Revisiting the genesis of the adakite-like granitoids in collisional zones: Water-fluxed melting of intermediate to felsic rocks with dilution by low Sr/Y phases
文献类型：期刊论文
| 作者 | Xie, Yuan-Hui1,8; Schwartz, Joshua J.7; Li, Xiao-Wei1,8; Cai, Keda1,8; Thomas, Bader6; Li, Huan5; Wang, Fang-Yue3,4; Zhang, Xiao-Bing2; Mo, Xuan-Xue1,8; Dong, Guo-Chen1,8 |
| 刊名 | AMERICAN MINERALOGIST
 |
| 出版日期 | 2024-04-25 |
| 卷号 | 109期号:4页码:709-728 |
| 关键词 | Adakitic rock antecryst dilution pyroxene-bearing granodiorite water-fluxed melting |
| ISSN号 | 0003-004X |
| DOI | 10.2138/am-2022-8873 |
| 英文摘要 | High-Sr/Y granitoids in continental settings are sometimes erroneously regarded as the products derived from partial melting of thickened/delaminated mafic lower curst under relatively higher pressures (>1.5 GPa) in a collisional orogenic setting. In fact, multiple magmatic processes in the trans-crustal magma system, such as recycling of antecrysts, crustal assimilation, and fractional crystallization, can create or modify the primary "adakitic" signature. As a result, the generation of adakitic magmas in continental settings remains controversial from a bulk-rock perspective. Here, we address the origin of adakitic plutonic rocks through geochemical and textural characterization of rock-forming minerals in the pyroxene-bearing Zhuyuan granodiorite, West Qinling, China. The Zhuyuan granodiorite formed in a post-collisional setting and primarily consists of resorbed orthopyroxene, three types of clinopyroxene, amphibole, two types of plagioclases, K-feldspar, biotite, and quartz. Type-1 Cpx has high X-Mg (70.0-81.7). Type-2 Cpx displays normal zoning and decreasing X-Mg (80.9 to 71.5) from the core to rim. Type-3 Cpx is reversely zoned, where the rims have higher X-Mg (75.5-86.9), Ni, Cr, suggesting a recharge event. Orthopyroxene has high-Ni and -Cr contents, as well as high X-Mg (80.9-82.8), indicative of antecrysts that grew in mafic magma reservoirs. The injection of magmas from different sources is supported by sieve-textured plagioclase and crystal size distributions of non-poikilitic amphibole. Finally, non-sieve textured plagioclase, biotite, K-feldspar, and quartz are late-crystallized phases, indicative of an orthocrystic origin. The melts in equilibrium with these orthocrysts display significantly higher Sr/Y values than the magma batches that crystallized other mafic phases (i.e., amphibole, clinopyroxene, and orthopyroxene). Thus, we propose that the system involved an initial high-Sr/Y melts in equilibrium with the orthocryst assemblage was generated by water-fluxed melting of intermediate to felsic sources. The addition of low Sr/Y non-orthocrysts (e.g., amphibole and pyroxene) and associated melt diluted the original "adakitic signal" in the magma reservoir and drove the bulk composition to more mafic values. Consequently, the Zhuyuan pyroxene-bearing granodiorite represents a mixture of crystals with diverse origins and distinct magma batches of various compositions (from felsic to mafic compositions). Our study emphasizes that the origin of adakitic granitoids cannot be clearly deciphered without geochemical analysis of the constituent minerals. We also suggest that Sr/Y values in plutons should be cautiously used in paleo-crustal thickness estimates in collisional settings because of possible open system scenarios as described here. |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| 语种 | 英语 |
| WOS记录号 | WOS:001191907900005 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/77205]  |
| 专题 | 同位素地球化学国家重点实验室 |
| 通讯作者 | Li, Xiao-Wei; Cai, Keda |
| 作者单位 | 1.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China 2.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 3.Hefei Univ Technol, Sch Resources & Environm Engn, Hefei 230009, Peoples R China 4.Hefei Univ Technol, Ore Deposit & Explorat Ctr, Hefei 230009, Peoples R China 5.Cent South Univ, Key Lab Metallogen Predict Nonferrous Met & Geol E, Minist Educ, Changsha 410083, Peoples R China 6.Peking Univ, Sch Earth & Space Sci, Beijing 100087, Peoples R China 7.Calif State Univ Northridge, Dept Geol Sci, Northridge, CA 91330 USA 8.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xie, Yuan-Hui,Schwartz, Joshua J.,Li, Xiao-Wei,et al. Revisiting the genesis of the adakite-like granitoids in collisional zones: Water-fluxed melting of intermediate to felsic rocks with dilution by low Sr/Y phases[J]. AMERICAN MINERALOGIST,2024,109(4):709-728. |
| APA | Xie, Yuan-Hui.,Schwartz, Joshua J..,Li, Xiao-Wei.,Cai, Keda.,Thomas, Bader.,...&Dong, Guo-Chen.(2024).Revisiting the genesis of the adakite-like granitoids in collisional zones: Water-fluxed melting of intermediate to felsic rocks with dilution by low Sr/Y phases.AMERICAN MINERALOGIST,109(4),709-728. |
| MLA | Xie, Yuan-Hui,et al."Revisiting the genesis of the adakite-like granitoids in collisional zones: Water-fluxed melting of intermediate to felsic rocks with dilution by low Sr/Y phases".AMERICAN MINERALOGIST 109.4(2024):709-728. |
入库方式： OAI收割
来源：广州地球化学研究所
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