【作者】 赵国春；

【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， 2003， 博士

【摘要】 燕辽地区素有地质“摇篮”之称，自翁文灏在70余年前提出Yenshan Movement(燕山运动)以来，它以其独特的大地构造位置、复杂的构造特征、组成及其演化过程，特别是该地区在很短的时间间隔内发生了大规模、多幕式构造—岩浆活动，更引起世界地学界的极大关注。通过多次幕式火山喷发-构造变形-盆地充填-地壳隆升事件序列的厘定，从火山活动节律特征、火成岩构造组合类型、时空分布及其演化和构造变形的历史记录，利用岩石学、地球化学、同位素地质学等方法，反演深部过程与浅部响应等来阐明造山过程，建立与不同级别岩浆活动节律对应的壳幔动力学系统，追索壳幔深部过程，已成为当今地球动力学研究的前沿课题之一。在岩浆活动节律与深部壳幔过程的关系研究方面，才刚刚开始，本项研究正是在这样的背景开始的。燕辽地区位于中国东部北东向展布的西太平洋构造域与近东西向分布的古亚洲构造域交叉复合部位。为了揭示该区燕山期火山岩火山活动的时空分布与演化特征，探讨与深部壳幔过程的关系，选择了燕山期火山岩地层发育比典型的北京西山、内蒙多伦、冀北和部分辽西等地区，系统的测制了燕山期火山岩重点地层剖面，通过野外大量的详细观察，从建立最小的火山喷发单元开始，逐步地建立火山活动节律的级别，结合区域地层对比，建立了一个比较完整的燕山期火山活动节律及其级序。在此基础上，通过火山岩石学、矿物学、火山地质学、地球化学及同位素地质学的综合研究，探讨了燕辽地区燕山期火山活动节律与造山—深部。主要取得了如下成果：1、系统地提出了火山活动节律划分的原则和方法。把火山活动节律划分为五个级别，即巨旋回(gigantic-cycle)、大旋回(megas-cycle)、旋回(sub-cycle)、小旋回(micro-cycle)、亚旋回(sub-cycle)和韵律(rhythm)。进而指出了火山活动节律的层次性特征。2、通过对燕辽地区燕山期发育的四套火山岩的岩石学、火山地质学、地球化学、同位素年代学的综合研究，通过运用综合方法进行区域地层对比和分析火山喷发盆地火山岩地层特征的基础上，将本区燕山期火山活动节律，划分为1个二级节律(大旋回)、4个三级节律(旋回)、11个亚三级节律(小旋回)、24个四级节律(亚旋回)和多个五级节律(韵律)等，论述了各级火山活动节律特征及其时空演化和区域对比。3、在火山活动节律的划分、区域对比的基础上，研究了各级节律火山岩的岩石学、矿物学、地球化学和同位素地质学特征，将研究区燕山期火山岩划分为碱性玄武岩系列、高钾钙碱性系列和钾玄岩系列。4、在岩石系列划分的基础上，通过火成岩构造组合、岩石地球化学特征、同位素示踪等，论证了燕辽地区燕山期火山岩以钙碱性系列为主，火山岩属于陆内靠陆缘大地构造环境。总体处于挤压的构造环境中，并发生多次构造反转。5、通过岩石化学、微量元素、稀土元素的研究，探讨了不同级别节律的火山岩成因、岩浆演化等特征，认为本区燕山期火山岩有三个岩浆源区，即地幔源、地壳源和壳幔混源，早侏罗世的南大岭旋回的基性岩浆，起源于上地幔；中侏罗世髫髻山旋回火山岩是在相对挤压环境中，岩浆起源于壳幔过渡带；晚侏罗世无负Eu异常的酸性岩浆来源于下地壳的古老结晶基底的局部熔融，有负Eu异常的酸性岩浆来源于上地壳的局部熔融；早白垩世火山岩基性岩浆起源于上地幔，中性岩浆起源于下地壳底部的壳幔过渡带。同时提出本区燕山期中酸性火山岩多存在地幔物质的贡献。进而提出了本区火山岩以壳幔混源为主的认识，说明了本区燕山期强烈的壳幔相互作用特征。6、探讨了火山活动节律的反序、正序特征的形成原因，反演了所对应的深部岩浆房特征及过程，得出亚旋回中形成反序现象主要由带状岩浆房演化引起，形成正序现象的主要原因是岩浆房的再充填，同时说明了本区燕山期存在多级岩浆房。 7、通过火山岩踢，的研究，得出了研究区燕山期火山岩的形成太平洋板块无直接的联系。进一步论证了本区燕山期岩石圈拆沉一减薄特征，计算本区燕山期各期、各地区的地壳厚度和晚侏罗世莫霍面深度，得出了燕山期本区地壳总体是增厚的，不同时期的平均厚度为:早侏罗世约(190一17OMa)地壳厚度约为49Km，中侏罗世(166一154Ma)地壳厚度为50Km(京西)一55Km(滦平)，平均53Km，晚侏罗世(147一140Ma)地壳厚度为64一118km，平均为93Km，早白至世(136一120Ma)地壳厚度为48一18lKm，平均为71Km。区内不同地区晚侏罗世地壳厚度总的西厚东薄，北厚南薄;早白坚世南厚北薄，西厚东薄。总体为侏罗纪时期地壳是逐渐增厚，早白至世时期地壳又相对减薄。 8、对多伦地区兴安岭群火山岩进行‘OAr一狱r法、Rb一Sr法系统同位素测年，得到了有价值的12个火山岩新的年龄数据，并对这些年龄的可靠性从区域地质背景上进行约束，建立了该区燕山期区域地层对比框架。 9、探讨了研究区燕山期火山活动节律与造山一深部过程的祸合关系及其特征，进一步说明了火山活动节律的深部成因。认为火山活动期(时限约为130 Ma)可能代表40oKm以上的对流系统;火山活动旋回(时限约为10一20 Ma)代表以地慢加热一冷却过程;火山活动小旋回(时限约为3一8 Ma)代表更多还原

