黄河三角洲冰携泥现象及其产出的冰成沉积构造

通过野外实地考察、实验模拟，在黄河三角洲发现了一种非常特殊的、冰-（水-）泥共同作用而形成的冰携泥现象。冬末春初，冰雪融化，位于冰层底部的细粒碎屑沉积物质（粉砂或粘土）常被冰向上携起。研究认为，冰携泥的发育过程可以分为三个阶段：沉积物的破碎、冰层底部融化-泥沙被冰垂向搬运及泥沙下落-冰成球粒等的形成。在冰携泥的整个过程中可产出冰劈裂缝、冰成球粒和冰成泥沙片等特殊的沉积现象（构造），它们是冰携泥现象留下的重要的地质记录，对于恢复这一特殊现象及其形成的环境条件具有重要的指示意义。另外，初步探讨了冰携泥现象形成的两种可能机制：毛细作用和冰融水对流作用，并认为在冰融水能及时渗漏或排出的开放系统中，只有毛细作用机制发生作用；在冰融水不能被渗漏或排出的密闭系统中，两种机制共同发生作用。     

新疆乌伦古湖沉积物粒度特征揭示的环境信息

在放射性同位素210Pb、137Cs定年的基础上,通过对沉积物粒度参数的分析,探讨了近200年来乌伦古湖沉积物粒度敏感组分特征及其环境意义。研究表明,乌伦古湖WL孔沉积物以黏土和细粉砂为主,但在1970 AD前后,粒度参数发生了突变,其中>16 μm组分所占含量迅速升高,在约1830~1842 AD及1910 AD前后这两个时期,沉积物的粒度参数也有较显著的变化。对沉积物粒度频率分布曲线的分析表明,在对应时期内,沉积物的搬运介质或搬运动力发生了变化。基于此,首先通过粒径-标准偏差方法提取了粒度中的敏感组分C2（7~25 μm）,进而通过粒度敏感组分与器测气象数据的相关性分析,明确了组分C2含量的环境指示意义。结果表明,组分C2含量的大小与研究区冬、春季温度和冬季降水量大小有关,反映了积雪融水入湖的强度。在约1830~1842 AD、1910 AD前后,组分C2含量偏高,反映入湖水量较大、湖泊水位较高。而20世纪60年代到70年代,沉积物粒度参数的显著变化与流域人类活动的影响有关。     

新疆三塘湖盆地走滑构造特征与油气勘探

通过对钻井岩心资料系统观察以及地震资料的全面检查,证实新疆三塘湖盆地内存在走滑构造,表现为简单走滑(逆—平移)断层和正花状走滑断层两种基本形式。在中央拗陷带内走滑断层与边界主断层斜交并呈“雁列式”排列,表明走滑构造可能在边界断层发生大规模逆冲兼右行走滑时形成,其形成时期可能为喜山期。同时走滑构造对油气的生成、运移与聚集起着重要的控制作用。     

南海西缘断裂带走滑特征及其形成机理初步研究

南海西缘断裂带是南海西部最主要的构造要素,从北到南贯穿了该区主要的沉积盆地,具有走滑断裂的性质。由于不同地质时期走滑方向的不同,形成了不同的断层组合,主要表现为负花状构造和北东向、北西向两组雁列断层以及平面上双马尾状构造组合。主体断裂带以单条式为主,区段式活动特征明显。在南北盆地之间的构造转换带表现为负花状构造-犁式断裂-多米诺式反向调节正断层的组合。综合分析认为,南海西缘断裂是一组长期活动的断裂带,大规模走滑活动从中始新世至第四纪时期,主要为右旋走滑,应力以张扭作用为主;但是在中中新世末期,走滑方向曾经发生转变,为左旋走滑,转为压扭应力,造成区域隆升,导致地层被剥蚀,南海西部盆地现今沉积-构造格局基本形成。     

走滑盆地形成机制及沉积特征

走滑盆地形成机制及沉积特征许敏（能源地质系）０前言走滑盆地的形成与沿走滑断层的局部拉伸有关。这些走滑断层大多与板块构造有关，形成于多种地球动力学环境。如大洋和大陆的转换部位、岛弧、缝合状碰撞边界，以内陆和大陆边缘环境最为常见。走滑断层的主体在平面上呈...     

