广西大厂拉么锌铜多金属矿床成岩成矿作用年代学研究   总被引：20，自引：1，他引：19  

李华芹  王登红  梅玉萍  梁婷  陈振宇  郭春丽  应立娟 《地质学报》2008,82(7):912-2008-01-30

本文对广西大厂矿田拉么矿区内出露的酸性侵入岩和矿石进行了精细的年代学研究,分别获得龙箱盖含斑黑云母花岗岩锆石原位SHRIMP UPb和全岩RbSr等时线年龄为94±4Ma（95%可信度）和98.6±1.9Ma（95%可信度）,矽卡岩成矿期锌铜矿石中石英矿物RbSr等时线年龄为98.6±6Ma（95%可信度）。上述测定结果表明,拉么锌铜多金属矿床的成矿年龄与相关岩体的成岩年龄接近,均形成于早白垩世晚期。  相似文献   

Ibla cumingi (Crustacea, Cirripedia) -A Gonochoristic Species (Anatomy, Dwarfing and Systematic Implications)     

Waltraud  Klepal 《Marine Ecology》1985,6(1):47-119

Abstract. Ibla cumingi (Crustacea, Cirripedia) is a gonochoristic species with dwarf males. The anatomy of both sexes is described and compared with that of other Cirripedia s. str. Systematic implications on the basis of anatomy and biology are given. The degree of dwarfing in the male and the possible cause and way of reduction are discussed.  相似文献   

自由生活海洋线虫的系统分类学   总被引：1，自引：0，他引：1  

张志南  周红 《中国海洋大学学报(自然科学版)》2003,33(6):891-900

自由生活海洋线虫是海洋中最丰富的后生动物 ,它属于小型底栖动物的永久性成员 ,即分选时 ,可通过 0 .5 mm或 1 mm网筛但被 0 .0 31 mm或 0 .0 4 2 mm孔径网筛蓄留的动物 ,本文讨论线虫在动物界的分类地位 ,与相近动物类群的亲缘关系 ,泄腺纲与泄管纲分类系统的由来和演变。海洋线虫属于泄腺纲 ,由 Bremerhaven种名录和 L orenzen确立的分类系统已得到广泛的应用。海洋线虫的分类系统仍处在发展和完善中 ,需要发现更多更有价值的共近裔性状用于物种水平和较高分类阶元的分析和鉴定  相似文献   

关于胶莱盆地东南缘基性火山熔岩喷发时代上限的讨论          下载免费PDF全文

赵广涛  曹钦臣  冯叶  李巍然 《海洋科学》1993,17(6):64-66

首次对采自青岛即墨WN部两个深钻孔中新鲜玄武岩样品进行Rb-Sr同位素测年,测定年龄值为65.77±13.6Ma。认为该年龄值代表了胶莱盆地东南缘基性火山熔岩喷发的时代上限,对于整个胶莱盆地中基性火山岩的划分和对比具重要的年代学意义。  相似文献   

康定杂岩Rb-Sr、Sm-Nd同位素系统及其意义   总被引：1，自引：0，他引：1  

陈岳龙  王忠  罗照华  李大鹏  赵俊香 《现代地质》2008,22(5)

通过对康定—冕宁地区出露的英云闪长岩、黑云角闪斜长片麻岩、角闪变粒岩全岩及其中所分离出的角闪石、黑云母、斜长石、钾长石的Rb-Sr、Sm-Nd同位素的系统测定,结合岩石的锆石U-Pb年龄结果,确定这些变质杂岩由于经历了复杂的形成过程与变质历史,Rb-Sr、Sm-Nd同位素体系难以确定其结晶年龄。由单矿物与全岩Rb-Sr、Sm-Nd体系拟合的~700 M a的等时线年龄反映了角闪岩相-高角闪岩相的变质作用年龄。Sm-Nd同位素体系由于在变质作用过程中的部分开放性,很容易给出无意义的较老的混合年龄。康定杂岩结晶后并没有经历麻粒岩相变质作用,区域上所含的麻粒岩透镜体可能是新元古代(773~721 M a)期间由Rod in ia超大陆裂解产生的新生洋壳向扬子克拉通陆块俯冲消减过程的变质产物。俯冲到一定深度后,由于板片被拉断,软流圈上涌导致变质洋壳板片岩石、先前底侵变质的镁铁质岩石及扬子陆块长英质基底岩石发生部分熔融,以镁铁质岩石熔融产生的熔浆为主(>70%),与长英质基底岩石熔融产生的熔浆混合形成w(Na2O)/w(K2O)>1的TTG组合。  相似文献   

福建行洛坑大型钨矿的地质特征、成矿时代及其找矿意义   总被引：24，自引：2，他引：22  

张家菁  陈郑辉  王登红  陈振宇  刘善宝  王成辉 《大地构造与成矿学》2008,32(1):92-97

行洛坑钨矿是目前福建最大也是武夷山成矿带最大的钨矿,已知储量主要分布于岩体内部,宜归属于斑岩型钨矿范畴。本文通过Re-Os法和Rb-Sr等时线法测定花岗岩体中辉钼矿的Re-Os等时线年龄为156.3±4.8Ma,石英脉中流体包裹体的Rb-Sr等时线年龄为147.5±2.9Ma,表明成矿作用与岩浆岩的形成基本同步,并延续了大约10Ma。因此,行洛坑钨矿虽然属于斑岩型钨钼矿但岩体以外的空间也可能找到石英脉钨矿,而整个武夷山成矿带中生代持续而复杂的成矿历史预示了其良好的找矿前景。  相似文献   

