【作者】 赵凤清；

【导师】 邓晋福；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2006， 博士

【摘要】 近年来,华北地块古元古代构造单元划分和构造演化的研究取得了一些重要进展,识别出华北中部造山带,并尝试性从造山带理论解释古元古代构造演化。地处华北地块南缘中条山地区古元古代变质地层发育齐全,古元古代岩浆作用活动频繁,是研究古元古代地壳生长及演化十分理想的地区。通过对该区古元古代地质学、同位素年代学和地球化学进行深入的研究,提出该区古元古代地壳具幕式增生特点,2500Ma前后存在巨量地壳生长,识别出2300Ma构造-热事件,中条运动奠定了基底构造格架。涑水杂岩的时代归属问题是中条山地区长期争论的重大地质问题之一,时代归属在存在太古代和古元古代分歧。本文在详细的野外地质学研究的基础上,结合精确同位素测年研究,将传统的涑水杂岩解体为狭义的太古代涑水杂岩、古元古代冷口变质火山岩和3期古元古代变质花岗岩。在详细的锆石成因矿物学研究的基础上,使用颗粒锆石SHRIMP方法测定了绛县群铜矿峪组火山岩的时代,获得的成岩时代为2274Ma,表明绛县群的时代为古元古代,并非太古代。通过中条山地区古元古代变质岩浆岩的同位素地球化学和元素地球化学研究,识别出2300Ma前后弧岩浆岩建造,包括2333Ma的冷口变质火山岩和2321Ma的寨子英云闪长岩,前者为弱亏损岩石圈地幔部分熔融的产物,后者为较高压力条件下深部地壳分熔作用的产物。首次辨别出2274-2250Ma后造山伸展构造环境形成的岩浆岩组合,包括铜矿峪火山岩、横岭关钙碱性花岗岩和烟庄A-型花岗岩,提出铜矿峪火山岩为遭受交代作用改造的岩石圈地幔在较浅深度发生较高程度分熔作用的产物,而花岗质岩石为深部地壳TTG岩石分熔作用的产物。基于上述研究,提出中条山地区很可能存在2350-2250Ma汇聚造山事件。通过地球物理、地质学、地球化学和年代学综合研究,探索了中条山地区古元古代岩石圈组成、性质。提出中条山地区岩石圈地幔成分为弱亏损地幔-原始地幔,下地壳底部以麻粒岩相变质镁铁质岩石为主,夹麻粒岩相变质副变质岩,而中、上地壳主体由角闪岩相-绿片岩相变质的变质表壳岩和变质深成岩构成。通过综合性研究,建立了中条山地区有时间维标志用地质语言表述的岩石圈结构模式。利用单颗粒锆石测年工作中获得的继承和/或捕获锆石年龄信息以及岩浆岩的Nd模式年龄,提出中条山地区最早陆核可能形成于3.3-3.0Ga,晚太古代2.8-2.5Ga期间是中条山地区地壳的重要生长阶段,2350-2250Ma存在强烈地壳增生,中条运动(时限为1.9±0.lGa)是中条山地区的一次重要的造壳事件。更多还原

【Abstract】 In the last few years, great progress has been made in understanding the tectonicdivision and evolution of the North China Craton. Collisional models have been applied tothe Craton, including recognition of a Paleoproterozoic collisional orogen, called theTrans-North China Orogen, which separates the Craton into two distinct blocks, called theEastern and Western Blocks. Zhongtiao Mountains is situated in southern margin of northChina Block where the Paleoproterozoic supracrustal rocks is well exposed and igneousrocks is well developed. Detail geological and geochronological studies suggest thatArchean and Paleoproterozoic custal growths in Zhongtiao have episodic characteristics.Controversy has surrounded the classification of Sushui Complex,with some peopleproposing that Sushui Complex should be Archean age, whereas others classified it intoPaleoproterozoic age. Detail structural, geochemical and geochronological investigationsindicated that the previous Sushui Complex contains both of Archean rocks andPaleoproterozoic rocks in which the Paleoproterozoic rocks consists of Lengkoumetamorphic volcanics and 3 suites of metamorphic granitoids. The age of Tongkuangyuvocanics is a controversial issue in Zhongtiao Mountains. Combining mineral studies,SHRIMP dating for zircon from acid volcanics is 2274±14Ma(1σ), inferring an age ofPaleoproterozoic nor Archean.2300Ma island arc igneous rocks has been identified from the geochemical studies,which includes Lengkou metamorphic volcanics with age of 2333Ma and Zhaizimetamorphic tonalitic gneisses with age of 2321Ma. Geochemical character indicates thatthe volcanics is derived by partial melting of weakly depleted mantle and the TTG isformed by partial melting of of mafic rock in deep crust at high pressure. Thepost-collisional magmas between 2274Ma and 2250Ma is recognized, includingTongkuangyu volcanics, Henglingguan calcalkaline granites and Yanzhuang A-typegranites. The Tongkuangyu vocanics is the products of partial melting from metasomaticlithosphere mantle at shallow depth. The granites were derived by partial melting of TTG indeep crust. The geological and geochemical of igneous rocks indicates that the orogenicevent may be occurred between 2350-2250Ma in Zhongtiao Mountains.The nature and compostions of Paleoproterozoic lithosphere of Zhongtiao Mountainshave been discussed from comprehensive studies on geology, geophysics and geochemistry.Geochemical evidences provided a new idea that the lithospheric mantle exhibits weaklydepleted to primitive nature in composition. The lower part of lower crust is composedchiefly of mafic granulites and minor metamorphic supracrustal rocks and the upper partcontains mainly intermediate granulites, whereas the middle and upper crust consisits ofmetamorphic supracrustal rocks and igneous plutons ranging metamorphism fromamphibolite to greenschist phases. Detail geological and geochronological studies indicatesthat the primary crust of Zhongtiao Mountains occurred at 3.3-3.0Ga, considerable crustformed between 2.8-2.5Ga, a great deal of crust grows with time span from 2350Ma to2250Ma and final cratonization(Zhongtiaonian Movement) occurred at the age of 1900±50Ma.更多还原