Metamorphic CO2 emissions from the southern Yadong-Gulu rift, Tibetan Plateau: Insights into deep carbon cycle in the India-Asia continental collision zone
Metamorphic CO2 emissions from the southern Yadong-Gulu rift, Tibetan Plateau: Insights into deep carbon cycle in the India-Asia continental collision zone
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青藏高原亚东-古鲁裂谷南部变质二氧化碳排放：印度-亚洲大陆碰撞带深层碳循环的见解
DOI：
10.1016/j.chemgeo.2021.120534
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发表时间：
2021-12
期刊：
影响因子：
3.9
通讯作者：
Li Ying
中科院分区：
文献类型：
--
作者：
Zhang Maoliang;Zhang Lihong;Zhao Wenbin;Guo Zhengfu;Xu Sheng;Sano Yuji;Lang Yunchao;Liu Congqiang;Li Ying
伸展裂谷系统为向大气中释放大量深源CO2提供了重要途径。大陆裂谷带（例如，东非裂谷），因此调用是重要的理解之间的联系CO2释气和全球气候变化与大陆分裂。然而，深源CO2排放从大陆碰撞带的伸展裂谷系统仍然知之甚少。本文以青藏高原南部最大的拉张裂谷-亚东-古鲁裂谷（YGR）南段热液CO2排放为研究对象，旨在揭示印度-亚洲大陆碰撞带与裂谷相关的CO2排放。对土壤CO2扩散排放的现场测量表明，康布、蒙扎和茶多热液田的平均土壤CO2通量分别为40、700和255 g m−2d−1。结合YGR中部和北方的平均土壤CO2通量（20-437 g m−2d−1），我们推测整个裂谷的CO2脱气模式相对稳定。YGR的土壤CO2通量的幅度高于东非裂谷系的代表性地区。3 He/4 He的证据表明，扬子古陆南部的CO2流体为纯地壳成因，而中部和北方裂谷段则有地幔CO2的参与。这与扬子江中部和北方的岩浆-碳酸盐作用模式不同，表明扬子江南部不同深度地壳岩石的变质脱碳酸作用是扬子江南部CO2成因的主要原因。基于热液气体He-CO2系统学的三元混合计算表明，碳酸盐岩对总碳储量的贡献占主导地位，而地幔CO2的贡献在YGR南部不存在，但在北方YGR可辨别。地壳CO2的高比例（>90%）将YGR与大陆裂谷带中主要由地幔CO2供给的伸展裂谷区分开来。研究结果揭示了印度-亚洲大陆碰撞带增生楔中地壳尺度的碳循环，以及扬子江中段和北方的岩浆前缘背景，勾勒出大陆碰撞带裂谷相关CO2排放的一条横断面。这将有助于更好地理解大陆组装在深源CO2排放和全球碳预算中的作用。
Extensional rift systems provide important pathways for the release of large amounts of deeply-sourced CO2into the atmosphere. Continental rifting zones (e.g., East African rift) are thus invoked to be important for understanding the links between CO2outgassing and global climate change associated with continental breakup. However, deeply-sourced CO2emissions from extensional rift systems in continental collision zones remain poorly understood. Here, we focus on hydrothermal CO2emissions from the southern segment of the Yadong-Gulu rift (YGR), the largest extensional rift in southern Tibetan Plateau, aiming at delineating rift-related CO2emissions from the India-Asia continental collision zone. In-situ measurements of diffuse soil CO2emissions indicate that average soil CO2fluxes from the Kangbu, Mengzha, and Chaduo hydrothermal fields are 40, 700, and 255 g m−2d−1, respectively. Combined with average soil CO2fluxes (20–437 g m−2d−1) from central and northern YGR, we speculate a relatively steady-state CO2degassing pattern for the entire rift. The magnitude of soil CO2fluxes of the YGR is higher than that of representative areas of the East African rift system. Evidence from3He/4He reveals a pure crustal origin for CO2-bearing fluids in southern YGR, while the involvement of mantle CO2is recognized in the central and northern rift segments. We suggest that metamorphic decarbonation of crustal rocks at variable depths is the primary cause for CO2origin in southern YGR, which differs from the magma‑carbonate interaction model of central and northern YGR. Ternary mixing calculation based on He-CO2systematics of hydrothermal gases indicates dominant contributions from carbonate rocks to total carbon inventory, with mantle CO2contributions absent in southern YGR but discernible in northern YGR. The characteristic high proportions of crustal CO2(>90%) distinguish the YGR from extensional rifts fed primarily by mantle CO2in continental rifting zones. Our results reveal a crustal-scale carbon cycle in accretionary wedge of the India-Asia continental collision zone, together with magmatic front setting of the central and northern YGR, outlining a transect of the rift-related CO2emissions across continental collision zones. This would contribute to better understanding the role of continental assembly in deeply-sourced CO2emissions and global carbon budget.
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影响因子：
3.9
作者：
A. Sinclair
通讯作者：
A. Sinclair
DOI：
10.1016/j.jngse.2020.103304
发表时间：
2020-06-01
影响因子：
--
作者：
Cao, Chunhui;Zhang, Mingjie;Zhou, Zheng
通讯作者：
Zhou, Zheng
影响因子：
2.9
作者：
A. J. Ellis;R. Golding
通讯作者：
A. J. Ellis;R. Golding
影响因子：
4.6
作者：
Kagoshima T;Sano Y;Takahata N;Maruoka T;Fischer TP;Hattori K
通讯作者：
Hattori K
影响因子：
16.6
作者：
Girault F;Adhikari LB;France-Lanord C;Agrinier P;Koirala BP;Bhattarai M;Mahat SS;Groppo C;Rolfo F;Bollinger L;Perrier F
通讯作者：
Perrier F