya, India (2023)
  • Author(s): Bose Narayan、Imayama Takeshi、Kawabata Ryoichi、Gupta Saibal、Yi Keewook
  • Journal Title: Journal of Earth System Science Volume: 132 Issue: 1 Pages: 6-6
  • DOI: 10.1007/s12040-022-02019-4
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Chemical mass transport during deformation and metamorphism: Insights from the Main Central Thrust and its footwall of Western Arunachal Himalaya, NE India (2022)
  • Author(s): Kalita Pranjit、Phukon Purbajyoti、Goswami Tapos K.、Imayama Takeshi、Srivastava Hari B.
  • Journal Title: Lithos Volume: 416-417 Pages: 106641-106641
  • DOI: 10.1016/j.lithos.2022.106641
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Eocene to Miocene metamorphic evolution and tectonic implication of the Ilam Nappe in Nepal Himalaya: Constraints from P?T conditions and monazite petrochronology (2022)
  • Author(s): Imayama Takeshi、Hoshino Ryuhei、Yi Keewook、Kawabata Ryoichi
  • Journal Title: Journal of Asian Earth Sciences Volume: 234 Pages: 105276-105276
  • DOI: 10.1016/j.jseaes.2022.105276
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Neoproterozoic and middle Paleozoic geological events in the eastern Wolhyeonri complex of the southwestern Gyeonggi Massif, South Korea, and their tectonic correlations in northeastern Asia. (2021)
  • Author(s): Imayama, T., Oh*, C. W., Jeon, J., and Yi, K.
  • Journal Title: Lithos Volume: 382-383 Pages: 105923-105923
  • DOI: 10.1016/j.lithos.2020.105923
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Thematic issue: Evolution of Nepal Himalaya (2021)
  • Author(s): Sakai Harutaka、Iwano Hideki、Imayama Takeshi
  • Journal Title: Island Arc Volume: 30 Issue: 1
  • DOI: 10.1111/iar.12413
  • Peer Reviewed
• [Journal Article] Multi‐stage metamorphic history of the Oki gneisses in Japan: Implications for Paleoproterozoic metamorphism and tectonic correlations in northeastern Asia (2021)
  • Author(s): Kawabata Ryoichi、Imayama Takeshi、Kato Takenori、Oh Chang‐Whan、Horie Kenji、Takehara Mami
  • Journal Title: Journal of Metamorphic Geology Volume: 40 Issue: 2 Pages: 257-286
  • DOI: 10.1111/jmg.12627
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Tectonic discontinuity, partial melting and exhumation in the Garhwal Himalaya (Northwest India): Constrains from spatial and temporal pressure-temperature conditions along the Bhagirathi valley (2021)
  • Author(s): Kawabata Ryoichi、Imayama Takeshi、Bose Narayan、Yi Keewook、Kouketsu Yui
  • Journal Title: Lithos Volume: 404-405 Pages: 106488-106488
  • DOI: 10.1016/j.lithos.2021.106488
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Variability of protoliths and pressure-temperature conditions of amphibolites from the Ohmachi Seamount (Izu-Bonin-Mariana arc): Evidence of a fossil subduction channel in modern intra-oceanic arcs. (2020)
  • Author(s): Imayama*, T., Ueda, H., Usuki, T., Minami, M., Asahara, Y., and Nagahashi, T.
  • Journal Title: Mineralogy and Petrology Volume: 114 Issue: 4 Pages: 305-318
  • DOI: 10.1007/s00710-020-00705-z
  • Peer Reviewed
• [Journal Article] The absence of high-pressure metamorphism in the inverted Barrovian metamorphic sequences of the Arun area, eastern Nepal and its tectonic implication (2020)
  • Author(s): Imayama*, T., Uehara, S., Sakai, H., Yagi, K., Ikawa, C., and Yi, K.
  • Journal Title: International Journal of Earth Sciences Volume: 109 Issue: 2 Pages: 465-488
  • DOI: 10.1007/s00531-019-01816-5
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Late Permian to Early Triassic back-arc type volcanism in the southern Mongolia volcano-plutonic belt of the Central Asian Orogenic Belt: Implication for timing of the final closure of the Palaeo-Asian Ocean (2019)
  • Author(s): Imayama, T., Koh, Y., Aoki, K., Saneyoshi, M., Yagi, K., Aoki, S., Terada, T., Sawada, Y., Ikawa, C., Ishigaki, S., Toyoda, S., Tsogtbaatar, Kh, and Mainbayar, B.