【Abstract】 The Yanshan-Liaoning area is called as the "cradle of geology". It is the first time that the geologist, Wen Wenghao, has put forward the "Yanshan Movement" before 70 years. From then on the Yanshan-Liaoning area had been paying attention by the geologists all over the word because it lies in the particular tectonic background, has the complex structural features, structural units, and the geological history of evolution, particularly large-scale, multi-phrase tectonic movement and magmatic activity took place in the short geological time. After the volcanic eruption of multi-phrase cycle-deformation, filling of basin, crustal uplifting event being studied, this dissertation tries constructing the different degree rhythm of magma activity corresponding with crust-mantle dynamic system, studying the crust-mantle deep processes. Based on the studies on the characteristics of volcanic rhythm, igneous rocks assemblages, temporal and spatial distribution of igneous rocks, tectonic deformation, the author has utilized the methods of petrology, geochemistry, isotopic geology et al. to do research on the above-mentioned geological problems.The yanshan-Liaoning area lies in the crossover zone of the NE-directed West Pacific Ocenic structural system and near SW-directed Paleoz-Asian structural system. To make the yanshanian volcanic tempral and spatial distribution and evolution law clear, study the relationship of the deep crust-mantle processes and the volcanic rocks, the author selects the typical areas, Xishan of Beijing, Duolun of Inner Mongolia, West Liaoning, as the study areas where the volcanic rocks strata are developed. Through the emphasised geological profiles of Yanshanian volcanic strata being surveyed, much field work being done detailly, the small volcanic eruptive units have been defined originally, the levels of volcanic activity rhythm being constructed gradually, as a result, a integrated and systemic rhythm of Yanshanian volcanic acivity has been constructed. Fininaly the rhythm of Yanshanian volcanic acivity in the Yanshan-Liaoning area and Orogenic-deep process is disscussed. Some results are obtained as following.1.To provide the systemic classicification and method about the rhythm of volcanic activity, the rhythm of volcanic activity is divided into 5 levels: gigantic-cycle, megas-cycle, cycle, micro-cycle sub-cycle, rhythm.2. On the basis of study on petrology, volcanic geology, geochemistry, isotopic chronology, antitheses of the regional strata and 4 suits of volcanic rock stratum of the Yanshan-Liaoning area, the rhythm of Yanshanian volcanic activity is divided into 1 gigantic-cycle, 4 cycles, 11 micro-cycles, 24 sub-cycles and many rhythms. In addition, the temporal and spatial evolution and regional contrast of every-level rhythms are discussed.3.Based on the study on classifications of rhythm of volcanic activity and regional contrast, the petrology, mineralogy, geochemistry, and isotopic characteristics of every-level rhythms are discussed. At last the rhythm of Yanshanian volcanic rocks is classified into three series such as alkaline basalt, HKCA, calc-alkaline Shoshonite.4.Based on the study of rock series, assemblage of igneous rock, characteristic of geochemistry, trace effect of isotope, the Yanshanian volcanic rocks of Yanshan-Liaoning area aremainly calc-alkaline series, which should belong to the products of near continental margin of intracontinental tectonic setting. During the Yanshanian phrase, the area is in the condition of contractional background, with multi-staged tectonic reversion.5.Through studying the origin of volcanic rocks and the characteristics of magma evolution, it concludes that there exist 3 originated areas of magma-from mantle, crust, and mantle-crust exchange. The basic magma of Nandaling volcanic rocks of Early Jurassic is derived from Upper mantle; the magma of Tiaojishan volcanic rocks of Mid Jurassic is formed in the contractional tectonic setting, and derived from the transition zone of crust and mantle interaction; the acid更多还原