乌伦古湖沉积物粒度特征及其古气候环境意义

利用乌伦古湖沉积钻孔的粒度资料,分析了粒度频率曲线、粒度参数和粒度组成等粒度特征,并探讨了乌伦古湖粒度代表的古气候意义。结果表明乌伦古湖沉积物频率曲线主要是正态单峰型,反映流水作用为主要沉积作用。岩芯下部（225197cm）沉积物分选较差,偏度和尖度较大,为浅水沉积环境;中部（197103cm）分选由差变好,物源由复杂变单一,为浅水沉积向深水沉积过渡环境;上部（1030cm）分选较好,物源单一,中值粒径减小,反映了湖水位的下降。沉积物粒度特征反映了乌伦古湖地区全新世降水、流水和风力作用以及湖面水位高低的变化。乌伦古湖一万年来的古气候环境演化大致经历了102507720cal.aBP的干旱、77202800cal.aBP的湿润和2800cal.aBP以来的偏干三个阶段。      

新疆北部卡拉麦里晚古生代走滑构造及其叠加变形序次

大型走滑断裂构造是大陆地壳内部基本的构造变形样式,通常是大陆地壳形成的标志.卡拉麦里构造带是新疆东准地区构造演化研究的重要构造单元.前人的研究认为卡拉麦里构造带是板块碰撞形成的缝合带.本文结合野外考察、构造分析和年代学工作认为,该构造带主要反映了走滑构造带的特点.在遥感影像上,卡拉麦里构造带呈断续的线状延伸特征.地震剖面上,卡拉麦里断裂带主断面产状近于直立向下延伸至基底,与一般张性断层、压性逆冲断层所显示的上陡下缓的铲状特征截然不同.野外考察显示,该构造带发育密集而陡立劈理,主断面附近劈理面倾角近于直立,在相对较浅层次的地层上,劈理面成花状散开,体现花状构造的特点.卡拉麦里构造带内的石炭系、泥盆系地层以及蛇绿岩系受到强烈改造,超糜棱岩化、糜棱岩化、千枚岩化现象普遍.糜棱岩中,硅质岩透镜体拖尾指示右旋走滑特征,与同构造岩脉次级张裂面指示的结果相一致.结合前人研究资料以及地层变形证据,可以推断构造带活动时限为270～260Ma.因此,卡拉麦里构造带是一条在晚古生代-早中生代活动的右旋剪切走滑构造带,准东地区与卡拉麦里构造带相关的缝合带确认,必须以卡拉麦里走滑构造带性质的准确厘定为基础.卡拉麦里构造二叠纪时期的走滑活动性质的确定,指示新疆北部二叠纪大陆地壳已经形成,而且,新疆北部后期叠加构造变形序次研究也显示具有大区域上的共性,指示新疆北部二叠纪以来进入基本统一大陆内部构造演化阶段.     

黄河三角洲的冰融沉积构造及其研究意义

冰成沉积构造是在冰直接控制下而形成的沉积构造,冰融沉积构造是其中的一类。通过对黄河三角洲的野外地质考察,发现并描述了7种冰融沉积构造：冰融水流痕、冰成裂流痕、冰融丘(冰融痕)、冰成泥沙片、冰成泥沙笋、冰成豆粒和冰成根状构造。冰融沉积构定的指示意义。最后,系统总结了冰成沉积构造的分类。     

新密煤田层滑构造特征及其对煤层的影响浅析

新密煤田是河南省的主要产煤地之一,其地质构造多以高角度的正断层为主,新密煤田还发育滑动构造和层间滑动构造,而层间滑动构造由于没有造成明显的地层缺失,在地质勘探过程中不易被发现,对煤矿生产建设影响较大。本文列举了新密煤田的层滑构造实例,并对其造成的影响进行了浅析。     

Geochemistry and Tectonic Significance of Alkali Granites along the Ulungur River,Xinjiang

In North Xinjiang there is an alkali granite belt extending in the NW-SE direction along the southern band of the Ulungur River and running parallel to the suture zone,i.e.,Aermantai-Zhaheba Ophiolitic Melange Zone ,between the Junggar Plate and the Altay Orogenic Belt.Whole -rock Rb-Sr isochron ages of the Ulungur alkali granites are within the range of 292-309Ma, showing that they were genetically connected with the latest episode of Hercynian magmatism subsequent to the syncollision S-type and post-collision uplifting I-type granitoids in the Altay region .The alkali granites are miner-alogically characterized by the occurrence of aegirine and arfvedsonite and chemically by high silicon and alkali,low calcium and magnesium and abundant high-field elements, being typical A-type granites .The alkali granites were formed in the final stage of the Hercynian calc-alkaline magmatic cycle in a very short period of time .They are in line with the post-orogenic A-type(PA-type)granites, implying that the tectonic regime was changed from compression to extension.     