  • Journal Title: Journal of Geodynamics Volume: 131 Pages: 101650-101650
  • DOI: 10.1016/j.jog.2019.101650
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Research report of the Tso Morari ultra-high pressure metamorphic complex in Ladakh, NW India (2019)
  • Author(s): Imayama, T., and Dutta, D.
  • Journal Title: Bull. Inst. Front. Sci. Tech, Okayama Univ. of Sci. Volume: 1 Pages: 49-52
  • NAID: 40022237185
• [Journal Article] 1.74 Ga crustal melting after rifting at the northern Indian margin: investigation of mylonitic orthogneisses in the Kathmandu area, central Nepal. (2018)
  • Author(s): Imayama Takeshi、Arita Kazunori、Fukuyama Mayuko、Yi Keewook、Kawabata Ryoichi
  • Journal Title: International Geology Review Volume: 61 Issue: 10 Pages: 1207-1221
  • DOI: 10.1080/00206814.2018.1504329
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Early Oligocene partial melting via biotite dehydration melting and prolonged low-pressure-low-temperature metamorphism of the upper High Himalaya Crystalline Sequences in far-eastern Nepal. In: Sharma, R., Villa, I. M. and Kumar, S. (eds.), Crustal Architecture and Evolution of the Himalaya-Karakoram-Tibet Orogen (2018)
  • Author(s): Imayama, T., Takeshita, T., Yi, K. and Fukuyama, M.
  • Journal Title: Geological Society, London, Special Publications Volume: 481 Issue: 1 Pages: 1-27
  • DOI: 10.1144/sp481.2
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Inverted metamorphism in the Ilam Nappe, far-eastern Nepal (2018)
  • Author(s): Imayama, T. and R. Hoshino
  • Journal Title: Bull. Res. Inst. Nat. Sci., Okayama Univ. of Sci. Volume: 44 Pages: 11-15
  • NAID: 40022022893
  • Int'l Joint Research
• [Presentation] Early Paleozoic rift-related magmatic origin of the Tso Morari Complex (NW Indian Himalayas) and the protolithic diversity of the Himalayan high and ultrahigh-pressure rocks. (2022)
  • Author(s): Dripta, D., Imayama, T., and Yi, K.
  • Organizer: 2022 AGU meeting
  • Int'l Joint Research
• [Presentation] Early Paleozoic rift-related magmatism recorded in the ultrahigh-pressure Tso Morari Complex (NW Indian Himalaya) (2022)
  • Author(s): Imayama, T., Dripta, D., and Yi, K.
  • Organizer: 2022 Korean Geological Society conference
  • Int'l Joint Research / Invited
• [Presentation] Eocene to Miocene metamorphic evolution and tectonic implication of the Ilam Nappe in Nepal Himalaya: Constraints from P-T conditions and monazite petrochronology. (2022)
  • Author(s): Imayama, T., Hoshino, R., Yi, K., and Kawabata, R.
  • Organizer: 2022 Italian Geological Society conference
  • Int'l Joint Research / Invited
• [Presentation] Eocene to Miocene metamorphic evolution and tectonic implication of the Ilam Nappe in Nepal Himalaya: Constraints from P-T conditions and monazite petrochronology (2022)
  • Author(s): Imayama, T., Hoshino, R., Yi, K., and Kawabata, R.
  • Organizer: 2022 Goldschmidt Conference
  • Int'l Joint Research
• [Presentation] Eocene to Miocene metamorphic evolution and tectonic implication of the Ilam Nappe in Nepal Himalaya: Constraints from P-T conditions and monazite petrochronology (2022)
  • Author(s): Imayama, T., Hoshino, R., Yi, K., and Kawabata, R.
  • Organizer: 2022地球惑星連合大会
• [Presentation] Channel-flow induced 'normal faulting' in the Himalaya: a case study from the Jhala Normal Fault, Garhwal Higher Himalaya, NW India (2022)
  • Author(s): Bose, N., Imayama, T., Kawabata, R., Gupta, S., and Yi, K.
  • Organizer: 2022 EGU General Assembly
  • Int'l Joint Research
• [Presentation] Neoproterozoic and middle Paleozoic geological events in the eastern Wolhyeonri complex of the southwestern Gyeonggi Massif, South Korea, and their tectonic correlations in northeastern Asia. (2021)
  • Author(s): Imayama, T., Oh, C.W., Jeon, J., and Yi, K.