Paleoproterozoic accretion in the Northeast Siberian craton: Isotopic dating of the Anabar collision system   总被引：1，自引：0，他引：1  

O. M. Rosen  L. K. Levskii  D. Z. Zhuravlev  A. Ya. Rotman  Z. V. Spetsius  A. F. Makeev  N. N. Zinchuk  A. V. Manakov  V. P. Serenko 《Stratigraphy and Geological Correlation》2006,14(6):581-601

Geochronological database considered in the work and characterizing the Anabar collision system in the Northeast Siberian craton includes coordinated results of Sm-Nd and Rb-Sr dating of samples from crustal xenoliths in kimberlites, deep drill holes, and bedrock outcrops. As is inferred, collision developed in three stages dated at 2200–2100, 1940–1760, and 1710–1630 Ma. The age of 2000–1960 Ma is established for substratum of mafic rocks, which probably originated during the lower crust interaction with asthenosphere due to the local collapse of the collision prism. Comparison of Sm-Nd and Rb-Sr isochron dates shows that the system cooling from ≈700 to ≈300°C lasted approximately 300 m.y. with a substantial lag relative to collision metamorphism and granite formation. It is assumed that accretion of the Siberian craton resulted in formation of a giant collision mountainous structure of the Himalayan type that was eroded by 1.65 Ga ago, when accumulation of gently dipping Meso-to Neoproterozoic (Riphean) platform cover commenced.  相似文献   

Chemical, Isotopic, and Fluid Inclusion Evidence for the Hydrothermal Alteration of the Footwall Rocks of the BIF-Hosted Iron Ore Deposits in the Hamersley District, Western Australia     

Makoto Haruna    Takahiro Hanamuro    Kaoru Uyeda    Hirokazu Fujimaki  Hiroshi Ohmoto 《Resource Geology》2003,53(2):75-88

Abstract. The petrography, chemical, fluid inclusion and isotope analyses (O, Rb-Sr) were conducted for the shale samples of the Mount McRae Shale collected from the Tom Price, Newman, and Paraburdoo mines in the Hamersley Basin, Western Australia. The Mount McRae Shale at these mines occurs as a footwall unit of the secondary, hematite-rich iron ores derived from the Brockman Iron Formation, one of the largest banded iron formations (BIFs) in the world. Unusually low contents of Na, Ca, and Sr in the shales suggest that these elements were leached away from the shale after deposition. The δ¹⁸O (SMOW) values fall in the range of + 15.0 to +17.9 per mil and show the positive correlation with calculated quartz/sericite ratios of the shale samples. This suggests that the oxygen isotopic compositions of shale samples were homogenized and equilibrated by postdepositional event. The pyrite nodules hosted by shales are often rimmed by thin layers of silica of varying crystallinity. Fluid inclusions in quartz crystals rimming a pyrite nodule show homogenization temperatures ranging from 100 to 240C for 47 inclusions and salinities ranging from 0.4 to 12.3 wt% NaCl equivalent for 18 inclusions. These fluid inclusion data give direct evidence for the hydrothermal activity and are comparable to those of the vein quartz collected from the BIF-derived secondary iron ores (Taylor et al, 2001). The Rb-Sr age for the Mount McRae Shale is 1,952 ± 289 Ma and at least 200 million years younger than the depositional age of the Brockman Iron Formation of ∼ 2.5 Ga in age. All the data obtained in this study are consistent with the suggestion that high temperature hydrothermal fluids were responsible for both the secondary iron ore formation and the alteration of the Mount McRae Shale.  相似文献   

早元古代滹沱群玄武岩Rb-Sr、Sm-Nd同位素体系初论     

王汝铮 《华北地质》1997,(1)

本文给出的滹沱群下亚群青石村组玄武岩Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ全岩等时线年龄为２０４５．８±１７和２３６９±３０Ｍａ（Ｚ），角门石４０Ａｒ－３９Ａｒ坪年龄和最高视年龄为１３６４±１９和１９３２±１９Ｍａ（１）；中亚群河边村组玄武岩Ｒｂ－Ｓｒ全岩等时线年龄图的投点呈完全离散状，Ｓｍ－Ｎｄ全岩等时线年龄为２３２２±３１Ｍａ（２），角门石４０Ａｒ－３９Ａｒ坪年龄和最高视年龄为１３６０和１７４２±１７Ｍａ（１）。根据上述Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ数据与已知青石村组、河边村组单颗粒锆石Ｕ－Ｐｂ法确定的成岩年龄２４５０±１０和２４００±２０Ｍａ（２）的明显差别，４０Ａｒ－３９Ａｒ均揭示为较典型受扰动的年龄谱和较发育的透人性构造、晚期岩脉等地质证据，认为Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ是重设的同位素体系。  相似文献   

冀西北东坪金矿床含金石英脉石英流体包裹体Rb-Sr等时线及其地质意义   总被引：8，自引：2，他引：8  

莫测辉  王秀璋  程景平  梁华英 《地球化学》1997,26(3):20-27

用石英流体包裹体Ｒｂ－Ｓｒ等时线法测得产于碱性岩体中具有超大型潜力的东坪金矿床含金石英脉的年龄为（１０３±８）Ｍａ，远晚于赋矿岩体的就位时间（元古宙），显示了成岩与成矿是两期不同构造运动的产物，两者之间没有直接的成因联系。８７Ｓｒ／８６Ｓｒ示踪结果显示成矿物质主要来源于赋矿碱性岩体。研究结果认为，东坪金矿是后期与大气降水热液有关的改造成矿作用的产物。  相似文献