华北克拉通太古宙TTG岩石的时空分布、组成特征及形成演化:综述

发布时间：2018-03-20 09:44

本文选题：TTG　切入点：华北克拉通　出处：《岩石学报》2017年05期 　论文类型：期刊论文

【摘要】：华北克拉通具有3.8Ga以上的演化历史,TTG是其地质记录的最重要载体。华北克拉通太古宙(特别是中太古代以前)地质演化在很大程度上与TTG岩石密切相关。在华北克拉通,始太古代(3.6~4.0Ga)TTG岩石仅在鞍本地区被发现,但冀东地区已在多种变质碎屑沉积岩中发现大量3.6~3.88Ga碎屑锆石;古太古代(3.2~3.6Ga)TTG岩石在鞍本、冀东、信阳地区被识别出来;中太古代(2.8~3.2Ga)TTG岩石在鞍本、冀东、胶东、鲁山等地存在;可把新太古代(2.5~2.8Ga)进一步划分为早期和晚期两个阶段:新太古代早期(2.6~2.8Ga)TTG岩石已在10余个地区被发现,新太古代晚期(2.5~2.6Ga)TTG岩石几乎在每一个太古宙基底岩石出露区都存在。野外地质、锆石定年、元素地球化学和Nd-Hf同位素组成研究表明,中太古代以前TTG岩石局部存在,主要分布于Wan et al.(2015)所划分的三个古陆块中;新太古代TTG岩石广泛分布,是陆壳增生最重要时期岩浆作用的产物。TTG岩石类型随时代变化,3.1~3.8Ga和2.7~2.9Ga TTG岩石分别主要为奥长花岗岩和英云闪长岩;2.5~2.6Ga期间花岗闪长岩大规模出现,并有壳源花岗岩广泛分布,表明这时陆壳已有相当的成熟度。奥长花岗岩轻重稀土分异程度从弱到强的时间出现在~3.3Ga;2.5~3.3Ga的TTG岩石轻重稀土分异程度变化很大,表明其形成条件存在很大差异。TTG岩石主要为新生地壳,但也有相当部分为壳内再循环产物或形成过程中受到陆壳物质影响。华北克拉通中太古代以前的主要构造机制是板底垫托或地幔翻转作用,新太古代晚期板块构造体制可能已起作用。
[Abstract]:TTG is the most important carrier of the geological records of the North China Craton, which has a history of more than 3.8 Ga. The geological evolution of the North China Craton Archean (especially before the Middle Archean) is closely related to the TTG rocks to a great extent. The early Archean TTG rocks were only found in the Anben area, but a large number of 3.6Ga-3.88Ga detrital zircons have been found in various metamorphic clastic sedimentary rocks in Jidong area, while the paleoArchean 3.2Ga-3.6GaTTG rocks have been identified in the Anben, Jidong and Xinyang areas. The MesoArchean TTG rocks are located in Anben, Jidong, Jiaodong, Lushan, etc. They can be further divided into two stages: early and late NeoArchean: early NeoArchaean 2.62.8GaTTG rocks have been found in more than 10 regions. In the late NeoArchaean period, the late NeoArchaean TTG rocks were found in almost every Archean basement rock outcrop. Field geology, zircon dating, elemental geochemistry and Nd-Hf isotopic composition indicate that the TTG rocks before the Middle Archean exist locally. It is mainly distributed in three paleocontinent blocks divided by Wan et al.2015. NeoArchean TTG rocks are widely distributed, TTG rock type is the product of magmatism in the most important period of continental crust accretion. TTG rock types vary with the ages. The main rocks of TTG are mainly dolomite and dolomite during the period of 2.5 and 2.6 Ga, respectively, and the granodiorite is widely distributed in crust-derived granodiorite. It is indicated that the continental crust has already been quite mature at this time. The degree of light and heavy rare earths differentiation of the Ordovician granite from weak to strong occurred in the TTG rocks with 3.3Ga2.5 and 3.3Ga, which changed greatly in the degree of REE differentiation. It shows that there is a great difference in the formation conditions. The TTG rocks are mainly new crust. However, some of them are the products of intra-crustal recycling or are influenced by continental crust materials during their formation. The main tectonic mechanism of the North China Craton before the Archean is the slab backing or mantle inversion. The late NeoArchaean plate tectonics may have been active.
【作者单位】：中国地质科学院地质研究所北京离子探针中心;
【基金】：国家“973”项目(2012CB416600) 国家自然科学基金项目(41172127、41472169) 中国地质调查局项目(DD20160121-03、12120115070301、1212010811033、12120114021301)联合资助
【分类号】：P542;P588.12

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