海南岛北西部前寒武纪花岗质岩SHRIMP锆石U-Pb年龄及地质意义

对海南岛北西部戈枕地区侵位于古中元古代抱板群花岗质岩进行了CL成像制约下的SHRIMP锆石U-Pb年龄测定,获得了1455±12Ma的U-Pb谐和年龄、1454±12Ma有利的207Pb/206Pb中值年龄。结合该花岗质岩锆石内部结构、岩浆源区和变形变质特征,以及前人多种定年成果,认为该花岗质岩结晶年龄应为~1450Ma,随后于~1400Ma经历了一次构造-热变质事件;Rodinia超大陆聚合前,华夏地块(包括海南岛、或至少是海南岛北西部)最可能位于劳伦大陆南缘的西南延伸部分。研究结果还暗示华夏地块(包括海南岛)所经历的格林威尔造山事件可能较扬子地块偏早,古、中元古代抱板群沉积上限应约束在~1450Ma。     

海南岛西部戈枕含金剪切带花岗质糜棱岩中锆石SHRIMP U-Pb年代学及其地质意义

海南岛西部的中元古代抱板群混合岩主要沿北东向戈枕剪切带展布,近年来的研究逐渐揭示混合岩的原岩为花岗质岩石,是遭受强烈剪切作用改造的糜棱岩。本文选择土外山金矿的花岗质糜棱岩和不磨金矿的糜棱岩化花岗岩进行锆石SHRIMP U-Pb年代学测试,3件样品的锆石SHRIMP U-Pb谐和线年龄值分别为1439.1±8.4Ma(样品13JC-8-1,MSWD=0.85,n=14)、1436.9±8.3Ma(样品13JC-41,MSWD=0.54,n=10)和1448±13Ma(样品BM-3,MSWD=0.56,n=10),代表其原岩的侵位时代。结合研究区已有的研究成果,本文认为海南岛西部花岗质岩类和沿戈枕剪切带出露的糜棱岩原岩结晶年龄为~1450Ma,之后于~1400Ma经历一期构造-热变质事件;海南岛应为华夏地块的一部分,在Rodinia超大陆聚合前,华夏地块(包括海南岛,至少包括海南岛北西部)最有可能位于劳伦大陆南缘的西南延伸部分,华夏地块(包括海南岛)所经历的格林威尔造山事件可能较扬子板块偏早。     

海南公爱地区抱板群花岗片麻岩的年代学、地球化学及其构造意义

海南岛地处华南陆块南缘,紧邻印支陆块,大地构造位置独特,其地质特征一直备受关注。厘定该地区中元古代岩石的成因对恢复华南中元古代构造演化具有重要意义。海南岛西部公爱地区花岗质岩石与围岩抱板群变沉积岩呈侵入接触关系,绝大部分岩石片麻状构造发育、韧性剪切标志明显。这些岩石高SiO_2、K_2O、Al_2O_3、Rb、U,贫CaO、MgO、FeO~T、TiO_2,铝饱和指数A/CNK1.1,具S型花岗岩特点,稀土元素配分模式类似于抱板群变沉积岩,全岩ε_(Nd)(t)=-2.02~-2.38,Nd同位素二阶段亏损模式年龄(t_(DM2)~(Nd))为2.2~2.3 Ga,锆石Hf同位素ε_(Hf)(t)=-5.4~4.0,Hf同位素二阶段亏损模式年龄t_(DM2)~(Hf)=1.71~2.53 Ga。对四个代表性花岗片麻岩样品进行LA-ICP-MS锆石U-Pb定年,其~(207)Pb/~(206)Pb加权平均年龄为1444±15 Ma、1439±19 Ma、1433±31 Ma和1450±23 Ma,属中元古代。综合区域研究资料认为,海南岛西部公爱地区中元古代花岗质岩石的熔融源区为类似抱板群变沉积岩组分,推测其产出于大陆边缘构造背景,是哥伦比亚超大陆边缘的增生产物。     