  • Organizer: 2021変成岩などシンポジウム
• [Presentation] Multiple igneous activities recorded in the Nidar ophiolite complex, eastern Ladakh (2021)
  • Author(s): 佐藤成修, 今山武志, Dutta Dripta
  • Organizer: 2021 Japan Geoscience Union Meeting
• [Presentation] 南モンゴルペルム紀－三畳紀火山岩類と中央ネパール古原生代花崗岩類の起源とテクトニクス (2021)
  • Author(s): 今山 武志
  • Organizer: 2021日本地質学会
  • Invited
• [Presentation] 福島県南部，二岐山火山の噴火史とマグマ供給系 (2021)
  • Author(s): 渡部将太，長谷川健，小畑直也，豊田新，今山武志
  • Organizer: 2021日本地質学会
• [Presentation] Multi-stage metamorphic history of the Oki gneisses in Japan: Implications for Paleoproterozoic metamorphism and tectonic correlations in northeastern Asia (2021)
  • Author(s): Imayama, T., Kawabata, R., Kato, T., Oh, C. W., Horie, K., and Takehara, M.
  • Organizer: 2021日本鉱物学会
  • Invited
• [Presentation] 北西インドNidarオフィオライト層火成岩類の岩石学・地球化学的研究 (2021)
  • Author(s): 佐藤成修, 今山武志, Dutta Dripta, 金田泰明, 渡部将太, 長谷川健, 南雅代, 若杉勇輝, 若木重行
  • Organizer: 2021日本鉱物学会
• [Presentation] Tectonic discontinuity, partial melting and exhumation in the Garhwal Himalaya (Northwest India): Constrains from spatial and temporal pressure-temperature conditions along the Bhagirathi valley (2021)
  • Author(s): Imayama, T., Kawabata, R., Bose, N., Yi, K., and Kouketsu, Y.
  • Organizer: 2021 AGU meeting
  • Int'l Joint Research
• [Presentation] 隠岐片麻岩の複数変成作用と起源 (2020)
  • Author(s): 今山 武志
  • Organizer: 日本地球化学会第 67回年会
• [Presentation] Late Permian to Early Triassic back-arc type volcanism in the southern Mongolia volcano-plutonic belt of the Central Asian Orogenic Belt: Implication for timing of the final closure of the Palaeo-Asian Ocean. (2020)
  • Author(s): Imayama, T., Koh, Y., Aoki, K., Saneyoshi, M., Yagi, K., Aoki, S., Terada, T., Sawada, Y., Ikawa, C., Ishigaki, S., Toyoda, S., Tsogtbaatar, Kh, and Mainbayar, B.
  • Organizer: Frontier Symposium on Geohistory of East Asia and Okayama
  • Int'l Joint Research
• [Presentation] Variability of Protoliths and P-T Conditions of Amphibolites from the Ohmachi Seamount (Izu-Bonin-Mariana Arc) (2020)
  • Author(s): Imayama, T., Ueda, H., Usuki, T., Minami, M., Asahara, Y., and Nagahashi, T.
  • Organizer: 2020 Goldschmidt Conference
  • Int'l Joint Research
• [Presentation] 北西インド Uttarakhand 地域の流体飽和による漸新世 Barrovian 型変成作用 (2019)
  • Author(s): 川端凌市・今山武志・Narayan Bose・Yi Keewook・纐纈佑衣
  • Organizer: OUSフォーラム2019
• [Presentation] Polymetamorphic evolution of the Oki gneisses in Japan: Implications for the Paleoproterozoic metamorphism and its tectonic correlation in northeastern Asia (2019)
  • Author(s): Imayama, T., Kawabata, R., Kato, T., Horie, K., and Takehara, M.
  • Organizer: 2019 Fall Joint Conference of the Korean Geological Sciences
  • Int'l Joint Research / Invited
• [Presentation] The inverted Barrovian metamorphic sequences and fluid-present melting in the Arun area, eastern Nepal (2019)
  • Author(s): Imayama, T., Uehara, S., Sakai, H., Yagi, K., Ikawa, C., and Yi, K.
