Beishan orogenic belt passed complex geological evolution by multistage plate divergence-subduction-collision-fitting, with the characteristics of ploycycle multiple orogeny. Through studying about tectonic units established, old plates rebuilded, original basins restored, texture and structure of orogenic belt, mechanism and model of orogeny, it is definded that the type of Beishan orogenic belt is continent-accretion arc collosion orogenic belt.

北山造山带经历多期次、多阶段的板块裂解-俯冲-碰撞-拼合的复杂地质演化历程,具多旋回复合造山的特色。通过对造山带构造单元的建立、古板块重建、原型盆地恢复、造山带结构、构造特征及造山机制和模式的研究,确定北山造山带类型为陆-增生弧碰撞造山带。

On the basis of 1:250 000 scale regional geological survey of the Mazongshan map,through studied the volcanic-sedimentary formation,the evolution of magmatic rocks squence,the characteristics of metamorphism and space of every tectonic units of Beishan orogenic belt,and applied tectonic facies division theories,according to the characteristic of belt,Beishan polycycle multiple orogenic belt is respectively divided 15 sorts tectonic facies,and discussed its tectonic framework and tectonic evolution model in the Paleo soic.

根据1:25万马鬃山幅区调填图资料,从造山带不同构造单元的火山-沉积建造、岩浆岩序列演化、变质变形特征及时空配位关系研究入手,应用大地构造相划分理论,根据北山多旋回复合造山带的特点,识别出15种大地构造相,并探讨了北山古生代构造格局与构造演化模式.

Much remains to be discovered concerning the time of collision of the Paleoasian Ocean and the Late Paleozoic evolution in the Beishan orogenic belt. The insufficient research on the Late Paleozoic strata of the Beishan orogenic belt, to a great extent, limits the further discussion of the tectonic evolution. This paper shows that the LA-ICP-MS zircon U-Pb ages of the "Early Carboniferous Lvtiaoshan and Baishan formations" and the "Early Permian Shuangbaotang Formation" volcanics from the Hongshishan area are 296.8±3.5Ma, 314.9±3.3Ma, and 299.4±5.9Ma respectively, which belong to the Late Carboniferous-Early Permian Ganquan Formation of the Beishan orogenic belt. The relationship between the "Shuangbaotang Formation" and "Baishan Formation" should not be disconformable as thought before, which suggests an entire Carboniferous-Permian rift basin. And the unconformity between the "Lvtiaoshan Formation" and the Middle Devonian could be the one between the Ganquan Formation and the Middle Devonian, which implies the closure of the Paleoasian Ocean between the Middle Devonian and Early Carboniferous.

北山地区古亚洲洋的闭合时间和晚古生代构造演化倍受关注且久有争议。晚古生代地层及其接触关系对探讨以上问题具有重要意义,但该区地层学研究薄弱,很大程度上制约了对构造演化的深入讨论。本文获得的北山红石山地区上古生界"下石炭统绿条山组、白山组"和"下二叠统双堡塘组"火山岩的LA-ICP-MS 锆石U-Pb年龄,分别为296.8±3.5Ma、314.9±3.3Ma和299.4±5.9Ma,时代为晚石炭世-早二叠世,相当于北山地区干泉组层位。原"白山组"与"双堡塘组"之间的平行不整合不成立,表明石炭纪-二叠纪为同期裂谷盆地。原"绿条山组"与中泥盆统的角度不整合实为干泉组与中泥盆统的角度不整合,代表了古亚洲洋的闭合与增生造山时间发生在中泥盆世与早石炭世之间。

北山地区位于华北板块、塔里木板块和哈萨克斯坦板块的交汇地带, 构造-岩浆活动强烈.本文对交叉沟石英闪长岩进行了锆石LA-ICP-MS U-Pb定年,获得的加权平均年龄为306.3±1.2 Ma,结果表明岩体形成于晚石炭世.岩石地球化学分析结果显示,SiO2含量为58.67％～63.31％,属于中酸性岩系列,Al2 O3含量高(15.20％～17.56％),K2O/Na2O为0.42～0.67,显示了相对富钠、低钾的特征,岩石里特曼指数(σ)为 1.13～1.53,A/NCK=0.88～0.96,属于准铝质中钾钙碱性系列;稀土总量较低(平均为81.01×10-6),具有相对平缓的富集轻稀 土元素的配分形式和弱的负Eu异常(δEu为o.80～0.93);在微量元素原始地幔标准化蛛网图上,相对富集Rb、Sr、K等大离子亲石元素,亏损 Nb、Ta、P和Ti等高场强元素.结合区域地质背景,认为交叉沟石英闪长岩形成的构造背景为陆缘弧,进而认为交叉沟地区在晚石炭世存在洋-陆俯冲作用, 而且红石山-百合山-蓬勃山洋完全闭合时限晚于晚石炭世.