Holocene climate reconstructions of Ulungur Lake (Xinjiang,China) inferred from ostracod species assemblages and stable isotopes

In this paper, the data on the paleoclimatic and paleoenvironmental changes during the Holocene are presented and a discussion is made on a 225-cm-long sediment core from Ulungur Lake, located in Northwest China. The chronology is constructed from six AMS radiocarbon dates on the bulk organic matter. On the basis of the analysis of ostracod assemblages and the shell stable isotopes, the core is divided into three paleoclimatic and paleoenvironmental evolution stages: 9 985–5 250 cal.aB.P. stage is the wettest phase of the core section. The climate changed from moderate-dry to cool-wet, and then to warm-wet in turn, and the lake level rose accordingly, showing the characteristic of a high lake level. 5 250–1 255 cal.aB.P. stage was the driest phase of the core sediment. The climate turned from the early warm-dry to the late warm-wet and the lake level fell and rose again. Finally, the 1 255 cal.aB.P. stage was the medium stage of the section. The temperature was low and then increased after the 1920s and the climate was dry. The whole climatic and environmental evolution records of Lake Ulungur were not only in agreement with the sporopollen record of the same core but also in agreement with the record of environmental changes of adjacent areas. It responded to regional environmental changes and global abrupt climate events, following the westerly climate change mode on 100-year-scale, primarily with cold-wet and warmdry characteristics. __________ Translated from Quaternary Sciences, 2007, 27(3):382–391 [译自:第四纪研究]     

兴国地区旋滑构造特征及形成机制

通过兴国地区基底褶皱,盖层褶皱,弧形构造及岩浆活动的研究,阐述了该区旋滑构造的特征,并对其形成机制进行了探讨。     

新疆民丰县枯水湖锑矿点矿石特征及成因浅析

枯水湖锑矿点位于新疆和田地区民丰县城南东侧约130km、黄羊岭锑矿点南西侧约50km;构造上位于阿尔金断裂(南东侧)、中昆仑断裂带(南西侧)以及郭扎错-西金乌兰湖结合带(北侧)三者交汇复合的三角形区域内。该区成矿地质条件良好、找矿潜力巨大。笔者通过对枯水湖锑矿点野外地质调查及矿石手标本、光片、薄片进行详细观察与鉴定, 查明了野外矿化带分布特征、矿石成分以及矿石主要具有低温热液充填(-交代)作用所形成的组构特征等;并粗略划分出4个成岩(矿)时期和至少1个构造活动期。此外, 对比研究了该锑矿点与相邻的3个锑矿床的成矿地质特征, 初步认为4者应同属一个成矿系统。该锑矿点(床)为受构造(岩浆)活动控制的低温热液充填(交代)型矿点(床)。     

东南极洲中山站附近1年生海冰的发育和结构特征及其对生物群落的影响(英)

Sea ice growth, characteristics and ice algal biomass were measured at four sites off Zhongshan Station (66°22, 24" S, 76°22, 40" E), East Antarctica in 1992. The ice formed in late March,grew stablely and reached its highest thickness of 174 cm in November and December. The difference　between measured ice thickness and the calculated values from the classical Stephen formula are small,suggesting that the heat flux from the ocean to the underside of the ice at this area is not obvious.The results of sea ice analysis show that the sea ice consists mainly of congelation ice, and the frazil　ice only occurs at the top of sea ice, no snow or platelet ice is found. When the ice thickness reached its　　highest values in late spring, congelation ice contained average 89. 5 % of the total column crystal 　structure, the remaining 10. 5% consisted of frazil ice, and the ice thicknesses above the congelation ice layers were mostly consistent throughout the year, suggesting that the sea ice developed in a relativelycalm environment after the top layer of ice had formed and grew downwards only.Congelation ice fabrics shows frequent moderate to strong alignments at almost all depths, and thedegree of preferred orientation mostly increased with depths. In the sub--structure of congelation ice,the plate width are in a range of 0. 55 to 1. 05 mm with an average value of 0. 76 mm. No apparent pattern occurs in its vertical profiles.Ice crystal composition is one of the major factors influencing the ice algal biomass, and the effectsof crystal alignments and ice plate width of congelation ice are not apparent.     

