滨海多层含水层系统中海潮引起的地下水位波动     

郭巧娜  李海龙  夏玉强  李国徽 《地下水》2007,29(2):27-31

通过对一个滨海多层含水层系统的考察,该含水层系统由上、下弱透水层和介于中间的承压含水层组成,海底露头处被淤泥层覆盖.建立了描述该系统中地下水水头随潮汐波动的数学模型,并得到其解析解.该解析解与六个基本参数有关,分别是承压含水层的海潮传播参数,淤泥层的无量纲透水系数,上下弱透层与承压含水层贮水率的比率 (无量纲)和上下弱透层的无量纲越流.当这些参数取某些特殊值时,我们的解便化简为前人考虑的几种简单情形对应的解.分析表明,承压含水层中地下水水头波幅是上、下弱透水层贮水率和越流系数的减函数,是淤泥层相对透水系数的增函数;波动相位(时滞)是上、下弱透水层贮水率和越流系数的增函数,是淤泥层相对透水系数的减函数.  相似文献   

萃取富集-火焰原子吸收法测定碳酸钙中铅和镉     

黄俭惠  邱丽 《矿产与地质》2007,21(4):479-481

将碳酸钙试样用盐酸溶解后,在0.6mol/L的盐酸介质中,用KI-MIBK萃取试样中微量的铅和镉,有机相用原子吸收分光光度法测定。该方法测定铅的相对标准偏差为2.38%-6.31%,回收率为96.5%-97.0%;测定镉的相对标准偏差为4.50%-5.52%,回收率为96%-102.8%。结果可靠,具有灵敏、准确、快速、选择性好等优点。适用于碳酸钙中铅、镉的测定。  相似文献   

贵州兴仁滥木厂汞铊矿床矿物扫描电镜研究   总被引：2，自引：0，他引：2  

张杰  孙传敏  张宝贵  杨恩林 《矿物学报》2007,27(3):505-510

贵州兴仁滥木厂汞、铊矿床，矿体主要产出于上二叠龙潭组和长兴组泥岩、灰岩、泥质灰岩、硅质岩、煤岩和碳质页岩等混杂岩系。利用扫描电子显微镜及能谱分析等研究手段，对该矿床的物质组成、矿物成分特征及微观特征进行了探讨，为成矿元素汞、铊的赋存状态，生物成矿特征研究等提供矿物学资料。  相似文献   

楚雄龙岗地区超级不整合与金成矿     

郑明秋  谢先柏  李才先 《云南地质》2007,26(4):397-403

龙岗地区陇川运动-华力西运动间造成整个古生代地层缺失，中上三叠统直接覆于下元古界哀牢山岩群、大红山岩群等基底岩系之上，本文称为“超级不整合”。华力西期-喜马拉雅期历次地壳事件在“超级不整合”接触带形成“矿质”的“浪淘砂”式、叠次‘堆积’作用，对该区金成矿有决定性作用，先后发现小水井与大龙潭两个典型金矿床。前者为“地下水热卤水溶滤中低温热液蚀变角砾岩微粒浸染型金矿床”，可类比为“卡林型”；后者为“原生沉积地下热水溶滤中低温热液蚀变砂砾岩微粒-粗粒型金矿床”，为该区首次发现的新类型。  相似文献   

镇康芦子园铅锌矿床特征及成因   总被引：7，自引：0，他引：7  

董文伟  陈少玲 《云南地质》2007,26(4):404-410

芦子园铅锌矿产于镇康复背斜核部寒武系沙河厂组大理岩、板岩、片岩地层中，沿背斜轴部产生的断层及层间破碎带是主要的容矿构造，成矿物质来源于地层、酸性及基性岩浆热液，矿床成因为沉积-热液改造叠生型铅锌矿床。  相似文献   

2-D Crustal thermal structure along Thuadara-Sindad DSS profile across Narmada-Son lineament,central India   总被引：1，自引：0，他引：1  

S. N. Rai  S. Thiagarajan 《Journal of Earth System Science》2007,116(4):347-355

Central India is traversed by a WSW-ENE trending Narmada-Son lineament (NSL) which is characterized by the presence of numerous hot springs, feeder dykes for Deccan Traps and seismicity all along its length. It is divided in two parts by the Barwani-Sukta Fault (BSF). To the west of this fault a graben exists, whereas to the east the basement is uplifted between Narmada North Fault (NNF) and Narmada South Fault (NSF). The present work deals with the 2-D thermal modeling to delineate the crustal thermal structure of the western part of NSL region along the Thuadara-Sindad Deep Seismic Sounding (DSS) profile which runs almost in the N-S direction across the NSL. Numerical results of the model reveal that the conductive surface heat flow value in the region under consideration varies between 45 and 47mW/m². Out of which 23mW/m² is the contribution from the mantle heat flow and the remaining from within the crust. The Curie depth is found to vary between 46 and 47 km and is in close agreement with the earlier reported Curie depth estimated from the analysis of MAGSAT data. The Moho temperature varies between 470 and 500°C. This study suggests that this western part of central Indian region is characterized by low mantle heat flow which in turn makes the lower crust brittle and amenable to the occurrence of deep focused earthquakes such as Satpura (1938) earthquake.  相似文献   