甘肃北山地区主体属塔里木板块的北缘,其内部可划分出北、中、南三个构造带.北带主体为加里东期岛弧带.北山地区于古生代经历了弧一盆体制及裂陷槽的活动大陆边缘的发展,总体上经历了前寒武纪古陆壳形成阶段、加里东期岛弧及陆缘裂陷一闭合阶段、海西期岛弧期后构造一岩浆活动及陆壳再次裂陷一闭合阶段和中、新生代差异断块升降阶段.

甘新蒙北山地区地处天山东段、北山及阿拉善地区 ,为古生代哈萨克斯坦板块、塔里木板块和华北板块交汇地带。可分为 7个二级构造单元 (构造区 )、2 6个三级构造单元 (地块、褶皱带 )。该区构造演化史漫长而复杂。太古宙时期 ,是古陆核形成萌芽阶段 ,古元古代初陆壳开始生成 ,出现薄壳结构的宽广的裂陷活动带 ,到了中、新元古代后期显露出板块构造运动 ,新元古代晚期经历重大热事件———晋宁运动 ,发生陆块间汇聚—碰撞并形成了榴辉岩—花岗岩岩浆带。震旦纪在晋宁期的拼合古陆上再一次裂解 ,经历了板块构造演化史。晚古生代 ,本区主体转入板内构造时期 ,以开合构造为主 ,花岗岩浆活动广泛发育。中、新生代进入板内造山和现今的盆山构造格局时期

During Paleozoic, the crustal movement was intense in Beishan area, which mainly found expression in the splitting of Early Palaeozoic unified continent and the formation of ocean basin in Middle Ordovician. At the end of Silurian, the oceanic basin was underthrusting in SN direction and was finally closed, that caused the collage between the northern side of the Kazakhstan plate and the southern Tarim plate as well as the formation of a relatively uniform plate. In Late Paleozoic, another movement occurred. From Carboniferous to Permian, the acid-intermediate magmatic intrusions in these areas made up important geological events. The outcropped area of granite occupies 1/3 of the total area. Nevertheless, researchers tend to ignore the crustal movement, especially the intrusion of granitic magma in Devonian period. The authors hold that the volcano-sedimentary and tectonic activities did occur in Devonian, so there existed strong magmatic intrusive activities in these areas in Hercynian period. Petrological and geochemical researches were conducted, and zircon SHRIMP U-Pb dating was performed for three granites, which yielded ages of (355±4) Ma, (359±4) Ma, (355±5) Ma respectively, suggesting that Dongqiyishan granitic batholith was formed in Late Devonian instead of in Middle Hercynian. It is thus thought that the collisional orogenesis in the Beishan Mountain during Early Late Paleozoic was accompanied by strong granitic magma activity, which played an important role in deepening the crustal evolution process of Palaeozoic in Beishan area.

古生代时期, 北山地区的地壳活动非常强烈, 主要表现为: 早古生代初期大陆的裂解, 一直到中奥陶世广阔大洋盆的发育。志留纪末, 洋盆在自南向北的俯冲中封闭, 使北侧的哈萨克斯坦板块和南侧的塔里木板块拼贴, 并在碰撞造山过程中又构成了一个相对统一的陆块。在晚古生代, 北山地区地壳又在另外一种形式中异常强烈活动, 特别是自石炭纪到二叠纪, 大规模的中酸性岩浆侵入活动构成本区重要的地质事件, 其出露的花岗岩类占到了全区总面积的近1/3, 但泥盆纪时期的地壳活动, 特别是花岗岩浆的侵入活动常被人们忽视, 笔者据泥盆纪时期的沉积-火山作用及挤压构造活动也较发育认为, 海西早期也应有较强的花岗岩浆侵入活动。本文有针对性地对北山地区, 原定为海西中期的东七一山花岗岩岩基, 在岩石学和地球化学等方面研究基础上, 对3处岩石中锆石首次进行了SHRIMP U-Pb年龄测定, 其结果分别是(355±4) Ma、 (359±4) Ma、(355±5) Ma, 这表明东七一山花岗岩形成于泥盆纪晚期, 从而确定了北山晚古生代早期也有花岗岩浆的强烈活动, 这对深化北山古生代地壳演化过程有积极意义。

