Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision
ABSTRACT: The timing of the initial Indo-Asian collision is a subject of debate for a long time. Besides, the magmatic trace of the collisional process is also unclear. In the present study, the authors report Early Eocene leucocratic sill/dike swarms in the northern edge of the Nymo intrusive compl...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2021-03-01
|
| Series: | China Geology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2096519221000057 |
| _version_ | 1811170522936901632 |
|---|---|
| author | Xu-xuan Ma Li-E Gao Zhong-bao Zhao Xi-jie Chen Hai-bing Li |
| author_facet | Xu-xuan Ma Li-E Gao Zhong-bao Zhao Xi-jie Chen Hai-bing Li |
| author_sort | Xu-xuan Ma |
| collection | DOAJ |
| description | ABSTRACT: The timing of the initial Indo-Asian collision is a subject of debate for a long time. Besides, the magmatic trace of the collisional process is also unclear. In the present study, the authors report Early Eocene leucocratic sill/dike swarms in the northern edge of the Nymo intrusive complex of the Gangdese belt, southern Tibet. The Nymo intrusive complex was emplaced at ca. 50 –47 Ma and surrounded by the metamorphosed Jurassic-aged Bima Formation volcano-sedimentary sequence along its northern side. At outcrops, the leucocratic sills/dikes intruded along or truncated the deformed foliations of the host Bima Formation, which has been subject to high-temperature amphibolite-facies metamorphism at ca. 50 –47 Ma. Detailed cathodoluminescence image analyses reveal that the zircon grains of the leucocratic sills/dikes have core-mantle textures. The cores yield the Jurassic ages comparable to the protolith ages of the Bima Formation. In contrast, the mantles of zircon grains yield weighted mean ages of ca. 49–47 Ma, representing the crystallization timing of these leucocratic sills/dikes. The coeval ages for the Nymo intrusive complex, the high-temperature metamorphism, and the leucocratic sills/dikes indicate that a close relationship exists among them. The authors tentatively suggest that these leucocratic sills/dikes were generated from partial melting of the Jurassic-aged Bima Formation volcanic rocks, triggered by the high heat from the magma chamber of the Nymo intrusive complex. This Early Eocene tectono-thermal event of coeval magmatism, metamorphism and partial melting was most likely formed during the Indo-Asian collisional setting.©2021 China Geology Editorial Office. |
| first_indexed | 2024-04-10T16:57:59Z |
| format | Article |
| id | doaj.art-e781f636d10f4a2e9955e82fd7402021 |
| institution | Directory Open Access Journal |
| issn | 2096-5192 |
| language | English |
| last_indexed | 2024-04-10T16:57:59Z |
| publishDate | 2021-03-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | China Geology |
| spelling | doaj.art-e781f636d10f4a2e9955e82fd74020212023-02-07T04:22:28ZengKeAi Communications Co., Ltd.China Geology2096-51922021-03-01415666Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collisionXu-xuan Ma0Li-E Gao1Zhong-bao Zhao2Xi-jie Chen3Hai-bing Li4Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China; Corresponding author: E-mail address: xuxuan.ma@hotmail.com (Xu-xuan Ma).Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, ChinaInstitute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, ChinaDevelopment and Research Center of China Geological Survey, Beijing 100037, ChinaInstitute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, ChinaABSTRACT: The timing of the initial Indo-Asian collision is a subject of debate for a long time. Besides, the magmatic trace of the collisional process is also unclear. In the present study, the authors report Early Eocene leucocratic sill/dike swarms in the northern edge of the Nymo intrusive complex of the Gangdese belt, southern Tibet. The Nymo intrusive complex was emplaced at ca. 50 –47 Ma and surrounded by the metamorphosed Jurassic-aged Bima Formation volcano-sedimentary sequence along its northern side. At outcrops, the leucocratic sills/dikes intruded along or truncated the deformed foliations of the host Bima Formation, which has been subject to high-temperature amphibolite-facies metamorphism at ca. 50 –47 Ma. Detailed cathodoluminescence image analyses reveal that the zircon grains of the leucocratic sills/dikes have core-mantle textures. The cores yield the Jurassic ages comparable to the protolith ages of the Bima Formation. In contrast, the mantles of zircon grains yield weighted mean ages of ca. 49–47 Ma, representing the crystallization timing of these leucocratic sills/dikes. The coeval ages for the Nymo intrusive complex, the high-temperature metamorphism, and the leucocratic sills/dikes indicate that a close relationship exists among them. The authors tentatively suggest that these leucocratic sills/dikes were generated from partial melting of the Jurassic-aged Bima Formation volcanic rocks, triggered by the high heat from the magma chamber of the Nymo intrusive complex. This Early Eocene tectono-thermal event of coeval magmatism, metamorphism and partial melting was most likely formed during the Indo-Asian collisional setting.©2021 China Geology Editorial Office.http://www.sciencedirect.com/science/article/pii/S2096519221000057Leucocratic sill/dike swarmEarly EoceneIndo-Asian collisionGangdeseTibetChina |
| spellingShingle | Xu-xuan Ma Li-E Gao Zhong-bao Zhao Xi-jie Chen Hai-bing Li Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision China Geology Leucocratic sill/dike swarm Early Eocene Indo-Asian collision Gangdese Tibet China |
| title | Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision |
| title_full | Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision |
| title_fullStr | Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision |
| title_full_unstemmed | Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision |
| title_short | Early Eocene leucocratic sill/dike swarms in the Gangdese belt, southern Tibet: Tectonic implications for Indo-Asian collision |
| title_sort | early eocene leucocratic sill dike swarms in the gangdese belt southern tibet tectonic implications for indo asian collision |
| topic | Leucocratic sill/dike swarm Early Eocene Indo-Asian collision Gangdese Tibet China |
| url | http://www.sciencedirect.com/science/article/pii/S2096519221000057 |
| work_keys_str_mv | AT xuxuanma earlyeoceneleucocraticsilldikeswarmsinthegangdesebeltsoutherntibettectonicimplicationsforindoasiancollision AT liegao earlyeoceneleucocraticsilldikeswarmsinthegangdesebeltsoutherntibettectonicimplicationsforindoasiancollision AT zhongbaozhao earlyeoceneleucocraticsilldikeswarmsinthegangdesebeltsoutherntibettectonicimplicationsforindoasiancollision AT xijiechen earlyeoceneleucocraticsilldikeswarmsinthegangdesebeltsoutherntibettectonicimplicationsforindoasiancollision AT haibingli earlyeoceneleucocraticsilldikeswarmsinthegangdesebeltsoutherntibettectonicimplicationsforindoasiancollision |