滇南新元古代的岩浆作用：来自瑶山群深变质岩SHRIMP锆石 U-Pb年代学证据

滇南瑶山—哀牢山地区出露一套呈NW—SE向狭长条带状展布的深变质岩系——下元古界瑶山群和哀牢山群,并认为存在前寒武纪的结晶基底。本文选取瑶山群眼球状花岗质糜棱岩和金平阿得博的片麻状花岗岩作为研究对象,进行SHRIMP锆石U-Pb定年。结合阴极发光图像,获得岩浆锆石的结晶年龄为828±6.2Ma(N=11,MSWD=1.8)和748～801Ma。同时,作者在墨江-元江剖面的哀牢山群黑云母花岗闪长质片麻岩中获得SHRIMP锆石核部U-Pb年龄为769～893Ma。研究揭示滇南的瑶山和哀牢山地区存在新元古代岩浆作用。瑶山群中古老残余锆石核部的984Ma年龄和哀牢山群中古老残余锆石核部年龄1104～1353Ma及2655Ma,表明该区存在中元古代或太古代的结晶基底,研究区很可能位于南华裂谷与康滇裂谷的交汇部位,新元古代的岩浆活动可能与Rodinia超大陆聚合——裂解过程有关。这为构筑Rodinia超大陆聚散过程和揭示华南大地构造演化史提供年代学方面证据。     

内蒙古西部温都尔庙群的时代及其在中亚造山带中的位置

内蒙古西部的温都尔庙群下部为含铁石英岩、变质火山岩与绢云石英片岩,上部由各类绢云石英片岩、石英岩组成,局部夹碳酸盐沉积。利用SHRIMP和ICP-MS定年方法,获得该群下部的变质火山岩时代为(460±4) Ma,上部绢云石英片岩中最年轻的峰值年龄为417 Ma和444 Ma。结合已有的锆石年龄分析结果,本文认为温都尔庙群的发育时代可能为500~415 Ma。根据温都尔庙群的物质组成,推测其形成于松辽-浑善达克地块周围的大陆边缘海域并命名为温都尔庙洋,代表我国境内早古生代时期的古亚洲洋。根据碰撞造山带理论探讨了温都尔庙群的构造位置,提出在早-中古生代时期,以温都尔庙群为代表的古亚洲洋发生了向南部华北地块和向北部兴安-艾力格庙地块的双向俯冲,其主体部分形成南、北两个加积楔,而其边缘部分卷入南、北混杂岩带成为基质,因此温都尔庙群的褶皱及变质历史记录了中亚造山带东段的演化过程。对碎屑锆石年龄分布的研究表明,温都尔庙群的前寒武纪物源特征与蒙古国下古生界的相似,而与华北陆块显著不同,表明温都尔庙群的物源很可能来自华北陆块之外的前寒武纪古陆。     

海南岛抱板杂岩记录的多期构造热事件：锆石和独居石U-Pb年代学的制约

抱板杂岩(抱板群)是海南岛目前已发现的最古老前寒武纪结晶基底,记录了多期构造热事件,是研究海南岛大地构造属性的重要窗口。本文通过对海南岛冲卒岭地区抱板杂岩变质沉积岩、变质基性岩和伟晶岩脉的锆石和独居石LA-ICP-MS U-Pb年代学研究,来确定抱板杂岩所经历的多期构造热事件及其所代表的构造意义。研究结果显示,抱板杂岩主要由中元古代变质沉积岩、花岗质片麻岩和变质基性岩组成,经历了中元古代晚期-新元古代早期(1.3～0.9Ga)、早古生代(470～440Ma)、三叠纪(～230Ma)等多期构造热事件的改造。中元古代晚期-新元古代早期构造热事件与罗迪尼亚超大陆的汇聚有关;早古生代构造热事件与东冈瓦纳古陆北缘的增生造山作用有关;三叠纪构造热事件是印支陆块与华南陆块碰撞拼合的远程响应。综合上述研究成果和区域对比分析,认为海南岛与印支陆块具有相似的前寒武纪结晶基底和多期构造热事件的记录,表明二者具有明显的亲缘关系。     