Lots of early-middle Paleozoic granitoids occur in Liuyuan area of Be ishan. The Shuangfengshan granitic pluton in Liuyuan is characterized by high Si, alkali (AR=3.99～5.05, NK/A＞0.85), FeOT/ MgO and 10000×Ga/Al values, and low Al2O3, CaO and MgO content, showing metaluminous and alkali features. The granites show high REE, slight richness of LREE, a weak fractionation between LREE and HREE, and an evidently negative Eu anomaly. They are enriched in Rb, Th, Zr and Hf, strongly depleted in Ba, Sr, P, Eu and Ti, and slightly depleted in Ta and Nb. These rocks also have high Rb/Nb and Y/Nb ratios, implying the aluminous A2-type granite. The LA-ICP-MS zircon U-Pb dating yielded a 206Pb/238U age of 415±3 Ma(MSWD=1.5), considered to be the emplacement age of the Shuangfengshan granitic pluton. All these geochemical features indicate that these granites probably resulted from the earlier calc-alkali ne granitic magmas which might crystallized from differentiation of granodioritic magmas formed by partial melting of continental crust (oceanic crust and island arc) due to the underplating of the mantle-derived magma. Based on characteristics of outcrops, chronology, geochemistry and geological setting, the authors hold that the Shuangfengshan granitic pluton might be a post-orogenic or late stage orogenic pluton. The Early Devonian Shuangfengshan A-type granite is the oldest A-type granitic pluton ever found in Beishan, which provides important information for the researches on magmatic and tectonic evolution.

北山柳园地区分布有大量的早中古生代花岗岩类岩石. 柳园双峰山岩体具有高硅、高碱（AR=3.99～5.05，NK/A＞0.85）、高FeOT/ MgO比值和10000×Ga/Al值、低Al2O3、贫CaO和MgO的特征，显示出准铝质、碱质花岗岩的特点；∑REE较高，LREE略富集，轻重稀土元素分馏不十分明显，Eu负异常明显；相对富集Rb、K、Pb等大离子亲石元素（LILE），强烈亏损Ba、Sr、P、Eu、Ti，弱亏损Ta、Nb等元素；同时具有较高的Rb/Nb和Y/Nb比值，显示了A2型铝质花岗岩的特征. 采用LA-ICP-MS锆石U-Pb定年方法，获得双峰山岩体的206Pb/238U年龄为415±3 Ma（MSWD= 1.5），代表该岩体的形成年龄，即双峰山岩体形成于早泥盆世。地球化学及Nd同位素特征 综合分析显示 ，该岩体可能由幔源岩浆底侵导致上覆地壳物质（可能由洋壳和岛弧建造组成）部分熔融形 成的花岗闪长质岩浆经进一步结晶分异作用形成，为该区较早的钙碱性花岗岩演化到后期的 产物. 岩体特征、年代学、地球化学和地质背景综合分析结果表明，该岩体形成于后造山或 造山作用演化晚期阶段. 双峰山早泥盆世A型花岗岩为目前北山地区发现的最老的A型花岗岩 ，这对探讨古生代花岗岩成因类型及岩浆演化具有重要的意义

摘　要： 对甘肃北山地区芨芨台子蛇绿岩组成单元中辉长岩进行LA—ICP—MS锆石U—Pb年龄测 定，结果表明，芨芨台子蛇绿岩形成于321．2±Ma3．7Ma，相当于早石炭世；结合近年来对其东部小黄山蛇绿岩的测年结果，认为芨芨台子-小黄山蛇绿 岩带形成于早石炭世。它们是北山早古生代洋盆俯冲消减和碰撞造山后裂谷拉伸的产物。

