幕阜山西南缘黄柏山稀有金属伟晶岩密集区的发现及意义   总被引：1，自引：1，他引：0  

李鹏  李建康  张立平  黄志飚  刘翔  周芳春  曾乐 《矿床地质》2019,38(5):1069-1076

幕阜山地区是中国重要的稀有金属矿集区。中国地质科学院矿产资源研究所与湖南省核工业地质局三一一大队在总结区域稀有金属成矿规律的基础上,于2019年度在幕阜山西南缘黄柏山地区新发现稀有金属伟晶岩密集区一处。区内伟晶岩呈现出良好的铌钽锂成矿性,易于开采、分选及运输,具有较高的经济价值。区域伟晶岩具较高的岩浆分异演化程度,且呈现出较为清晰的稀有金属矿化分带,具有良好的成矿潜力。  相似文献   

微生物沉积碳酸钙固化砂质黏性紫色土试验研究   总被引：1，自引：0，他引：1  

沈泰宇  汪时机  薛乐  李贤  何丙辉 《岩土力学》2019,40(8):3115-3124

重庆紫色土是一种砂质黏性土,地区降雨集中,水力冲蚀作用剧烈,极易产生水土流失,微生物诱导方解石沉积(MICP)技术因能耗低、污染小而广泛应用于土体加固中。通过正交试验优化了巨大芽孢杆菌(BNCC 336739)的培养基和培养条件,活菌数增长126%,活性良好。采用巨大芽孢杆菌,进行低水压(9.8kPa)灌注固化砂质黏性紫色土试验,探究了固化效果的变化规律。结果表明:随固化次数增加,碳酸钙生成量和干密度逐级增加,无侧限抗压强度与碳酸钙生成量正相关;碳酸钙有效沉积越来越少,强度提高趋于稳定,固化9次后强度提高77%;随孔隙被碳酸钙填充和上下碳酸钙硬壳的形成,渗透性不断降低,最终下降两个数量级;通过试样上、中、下三部分碳酸钙生成量C的样本标准差s来反映碳酸钙分布离散程度,发现割线弹性模量在s的影响下随C增加而波动上升,波动表现为在C相近或s相差很大时,s越小割线弹性模量越大。研究成果可以为MICP技术在紫色土地区的地基、边坡加固和水土流失防护等工程应用提供科学依据和参考。  相似文献   

塔中Ⅲ区碳酸盐岩储层去泥质反演及泥质充填判别     

华晓琴  史乐  梁涛  赵文苹 《新疆地质》2019,(1):90-95

塔里木盆地塔中Ⅲ区奥陶系碳酸盐岩储层是近年来勘探重点区域,良里塔格组储层内沉积泥质灰岩条带,以及一间房组洞穴顶部存在的沉积泥质条带,给储层预测带来了较大难度。为提高储层预测精度,分析奥陶系良里塔格组和一间房组储层内泥质展布规律,建立沉积泥质灰岩条带背景纵波阻抗体,完成了无井约束叠后地质统计学反演。研究结果表明,无井反演储层预测纵向发育位置、储层级别和已钻井吻合较好。利用叠前同时反演得到纵横波速比,通过纵波阻抗与纵横波速比交会图分析法,划分了一间房组优质储层、泥质充填储层、基质灰岩分布区间,对洞穴型储层泥质充填、叠前流体预测反演进行探索,确保储层预测的可靠性。  相似文献   

探地雷达技术对表层岩溶带典型剖面组构刻画与界面识别   总被引：1，自引：0，他引：1  

高强山  彭韬  付磊  王世杰  曹乐  程倩云 《中国岩溶》2019,38(5):759-765

表层岩溶带是岩溶研究的重要对象,以往研究以剖面调查半定量为主,文章利用探地雷达属性技术对其发育情况进行定量研究。选取3个表层岩溶带的典型剖面（浅裂隙土、深裂隙土、厚土层覆盖）,并采集探地雷达数据,通过提取相干体属性和均方根振幅属性来挖掘雷达数据中的潜在信息,用于区分介质组构和识别发育深度界面。结果表明,均方根振幅属性较好地区分出了浅裂隙土型和深裂隙土型的岩土介质,厚土层覆盖型的犁耕层与非犁耕层土壤介质;相干体属性能较好地识别出表层岩溶带和下部完整基岩,定量化其发育厚度。   相似文献   

