| 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 |
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| 引用本文： | 万渝生,董春艳,任鹏,白文倩,颉颃强,刘守偈,谢士稳,刘敦一.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[J].岩石学报,2017,33(5):1405-1419. |
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| 作者姓名： | 万渝生 董春艳 任鹏 白文倩 颉颃强 刘守偈 谢士稳 刘敦一 |
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| 作者单位： | 中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037,中国地质科学院地质研究所, 北京离子探针中心, 北京 100037 |
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| 基金项目： | 本文受国家“973”项目（2012CB416600）、国家自然科学基金项目（41172127、41472169）和中国地质调查局项目（DD20160121-03、12120115070301、1212010811033、12120114021301）联合资助. |
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| 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。
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| 关 键 词： | TTG 华北克拉通 太古宙 锆石年龄 Nd-Hf同位素 |
| 收稿时间： | 2016/10/20 0:00:00 |
| 修稿时间： | 2016/12/22 0:00:00 |
Spatial and temporal distribution, compositional characteristics and formation and evolution of Archean TTG rocks in the North China Craton: A synthesis |
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| WAN YuSheng,DONG ChunYan,REN Peng,BAI WenQian,XIE HangQiang,LIU ShouJie,XIE ShiWen and LIU DunYi.Spatial and temporal distribution, compositional characteristics and formation and evolution of Archean TTG rocks in the North China Craton: A synthesis[J].Acta Petrologica Sinica,2017,33(5):1405-1419. |
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| Authors: | WAN YuSheng DONG ChunYan REN Peng BAI WenQian XIE HangQiang LIU ShouJie XIE ShiWen and LIU DunYi |
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| Institution: | Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China and Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China |
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| Abstract: | Tonalite-Trondjemite-Granodiorite (TTG) rocks are the most important Archean geological records in the North China Craton (NCC) which has had a long geological history back to ca. 3.8Ga ago. Eoarchean (3.6~4.0Ga) TTGs have only been identified in the Anshan-Benxi (Anben) area, although abundant 3.6~3.88Ga detrital zircons were discovered in several types of metasedimentary rocks in eastern Hebei; Paleoarchean (3.2~3.6Ga) TTGs occur in Anben, eastern Hebei and Xinyang; Mesoarchean (2.8~3.2Ga) TTGs occur in Anben, eastern Hebei, eastern Shandong and Lushan. Early Neoarchean (2.6~2.8Ga) TTGs have been discovered in more than 10 areas, whereas Late Neoarchean TTGs almost occur in every Archean area. The common features of the Archean TTGs in the NCC are summarized as follows. 1) >2.8Ga TTGs locally occur in the NCC, only accounting for less than 5% of the Archean TTGs in the basement. They do not show an increasing trend in distribution with time, but this may be due to uneven reworking of old rocks during later geological processes. >2.6Ga TTGs mainly occur within the three ancient terranes identified by Wan et al. (2015). Neoarhean TTGs widely occur all over the NCC, same as other cratons in showing that the Neoarchean is the most important period of continental growth; 2) 3.1~3.8Ga and 2.7~2.9Ga intrusive rocks mainly are trondhjemite and tonalite, respectively, with some gabbro, diorite and crustally derived granites. Both the trondhjemite and tonalite are important during the period of 2.5~2.6Ga, it is until then that granodiorites widely occur together with K-rich granite (including monzogranite and syenogranite), a result of continental crust becoming high maturity; 3) TTG rocks exhibit variable REE contents from weakly to strongly fractionated REE patterns at ~3.3Ga. This may be a result of thickening of continental crust during that period. 2.5~3.3Ga TTGs show large variations in REE patterns, although many of them have strong REE differentiation patterns, indicating variable forming conditions. Whole-rock Nd isotopes and Hf-in-zircon isotopes indicate that juvenile additions played important roles in formation of TTGs, however, crustal recycling was also necessary to account for the composition features of some TTGs, including 3.8Ga trondjemitic rocks in the Anben area; 4) Long-term magmatism from 2.9Ga to 3.8Ga related to mantle activity and crustal reworking widely occurred in Anben. In eastern Hebei, detrital zircons record almost continuous ages ranging from 3.4Ga to 3.88Ga, although only 3.0~3.4Ga rocks were discovered until now. These suggest that mantle underplating or overturn activity may have been the main mechanism of continental growth and reworking before the Mesoarchean in the NCC. In contrast, continental growth was extensive and strong during the Neoarchean period, as suggested by the vast quantity of TTGs, the ~2.5Ga tectono-thermal event was well developed, as recorded by metamorphic and anatectic zircons. These indicate that the continental crust of the NCC became thick enough at that time. It is considered that plate tectonics began to play an important role in the NCC during the Late Neoarchean. |
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| Keywords: | TTG North China Craton Archean Zircon age Nd-Hf isotopes |
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