Abstract： Researches on tectonic formation, evolution and subdivision in China have had a history of more than 100 years. There are several kinds of opinions concerning the tectonic subdivision of China, which are based on different sorts of epistemology and methodology regarding the formation and evolution of the continental crust. Tectonic subdivision blueprints guided by “three mainstream tectonic views” include Mr. Huang Jiqing's polycyclic tectonics, Mr. Wang Hongzhen's historical tectonics and Mr. Li Chunyu's plate tectonics. The ideas of these researchers have been playing a guiding role in this field and hence have had extensive and profound influence in China. Nowadays tectonic subdivision seems to be the key to the research on micro-structures of plates in that it is not only a theoretical problem in the study of plate tectonics but also a practical problem which must be solved immediately so as to help perform studies in such aspects as regional geology, metallogenic prognosis and mineral resources evaluation. In this paper, the tectonic subdivision is based on records of stratigraphic division and correlation, sedimentary formation, volcanics formation, intrusive magmatism, metamorphism and deformation, and consistent with the classic division theory of “three mainstream tectonic views” in China. Guided by theories of plate tectonics and earth dynamics, based on the requirements of metallogenic regularity and mineral energy resource prognosis, and following the main line of spatial-temporal structure analysis of tectonic facies environment of different-sized stable ancient continent block domains and different episodic orogenic systems, the authors have divided the tectonic environment of China into continent block domains and orogenic systems, which include nine first-order tectonic units and fifty-six corresponding second-order tectonic units. As there are a number of major tectonic problems in China that remain to be solved in future, a prolonged painstaking efforts are still needed for more accurate subdivision.

提要：中国大地构造形成演化与大地构造分区研究已有百余年的历史，整体论述中国构造分区，都以不同学派对中国大陆地壳形成演化的不同认识论和方法论，有不同的方案。以黄汲清先生等多旋回构造观、王鸿祯先生等历史大地构造观和李春昱先生等板块构造观的“三大主流大地构造观”为指导思想的大地构造划分方案，是集中国地质构造之大成，在全国起指导作用，影响既广泛且深远。板块构造单元划分是当前板块构造细结构研究的关键问题。它既是板块构造研究的理论问题，也是区域地质研究和成矿预测评价亟待解决的实际问题。本文的大地构造分区图的编制是以地层划分和对比、沉积建造、火山岩建造、侵入岩浆活动、变质变形等地质记录为基础，承接融合中国“三大主流大地构造观”的经典划分理念，在板块构造—地球动力学理论指导下，以成矿规律和矿产能源预测的需求为基点，以不同规模相对稳定的古老陆块区和不同时期的造山系大地构造相环境时空结构分析为主线，以特定区域主构造事件形成的优势大地构造相的时空结构组成和存在状态为划分构造单元的基本原则，划分出中国的大地构造环境主要由陆块区和造山系组成为9个一级构造单元，以及相应的56个二级构造单元。中国大地构造研究还存在一系列重大科学问题，较准确地划分尚需很长时间的不懈努力。

北山岩群是内蒙古北山地区重要的前寒武纪变质地层之一.对该岩群石英岩进行了LA-ICP-MS锆石U-Pb定年,碎屑锆石核部获得207pb/20pb年龄值范围为921～3011 Ma之间,主要的峰值年龄为1 329 Ma,属于中元古代;锆石幔部获得206pb/238U峰值年龄为433 Ma,属于早志留世.剖面测制得知岩石组合可归纳为三部分:由下到上依次为石英岩-石英片岩-大理岩,据此将其划分为三个岩段,第一岩段为石英岩,第二岩段为石英片岩,第三岩段为大理岩.结合区域沉积环境和构造演化,认为石英岩原岩沉积时代不早于921Ma.

