|
|
扬子地块西南缘新元古代辉长岩年代学及其地质意义
|
Abstract:
滇西点苍山–哀牢山构造带是扬子地块西南缘的重要组成部分，保存有大量前寒武纪岩石学记录，是探究扬子地块西南缘前寒武纪构造演化历史的良好载体。本文选取点苍山–哀牢山构造带北段点苍山地区的基性岩为研究对象，通过锆石U-Pb年代学测试分析，显示点苍山基性岩的形成时代为779 ± 5 Ma，属于新元古代时期，表明点苍山地区发育新元古代岩浆活动。结合区域地质资料与前人研究成果，扬子地块西南缘的点苍山–哀牢山构造带发育有广泛的新元古代岩浆活动，形成了从酸性岩到基性岩等不同的岩石类型，形成时代主要集中在870~720 Ma，持续时间如此长的岩浆活动可能与扬子地块周缘的持续俯冲有关。
The Diancangshan-Ailaoshan tectonic belt in western Yunnan is a crucial part of the southwestern margin of the Yangtze Block, preserved a wealth of Precambrian petrology records, serving as an excellent medium for exploring the Precambrian tectonic evolutionary history of the southwestern Yangtze Block. This study focuses on the basic rocks from the northern section of the Diancangshan area within the Diancangshan-Ailaoshan tectonic belt. Through zircon U-Pb geochronological testing and analysis, it is revealed that the DianCangshan basic rocks were formed at 779 ± 5 Ma, belonging to the neoproterozoic era, indicating the presence of neoproterozoic magmatic activity in the Diancangshan area. In conjunction with regional geological data and previous research findings, the Diancangshan-Ailaoshan tectonic belt on the southwestern margin of the Yangtze Block has experienced extensive neoproterozoic magmatic activity, resulting in a variety of rock types from acidic to basic rocks, with formation ages predominantly concentrated between 870~720 Ma. The prolonged duration of such magmatic activity may be related to the continuous subduction along the periphery of the Yangtze Block.
| [1] | 陆松年, 李怀坤, 陈志宏, 等. 新元古时期中国古大陆与罗迪尼亚超大陆的关系[J]. 地学前缘, 2004, 11(2): 515-523. |
| [2] | 李献华, 李武显, 何斌. 华南陆块的形成与Rodinia超大陆聚合-裂解——观察、解释与检验[J]. 矿物岩石地球化学通报, 2012, 31(6): 543-559. |
| [3] | Zhang, X.Q., Zhang, H.F., Zou, H.B. (2020) Rift-Related Neoproterozoic Tholeiitic Layered Mafic Intrusions at Northern Yangtze Block, South China: Mineral Chemistry Evidence. Chemicals & Chemistry, 356-357, Article 105376. https://doi.org/10.1016/j.lithos.2020.105376 |
| [4] | 朱强, 施珂, 吴礼彬, 等. 扬子板块新元古代中期的持续俯冲作用: 来自南华纪岛弧火山岩年代学和岩石地球化学新证据[J]. 地学前缘, 2020, 27(4): 17-32. |
| [5] | 裴先治, 李佐臣, 丁仨平, 等. 扬子地块西北缘轿子顶新元古代过铝质花岗岩: 锆石SHRIMP U-Pb 年龄和岩石地球化学及其构造意义[J]. 地学前缘, 2009, 16(3): 231-249. |
| [6] | Hu, P.Y., Zhai, Q.G., Wang, J., et al. (2020) U-Pb Zircon Geochronology, Geochemistry, and Sr-Nd-Hf-O Isotopic Study of Middle Neoproterozoic Magmatic Rocks in the Kangdia Rift, South China: Slab Rollback and Backarc Extension at the Northwestern Edge of the Rodinia. Precambrian Research, 347, Article 105863. |
