SHRIMP zircon dating and LA-ICPMS Hf analysis of early Precambrian rocks from drill holes into the basement beneath the Central Hebei Basin, North China Craton

Geoscience Frontiers

卷:5

Alfred Kröner¹  Zejiu Wang²  Yusheng Wan³  Dunyi Liu³  Runlong Fan³  Hangqian Xie³  Chunyan Dong³  Yuansheng Geng³  Yuhai Zhang³  Huiyi Sun³  Xianzheng Zhao⁴ 

[1] Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;

[2] Chinese Academy of Geological Sciences, Beijing 100037, China;

[3] Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;

[4] North China Oilfield Company of PetroChina, Renqiu 062552, China;

关键词: Early Precambrian;    North China Craton;    Drill hole;    Zircon dating;    Hf isotopic analysis;   

DOI  :  10.1016/j.gsf.2014.02.007

来源: DOAJ

【 摘 要 】

The Central Hebei Basin (CHB) is one of the largest sedimentary basins in the North China Craton, extending in a northeast–southwest direction with an area of >350 km2. We carried out SHRIMP zircon dating, Hf-in-zircon isotopic analysis and a whole-rock geochemical study on igneous and metasedimentary rocks recovered from drill holes that penetrated into the basement of the CHB. Two samples of gneissic granodiorite (XG1-1) and gneissic quartz diorite (J48-1) have magmatic ages of 2500 and 2496 Ma, respectively. Their zircons also record metamorphic ages of 2.41–2.51 and ∼2.5 Ga, respectively. Compared with the gneissic granodiorite, the gneissic quartz diorite has higher ΣREE contents and lower Eu/Eu* and (La/Yb)n values. Two metasedimentary samples (MG1, H5) mainly contain ∼2.5 Ga detrital zircons as well as late Paleoproterozoic metamorphic grains. The zircons of different origins have εHf (2.5 Ga) values and Hf crustal model ages ranging from 0 to 5 and 2.7 to 2.9 Ga, respectively. Therefore, ∼2.5 Ga magmatic and Paleoproterozoic metasedimentary rocks and late Neoarchean to early Paleoproterozoic and late Paleoproterozoic tectono-thermal events have been identified in the basement beneath the CHB. Based on regional comparisons, we conclude that the early Precambrian basement beneath the CHB is part of the North China Craton.

【 授权许可】

Unknown