The Haladala pluton in northeast Tekes County is the largest basic-ultrabasic layered pluton in West Tianshan area; nevertheless, little work has been done on its petrogenesis. In this paper, the authors conducted a detailed study of its geochemistry and geochronology. With the data obtained in combination of regional tectonic evolution, this paper discusses its petrogenesis, tectonic setting and geological significance. This pluton consists of a series of gabbroic rocks such as troctolite, olivine gabbro, hornblende gabbro and gabbro. Secondary ion microprobe (SIMS) zircon U-Pb dating indicates that the gabbroic rocks crystallized at the age of 306.2 ± 2.7 Ma, belonging to the Late Carboniferous. These gabbroic rocks have SiO2 values ranging from 44.49% to 48.46% with low content of K2O and Na2O and high average Mg# value of 71.4. Chemical compositions of these rocks are tholeiitic, but show a variation trend with the magmatic evolution from low-K tholeiite series to calc-alkaline series and even high-K calc-alkaline series. Some samples show abnormally high MgO, Al2O3 and CaO content, which may be due to the accumulation of olivine and plagioclase. They are also significantly enriched in LILE such as Rb, Ba, K, Pb and Sr, but depleted in HFSE such as Nb, Ta and Ti, with La/Nb>1.4. All these data indicate characteristics of arcmagmas derived from fluid metasomatized mantle wedge. Their Th negative anomaly suggests that the magmas may have been contaminated by the lower crust. These rocks have low content of total REE with weak differentiation of LREE from HREE. Due to the role of plagioclase accumulation, some samples have significant positive Eu anomalies. Compared with the mafic plutons of different ages exposed in adjacent areas in North Xinjiang, the Haladala pluton has unique petrological and geochemical characteristics, which may imply that they contain both arc-like magma components and components from extensional environment magmatism. The compositional characteristics suggest that the rocks might have been formed during the change of the tectonic framework from compression to extension. Regional tectonic history indicates that there was a shift (from compression to extension) in the tectonic framework of West Tianshan region during Late Carboniferous to Early Permian. The authors made an overall analysis of various rocks concerning their petrologic and geochronologic features at the northern and southern edge of the Yili-Central Tianshan plate, and found out that the Yili plate underwent a transition from the subduction and collision to post-collision circumstances in 293～313 Ma. Based on geochronological and geochemical characteristics of the Haladata pluton, the authors believe that the Tekesi area was at the stage of this transition of tectonic settings. It is suggested that the late Paleozoic gabbroic rocks (the Haladala pluton) in Tekes County might also have been formed in this transition stage. Hence, these rocks may indicate a change of tectonic framework in the West Tianshan area and provide evidence for the presence of magmatism in this region during the tectonic frame change.

西天山特克斯县东北部的哈拉达拉岩体是西天山出露规模最大的层状基性－超基性侵入岩体，主要由橄长岩、橄榄辉长岩、角闪辉长岩和辉长岩组成。本文获得该辉长质岩体锆石SIMS U-Pb年龄为306.2 ± 2.7 Ma，属于晚石炭世。该岩体SiO2含量范围为44.49%～ 48.46%，K2O、Na2O含量低，Mg、Fe含量较高，Mg#平均值达71.4。岩体具有拉斑玄武岩系列特征，且有从低钾拉斑系列向钙碱性系列和高钾钙碱性系列演化的趋势。部分样品的MgO、Al2O3和CaO含量偏高，可能为橄榄石和斜长石的堆晶所致。岩体明显富集Rb、Ba、K、Pb、Sr等大离子亲石元素，亏损Nb、Ta、Ti等高场强元素，La/Nb比值大于1.4，与流体交代地幔楔熔融的弧火成岩浆特征类似。岩体具有Th负异常，暗示岩浆活动过程中可能混染了下地壳成分。岩体稀土元素总量较低，轻、重稀土元素分异较弱，由于斜长石堆晶作用，部分样品具有明显的正Eu异常。区域构造演化和岩石学资料等显示西天山在晚石炭世―早二叠世大地构造格架演化发生了转变，特克斯地区处于俯冲碰撞阶段向碰撞后伸展阶段变化的过渡环境中，特克斯晚古生代辉长岩体很可能是在这种构造体制的转变过程中形成的，指示了西天山大地构造演化从弧环境下的挤压碰撞到陆内伸展环境的转变。