Early Paleozoic gabbro-granitoid associations in eastern segment of the Mongolian-Okhotsk foldbelt (Amur River basin): Age and tectonic position     

A. A. Sorokin  A. B. Kotov  E. B. Sal’nikova  N. M. Kudryashov  V. P. Kovach 《Stratigraphy and Geological Correlation》2007,15(3):241-257

Magmatic rocks of the Pikan and Un’ya massifs situated in eastern segment of the Mongolian-Okhotsk foldbelt are studied using isotopic-geochronological (U-Pb zircon dating) and geochemical methods. Two rock complexes different in age are recognized in the Pikan massif: the high-Al gabbro-tonalite association of the Middle Ordovician (468 ± Ma) and granodiorite-granite association of the Late Silurian-Early Devonian (415 ± 7 Ma). The Late Ordovician age (454 ± 5 Ma) is established for leucocratic granites of the Un’ya massif. As is suggested, the Pikan and Un’ya massifs are “allogenic blocks” detached from continental framework of the Mongolian-Okhotsk foldbelt and tectonically emplaced into the foldbelt structure at the last stage of its development.  相似文献   

A numerically calibrated reference level (MP28) for the terrestrial mammal-based biozonation of the European Upper Oligocene     

Dieter F. Mertz  Paul R. Renne  Michael Wuttke  Clemens Mödden 《International Journal of Earth Sciences》2007,96(2):353-361

The fauna of the Enspel (Westerwald) and the neighbouring Kärlich (Neuwied basin) fossil deposits correspond to the Upper Oligocene Mammal Paleogene (MP) reference level 28 and 28–30, respectively. Basaltic flows and a trachyte tuff terminating and predating the fossil deposit sedimentation allow to numerically calibrate the MP reference levels by radioisotope dating. Laser fusion ⁴⁰Ar/³⁹Ar step heating on volcanic feldspars yield a time interval of 24.9–24.5 Ma for reference level MP28 at Enspel and a maximum age of 25.5 Ma for the time interval MP28–MP30 at Kärlich. Interpolation between the time intervals determined for the Enspel reference level MP28 and the age of the global Oligocene/Miocene boundary of 24.0 ± 0.1 Ma taken from literature results in time intervals of 24.5–24.2 Ma and 24.2–23.9 Ma for the younger reference levels MP29 and MP30, respectively. These intervals of ≤ 0.4 m.y. for MP reference levels of the latest Oligocene are short relative to older Oligocene MP reference levels 21–27 between 34 and 25 Ma. Since subdivision into MP reference levels essentially is based on assemblages of mammal taxa and on evolutionary changes in tooth morphology of mammals short MP time intervals during the latest Oligocene indicate a rapid evolutionary change relative to the early Oligocene.  相似文献   

X-ray diffraction investigation of native Si-Fe alloy minerals from Luobusha, Tibet     

Li Guowu  Shi Nicheng  Xiong Ming  Ma Zhesheng  Bai Wenji  Fang Qingsong 《Frontiers of Earth Science》2007,1(1):21-25

The origin of native Si-Fe alloy mineral is thought to be related with mantle and aerolite. The native Si-Fe alloy minerals from podiform chromites of the Luobusha ophiolite in the Yarlong Zangbo suture zone were examined by a new method for powder-like diffractograms of small single crystals, using an SMART APEX-CCD area-detector X-ray diffractometer. The powder diffraction pattern shows that the minerals are composed of FeSi, FeSi₂, β-FeSi₂ and native silicon. The association of these minerals suggests that the crystallization order of the mineral may be from early to late FeSi→FeSi₂→native silicon, accompanied by gradually increasing deoxidization. Translated from Acta Petrologica et Mineralogica, 2005, 24(5): 453–456 [译自: 岩石矿物学杂志]  相似文献   

COSMOGENIC ¹⁰BE-AGES FROM THE STORE KOLDEWEY ISLAND, NE GREENLAND     

LENA HÅKANSSON  ANGELA GRAF  STEFAN STRASKY  SUSAN IVY-OCHS  PETER W. KUBIK  CHRISTIAN HJORT  CHRISTIAN SCHLÜCHTER 《Geografiska Annaler: Series A, Physical Geography》2007,89(3):195-202

Earlier work in northeast Greenland has suggested a limited advance of the Greenland Ice Sheet during the Last Glacial Maximum (LGM). However, this concept has recently been challenged by marine geological studies, indicating grounded ice on the continental shelf at this time. New ¹⁰Be‐ages from the Store Koldewey island, northeast Greenland, suggest that unscoured mountain plateaus at the outer coast were covered at least partly by cold‐based ice during the LGM. It is, however, still inconclusive whether this ice was dynamically connected to the Greenland Ice Sheet or not. Regardless of the LGM ice sheet extent, the ¹⁰Be results from Store Koldewey add to a growing body of evidence suggesting considerable antiquity of crystalline unscoured terrain near present and Pleistocene ice sheet margins.  相似文献