| [7] | Cai, Y.F., Liu, H.C., Feng, Z.H., et al. (2020) Neoproterozoic Active Margin of the SW South China Block: Constraints from U-Pb Ages, Sr-Nd Isotopes and Geochemical Data for the Gabbro and Granodiorite along the Ailaoshan Tectonic Belt. Lithos, 358-359, Article 105387. https://doi.org/10.1016/j.lithos.2020.105387 |
| [8] | 云南省地矿局. 云南省区域地质志[M]. 北京: 地质出版社, 1990. |
| [9] | 朱炳泉, 常向阳, 邱华宁, 等. 云南前寒武纪基底形成与变质时代及其成矿作用年代学研究[J]. 前寒武纪研究进展, 2001, 24(2): 75-82. |
| [10] | 刘昊茹.云南瑶山群新元古代岩浆作用的年代学和地球化学特征及其地质意义[D]: [硕士学位论文]. 桂林: 桂林理工大学, 2023. |
| [11] | Chung, S.L., Lee, T.Y., Lo, C.H., et al. (1997) Intraplate Extension Prior to Continental Extrusion along the AilaoShan-Red River Shear Zone. Geology, 25, 311-314. https://doi.org/10.1130/0091-7613(1997)025%3C0311:IEPTCE%3E2.3.CO;2 |
| [12] | Deng, J., Wang, Q., Li, G., et al. (2014) Cenozoic Tectono-Magmatic and Metallogenic Processes in the Sanjiang Region, Southwestern China. Earth-Science Reviews, 138, 268-299. https://doi.org/10.1016/j.earscirev.2014.05.015 |
| [13] | 黄学猛, 许志琴, 张进江. 哀牢山-红河断裂带新生代构造转换及其动力学机制[J]. 地球学报, 2017, 38(z1): 7-10. |
| [14] | 麻艺超, 蔡永丰, 马莉燕, 等. 滇西点苍山新元古代斜长角闪岩的成因: 来自锆石U-Pb年龄和全岩地球化学的证据[J]. 地球科学, 2021, 46(8): 2860-2872. |
| [15] | 王二七, 樊春, 王刚, 等. 滇西哀牢山-点苍山形成的构造和地貌过程[J]. 第四纪研究, 2006, 26(2): 220-228. |
| [16] | Xu, J., Xia, X.P., Yin, C.Q., et al. (2022) Geochronology and Geochemistry of the Granitoids in the Diancangshan-Ailaoshan Fold Belt: Implications on the Neoproterozoic Subduction and Crustal Melting along the Southwestern Yangtze Block, South China. Precambrian Research, 383, Article 106907. https://doi.org/10.1016/j.precamres.2022.106907 |
| [17] | 张进江, 钟大赉, 桑海清, 等. 哀牢山-红河构造带古新世以来多期活动的构造和年代学证据[J]. 地质科学, 2006, 4l(2): 291-310. |
| [18] | 翟明国, 从柏林. 对于点苍山-石鼓变质带区域划分的意见[J]. 岩石学报, 1993, 9(3): 227-239. |
| [19] | 李宝龙, 季建清, 王丹丹, 等. 滇南新元古代的岩浆作用: 来自瑶山群深变质岩SHRIMP锆石U-Pb年代学证据[J]. 地质学报, 2012, 86(10): 1584-1591. |
| [20] | 蔡永丰, 王岳军, 刘汇川, 等. 哀牢山新元古代斜长角闪岩的形成时代、地球化学特征及其大地构造意义[J]. 大地构造与成矿学, 2014, 38(1): 168-180. |
| [21] | Cai, Y.F, Wang, Y.J., Cawood, P.A., et al. (2015) Neoproterozoic Crustal Growth of the Southern Yangtze Block: Geochemical and zircon U-Pb Geochronological and Lu-Hf Isotopic Evidence of Neoproterozoic Diorite from the Ailaoshan Zone. Precambrian Research, 266, 137-149. https://doi.org/10.1016/j.precamres.2015.05.008 |
| [22] | Li, D.P., Chen,Y.L., Kang, H., et al. (2018) Neoproterozoic Continental Arc System along the NW Margin of Rodinia Supercontinent: Constraints from Geochronological and Geochemical Studies of Neoproterozoic Granitoids in the Diancangshan Massif. Lithos, 316-317, 77-91. https://doi.org/10.1016/j.lithos.2018.07.011 |