The Haladala basic-ultrabasic pluton in southwest Tianshan Mountains consists of troctolite, olivine gabbro and gabbro. Typical cumulate textures occur in the troctolite and olivine gabbro. The cumulate minerals are mainly of olivine and plagioclase. The inter-cumulate minerals are mainly of pyroxene, amphibole and phlogopite. Gabbro shows typical gabbro-ophitic textures. Fractional crystallization played an important role in the formation of the Haladala intrusion. The zircon SHRIMP dating indicates that the gabbro crystallized at Late Carboniferous (308.3±1.8Ma, MSWD=0.86, n =15). The REE distribution patterns of the Haladala rocks are similar to that of the E-MORB. The studied samples with initial 87 Sr/ 86 Sr of 0.7040~0.7050 contain relatively abundant Rb, Cs, Ba and Sr. All these data suggest that the source of the Haladala magma was an enriched mantle. Based on their flat REE distribution patterns and geochemistry of other trace elements, we suggest that the rocks of mantle source are amphibole-bearing spinel lherzolite. The metasomatism caused by the subduction fluid of the Paleo- south Tianshan Ocean led to the formation of the enriched mantle. According to calculation, the primary magma of the Haladala pluton was formed by 10%~15% partial melting of amphibole-bearing spinel lherzolite.

西南天山哈拉达拉侵入体由橄长岩、橄榄辉长岩和辉长岩组成，橄长岩和橄榄辉长岩具有典型的堆晶结构，堆晶矿物以斜长石和橄榄石为主。辉石、角闪石和金云母主要为堆晶间隙矿物。辉长岩发育辉长—辉绿结构。结晶分异作用在岩浆演化过程中起重要作用。对从辉长岩中分选出来的锆石进行的SHRIMP年代学研究表明，辉长岩形成于308.3±1.8Ma （MSWD=0.86， n= 15）。哈拉达拉岩体稀土元素配分模式与E-MORB相似，具有高Rb、Cs、Ba及Sr的特点， 87 Sr/ 86 Sr初始比值0.7040~0.7050。这些特征表明，岩浆源区具有富集地幔的特征(古南天山洋俯冲流体交代形成了富集地幔)。根据平坦的稀土元素配分模式以及Gd、Sm、Nb、Zr等微量元素的地球化学行为判别，岩浆源区岩石为含角闪石的尖晶石二辉橄榄岩。批式熔融模拟计算显示，地幔岩10%~15%的部分熔融能够形成哈拉达拉岩体的母岩浆。母岩浆通过48%~50%的结晶分异作用则能够形成哈拉达拉岩体。早期结晶的橄榄石和斜长石通过堆晶作用形成橄长岩和橄榄辉长岩，剩余岩浆结晶形成辉长岩。

北山造山带位于中亚造山带南缘，主要由一系列俯冲增生杂岩体构成。在其宽缓的造山区内，零散地分布着前寒武纪岩石。由于古生代以来强烈的造山作用和随后的陆内造山作用的改造，造成北山内的前寒武纪岩石和古生代以来的造山带产物难以区分。因此，关于北山造山带内的前寒武系归属问题，一直以来争议很大。本文在详细野外地质工作的基础上，报道了位于北山造山带中部的马鬃山地块内前寒武纪副变质岩的岩相学、锆石U Pb年代学和Hf同位素研究。该岩石较高的变质程度、岩石组合、碎屑锆石年龄谱特征均显示其和北山造山带内古生代的残余被动大陆边缘产物不同，属于北山造山带内残余的前寒武纪基底，且沉积时代在中元古代约1.1~1.45 Ga之间。结合前人的研究，得出以下认识:北山的前寒武纪物质在中元古（约1.0 Ga）之后，显示出和塔里木克拉通、蒙古地块均相似的特征，表明三者均卷入了Rodina超大陆的聚散事件。在中元古代及其之前（约1.1 Ga之前）则显示多源区的特征。本文中的北山造山带中元古代副变质岩显示了中元古代及其之前与塔里木克拉通不同，与蒙古地块相似的特征。锆石的Hf同位素分析进一步揭示了北山造山带前寒武纪副变质岩和敦煌地块均记录了古太古代中晚期的新生地壳加入事件，显示了与塔里木克拉通的差异。这也暗示了敦煌地块和北山造山带在中元古代（约1.45 Ga）之前可能具有统一的前寒武纪基底。