北天山温泉群的地质特征、时代和构造意义

北天山温泉群长期以来被认为是古元古代的变质岩。最新的野外调查和锆石SHRIMP U-Pb 测年结果表明,温泉群可 以划分为三个岩石构造单元：（1）前早新元古代变质火山岩和变质沉积岩,主要包括斜长角闪岩、云母片岩、石英片岩、 黑云母片麻岩、大理岩等;（2）早新元古代混合岩和正片麻岩;（3）早古生代未变质变形的辉长岩和闪长岩。上述三种岩 石组合类型均被后期二云母花岗岩（脉）所侵入。温泉县以南的混合岩和花岗片麻岩中锆石的SHRIMP U-Pb 年龄分别为 926±12 Ma 和907±11 Ma,与天山地区出露的新元古代花岗岩类的时代基本一致。结合前人对花岗片麻岩Nd 同位素组成 的研究,花岗片麻岩应为古老地壳物质部分熔融的产物,而同期的混合岩化作用则是新元古代地壳加厚和部分熔融的直接 地质证据。辉长岩和闪长岩侵入到温泉群花岗片麻岩和斜长角闪岩中,其中闪长岩的锆石SHRIMP U-Pb 年龄为452±7 Ma, 并含有1.1 Ga 和1.4 Ga 的继承锆石。根据前人的研究成果,本区早古生代辉长岩和闪长岩具有岛弧岩浆岩的地球化学特征, 可能与准噶尔-巴尔喀什洋的俯冲作用有关,这一俯冲增生作用最终导致伊犁北部与哈萨克斯坦陆块在志留纪拼贴造山, 并使温泉群前寒武纪变质岩与侵入岩发生变质变形作用。     

西藏拉萨地块过铝质花岗岩中继承锆石的物源区示踪及其古地理意义

富含继承锆石的过铝质花岗岩一般来源于富铝质岩石(如变泥质岩)的部分熔融,因而分析这些继承锆石的U-Pb年龄可以像分析沉积岩碎屑锆石的U-Pb年龄一样,提供过铝质花岗岩源区物质中碎屑沉积物物源区的丰富信息。本文报道了中部拉萨地块早侏罗世过铝质花岗岩的全岩地球化学和锆石U-Pb年代学数据,结合拉萨地块已有二叠纪和晚三叠世过铝质花岗岩的继承锆石年代学数据,总结了目前已有的拉萨地块过铝质花岗岩的继承锆石U-Pb年龄特征(共199个谐和测点)。这些过铝质花岗岩属强过铝质S型花岗岩,其中的继承锆石定义了1250~1100Ma(峰值1181±14Ma)和550~450Ma(峰值494±7Ma)2个最突出的年龄群,分别可比于拉萨地块古生代沉积岩的碎屑锆石年龄峰值(约1170Ma)和寒武纪火山岩的侵位时代,明显不同于西羌塘、安多和特提斯喜马拉雅新元古代-古生代沉积岩中的碎屑锆石年龄频谱。拉萨地块过铝质花岗岩中约1181Ma的继承锆石,可能与拉萨地块古生代沉积岩中的同期碎屑锆石一样,都来自澳大利亚南西部Albany-Fraser造山带和东南极Wilkes等地,而约494的继承锆石,既可能来自澳大利亚西部,也可能来自拉萨地块本地。本文提供了拉萨地块与澳大利亚大陆北缘具有古地理联系的过铝质花岗岩继承锆石U-Pb年龄证据。拉萨地块的研究实践表明,采用过铝质花岗岩继承锆石和古生代沉积岩碎屑锆石相结合的锆石U-Pb年代学方法,可为重建冈瓦纳大陆北缘其它微陆块的古地理和构造岩浆演化提供重要约束。     

胶东地区蓬莱群沉积岩碎屑锆石年龄和物源

分布于鲁东胶北地区蓬莱群为一套浅变质沉积岩，角度不整合覆盖在太古宙胶东群、元古宙粉子山群上。关于蓬莱群的沉积时代尚存较大的争议，认为是震旦纪或古生代沉积形成的。蓬莱群和五莲杂岩、北淮阳变质岩带都是位于大别-苏鲁超高压变质造山带北部的重要岩石构造单元。本文报道蓬莱群沉积岩碎屑锆石年龄和始同位素分析资料，并探讨其可能的物质来源。 在栖霞地区采集了14个蓬莱群样品，主要岩石为石英岩、千枚岩、片岩、页岩，从其中4个挑出了锆石样品。分选出的碎屑锆石均为浅棕色，浑圆状，反映锆石经历了搬运作用。CL图像显示绝大多数锆石颗粒具有清晰的韵律环带内部结构，具有岩浆成因特征。在中国科学院地质与地球物理所固体同位素地球化学实验室IsoProbe-T质谱计上，采用即蒸即测方法，测得锆石207Pb/206Pb比值，其对应的年龄值主要分布在1000~1800 Ma,峰值为1200 Ma和1600 Ma左右（图1)。应用中国科学院地质与地球物理所多通道等离子质谱计Neptune MC-ICP-MS测定碎屑锆石 同位素组成。根据所获得的同位素组成，计算得到比同位素模式年龄TDM(Hf）分布在1300~3200 Ma之间，峰值为1700 Ma左右；对应的初始εHf(1200 Ma）和εHf (1600 Ma）平均值分别为-5.8和2.9（图2)。 碎屑锆石1350~1800 Ma年龄段，特别是峰期的1600 Ma，可能对应全球广泛分布的非造山事件，可能和Columbia超大陆的裂解有一定的联系。大部分锆石初始εHf (1600 Ma）值大于0，可以说明岩浆来源为幔源。而1050~1300 Ma的锆石则可能与Rodinia超大陆的汇聚形成阶段或Grenville造山事件有较密切的联系。华北克拉通大量地出露太古宙末期（2500 Ma左右）和早元古代末期(1800 Ma左右）的岩石，但在所分析的蓬莱群沉积岩几乎没有显示，可能可以排除华北克拉通为主要的沉积物源。所获得的碎屑锆石年龄虽在扬子板块有一定的出露，但缺少与Rodinia裂解有关的晚元古代700~800 Ma的岩浆锆石信息。上述资料可能暗示沉积时代为1000~800 Ma之间，但与目前的古生物证据不吻合。因此，这些碎屑锆石年龄和铅同位素数据尚不能肯定蓬莱群变质沉积岩是来源于扬子陆块，还是游离于华北、扬子的一个微陆块。如果是一个微陆块，该微陆块与Columbia裂解作用和Grenville造山作用有关，但可能未遭受到Rodinia超大陆裂解事件的影响。     

东亚原特提斯洋(Ⅴ):北界西段陆缘属性及微陆块拼合

早古生代原特提斯洋在祁连造山带的分支本文称为古祁连洋。其洋内及邻区存在中祁连、阿拉善、柴达木、华北、扬子、塔里木等多个陆块、微陆块,处在一个复杂的多岛洋的环境中。祁连地区早古生代经历了较为复杂的俯冲拼合、碰撞造山过程。本文探讨了祁连造山带的几个构造单元构造属性,认为早古生代阿拉善微陆块南缘为被动大陆边缘,中祁连北缘为活动大陆边缘。阿拉善南部与之平行的龙首山构造单元为俯冲造山形成的增生楔体;北祁连构造带为一套俯冲增生杂岩,包含高压变质岩带、蛇绿岩带、岛弧岩浆和部分洋壳残片等,记录了古祁连洋壳从大陆裂解,洋壳形成,俯冲拼合,碰撞造山的造山过程。495Ma左右南祁连南部柴达木微陆块向北俯冲的影响,古祁连洋壳俯冲受阻,俯冲带向北后退,形成大岔大坂岛弧。弧前地区发生洋-洋俯冲事件,堆积增生大岔大坂、白泉门、九个泉等SSZ型北祁连蛇绿岩北带,并伴随第二期清水沟、牛心山、野牛滩等地岩浆事件。460Ma左右阿拉善微陆块和中祁连微陆块开始碰撞拼合,古祁连洋开始闭合。值得注意的是拼合过程不是均一的,存在自西向东斜向"剪刀式"的拼合方式,产生了由西向东年代变新的"S"型同碰撞岩浆岩。约440Ma古祁连洋闭合,进入陆内造山阶段。440Ma之后,拼合陆块处在一种拉伸的构造环境之下,金佛寺、牛心山、老虎山等地产生碰撞后岩浆岩。422~406Ma发生俯冲折返、高压榴辉岩和高压低温蓝片岩退变质作用,形成以紧闭不对褶皱为特征的第二幕变形。根据各陆块、微陆块碎屑锆石年龄谱分析对比,中祁连基底应与华北不同,而可能与扬子有关。Rodinia超大陆聚合之前,中祁连微陆块作为一个独立的微陆块与华北、扬子保持一定距离。1.0~0.8Ga Rodinia超大陆聚合过程中祁连微陆块与冈瓦纳北缘拼贴在一起,而距华北较远。随着Rodinia超大陆裂解,中祁连微陆块远离冈瓦纳,逐渐向华北靠近,500~400Ma原特提斯洋闭合,华北、阿拉善与中祁连拼合,并整体拼合到冈瓦纳大陆北缘。     

Delineation of capture zones for municipal wells in fractured dolomite, Sturgeon Bay, Wisconsin, USA

A wellhead protection study for the city of Sturgeon Bay, Wisconsin, USA, demonstrates the necessity of combining detailed hydrostratigraphic analysis with groundwater modeling to delineate zones of contribution for municipal wells in a fractured dolomite aquifer. A numerical model (MODFLOW) was combined with a particle tracking code (MODPATH) to simulate the regional groundwater system and to delineate capture zones for municipal wells. The hydrostratigraphic model included vertical and horizontal fractures and high-permeability zones. Correlating stratigraphic interpretations with field data such as geophysical logs, packer tests, and fracture mapping resulted in the construction of a numerical model with five high-permeability zones related to bedding planes or facies changes. These zones serve as major conduits for horizontal groundwater flow. Dipping fracture zones were simulated as thin high-permeability layers. The locations of exposed bedrock and surficial karst features were used to identify areas of enhanced recharge. Model results show the vulnerability of the municipal wells to pollution. Capture zones for the wells extend several kilometers north and south from the city. Travel times from recharge areas to all wells were generally less than one year. The high seasonal variability of recharge in the study area made the use of a transient model necessary. Electronic Publication     

Correlation of hydraulic conductivity with stratigraphy in a fractured-dolomite aquifer, northeastern Wisconsin, USA

This study integrated surface and subsurface stratigraphic data with geophysical logs and hydrogeologic data in order to characterize the hydraulic properties of the Silurian dolomite in northeastern Wisconsin. Silurian stratigraphy consists of predictable alternations of characteristic facies associations. A vertical profile of hydraulic conductivity, obtained from short-interval packer tests in a core hole that penetrates a majority of the Silurian section, indicates that hydraulic conductivity ranges over five orders of magnitude (10^–1 to 10^–6 cm/s). Matrix conductivity is generally low and varies with texture; the finer-grained restricted-marine and transitional facies being less permeable than the coarser-grained open-marine facies. High-conductivity values are generally associated with bedding-plane fractures, and fracture frequency is greater in the restricted-marine facies. High-flow features in 16 wells were identified using fluid-temperature/resistivity and heat-pulse flowmeter logs. Natural-gamma logs were used to identify the stratigraphic position of flow features in each well and to correlate flow features to specific stratigraphic horizons. By combining stratigraphic, geophysical, and hydrogeologic data, 14 high-permeability zones within the Silurian aquifer have been identified and correlated in wells more than 16 km apart. These zones parallel bedding, appear most pronounced at contacts between contrasting lithologies, and are most abundant in restricted-marine lithologies. Electronic Publication     

