U-Pb dating and Hf isotope study of detrital zircons from the Zhifu Group, Jiaobei Terrane, North China Craton: Provenance and implications for Precambrian crustal growth and recycling
U-Pb dating and Hf isotope study of detrital zircons from the Zhifu Group, Jiaobei Terrane, North China Craton: Provenance and implications for Precambrian crustal growth and recycling
复制标题
华北克拉通胶北地体芝罘群碎屑锆石的U-Pb定年和Hf同位素研究：物源及其对前寒武纪地壳生长和再循环的意义
DOI：
10.1016/j.precamres.2013.06.014
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发表时间：
2013-09-01
影响因子：
3.8
通讯作者：
Geng, Jianzhen
中科院分区：
文献类型：
--
作者：
Liu, Jianhui;Liu, Fulai;Geng, Jianzhen
出露于胶北地体东北部的芝罘群，自下而上分为老爷山组、冰营组和洞口组，主要由石英岩和含白云母、电气石的石英片岩组成。为了明确其物源和沉积时代，约束源区的地壳生长和再循环，我们对芝罘群石英片岩样品中的碎屑锆石进行了LA-ICP-MS U-Pb定年和原位Hf同位素研究。大多数分析的锆石颗粒具有振荡分区且 Th/U 比率 >0.4，表明火成岩成因。 270 个碎屑锆石 U-Pb 分析得出 U-Pb 年龄为 1709-3679 Ma，分为三个主要年龄群体：1.7-1.9 Ga，峰值在 1844 Ma，1.9-2.0 Ga，峰值在 1936 Ma，2.4-2.55 Ga，峰值在 2465 Ma，以及两个次要年龄群体2.2-2.35和2.6-2.7 Ga。最年轻群体的峰值年龄为1844 Ma，表明芝罘群的沉积必定是在1844 Ma之后。年龄为 1.7~2.35 Ga 的碎屑锆石可与吉林江山沿线构造前后的多相岩浆事件联系起来，大部分锆石的负 epsilon(Hf(t)) 值在+1.76~-18.02 之间，两阶段 Hf 模型年龄（T-DM2）集中在 2.7~3.0 Ga 附近，表明这些锆石的烃源岩为来自古代地壳的回收。年龄为2.4~2.9 Ga的碎屑锆石可能来源于胶北地体太古代花岗质片麻岩（主要是TTG），这些锆石的ε(Hf(t))值为+6.4~-7.53，T-Dm2为2.6~3.4 Ga（峰值与2.7~3.0 Ga相似），表明这些锆石的烃源岩锆石主要来源于与2.7-3.0 Ga附近地壳主要生长有关的新生地壳，以及少量的古地壳成分。年龄分别为3631和3679 Ma的两块碎屑锆石的负ε(Hf(t))值分别为-4.42和-1.51，T-Dm2分别为4137和4000 Ma，这意味着华北克拉通古大陆地壳(>3.6 Ga)的再循环和4.1 Ga之前的地壳生长。 (C) 2013 Elsevier B.V. 保留所有权利。
The Zhifu Group exposed in the northeastern Jiaobei Terrane is subdivided from base to top into the Laoyeshan, Bingying and Dongkou formations, and comprises mainly quartzites and muscovite- and tourmaline-bearing quartz schists. In order to define its provenance and depositional age, and to constrain the crustal growth and recycling of the source regions, we have conducted LA-ICP-MS U-Pb dating and in situ Hf isotopic study of detrital zircons from three quartz schists samples collected from the Zhifu Group. Most of the analyzed zircon grains have oscillatory zoning and Th/U ratios >0.4, suggesting igneous origins. 270 detrital zircons U-Pb analyses yield U-Pb ages of 1709-3679 Ma that cluster into three major age populations of 1.7-1.9 Ga with a peak at 1844 Ma, 1.9-2.0 Ga with a peak at 1936 Ma and 2.4-2.55 Ga with a peak at 2465 Ma, and two minor age populations of 2.2-2.35 and 2.6-2.7 Ga. The peaking age of 1844 Ma for the youngest age population indicates that the Zhifu Group must be deposited after 1844 Ma. Detrital zircons with ages of 1.7-2.35 Ga can be linked to pre- and post-tectonic polyphase magmatic events along the JLJB, and most of the zircons have negative epsilon(Hf(t)) values from +1.76 to -18.02 and two-stage Hf model ages (T-DM2) concentrating at similar to 2.7-3.0 Ga, indicating that source rocks of these zircons were derived from recycling of ancient crusts. Detrital zircons with ages of 2.4-2.9 Ga may have been sourced from the Archean granitoid (mainly TTG) gneisses in the Jiaobei Terrane, and these zircons have epsilon(Hf(t)) values from +6.4 to -7.53 and T-Dm2 of 2.6-3.4 Ga (peak at similar to 2.7-3.0 Ga), suggesting that source rocks of these zircons were mainly derived from juvenile crusts associated with a major crustal growth at similar to 2.7-3.0 Ga, and a limited amount of ancient crustal component. The two detrital zircons with ages of 3631 and 3679 Ma have negative epsilon(Hf(t)) values of -4.42 and -1.51 and T-Dm2 of 4137 and 4000 Ma, respectively, implying the recycling of ancient continental crust (>3.6 Ga) and crustal growth prior to 4.1 Ga in the NCC. (C) 2013 Elsevier B.V. All rights reserved.