改则格列戈阿尔辉长岩侵入于羌塘地体南缘木嘎岗日群，为研究班公湖—怒江缝合带在改则地区的演化提供新的强有力的约束。本文对辉长岩进行了LA-ICP-MS锆石U-Pb定年，结果显示格列戈阿尔辉长岩锆石U-Pb年龄加权平均值为122.9±1.6Ma，表明该辉长岩体形成时代为早白垩世中晚期。岩石地球化学研究表明，该区早白垩世辉长岩具有高Al2O3（15.39%～16.83%）、低TiO2（0.78%～0.92%）、贫P2O5（0.09%~0.17%）和低碱（Na2O+K2O= 3.93%~4.41%）的特点。稀土元素总量（ΣREE）为63.37×10-6～73.76×10-6，平均为68.84×10-6，稀土元素配分曲线呈右倾型，(La／Yb)N介于2.43～3.09之间，δEu=0.89～1.03，表现弱的负铕异常，具有明显的轻稀土富集，重稀土亏损特征。岩石微量元素总体上富集大离子亲石元素（LILE）Rb、Ba、Th、U等，显著亏损高场强元素（HFES）Nb、Ta、P、Ti等，Nb/Ta、 Zr/Hf比值接近或略低于原始地幔组成。根据地球化学特征和微量元素构造判别图结果表明，该辉长岩源区为被俯冲改造的岩石圈地幔源岩浆，岩浆在演化过程中遭受了上地壳物质的同化混染，并经历一定程度的结晶分异作用。格列戈阿尔辉长岩形成于班公湖—怒江洋向北俯冲构造环境下的岛弧环境，表明至少在122.9±1.6Ma期间班公—怒江洋盆正在向北俯冲。结合区域资料，研究区班公—怒江洋盆闭合时间应介于110~85Ma之间。

Sujishan gabbro rock body lies in the eastern Bogda Mountains as well as southwest of the Kalameili ophiolite belt , and covers an area of 1.8 km��2. The lithology is of quartz-amphibole gabbro including higher amphibole (20%) and magnetite crystallization, which indicates original magma is water-rich and high oxygen fugacity . Its petrochemical feature shows that the magma belongs to the tholeiitic series. Rocks are enriched in LILE( Cs, Rb, Ba, Th, U) and remarkably depleted in Nb, Ta, Zr, Hf . The characteristics of petrography and petrochemistry indicate that the source of magma may be modified by subduction metasomatic fluids, as well, Sujishan intrusion body is the product of oceanic crust subduction. Zircon U-Pb age of Sujishan gabbro is 308.1±3.3Ma, earlier than the emplacement of alkali granite in the Kalameili ophiolite belt and being in accord with the rifting activity period, which indicates the Bogda rift underwent a conversion from the overall extension stage to the confined extension stage. On space, the Sujishan gabbro located in the direction of forward motion, where the paleo-Asian Ocean plate was subducting towards Junggar plate. On time, the Sujishan gabbro was formed during the active stage of rifting., Moreover, the lithogeochemistry confirmed some characteristics related with oceanic subduction. All of these facts suggested that the Bogda rift was designated as a subduction-torn-type rift resulted from the oblique subduction of the paleo-Asian Ocean plate towards the Junggar plate along the Kalameili subduction belt. The stress adjustion of Bogda rift from extensional mechanism to extensional-collisional transiton mechanism aroused the emplacement of Sujishan gabbro.

苏吉山辉长岩体位于博格达碰撞造山带东段，卡拉麦里蛇绿混杂岩带西南侧，出露面积约1.8 km2，岩性为石英角闪辉长岩。苏吉山辉长岩体富含普通角闪石(20%)和磁铁矿物，表明原生岩浆富水、高氧逸度特征，岩石化学组成属于拉斑玄武岩系列，岩石弱富集大离子亲石元素Cs、Rb、Ba、Th、U，显著亏损Nb、Ta、Zr、Hf 和弱亏损Ti，显示源区为受俯冲流体交代改造的岩石圈地幔，应是洋壳俯冲的产物。苏吉山辉长岩体锆石U-Pb年龄为308.1±3.3Ma，早于卡拉麦里混杂岩带内碱性花岗岩侵位，介于博格达裂谷活动期，是裂谷作用由全面伸展向局限伸展转换的标志。苏吉山辉长岩空间上位于古亚洲洋板块沿卡拉麦里蛇绿混杂岩带向准噶尔板块斜向俯冲的前进方向，时间上介于博格达裂谷活动期，地球化学上显示洋壳俯冲的特征，各种事实表明，古亚洲洋沿卡拉麦里碰撞带向准噶尔板块斜向俯冲作用形成撕裂型博格达裂谷，博格达裂谷由伸展机制向伸展-碰撞过渡机制的应力调整导致了苏吉山辉长岩体的侵位。

