التفاصيل البيبلوغرافية
| العنوان: |
华北克拉通北缘白云鄂博矿区尖山组沉积源区、 时代及其地质意义. (Chinese) |
| Alternate Title: |
Sedimentary Provenance and Geochronology of Jianshan Formation in Bayan Obo Ore District, the Northern Margin of North China Craton and Their Geological Significance. (English) |
| المؤلفون: |
杨建军, 王东升, 余宏全, 李以科, 杨月后, 柯昌辉, 张丽, 赵剑, 赵阳, 郭宾 |
| المصدر: |
Journal of Earth Sciences & Environment; Sep2024, Vol. 46 Issue 5, p606-635, 30p |
| مصطلحات موضوعية: |
GEOLOGICAL time scales, HYDROTHERMAL alteration, METAMORPHIC rocks, ORE deposits, ZIRCON |
| Abstract (English): |
The Bayan Obo ore deposit is located in the northern margin of North China Craton. and its country rock, Jianshan Formation, is a set of greenschist facies rocks formed by regional metamorphism. The study on its formation age and provenance is of great significance for understanding the regional tectonic evolution. LA-ICP-MS zircon U-Pb geochronology was conducted on the metasandstone and metamorphic fine sandstone within Jianshan Formation. The zircon ages from metamorphic fine sandstone range from 2 645 Ma to 1 147 Ma, including two. main peak ages of 2 510 Ma and 1 390 Ma. respectively. The zircon ages from metasandstone range from 2 722 Ma to 1 847 Ma, including three main peak ages of 2 487 Ma. 1 925 Ma, and 1 859 Ma. respectively. Based on the REE characteristics of zircons, it is believed that zircons of sample By23281 displaying ages from 2 722 Ma to 1 847 Ma belong to typical detrital zircons and the formation age of Jianshan Formation should be later than 1 847 Ma. Based on the field characteristics. REE and morphology of zircons. the 1 761-1 147 Ma age of sample 25246 represents the process of subsequent hydrothermal alteration. further confirming the magmatic origin of dolomitic carbonate. Based on the previous chronological data in the ore district and its. periphery, it is advocated that Jianshan Formation is ultimately formed in the Mesoproterozoic. with its material sources coming from the Archean basement on the northern margin of North China Craton and metamorphic rocks from the Late Paleoproterozoic. In the Mesoproterozoic. Jianshan Formation is significantly altered by post-magmatic hydrothermal alteration of dolomitic carbonate. The ages of the clastic rocks in Bayan Obo ore district record the crustal accretion. collision and break-up events at the northern margin of North China Craton, providing powerful evidence for the study on the regional tectonic evolution during Archean-Proterozoic. [ABSTRACT FROM AUTHOR] |
| Abstract (Chinese): |
白云鄂博矿床位于华北克拉通北缘, 其围岩尖山组为一套绿片岩相硅质碎屑岩组合, 尖山 组的形成时代及物源研究对于理解区城大地构造演化和成矿过程具有重要意义。采用LA-ICP- MS方法对矿区尖山组的变质砂岩及变质细砂岩进行了锆石U-Pb年代学研究。变质细砂岩样品 Z5246 的锆石年龄为2645~1147 Ma. 包含两个主峰值年龄, 分别为2510和13901 Ma变质砂岩 样品 By23281 锆石年龄为2722~1847 Ma, 包含3个主峰值年龄, 分别为2487. 1925和1859 Ma。结合锆石稀土元素特征, 认为变质砂岩样品By23281中2722~1847 Ma的锆石属于未受热 液改造的碎屑锆石, 尖山组的形成时代应晚于1847 Ma:而結合野外特征、锆石形貌及稀土元素特 征, 认为变质细砂岩样品 Z5246中1761~1147 Ma的年龄反映了后期热液改造的过程, 也进一步 佐证了白云石碳酸岩的岩浆成因。结合矿区及周边已有的年代学数据, 认为矿区尖山组物源主要 来自华北克拉通北緣太古宙基底和古元古代晚期的变质岩, 最终形成于中元古代, 之后受到白云石 碳酸岩岩浆期热液的明显改造。矿区尖山组碎屑岩的年龄数据记录了华北克拉通北緣太古代——元 古代的陆壳增生、碰撞及裂解事件, 为研究太古代——元古代区域构造演化提供了有力证据。 [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |