吉林省西南部地区花岗岩类的构造环境

通过花岗岩类的地球化学研究,得出了本区花岗岩类形成的地质构造环境:早古生代晚期为岛弧环境,晚古生代是边(陆)缘海,中生代则为活动大陆边缘环境。这与地层地质学的结论相吻合,得到了相互印证。在不同时期,板块的运动方向是不断地变化的,相应地应力场也随其变化,与其相关的花岗岩成因类型亦有相应的变化。北西向断裂构造形成早,多阶段、长期活动,对花岗岩类的形成具有重要控制作用。     

大兴安岭南段早二叠世两类火山岩岩石地球化学特征及其构造意义

大兴安岭南段二叠系大石寨组发育两套火山岩，即林西地区拉斑玄武岩系列的细碧－角斑岩类和大石寨地区钙碱性岩石系列玄武岩和玄武安山岩类。细碧岩的主元素以富铁为特征，成分类似于N－MORB，微量元素表现为岛弧拉斑玄武岩的地球化学特征。细碧岩类形成于大石寨裂陷槽强烈拉张的中心位置，是地幔源区较高程度部分熔融的产生。大石寨地区玄武岩和玄武安山岩类的化学成分表现为大陆缘弧火山岩的地球化学特点，形成于大石寨裂隙槽拉张中心以外的环境，是地幔物质较低程度部分熔融和地壳物质严重混染的产物。大石寨裂隙槽中火山岩的这种独特的成分和组合特点可能反映了裂隙槽的形成是一个快速而短暂的强烈拉张过程。     

折多山花岗岩的成因及构造环境

每一地质环境都具有特定的岩浆－构造系列，对于花岗岩的类型与构造环境的关系一直是人们研究的热点之一。该文在综合同位素（Ｒｂ－Ｓｒ和Ｕ－Ｐｂ）和地球化学数据基础上，结合微观构造研究方法对康定西部沿鲜水河大型韧性平移剪切带分布的大型折多山花岗岩体的花岗岩类型及其相关的构造环境进行了细致的研究，并讨论了该岩体的侵位机制。研究表明，折多山花岗岩属地壳局部熔融产物，为Ｓ型花岗岩，它的侵位时间距今１２．８±１．     

大兴安岭南段锡多金属成矿系列

大兴安岭南段是我国北方最重要的锡-多金属成矿集中区.根据成矿花岗岩和成矿元素组合的不同,可分为3个成矿系列:锡(钨)成矿系列(Sn-W-Nb-Ta-Be)、锡-多金属系列(Sn-Ag-Cu-Pb-Zn)和含锡的多金属系列(Pb-Zn-Cu-Ag),3个系列的成矿时代相同(130～150Ma),均与大兴安岭南段燕山期花岗质岩浆作用有关.与锡(钨)成矿系列有关的花岗岩,主要是钾长花岗岩-花岗斑岩,具有钛铁矿系列花岗岩的特征;与含锡的多金属系列有关的花岗岩,主要是花岗闪长岩-石英二长岩类,具有I型或磁铁矿系列花岗岩的特征;而当钾长花岗岩类与花岗闪长岩-二长斑岩等构成花岗质杂岩体或定位在相近空间时,常形成锡-多金属共生组合.研究表明,锡-多金属系列是与含锡的钛铁矿系列和含多金属的磁铁矿系列两种不同花岗岩类有关的含矿热液同位叠加成矿的结果.高成熟度、富锡的锡林浩特元古宙变质岩的重融-分异演化,可能是形成大兴安岭南段锡富集的主要原因.     

大兴安岭南段北大山含锡石与不含锡石花岗岩特征对比

近年来,人们在大兴安岭南部发现了多处与白垩纪花岗岩相关的锡多金属矿床,但并非所有该时期的花岗岩都与锡矿伴生.为了解花岗岩伴生锡矿的形成条件,本文对内蒙古北大山岩体中的含锡石（磨盘山）与不含锡石（窟窿山）花岗岩开展了锡石U-Pb年龄、锆石U-Pb年龄、全岩地球化学及矿物地球化学分析测试,并进行岩石学、年代学和岩浆演化物理化学条件的对比.结果表明,窟窿山石英正长斑岩和磨盘山黑云母花岗岩的锆石U-Pb加权平均年龄分别为140.2±0.7 Ma和139.9±0.7 Ma,磨盘山黑云母花岗岩锡石U-Pb加权平均年龄为134.9±1.4 Ma,时代均属于早白垩世.全岩地球化学分析结果表明,这些岩石具有高硅（SiO₂=64.96%~76.71%）,富碱（Na₂O+K₂O=8.28%~9.03%）,过铝质（Al₂O₃=12.42%~15.88%）的特点.相对富集Th、Pb、Hf等元素,亏损Nb、Ta、Ti、Sr、P等元素.轻稀土相对重稀土明显富集,Eu异常明显.窟窿山石英正长斑岩与磨盘山黑云母花岗岩在哈克图解上,随着SiO₂含量增加,TiO₂、FeOT、Al₂O₃、CaO、Na₂O、P₂O₅含量逐渐降低,呈现较好的负相关关系,暗示二者具有同源性.但窟窿山样品的DI值为89,Sn含量为2×10?6;磨盘山样品具有较高的DI值（96~98）,Sn含量高（15×10?6~36×10?6）.从矿物学特征反演的物理化学条件推测,窟窿山岩体经历了温度降低、氧逸度升高的过程,而磨盘山岩体在降温过程中氧逸度进一步降低.另外,在流体卤素含量上,黑云母的Ⅳ（F）、Ⅳ（Cl）指示磨盘山花岗岩（Ⅳ（F）=0.95~1.15,Ⅳ（Cl）=-3.66~-3.54）相较于窟窿山石英正长斑岩（Ⅳ（F）=1.24~1.28,Ⅳ（Cl）=-2.96~-2.52）具有更高富集程度的Cl和F含量.综上,低氧逸度、高演化程度和高的F、Cl丰度是影响北大山地区花岗岩是否含锡的重要原因.      

Tin–polymetallic Mineralization in the Southern Part of the Da Hinggan Mountains, China

Abstract: The southern part of the Da Hinggan Mountains is the only tin-polymetallic concentration area in northern China. Based on ore-forming element assemblages, three metallogenic series, the Sn(W), paragenetic Sn–polymetallic, and poly-metallic series, are recognized. The Sn(W) series, consisting of greisen, skarn and vein types, is associated with ilmenite–series, potassic feldspar (Kf)–granites. The polymetallic Pb–Zn–Cu series with porphyry, skarn and vein types, is related to magnetite–series, granodiorite – monzonite. On the contrary, the paragenetic Sn-polymetallic series mineralization is associated with the coexisting igneous activities of Kf-granite and granodiorite–monzonite, and it is suggested that the paragenetic Sn-polymetallic series is caused by the superimposed mineralization with tin from ilmenite-series magma and polymetallic elements from magnetite-series magma–hydrothermal system. All the three series possess similar metallogenic age, concentrating on J₃–K₁ (130–150 Ma). The melting of high maturity and tin-rich Xilinhot Proterozoic complex (micro–massif) during Mesozoic period, could generate the ilmenite–series, tin-bearing felsic magma, and cause the tin mineralization in the southern part of the Da Hinggan Mountains.     

大兴安岭北部多年冻土监测进展

大兴安岭北部是我国多年冻土最为发育的地区之一, 多年冻土的存在和分布受植被、积雪等局地因素的影响十分显著, 形成了独特的兴安-贝加尔型多年冻土. 随着该区社会经济的发展, 多年冻土对寒区环境以及工程生产活动的影响越来越大. 近几年来逐步在大兴安岭北部建立了以多年冻土为主要研究对象的监测网络, 包括多年冻土地温监测网络、自动气象站、雪特性观测系统、活动层温度-水分观测系统以及地面融沉监测断面, 获得了一系列有意义的数据和成果. 做好大兴安岭北部多年冻土及其周围植被、气候及冻土灾害的监测具有重要的基础性和前瞻性科学价值.     

大兴安岭北部地区的南华系

莫尔道嘎镇等3幅1∶25万区域地质调查对原青白口系佳疙瘩组的含义进行了重新厘定。新厘定的佳疙瘩组剔除了原组内的石英岩、片岩和部分构造片岩,其岩石组合下部为片理化绢云母千枚岩、绢云母千枚岩、变质粉细砂岩等,上部为绢云母千枚岩、绢云母板岩、炭质板岩夹变安山岩、结晶灰岩。该组底部与古元古界兴华渡口岩群大理岩呈断层接触,顶部与震旦系额尔古纳河组结晶灰岩呈整合接触。在绢云母板岩、泥灰岩、细晶灰岩中采到大量微古植物:Lophosphaeridium,Lophominuscu-la,Trachysphaeridium和Symplasosphaeridium,在佳疙瘩组剖面中上部的变安山岩夹层中首次获得单颗粒锆石U-Pb蒸发法年龄723Ma±42Ma,证实了大兴安岭北部地区南华系的存在。     

Discovery and Significance of Quaternary Glacial Vestiges in the Hexigten Area of the Southern Da Hinggan Mountains, Inner Mongolia

1 Introduction Hexigten is situated at the eastern part of the Inner Mongolian Plateau, south of the Da Hinggan Mountains and northwest of Chifeng City, Inner Mongolia, China. It is also at the junction of the Da Hinggan Mountians, Inner Mongolian Plateau and Yanshan Mountains. It is about 650 km north of Beijing. The geographic coordinates are 116?30'?118?20'E and 42?20'?44?10'N (Fig. 1). The elevation range is from 1100 m to 1700 m, and the highest peak (2029 m) of the Da Hinggan…     

大兴安岭南部二叠纪-三叠纪之交孢粉化石及古气候环境分析

大兴安岭南部巴林右旗幸福之路苏木查干布拉格村老龙头组（原幸福之路组模式）剖面首次发现孢粉化石18属21种,以Cyclogranisporites sp.,Alisporites parvus De Jersey,Alisporites circulicorpus Clarke,Sulcatisporites rhombicus Qu,Lueckisporites virkkiae R.Potonie et Klaus,Piceites sp.为主。通过典型属种对比,结合已发现的动植物化石、孢粉组合及同位素测年结果分析,确定幸福之路地区老龙头组的时代为晚二叠世-早三叠世,即二叠系-三叠系界限存在于这套陆相连续沉积内部。孢粉化石的亲缘母体以发育种子蕨纲和松柏纲的针叶植物为主,指示当时研究区处于暖温带的干旱-半干旱的古气候环境。     

大兴安岭中北部晚侏罗世-早白垩世地层新认识

根据大兴安岭中北部地区晚侏罗世火山岩正常沉积夹层中所含叶肢介化石的研究成果和同位素年龄新资料，认为大兴安岭北部西坡被归入白音高老组中的“含Eosestheria的酸性、酸碱性火山碎屑岩和熔岩”不是白音高老组，应归入龙江组，层位与辽西义县组对比。大兴安岭主脊火山岩（满克头鄂博组、玛尼吐组、白音高老组）从南到北是同期火山活动作用的结果，不存在“穿时”现象，形成于晚侏罗世早中期，层位与冀北大北沟组对比。     

Metal deposits in the Da Hinggan Mountains,NE China: styles,characteristics, and exploration potential

The Da Hinggan Mountains mineral province (DHMP), northeastern China, is divided into three tectonic units and corresponding metallogenic belts. The tectonic units of the Da Hinggan Mountains are the Erguna fold zone on the northwest, the Hercynian fold zone on the north, and the Hercynian fold zone on the south. The corresponding metallogenic belts are the Erguna Cu-Pb-Zn-Ag-Mo-Au belt of the NW DHMP, the Cu-Pb-Zn-Mo-Fe-Au belt of the northern DHMP, and the Pb-Zn-Ag-Cu-Sn-Fe-Mo belt of the southern DHMP. Distinct ore bodies, mostly associated with Mesozoic granites and volcanics, comprise (1) hydrothermal vein deposits including Pb-Zn-Ag-(Cu) and W‐Sn-Cu, (2) exhalative (Pb-Zn-Ag, Cu) deposits, (3) porphyry (Cu, Au, Mo), (4) skarn (Fe, Zn, Cu), and (5) epithermal Au-Ag deposits. The hydrothermal veins are hosted by a range of different rock types, whereas the exhalative ores are confined to Permian strata. The porphyry deposits occur within granite porphyries. The epithermal deposits are related to Mesozoic volcanic-subvolcanic rocks and occur within superjacent igneous structures. The first type, represented by the Bairendaba deposit, shows many characteristics of hydrothermal deposits. The second type occurs in a Permian clastic-chemical sedimentary sequence. Most Fe-Zn-Cu deposits related to granites and granodiorites are skarns. Granodiorite and granite-related deposits are typical porphyry ores, formed during Hercynian and Mesozoic time. Promising metallogenic conditions and the recent discovery of many large metal deposits indicate that this mineral province has a great exploration potential.     

大兴安岭中段白音高老组流纹岩年代学、地球化学及其地质意义

对大兴安岭中段(阿尔山—柴河地区)白音高老组流纹岩进行了年代学、地球化学详细测试,结果表明:白音高老组流纹岩LA—ICP—MS锆石U—Pb表面年龄值为124.8~135.6 Ma,加权平均年龄值为127.0±0.5 Ma,形成时代为早白垩世;岩石主体属高硅高钾弱过铝质钙碱性系列;稀土元素配分模式图呈右倾型,轻重稀土分馏明显((La/Yb)N=3.12~10.28,平均7.57),铕弱负异常(δEu=0.18~0.73,平均0.53);大离子亲石元素Rb、Th、U相对富集,Ba、Sr明显亏损,高场强元素Zr较为富集,Ti强烈亏损。根据区域对比并结合他人研究成果,认为大兴安岭中段白音高老组流纹岩形成于早白垩世板内伸展环境,与太平洋板块俯冲关系密切。     

大兴安岭南段主要金属矿物的成分标型特征

内蒙古东部的黄岗-甘珠尔庙矿带是地处大兴安岭南段的锡乡金属矿带。矿带中各矿床的磁铁矿、锡石、方铅矿、闪锌矿的主元素和微量元素数据表明,这些矿床是属与燕山期岩浆活动有关的矽卡岩型、热液型、斑岩型和云英岩型矿床;其成矿金属组分中的铁来源于区域晚古生代海相中-基性火山岩,部分铅锌来源于区域二叠纪地槽沉积物。研究还表明,与燕山期偏碱性花岗岩有关的锡钨矿床和与燕山期中酸性花岗岩类有关的铅锌矿床其方铅矿、闪锌矿的微量元素含量及比值存在明显的差别。     

Re-Os Geochronology of Porphyry Molybdenum Deposit in South Segment of Da Hinggan Mountains,Northeast China

The ages for porphyry Mo deposits in south segment of Da Hinggan Mountains,Northeast China,are not well known.Five molybdenite samples from the Aolunhua(奥伦花) porphyry Mo deposit,five molybdenite samples from the Yangchang(羊场) porphyry-quartz vein Mo deposit and two molybdenite samples from the Banlashan(半拉山) porphyry Mo deposit were selected for Re-Os dating.Three deposits are spatial-temporally associated with the granite porphyry stock.Re-Os isochron age of 131.2±1.9 Ma was obtained for the Aolunhua porph...