On the radiogenic heat production of metamorphic,igneous, and sedimentary rocks

Sedimentary rocks cover-73% of the Earth's surface and metamorphic rocks account for approximately91% of the crust by volume. Understanding the average behavior and variability of heat production for these rock types are vitally important for developing accurate models of lithospheric temperature. We analyze the heat production of ～204,000 whole rock geochemical data to quantify how heat production of these rocks varies with respect to chemistry and their evolution during metamorphism. The heat production of metaigneous and metasedimentary rocks are similar to their respective protoliths. Igneous and metaigneous samples increase in heat production with increasing SiO_2 and K_2 O, but decrease with increasing FeO, MgO and CaO. Sedimentary and metasedimentary rocks increase in heat production with increasing Al_2 O_3, FeO, TiO_2, and K_2 O but decrease with increasing CaO. For both igneous and sedimentary rocks, the heat production variations are largely correlated with processes that affect K_2 O concentration and covary with other major oxides as a consequence. Among sedimentary rocks,aluminous shales are the highest heat producing(2.9 μW~(-3)) whereas more common iron shales are lower heat producing(1.7 μW m~(-3)). Pure quartzites and carbonates are the lowest heat producing sedimentary rocks. Globally, there is little definitive evidence for a decrease in heat production with increasing metamorphic grade. However, there remains the need for high resolution studies of heat production variations within individual protoliths that vary in metamorphic grade. These results improve estimates of heat production and natural variability of rocks that will allow for more accurate temperature models of the lithosphere.     

Using saline tracers to evaluate preferential recharge in fractured rocks,Floyd County,Virginia, USA

Potassium chloride (KCl) and potassium bromide (KBr) tracers were used to explore the role of geologic structure on groundwater recharge and flow at the Fractured Rock Research Site in Floyd County, Virginia, USA. Tracer migration was monitored through soil, saprolite, and fractured crystalline bedrock for a period of 3 months with chemical, physical, and geophysical techniques. The tracers were applied at specific locations on the ground surface to directly test flow pathways in a shallow saprolite and deep fractured-rock aquifer. Tracer monitoring was accomplished with differential electrical resistivity, chemical sampling, and physical monitoring of water levels and spring discharge. KCl, applied at a concentration of 10,000 mg/L, traveled 160 m downgradient through the thrust fault aquifer to a spring outlet in 24 days. KBr, applied at a concentration of 5,000 mg/L, traveled 90 m downgradient through the saprolite aquifer in 19 days. Tracer breakthrough curves indicate diffuse flow through the saprolite aquifer and fracture flow through the crystalline thrust fault aquifer. Monitoring saline tracer migration through soil, saprolite, and fractured rock provided data on groundwater recharge that would not have been available using other traditional hydrologic methods. Travel times and flowpaths observed during this study support preferential groundwater recharge controlled by geologic structure.     

Small scale study of groundwater flow in a fractured carbonate-rock aquifer at the St-Eustache quarry, Québec, Canada

A small-scale hydrogeological study was conducted in a fractured carbonate-rock aquifer located in a quarry to relate groundwater flow to the fracture network. The field study in the St-Eustache quarry, which integrates structural surveys, well logging and hydraulic tests, showed that the most important features that affect groundwater flow in the sedimentary aquifer are high hydraulic conductivity horizontal bedding planes. Vertical fractures are abundant in the quarry and throughout the region, but they have a minor effect on groundwater flow. To have a significant impact on the flow regime and lead to vertical groundwater flow, the permeability of all vertical joints need to be enhanced compared to what was generally observed at the site. Such an increase in permeability could potentially occur where dissolution and fracturing is more intense or at stress release locations such as near the surface in the quarry.     