| [23] | Li, X.H., Li, Z.X., Zhou, H., et al. (2002) U-Pb Zircon Geochronology, Geochemistry and Nd Isotopic Study of Neoproterozoic Bimodal Volcanic Rocks in the Kangdian Rift of South China: Implications for the Initial Rifting of Rodinia. Precambrian Research, 113, 135-154. https://doi.org/10.1016/S0301-9268(01)00207-8 |
| [24] | Wang, X.C., Li, X.H., Li, W.X., et al. (2007) Ca. 825 Ma Komatiitic Basalts in South China: First evidence for>1500？C Mantle Melts by a Rodinian Mantle Plume. Geology, 35, 1103-1106. https://doi.org/10.1130/G23878A.1 |
| [25] | Kou, C.H., Liu, Y.X., Huang, H., et al. (2018) The Neoproterozoic Arc-Type and OIB-Type Mafic-Ultramafic Rocks in the Western Jiangnan Orogen: Implications for Tectonic Settings. Lithos, 312-313, 38-56. https://doi.org/10.1016/j.lithos.2018.05.004 |
| [26] | Ao, W.H., Zhao, Y., Zhang, Y., et al. (2019) The Neoproterozoic Magmatism in the Northern Margin of the Yangtze Block: Insights from Neoproterozoic (950-706 Ma) Gabbroic-Granitoid Rocks of the Hannan Complex. Precambrian Research, 333, Article 105442. https://doi.org/10.1016/j.precamres.2019.105442 |
| [27] | 寇彩化, 刘燕学, 李江, 等. 江南造山带西段桂北四堡地区830 Ma辉长岩锆石SIMS U-Pb年代学和岩石地球化学特征及其岩石成因研究[J]. 地学前缘, 2022, 29(2): 218-233. |
| [28] | 孙洋, 马昌前, 张超. 大别山鲁家寨花岗岩地球化学、锆石年代学和Hf同位素特征: 扬子克拉通北东缘新元古代岩浆活动证据[J]. 地学前缘, 2011, 18(2): 85-99. |
| [29] | 秦利, 裴先治, 李佐臣, 等. 扬子板块西北缘碧口微地块新元古代大陆弧岩浆作用: 来自锆石U-Pb年代学、Hf同位素和地球化学证据[J]. 地球科学与环境学报, 2021, 43(4): 686-709. |
| [30] | 徐丽娟, 李萍, 刘铮, 等. 扬子地块西缘峨山新元古代A2型花岗闪长岩的成因及构造意义[J]. 岩石矿物学杂志, 2021, 40(2): 383-394. |
| [31] | Gao, R., Chen, C., Wang, H., et al. (2016) SINOPROBE Deep Reflection Profile Reveals a Neo-Proterozoic Subduction Zone beneath Sichuan Basin. Earth and Planetary Science Letters, 454, 86-91. https://doi.org/10.1016/j.epsl.2016.08.030 |
| [32] | Sun, W.H., Zhou, M.F., Gao, J.F., et al. (2009) Detrital Zircon U-Pb Geochronological and Lu-Hf Isotopic Constraints on the Precambrian Magmatic and Crustal Evolution of the Western Yangtze Block, SW China. Precambrian Research, 172, 99-126. https://doi.org/10.1016/j.precamres.2009.03.010 |
| [33] | 张慰. 扬子地台西南缘新元古代岩浆杂岩体的构造变形与地质意义[D]: [硕士学位论文]. 北京: 中国地质大学, 2017. |
| [34] | Jiang, G.Q., Sohl, L.E. and Christie-Blick, N. (2003) Neoproterozoic Stratigraphic Comparison of the Lesser Himalaya (India) and Yangtze Block (South China): Paleogeographic Implications. Geology, 31, 917-920. https://doi.org/10.1130/G19790.1 |
| [35] | Zhao, J.H., Pandit, M.K., Wang, W., et al. (2018) Neoproterozoic Tectonothermal Evolution of NW India: Evidence from Geochemistry and Geochronology of Granitoids. Lithos, 316-317, 330-346. https://doi.org/10.1016/j.lithos.2018.07.020 |
| [36] | 孙力. 扬子陆块西南缘中-新元古代沉积盆地构造演化及其地质意义[D]: [博士学位论文]. 武汉: 中国地质大学, 2022. |
