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1.
从区域构造入手,对单侯井田构造进行分析,认为井田内断层发育以走向NW—NE、落差≤5m的小型正断层为主,且主要分布于大中型构造的两侧.特别是在其弧形转折带附近往往形成“羽”状雁列的小断层密集带。断层垂向上多分布于4—7号煤层之间的厚煤层发育区,其严重破坏了煤层的连续及完整性,是影响煤层开采的最主要因素之一。井田褶皱构造相对不发育,以短轴小型背、向斜为主,均属缓波状褶曲,对煤层的开采无影响或影响较小。根据井田地质构造发育程度,对其进行预测及分区评价:井田东部为强烈的构造挤压带,以发育走向NW-近EW—NE向的大型逆掩断层为特点,构造最复杂;井田西北部是相对较轻微的构造挤压带,以发育走向NE向的逆断层为特征,构造较复杂;井田南部以发育近SN或NNW向正断层为主,构造相对简单。评价结果对矿井设计及采区与工作面布置有一定的指导作用。  相似文献   
2.
Iron-reducing activity of autochthonous bacteria from two temporary hydromorphic soils is evaluated by the study of iron reductive dissolution, as a function of water content. The release of ferrous iron in solution is coupled to the mineralization of soil organic carbon. Water soil saturation is not necessary for iron reductive dissolution, since the highest dissolution is obtained for a wet, but not water-saturated soil (100% of water holding capacity WHC), and dissolution is also very high in a soil at 75% WHC. To cite this article: S.J. Stemmler et al., C. R. Geoscience 336 (2004).  相似文献   
3.
The unexplored area of Azarhare in central Morocco is studied thanks to three sections composed of five lithological facies Main biostratigraphical and sedimentological results concern (1) the identification of Late Visean biozones, with important presence of problematic algae Ungdarella, (2) the regional extension of deposit sequences SD5, SD6 and SD7 previously defined, (3) and an analysis of the diagenetic kaolinite. To cite this article: A. Karim et al., C. R. Geoscience 337 (2005).  相似文献   
4.
斜列状的断裂、裂隙的排列组合,其中往往充填岩脉或矿脉,被称之为雁列或斜列构造。在内生脉状多金属矿床平面或剖面上,矿脉常出现斜列状排列的组合特征,关于它们的组合型式,特别是从空间上及定位分布规律方面,尚缺乏深入的研究。本文依据构成斜列型式的几个主要几何要素之间的关系将其划分为三种类型,进行了斜列构造型式空间定位分布特征的研究及其对隐伏矿脉预测意义的探讨。  相似文献   
5.
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.  相似文献   
6.
Abstract

Some unique coupled wind–water erosion processes exist in the desert-loess transitional zone in the middle Yellow River basin. Based on data from 40 stations on 29 rivers, a study was made on the influence of such processes on suspended sediment grain-size characteristics of the tributaries of the Yellow River. Results show that the percentage of >0.05-mm grain size decreases with the increased annual mean precipitation, but increases with the increase in the annual mean number of sand-dust storm days. The percentage of <0.01-mm grain size increases with the increase in the annual mean precipitation, but decreases with the increase in the annual number of sand-dust storm days. Based on annual mean data from 40 stations, multiple regression equations were established between the percentages of >0.05-mm grain size (r >0.05) and <0.01-mm grain size (r <0.01), annual mean precipitation (P m) and annual mean number of sand-dust storm days (D ss). On this basis, the relative contributions of the variations in D ss and P m to the variation in r >0.05 and r <0.01 were estimated. The results indicate that the variation in sand-dust storm frequency exerts greater influences on the variation in grain-size characteristics of suspended load than does the variation in annual mean precipitation. With the increase in the coupled wind–water processes index, expressed by P m/D ss, the percentage of >0.05-mm grain size in suspended sediment decreases and the percentage of <0.01-mm grain size increases. With the variation in P m/D ss, different combinations of r >0.05 with r <0.01 appear, which have some influence on the formation of hyperconcentrated flows. There exist some optimal ratios of coarse to fine fractions in suspended sediment that make sediment concentrations of hyperconcentrated flows the highest. The optimal r >0.05/r <0.01 value is related to some range of the index P m/D ss. When the P m/D ss index falls in this range, the optimum combination of relative coarse with fine sediments in the suspended load appears, and thus results in the peak values of sediment concentration.  相似文献   
7.
莺歌海盆地是发育在古红河断裂带之上的新生代盆地,晚第三纪的构造运动触发了盆地中热流体自超压封存箱向外大规模突破,使热流体及泥质的活动具有规律性成群成带的特征。本次实验基于相似理论,在对盆地的演化史及区域构造应力场充分分析的基础上,进行了晚第三纪盆地构造应力场的三维泥料模拟,证实了红河断裂右旋走滑派生的拉分效应控制了莺歌海盆地晚第三纪的构造活动,而晚第三纪的构造活动又是雁列式断裂展布及底辟体分布的主导因素。  相似文献   
8.
断层失稳错动热场前兆模式:雁列断层的实验研究   总被引:14,自引:4,他引:14       下载免费PDF全文
在实验室使用红外热像仪和接触式测温仪同步观测记录了压性和张性雁列断层失稳错动前后的热场变化过程.从实验记录中发现,在断层失稳引起温度场和热红外辐射亮温温度场上升之前,在两断层段之间的岩桥区发生降温变化.断层带开始升温发生在失稳前2~3 s内,岩桥区的降温却发生在失稳前约20s,这两个超前时间长度相差近一个量级.此类热场先降后升变化过程在雁列构造变形中有一定的普遍性,可能作为雁列断层失稳错动的热场前兆模式.根据实验观测结果,详细描述了上述热场变化的时间过程及其空间分布特征,分析了产生此种失稳前兆模式的机制,显著异常出现的条件及有利观测部位,讨论了它在地震前兆探索等研究中的意义.  相似文献   
9.
博格达山北麓山前断裂西段全长140 km ,由5 条雁列状排列的逆断裂组成。全新世时期,古牧地断裂的最新活动发生在6.82±0.54~4.87±0.39 Ka B.P.之间;四工河口断裂切割Ⅱ级河流阶地,最新活动时间与古牧地断裂大体相同;泉泉子断裂切割Ⅰ级河流阶地,最新活动发生在3.75±0.41 Ka B.P.;热水河断裂及东风牧场断裂由于缺乏断代年龄实测数据,无法对其最新活动时间作出判断,但是推断它们也是全新世活断裂  相似文献   
10.
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