清水泉辉长岩体位于东昆仑中缝合带清水泉蛇绿岩北侧，主要岩性为角闪辉长岩。该岩体的LA-ICP-MS锆石U-Pb测年结果为452.1±5Ma，形成时代为晚奥陶世。辉长岩体样品SiO2含量为43.89%～45.99%，Na2O含量为1.30%~2.32%，K2O含量为0.68%~1.39%，P2O5含量为0.26%~0.40%，TiO2含量较低，为0.74%~0.95%，MgO含量为5.72%~6.54%，Mg#值较低，为53~54。岩石地球化学特征显示，该岩体属于拉斑玄武岩系列，稀土元素表现出轻稀土元素富集、重稀土元素亏损的特点，微量元素以富集大离子亲石元素（Cs、Rb、Ba等，尤其以Ba的正异常最为突出）、亏损高场强元素（Nb、Ta、Ti、Zr、Hf）为特征。微量元素构造判别显示，其形成于活动陆缘岛弧构造环境。结合区域地质资料研究表明，清水泉辉长岩体可能形成于以清水泉蛇绿岩为代表的东昆仑中弧后有限洋盆向北俯冲的初始阶段。

Neoproterozoic igneous rocks on the northwestern margin of the Yangtze block can provide important information about the evolution of Rodinia supercontinent. In this paper, the petrology, geochemistry and isotopic data of the bojite from the Xinmin area of Micang Mountain region are presented. The Xinmin bojite displays low and limited SiO 2 content, enrichment of Al and Ca, low K, Ti and P, and medium Mg # , suggesting typical subalkaline, low-K theolite features. The low REE composition, enriched LREE patterns, and positive Eu anomalies (δEu=1.03~2.36) imply the accumulation of plagioclase. The large ion lithophile elements (Rb, Ba, Sr)show enrichment, whereas the high strength elements(Nb, Zr, Hf, Th)are relatively depleted. 87 Sr/ 86 Sr=0.703 858, 143 Nd/ 144 Nd=0.512 617, and εNd( t )=+3.1. The regional geological and geochemical characteristics reveal that the primary melts were derived from partial melting of depleted mantle rocks and underwent significant crustal contamination in the emplacement process. During this period, the northern margin of the Yangtze block was in a convergence environment and the tectonic environment of the Xinmin bojite was the back arc basin, and hence the Xinmin bojite was the product of the evolution of Rodinia supercontinent in the Neoproterozoic period.

扬子板块西北缘新元古代岩浆作用的研究对于探讨Rodinia超大陆的构造演化具有重要意义,对米仓山新民地区角闪辉长岩的岩石学和地球化学分析结果表明,岩石SiO 2 含量较低且变化范围较小,岩石富Al和Ca,低K、Ti、P,Mg # 值中等,属于亚碱性低钾拉斑岩石系列。岩石具有稀土元素总量相对较低、相对富集轻稀土元素和轻重稀土元素分馏程度低的特征,具弱Eu正异常,δEu=1.03~2.36。岩石总体上富集大离子亲石元素(Rb、Ba、Sr),亏损高场强元素(Nb、Zr、Hf、Th等), 87 Sr/ 86 Sr=0.703 858, 143 Nd/ 144 Nd=0.512 617,εNd( t )=+3.1。综合区域地质、地球化学特征,该岩体岩浆起源于亏损地幔的部分熔融,在上升侵位过程中可能受到了地壳物质的混染。在这时期,扬子板块北缘处于汇聚环境,新民角闪辉长岩形成于弧后盆地的构造环境,是Rodinia超大陆在新元古代期间演化过程中岩浆作用的产物。