排序方式： 共有22条查询结果，搜索用时 15 毫秒
1.
海南岛前寒纪岩石圈演化的记录：基性岩类岩石地球化学证据 总被引：8，自引：1，他引：8
海南岛前寒武纪基性岩类具有的不同的岩石地球化学特征，记录了海南岛前寒武纪大地构造环境和岩石圈的演化史。古中元古代时，琼中屯昌变基性－超基性岩，为大洋型火山岛弧低钾拉斑玄武岩，明显具有镁铁质－玄武质科马提岩特征，来源于高度亏损的地幔；与之同时代的琼西，则为一套具洋底玄武岩和岛弧拉弦玄武岩的过渡型玄武岩，是古俯冲带上部地幔楔和自消减带卷入地幔楔地壳物质所组成的混合端元部分熔融产物，具低亏损地幔特征，产生于弧后（或弧间）盆地环境；中新元古代的琼西变基性－超基性岩具铁镁质－超铁镁质科马提岩特征，来源于较高亏损的地幔，产于大洋板块边缘的构造环境。据此，可以推测，海南岛前寒武纪岩石圈演化至少经历了古中元古代的古板块俯冲、中新元古代的裂解二次事件，并伴随洋盆的出现。 相似文献
2.
Oxygen Isotope Exchange Kinetics Between Coexisting Minerals and Water in the Aral Granite Pluton of the Altay Mountains, Northern Xinjiang 总被引：2，自引：0，他引：2
Liu Wei Research Center of Mineral Resources Exploration Chinese Academy of Sciences Chinese Academy of Sciences BeijingHe Baichu Changsha Institute of Geotectonics Chinese Academy of Sciences Changsh Hunanand Chen ZhenshengYichang Institute of Geology Mineral Resources Chinese Academy of GeologicalSciences Yichang Hubei 《《地质学报》英文版》1996,70(4)
Coexisting quartz, feldspar and biotite vary widely in their δ18O values and display a remarkable 18O/16O disequilibrium relation; especially, a quartz-feldspar reversal (△ 18OQUartz_feldspar< 0) exsists in the Aral granite pluton of the Altay Mountains, northern Xinjiang. The 18O / 16O exchange reaction definitely occurred between granite and water. Initial δ18O values of the granite and exotic fluid are evaluated by the mass balance consideration. The conventional method of discrimination between various magma derivations simply with δ18O values of either whole rock or separate minerals is misleading and unreliable. Experiments carried out by the authors show that the 18O / 16O exchange reaction is not accompanied by what geologists describe as petrological and mineralogical alteration effect. This decoupling relation implies that exchange reaction occurs at a relatively high temperature during subsolidus-postmagmatic cooling of magmas. The exchange mechanism is mainly diffusion-controlled. It is 相似文献
3.
洞庭湖河湖疏浚对洪水位影响分析 总被引：2，自引：0，他引：2
洞庭湖是长江中游的重要调蓄湖泊，但由于接纳湘江、资水、沅江、澧水四水和长江三口洪水、泥沙，造成河道湖泊泥沙淤积，洪水位抬高，加重湖区的防洪负担，造成严重的洪涝灾害。根据洞庭湖河湖疏浚规划和典型河段疏挖竣工资料，运用水力学和水文学方法对疏浚前后洪水位的变化进行了分析。 相似文献
4.
This paper discusses the role of geologic structures in the occurrence of floods and how to prevent flood in the middle reaches of the Yangtze River, and gives the author's suggestion that the Luoshan Qiakou be expanded and the land reclaimed from Dongting Lake be returned to the lake in compliance with the law of geology. . 相似文献
5.
CHEN Guo PENG Shenglin DAI Tagen Geology Department Central South University of Technology Changsh Hunan 《《地质学报》英文版》2000,74(3):433-438
Following the paper entitled A Preliminary Proposal on Crustobody Geotectonics presented by the first author to the 30th IGC in 1996, this paper further extends and elucidates the concept of crustobody in order to make a unifying study of the evolution and motion of crustal structures and to understand the law governing the formation and development of the earth' crust. In this paper the characteristics of crustobody evolution-motion are given. The authors lay emphasis on the relationship between crustobody evolution-motion and tectonic metallogeny. In the end, a multiple dynamic system of the crustobody evolution-motion is discussed from internal and external dynamic forces, and the mantle creep in internal dynamic factors is paid special attention to. 相似文献
6.
