西南三江地区造山演化过程及成矿时空分布   总被引：8，自引：0，他引：8  

骆耀南  俞如龙 《矿物岩石》2001,21(3):153-159

三江地区单凭“一次造山”是难以圆满解释的。本文试以“多次造山”多期成矿”的思路作出合理说明。晚古生代－中生代早期多岛海造山阶段,羌塘弧、江达弧和临沧弧应为前锋弧,其后由一系列弧后盆地和岛弧或残余弧（或微大陆）组成。中生代中－晚期为陆内俯冲造山阶段,推测金沙江带、哀牢山带和龙门山－锦屏山带为俯冲主边界,从而形成本区燕山期重熔型花岗岩带,控制相应矿产的分布特征。新生代陆内转换造山阶段,造成特征的构造－岩浆－成矿带,具有生成大型或超大型矿床的潜力。  相似文献   

DT—1016型阴离子交换树脂分离富集金铂钯   总被引：17，自引：5，他引：17  

甘树才  段太成等 《岩矿测试》2002,21(2):113-116

研究了DT－1016型阴离子交换树脂对超痕量Au,Pt,Pd的吸附性能及条件。在0.025mol/L HCl介质中，流出速度为0.5-1.0mL/min时，Au,Pt和Pd的富集效果最佳，吸附率分别为99.72％，99.06％和97.95％，共存离子无显著性影响。用等离子体质谱测定标准物质中Au，Pt和Pd，其结果与标准值基本相符。检出限Au为0.27μg/L，Pt为0.40μg/L，Pd为0.19μg／L。对GBW 07294铂族元素国家标准物质进行精密度试验，RSD（n=8）Au为19．2％，Pt为28.1％，Pd为15.6％。  相似文献   

Decoupling of arsenic and iron release from ferrihydrite suspension under reducing conditions: a biogeochemical model     

André Burnol  Francis Garrido  Philippe Baranger  Catherine Joulian  Marie-Christine Dictor  Françoise Bodénan  Guillaume Morin  Laurent Charlet 《Geochemical transactions》2007,8(1):12

High levels of arsenic in groundwater and drinking water are a major health problem. Although the processes controlling the release of As are still not well known, the reductive dissolution of As-rich Fe oxyhydroxides has so far been a favorite hypothesis. Decoupling between arsenic and iron redox transformations has been experimentally demonstrated, but not quantitatively interpreted. Here, we report on incubation batch experiments run with As(V) sorbed on, or co-precipitated with, 2-line ferrihydrite. The biotic and abiotic processes of As release were investigated by using wet chemistry, X-ray diffraction, X-ray absorption and genomic techniques. The incubation experiments were carried out with a phosphate-rich growth medium and a community of Fe(III)-reducing bacteria under strict anoxic conditions for two months. During the first month, the release of Fe(II) in the aqueous phase amounted to only 3% to 10% of the total initial solid Fe concentration, whilst the total aqueous As remained almost constant after an initial exchange with phosphate ions. During the second month, the aqueous Fe(II) concentration remained constant, or even decreased, whereas the total quantity of As released to the solution accounted for 14% to 45% of the total initial solid As concentration. At the end of the incubation, the aqueous-phase arsenic was present predominately as As(III) whilst X-ray absorption spectroscopy indicated that more than 70% of the solid-phase arsenic was present as As(V). X-ray diffraction revealed vivianite Fe(II)₃(PO₄)₂.8H₂O in some of the experiments. A biogeochemical model was then developed to simulate these aqueous- and solid-phase results. The two main conclusions drawn from the model are that (1) As(V) is not reduced during the first incubation month with high Eh values, but rather re-adsorbed onto the ferrihydrite surface, and this state remains until arsenic reduction is energetically more favorable than iron reduction, and (2) the release of As during the second month is due to its reduction to the more weakly adsorbed As(III) which cannot compete against carbonate ions for sorption onto ferrihydrite. The model was also successfully applied to recent experimental results on the release of arsenic from Bengal delta sediments.  相似文献   

Erratum to “The Berit transect of the Tauride thrust belt, S Turkey: Late Cretaceous–Early Cenozoic accretionary/collisional processes related to closure of the Southern Neotethys” [Journal of Asian Earth Sciences 27 (2006) 108–145]     

Alastair H.F. Robertson  Timur Ustamer  Osman Parlak  Ulvi Can Ünlügen  Kemal Tal&#x;  Nurdan &#x;nan 《Journal of Asian Earth Sciences》2007,29(5-6):978-980

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Erratum: Geochronology of Late Cenozoic volcanism in the area of Lake Van,Turkey: An example of developmental dynamics for magmatic processes [Doklady earth sciences, 433(2), pp. 1031–1037]     

Lebedev  V. A.  Sharkov  E. V.  Keskin  M.  Oyan  V. 《Doklady Earth Sciences》2010,435(1):1548-1554