Stratification and water mass formation in the Arctic Ocean: some implications for the nutrient distribution   总被引：1，自引：1，他引：0  

Burt Rudels  Anne-Marie Larsson  Per-Ingvar Sehlstedt 《Polar research》1991,10(1):19-32

The mixing processes and the water formations (transformations) in the Arctic Ocean are reviewed and their influence on the stratification discussed. The relations between the stratification and the nutrient distribution are examined. The interactions between drifting sea ice and advected warmer and nutrient-rich waters favour an early biological activity. By contrast, in the central Arctic Ocean and over comparably deep shelf areas such as the northern Barents Sea, the possibilities for large productivity are more limited because of late melting, less nutrient supply, and in the central Arctic, less available light. The sedimentation of organic matter on the shelves and the remineralisation into cold, dense waters formed by brine rejection and draining off the shelves lead to a loss of nutrients to the deep waters, which must be compensated for by advection of nutrient rich waters to the Arctic Ocean.
Possible effects of a reduction of the river run-off on the stratification and the nutrient distribution are discussed.  相似文献   

First results obtained with DENIS     

E. Copet  B. De Batz  N. Epchtein  P. Fouqué  F. Lacombe  T. Le Bertre  D. Rouan  D. Tiphène  J. Borsenberger  S. Kimeswenger 《Astrophysics and Space Science》1994,217(1-2):25-26

We briefly report on the first astronomical results obtained with the DENIS camera at the ESO 1 meter telescope.  相似文献   

A study of shallow global mantle flow due to the accretion and subduction of lithospheric plates     

E. M. Parmentier  J. E. Oliver 《Geophysical Journal International》1979,57(1):1-21

Summary. Models of shallow, global mantle circulation due to the accretion and subduction of lithospheric plates are formulated as potential theory problems on a sphere. Subducting and accreting plate boundaries represent sources and sinks respectively for the sublithospheric flow. Solutions, which are obtained by finite difference approximations, give the instantaneous flow velocities within the asthenosphere compatible with plate boundaries and relative plate motions. Results are presented for present-day plate boundaries and relative plate motions for the case of a uniform viscosity asthenosphere and for that of a low viscosity zone at the base of the lithosphere. These results are discussed in terms of available geophysical data. Some of the implications of a shallow, mantle-wide circulation are also considered.  相似文献   

Vereinfachte Berechnung der Radioaktivität und der zugehörigen Streuung (inkl. Vertrauensintervall und Vertrauensgrenzen) mit Hilfe eines speziellen Rechenschiebers und passender Rechentabellen     

M. M. Bezzegh-Galántai  H. L. Le Roy 《Aquatic Sciences - Research Across Boundaries》1965,27(2):368-376

  相似文献   

Dynamics of an Abra alba population (bivalve-scrobiculariidae) in the Bay of Brest     

C. Hily  H. Le Bris 《Estuarine, Coastal and Shelf Science》1984,19(4):463-475

The Abra population studied, lived in a muddy-sand Melinna palmata community in the vicinity of the harbour of Brest. There were two periods of spawning in the year: June to August and end of autumn. Individuals 12 mm long can spawn after the first winter. Recruitment was regularly observed in 1 mm mesh sieves in May and September–October. Growth rings were formed in winter; a second growth ring in summer was correlated with spawning. The modal analysis showed a decreasing growth rate and maximum length for the successive cohorts over the three years surveyed. Growth characteristics observed in this population seem to be due to disturbances brought about by neighbouring dredgings which had just ended at the beginning of the study.  相似文献   

Remarks on the homogeneity of a sample used to determine the Hubble parameterH 0     

Gérard Le Denmat 《Astrophysics and Space Science》1976,45(1):159-161

In a recent series of papers, Sandage and Tammann reach the conclusion according to which the Hubble constant is everywhere the same. This result arises from the analysis of two samples (a nearby one and a remote one) of Sc-type galaxies, each sample separately giving the same <H ₀> mean value. We attempt to check whether or not the whole data from both the samples together are consistent with theH ₀=constant hypothesis at a suitable level of statistical significance.  相似文献