  • Organizer: 2019 Goldschmidt Conference
  • Int'l Joint Research
• [Presentation] CHIME年代測定による隠岐・島後片麻岩類の変成年代の推定 (2019)
  • Author(s): 今山武志・川端凌市・加藤 丈典
  • Organizer: 名古屋大学 宇宙地球環境研究所 共同利用・共同研究コミュニティミーティング
  • Invited
• [Presentation] Preservation of the early Oligocene Barrovian-type metamorphism caused the fluid-present melting along Bhagirathi River in the Uttaraganti area, NW India (2019)
  • Author(s): Kawabata, R., Imayama, T., Bose, N., Yi, K., and Kouketsu, Y.
  • Organizer: 34th Himalaya-Karakorum-Tibet workshop
  • Int'l Joint Research
• [Presentation] Classification of volcanic rocks in the Muslim Bagh area: Constraints from petrological characteristics and K-Ar ages (2019)
  • Author(s): Arao, M., Imayama, T., Yagi, K., Ikawa, T., Sawada, M., Siddiqui, R., and Khan, S.
  • Organizer: JSPS Japanese-German graduate externship International Workshop on “Volatile Cycles”
  • Int'l Joint Research
• [Presentation] Petrological and geochronological studies of the volcanic rocks in the Muslim Bagh area, Pakistan. (2019)
  • Author(s): 荒尾 眞成・今山武志・八木 公史・猪川 千晶・澤田 順弘・Rehanul Siddiqui・Said Khan
  • Organizer: 2019地球惑星科学連合大会
• [Presentation] Late Permian to Early Triassic back-arc type volcanism in the southern Mongolia volcano-plutonic belt of the Central Asian Orogenic Belt: Implication for timing of the final closure of the Palaeo-Asian Ocean. (2019)
  • Author(s): Imayama, T., Koh, Y., Aoki, K., Saneyoshi, M., Yagi, K., Aoki, S., Terada, T., Sawada, Y., Ikawa, C., Ishigaki, S., Toyoda, S., Tsogtbaatar, Kh, and Mainbayar, B.
  • Organizer: 2019地球惑星科学連合大会
• [Presentation] Early Oligocene partial melting via biotite dehydration melting and prolonged low- P/T metamorphism of the upper High Himalaya Crystalline Sequence in the far east of Nepal (2019)
  • Author(s): Imayama, T., Takeshita, T., Yi, K. and Fukuyama, M.
  • Organizer: 3rd International RINS Symposium －Metamorphism, deformation, and geochronology in orogeny－
  • Int'l Joint Research
• [Presentation] The early Oligocene Barrovian-type metamorphism related to fluid-saturated melting along Bhagirathi River in the Uttarakhand area, NW India (2019)
  • Author(s): Kawabata, R., Imayama, T., Bose, N., and Yi, K.
  • Organizer: 3rd International RINS Symposium －Metamorphism, deformation, and geochronology in orogeny－
  • Int'l Joint Research
• [Presentation] 北西インドヒマラヤBhagirathi川沿いの変成温度圧力条件と変成年代について (2018)
  • Author(s): 川端凌市・今山武志・Narayan Bose・Yi Keewook
  • Organizer: 「衝突山脈ヒマラヤの形成モデルの構築」研究集会, 京都大学
• [Presentation] 1.74 Ga crustal melting after rifting at the northern Indian margin: Investigation of mylonitic orthogneisses in the Kathmandu area, central Nepal (2018)
  • Author(s): Imayama, T., Arita, K. Fukuyama, M. Yi, K., and Kawabata, R.
  • Organizer: 33rd Himalaya-Karakorum-Tibet workshop
  • Int'l Joint Research
• [Presentation] 1.74 Ga crustal melting after rifting at the northern Indian margin: Investigation of mylonitic orthogneisses in the Kathmandu area, central Nepal (2018)
  • Author(s): Imayama, T., Arita, K. Fukuyama, M. Yi, K., and Kawabata, R.
  • Organizer: 15th Asia Oceania Geosciences Society meeting
  • Int'l Joint Research
• [Presentation] 1.74 Ga felsic magmatism formed via crustal melting: Investigation of mylonitic orthogneisses in the frontal zone of the Kathmandu Complex, central Nepal (2018)
  • Author(s): Imayama, T., Arita, K. Fukuyama, M. Yi, K., and Kawabata, R.
  • Organizer: 地球惑星科学連合大会
• [Remarks] 今山研究室 生命・地球・環境部門
  • URL: http://t-imayama.com/