云南香格里拉洛吉乡基性-超基性岩中单斜辉石矿物成分特征及其地质意义

云南香格里拉洛吉乡出露一套基性-超基性岩块,前人对其属性的认识有分歧.岩相学研究发现该岩块具有正堆积结晶和补堆积结晶的特点,岩石化学特征具有贫碱、高钙和低氧逸度的特征,其母岩浆为亚碱性系列,并且显示出堆晶层状岩系演化特征.对其中的单斜辉石进行了矿物成分及化学成分研究,结果表明辉石种属为透辉石,晶体中类质同像替代现象普遍,阳离子取代特征显示出形成于高温低压的条件.温压计算结果表明透辉石形成平均温度为1 084℃,平均压力为0.15 GPa,结合岩石的成分和演化特征,认为该岩石形成于洋中脊,属洋壳组成的基性-超基性堆晶岩系,为甘孜-理塘延伸带的残余产物.     

Evidence for structurally controlled recharge in the Blue Ridge Province,Virginia, USA

Physical and geophysical data collected at a fractured-rock research site in the Blue Ridge Province of Virginia, USA indicate that recharge rates to a fractured-rock aquifer are controlled by a small-scale thrust fault associated with regional thrust faulting. Recharge rates appear to be correlated to spatial variation in the hydraulic conductivity of the regolith, which has been influenced by weathering rates and the metamorphic and structural history of the underlying parent material. The angle of dip of the thrust-fault shear zone and the fracturing within the crystalline rock adjacent to the fault plane appear to serve as geologic controls that preferentially direct infiltrated meteoric water to a deeper confined fractured-rock aquifer. In-situ analysis of electrical resistivity, matric potential and moisture content shows two distinctly different recharge processes which are spatially correlated with the structure of the shallow subsurface (regolith overlying the vertically oriented shear zone and regolith overlying the thrust-fault hanging wall), and which have strong temporal correlations with the dynamics of the underlying saturated conditions. Recharge flux within the regolith overlying the vertically oriented shear zone is strongly controlled by the orientation and areal extent of the thrust-fault shear zone, highlighting the importance of accurate delineation of recharge areas in crystalline rock aquifer systems.     

伊犁盆地石炭系—二叠系含油气性特征

伊犁盆地是在前震旦系基础上发展形成的双层结构盆地，即内裂谷盆地—山间陆相盆地。经多次造陆运动后，盆地内普遍缺失震旦系、下古生界、泥盆系、下三叠统和白垩系。盆地内的生油层主要为海相石炭系阿克沙克组、也列莫顿组，陆相二叠系院山萨依组、塔姆其萨依组。生油中心主要位于伊什基里克山—脱勒斯拜克山以北的湖盆区内。储层主要以二叠系、三叠系和保罗系的碎屑岩为主。伊犁盆地虽然经历了多期构造运动的影响，地质结构更加复杂，沉积中心的不断西移，但仍然在中新生代地层的地表及井下发现大量油气显示，表明该盆地具备生储油能力。该盆地有利与不利因素并存，对盆地的进一步勘探应加强基础研究工作，以避免盲目投入。     

变质火山岩、火山碎屑岩的绿片岩相成岩格子和成岩格子的若干特征

变质火山岩、火山碎屑岩的绿片岩相成岩格子可用阳起石—黑云母—方解石—绿泥石—绿帘石—白云母六相三元系和钠长石—阳起石—黑云母—方解石—绿泥石—绿帘石六相三元系成岩格子来表示,石英往往为过剩组分。在只讨论两个强度相同的变量前提下,每个六相三元系的成岩格子都只可能有一对成对的成岩格子,且这对成岩格子的非封闭双变区的分区相同、分区之间的边界斜率相同、相应的单变线的排列顺序也相同,因此,六相三元系的每个成岩格子中的不变点数、单变线数、和双变区数之间的关系可用数学式来表示。     

论新疆东部黄山──镜儿泉杂岩带的构造属性

相当多的研究者认为,新疆东部黄山-镜儿泉杂岩为蛇绿混杂岩,是板块俯冲的标志。本文的研究表明：该杂岩带的物质形成是弧间伸展的产物,后因弧间闭合,形成了现今所见的混杂岩。