大别地区构造和地壳演化—来自河流碎屑锆石U-Pb-Hf同位素的制约【华南古大陆演化及其资源效应专辑】
- 收稿日期:
2023-10-30
- 网络出版日期:
2024-04-28
摘要: 地壳的形成与演化是研究早期地球向宜居星球演变的重要内容。大别地区早期基底岩石及其锆石年龄信息的相继发现,使得该地区成为研究早期地球的重要场所。与出露有限的基底岩石相比,河流沉积物中的碎屑锆石可较全面的反映物源区域地质演化信息,是探讨大陆地壳生长和演化的有效手段。本文对大别地区3条不同河流的碎屑沉积物中的锆石开展U-Pb-Hf同位素分析,得到的U-Pb锆石年龄峰值可分为4组:2676~2424Ma、2035~1812Ma、890~748Ma、140~120Ma。根据本文数据并结合前人研究成果,得到以下结论:(1)大别地区的岩浆活动记录可大致分为10个阶段,5个旋回。分别为3.0-2.9Ga,2.4-2.1Ga,1.8-0.9Ga,0.70-0.14Ga的平静期,与4.0~3.0Ga、2.9~2.4G、2.1~1.8Ga、0.9~0.7Ga、0.14~0.12Ga的爆发期。(2)大别地区主要经历了4期变质事件,分别发生在:新太古代晚期(~2.5Ga)、古元古代中期(~2.0Ga)、三叠纪(0.24-0.20Ga)与白垩纪(0.14-0.12Ga)。(3)大别地区主要经历了4个阶段的地壳生长事件:冥古宙时期初始地壳生长,4.4~4.1Ga巨量地壳生长;4.1~3.9Ga地壳生长较缓慢,无明显地壳生长;3.9~2.8Ga持续地壳生长;2.8~1.0Ga较缓速率地壳增长。(4)对比大别与黄陵地区岩浆、变质、地壳生长事件,两者在~2.0Ga之前区别明显,暗示在此之前两者更可能为独立的微陆块。
Tectonic and Crustal Evolution in the Dabie Region: Constraints from U-Pb-Hf Isotopes of River Clastic Zircons
- Received Date:
2023-10-30
- Available Online:
2024-04-28
Abstract: The formation and evolution of the Earth's crust is an important aspect of studying the early evolution of the Earth towards livable planets. The successive discovery of early basement rocks and their zircon age information in the Dabie region has made it an important place to study the early Earth. Compared with the limited exposure of basement rocks, the detrital zircons in river sediments can comprehensively reflect the geological evolution information of the source area, and are an effective means to explore the growth and evolution of continental crust. This article conducts U-Pb Hf isotope analysis of zircons in detrital sediments from three different rivers in the Dabie region. The U-Pb zircon age peaks obtained can be divided into four groups: 2676-2424 Ma, 2035-1812 Ma, 890-748 Ma, and 140-120 Ma. Based on the data in this article and previous research results, the following conclusions can be drawn: (1) The magmatic activity records in the Dabie region can be roughly divided into 10 stages and 5 cycles. The quiet periods are 3.0-2.9Ga, 2.4-2.1Ga, 1.8-0.9Ga, 0.70-0.14Ga, and the explosive periods are 4.0-3.0Ga, 2.9-2.4Ga, 2.1-1.8Ga, 0.9-0.7Ga, 0.14-0.12Ga, respectively. (2) The Dabie region mainly experienced four stages of metamorphic events, which occurred in the late Neoarchean (~2.5Ga), middle Paleoproterozoic (~2.0Ga), Triassic (0.24-0.20Ga), and Cretaceous (0.14-0.12Ga). (3) The Dabie region mainly experienced four stages of crustal growth events: initial crustal growth during the Mesozoic era, and massive crustal growth at 4.4-4.1Ga; The crustal growth at 4.1~3.9Ga is relatively slow, with no significant crustal growth; 3.9~2.8Ga sustained crustal growth; The crustal growth rate is relatively slow at 2.8~1.0Ga. (4) Compared to the magmatic, metamorphic, and crustal growth events in the Dabie and Huangling regions, there is a significant difference between the two before~2.0Ga, suggesting that the two were more likely independent micro landmasses before this time.
汪子祺, 田洋, 金巍, 邓新, 王晶, 童喜润, 柳潇. 大别地区构造和地壳演化—来自河流碎屑锆石U-Pb-Hf同位素的制约【华南古大陆演化及其资源效应专辑】[J]. 沉积学报. doi: 10.14027/j.issn.1000-0550.2024.0041
Tectonic and Crustal Evolution in the Dabie Region: Constraints from U-Pb-Hf Isotopes of River Clastic Zircons[J]. Acta Sedimentologica Sinica. doi: 10.14027/j.issn.1000-0550.2024.0041
Citation: |
Tectonic and Crustal Evolution in the Dabie Region: Constraints from U-Pb-Hf Isotopes of River Clastic Zircons[J]. Acta Sedimentologica Sinica. doi: 10.14027/j.issn.1000-0550.2024.0041
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