成熟勘探的矿集区非常有必要开展新一轮的找矿，但矿床模式的局限和大埋藏深度等困难制约了这些地区的预测性找矿发现。促进其预测性找矿发现的关键战略包括：勘查模型的创新、勘查技术的创新和各种信息的综合集成预测。勘查模型的创新必须包含基于地球动力学剖析的新成矿概念，动力学数值模拟是有效的创新手段之一；勘查技术创新的主要目的是加大探测深度和提高探测与解释的准确性，必须以详细可靠的地质资料为基础；综合信息集成是利用GIS和知识驱动及数据驱动的方法充分提取各种数据中的有用信息，集成为更加可靠的预测图。在这种思想的指导下，我们在铜陵凤凰山矿田进行了预测和勘查，并成功地发现了深部的隐伏矿床。 相似文献
7.
大兴安岭南段晚中生代双峰式火山作用 总被引：52，自引：24，他引：52
大兴安岭南段晚中生代克头鄂博组山岩表现出双峰式特征，主要由玄武质安山岩、英安岩和流纹岩组成。基性火山岩属于代钾拉斑系列，轻微富集LREE，Eu异常不明显（Eu/Eu=0.99-1.04)和HREE无明显分馏的特征（Dy/YbcN=1.030-1.089);富集大离子亲石元素（LILE）而亏损高场强元素（HFSE），尤其是强烈亏损Nb,Ta。英安岩和流纹岩为钙碱性系列，在REE配分模式上为LREE富集型，其中英安岩为Eu弱负异常（Eu/Eu=0.81-1.01)，流纹岩的Eu负异常明显（Eu^*/Eu=0.65-0.76)；在微量元素蛛网图上，英安岩类似于基性火山岩，流纹岩除了具LILE富集和HFSE亏损特征外，还显示出Sr,P,Ti等元素的强烈亏损，可能与岩浆演化过程中斜长石、磷灰石的分离结晶作用相关。晚中生代双峰式火山岩分离结晶的结果。流纹岩表现出较高的La/Sm比值和很高的K／P、K／Ti比值，其成因可能与地壳混染作用或与大陆中、下地壳重熔作用有关。结合区域晚中生代盆岭构造格局特征、大兴安岭南段晚中生代双峰式火山岩形成于造山后阶段，是岩石圈快速伸展体制下导致受早期流体交代的岩石圈地幔发生减压部分熔融作用的产物。 相似文献
8.
SHI Hebin ZHONG Hong LIU Yu DENG Jinyang 《《地质学报》英文版》2007,81(3):517-522
This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions. 相似文献
9.
通过对青藏高原腹地钻孔岩心剖面的最新研究,用层序地层学与年代地层学和气候地层学相结合的方法,分辨出可可西里地区苟弄措湖泊沉积记录(孔深7.25 m)约30 ka BP以来的古气候变化,并在孔深3.32～1.98 m处识别出“仙女本期”的3个气候颤动事件,即:①老仙女术事件(孔深3.32～2.62 m);②中仙女本事件(孔深2.62～2.43 m);③新仙女本事件(孔深2.43～1.98 m)。这3个气候颤动事件都是以冷干时段开始、以冷湿时段结束的,并有越向后期其冷干的时段越长的变化趋势,而其后的冷湿时段却具有等时的变化趋势。岩心沉积物的有机碳、有机氮和磁化率以及化学元素含量的变化,都与仙女本期气候变化具有十分吻合的变化态势。仙女术期气候在湖泊沉积物中的响应,在青藏高原环境演化中还是首次发现,为研究第四纪末次冰期冰消期以来的气候变化提供了新的信息。 相似文献
10.