An isotope-geochronological study has been performed to examine the products of Late Cenozoic collision volcanism on the northern coast of Lake Van, Turkey. We obtained 45 new K—Ar dates, based on which the principal time characteristics of volcanic activity in the region have been determined. Volcanic activity in the northern coast of Lake Van has lasted ∼15 myr; it has had an expressed discrete nature, when periods of intense volcanic activity alternated with long-lasting pose periods. Four stages of Neogene—Quaternary volcanism have been identified: Middle Miocene (15.0—13.5 Ma), Late Miocene (10—9 Ma), Pliocene (5.8—3.7 Ma), and Quaternary (1.0—0.4 Ma). The average duration of the stages was 1—2 myr; the stages were separated from each other with periods of inactivity of approximately equal lengths (∼3 myr). For each of the Pliocene and Quaternary stages, three additional phases of volcanism have been identified, which were separated from each other with short time intervals (a few hundred thousand years). The last burst of volcanic activity in the study area occurred ∼400 ka; similar to Quaternary volcanism in general, it was not characterized by a high intensity. An important result of the studies performed was to confirm the existence of a separate Middle Miocene stage of collision volcanism for the Caucasian—Anatolian Segment of the Alpine Fold Belt. New geochronological data generated presented in this paper indicate that Neogene—Quaternary volcanism in this portion of the belt started much earlier (∼15 Ma) than assumed by the majority of the previous researchers.  相似文献   

基于VBA的断面图绘制程序的实现     

范亚男  周宇 《测绘信息与工程》2014,(3):68-70

断面测量作为城市测量工作中的重要组成部分,其在市政设计及施工中起着重要作用。断面图作为断面测量工作提交给客户的重要成果资料,占有较大比重。断面图的绘制一般都有业主单位的特殊要求,绘制过程较为复杂,工作量较大。本文从实际工作出发,分析断面图绘制中可以提高效率的部分工作,并设计和编写程序以提高工作效率。  相似文献   

Light variations and flares on V471 tauri     

Z. Tunca  V. Keskin  S. Evren  C. Ibanoglu  M. C. Akan 《Astrophysics and Space Science》1993,204(2):297-304

Two-colour photometric observations of the white-dwarf and K-dwarf eclipsing binary V471 Tau were made during the last four years. The resulting light curves and thirteen timings of mid-eclipse are presented. During the observations two flares were obtained on September 23 and December23, 1992. Both events occurred just after the fourth contact. The increment in the brightness was measured as 0 _. ^m 067. The energy liberated by the flare was computed to be 5.43 × 10³² erg s^–1 in the JohnsonB band, which amounts 1.13 times that of the total radiation of the K-dwarf.  相似文献   

Time-lapse electrical resistivity tomography of a water infiltration test on Johannishus Esker,Sweden     

İnan Ulusoy  Torleif Dahlin  Bo Bergman 《Hydrogeology Journal》2015,23(3):551-566

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Recent photoelectric photometry of the newly discovered eclipsing system BD + 13o4708     

Varol Keskin  M. Can Akan 《Astrophysics and Space Science》1989,155(1):113-123

Two-colour photoelectric photometry of the eclipsing binary BD + 13^o4708 was carried out. Several features such as asymmetry in the branches, light difference between the maxima, an eccentric orbit, a dip around phase 0.2 are distinctive. The new light elements of the system were computed using also the previous times of primary minima given by Walker (1988).  相似文献   

Climate change in Turkey for the last half century   总被引：1，自引：0，他引：1  

Mete Tayanç  Ulaş İm  Murat Doğruel  Mehmet Karaca 《Climatic change》2009,94(3-4):483-502

Climate change and its urban-induced bias in selected Turkish cities is studied with a quality controlled temperature and precipitation data of Turkish stations in the period of 1950–2004. These stations are classified into two groups according to their populations; S1, including rural and suburban stations and S2, including large urban stations. Moving average signals, 365-day, and their digital low pass filtered versions are produced to eliminate the short term fluctuations and examine the possible trends or anomalies in climate data. Furthermore, ‘relative difference’ signals are introduced and applied to temperature and precipitation series to observe the actual local changes in the climate data independent from large-scale effects. Mann–Kendall test statistics are calculated for maximum, minimum, mean temperature and precipitation series and plotted on maps to determine any spatial trend patterns. Signal analysis show a cool period extending from early 1960s till 1993, generally with the lowest temperature values on 1992–1993 owing to the eruption of Mount Pinatubo. A last decade significant warming trend is observed in both of the series, S1 and S2, leading to 2000–2002 temperatures to be recorded as maximums in record history. The variability of urban precipitation series is generally larger than the rural ones, suggesting that urban stations can experience more frequent and severe droughts and floods. Though not significant, an increase in the urban precipitation compared to the rural one is also found. Spatial analysis resulted in significant warming in southern and southeastern parts of the country. Particularly, minimum temperature series show significant warming in almost all of the regions indicating the effect of urbanization. Significant decreases of precipitation amounts in the western parts of Turkey, such as Aegean and Trachea regions, are found. On the other hand, some Turkish northern stations show increases in precipitation of which some are significant.  相似文献