Features and Formation Mechanism of Faults and Potash-forming Effect in the Lop Nur Salt Lake, Xinjiang, China

1 Introduction The Lop Nur Salt Lake, located in the eastern part of the Tarim Basin, Xinjiang, China, has become a playa in the Quaternary. It is under the jurisdiction of Ruoqiang County, Xinjiang, being ~450 km east of Korla City, the capital of the Bayingolin Mongolian Autonomous Prefecture (Fig. 1), and 300 km south of the seat of Shanshan County. The geographic coordinates are 90o00'–91o30' E and 39o40'– 41o20' N. Field survey and drilling since 1995 have revealed an occurren…     

鄱阳湖沉积物粒度特征及其对形成演变过程的示踪意义

通过对鄱阳湖大汉湖ZK04钻孔沉积物的粒度分析,揭示了该地区沉积物粒度特征.结果表明,从湖滨到湖心沉积物粒度呈由砾石→粗砂→细砂→粉砂→黏土等逐渐变细的正旋回,其沉积时代可分为6个阶段:第1阶段(601～530 cm),M、KG、SD、SK都为曲线中最高峰,频率为4峰型,该阶段气候暖湿,彭蠡泽形成;第2阶段(530～3...     

乌伦古湖最低生态水位及生态缺水量

确定乌伦古湖的生态保护目标是流域水资源合理、高效配置的前提和基础.针对乌伦古湖冷水系淡水鱼类的生存繁殖特征,提出了基于干旱区湖泊鱼类～盐度～水量关系的湖泊最低生态水位计算方法,并根据该方法计算得到布伦托海和吉力湖的最低生态水位分别为476.12 m和478.12 m.由水量平衡关系进一步计算了湖泊最小生态需水量和接近9...     

青海湖东南岸现代滩坝沉积模式与识别标志

青海湖是研究湖泊滩坝的有利区域。通过对青海湖现代滩坝的实地考察和精细解剖,对滩坝的沉积特征、形成机制、沉积序列、沉积模式、识别标志等方面进行了系统研究。青海湖滩坝发育3种岩相,即块状砾质砂岩相、块状砾岩相和递变砂砾岩相。结合岩相分布和现代湖岸水动力观测,将青海湖波浪带划分为对称浪带、歪浪带、破浪带和冲洗浪带,并据此建立了青海湖滩坝沉积模式。提出滩坝相较于河口坝的4点关键识别标志:(1)岩性底界面接触关系差异,滩坝与下伏半深湖泥质沉积总是突变接触,有明显的突变面,而河口坝则是渐变接触;(2)滩坝垂向上发育典型的"ABC"序列,沉积物自底至顶呈细-粗-细的变化;(3)滩坝普遍发育冲洗层理,以及向陆倾斜的漫越层,而河口坝主要发育槽状交错层理;(4)砂体走向差异,滩坝砂体走向总体平行于湖岸,而河口坝砂体走向总体垂直于湖岸。     

山西黎城中元古界常州沟组微生物成因构造(MISS)及其地质意义

在山西黎城县西井镇彭庄至大井盘公路旁剖面以及黄崖洞景区发育大量的微生物成因构造(MISS),多发育在砂岩表面。由于构造形态奇特,被误以为各种遗迹化石或是不规则的泥裂构造。依据其形态特征、成因构造和前人分类方案,将研究区此类构造分为3种类型,即微生物席生长构造、微生物席破坏构造和微生物席腐烂构造,以及9个不同形态构造,即小瘤状突起、圆顶大瘤状突起、不规则侧向生长脊、大脊状生长构造、纺锤状脱水裂痕、多边形网状脱水裂痕、曲形脱水裂痕、微生物席砂片、砂火山构造,对9种不同形态的MISS进行了详细的论述。对研究区微生物成因构造(MISS)的成因进行了探讨,与豫西鲁山地区、贺兰山苏峪口地区、北京南口地区、河北兴隆地区发育的MISS及地层特征进行类比,认为MISS对华北地台中元古代地层对比以及古环境研究有重要的指导意义。