共查询到16条相似文献，搜索用时 156 毫秒
1.
2.
3.
研究剩余电磁效应的理想参数 总被引：2，自引：0，他引：2
在频谱激电法中利用剩余电磁效应(REM)研究地下电性分布已引起人们的重视。本文基于对数值计算结果的分析指出,选择适当高频fG,以偶极装置观测视复电阻率的相位φs0(fG),用相应条件下均匀大地的视复电阻率相位理论值(fG)对其作归一,所得比值参数φs0(fG)/(fG)是表示剩余电磁效应的理想参数。文中还结合数值计算结果和野外实测资料,分析了这一参数的异常特征和在油气探测中的应用效果。 相似文献
4.
在实际工作中,由于盲矿体与距离有限的中梯装置两个供电电极之间相互位置的原因,往往使得地下盲矿体实际处于某种非水平均匀极化条件之下,这就使所获得的ηs曲线以及由于移动供电电极获得的ηs曲线接头发生了不同程度的畸变。本文通过模拟激电中梯通常采用的装置形式,以体极化球体为例,运用点电源场公式计算其主剖面上的中梯ηs曲线及其接头来对上述畸变进行分析和讨论。本文还提出了在处理中梯ηs观测资料时应该注意的问题以及对推广激电ηs全域测量法的认识意见。 相似文献
5.
6.
山区找水的“相对衰减时法”探讨 总被引：1，自引：0，他引：1
实测资料表明,二次电场衰减时与视电阻率关系点分布区的下限存在正向密切区间、反向密切区间和不密切区间,即衰减时与视电阻率关系十分密切.忽视视电阻率的变化,有可能造成激电找水效果上的失误.针对衰减时与视电阻率关系的区间特性,我们采用“相对衰减时”的概念作为激电找水的含水因素(相对衰减时SR＝ρS/s).采用该参数的实际意义在于反向密切区间突出了含水异常,正向密切区间消除因极距增大引起的非水异常.因此,相对衰减时在研究山区地下水的富集情况时灵敏度较高.应用相对衰减时法在不同水文地质条件的山区找水中,取得了较好的效果,特别是在我国著名的玫瑰泉地下水工程中,在电阻率法和常用的衰减时法解释推断有困难时,能比较准确地确定了富水区,成井后获得水量6万t/d,建成大型农业地下水源地. 相似文献
7.
8.
拉萨地块中北部晚白垩世(约90Ma)拔拉扎含矿斑岩地球化学特征及其成因 总被引：8，自引：3，他引：5
拉萨地块中北部形成于90~88Ma的拔拉扎含矿斑岩具有明显的埃达克质岩特征:高SiO2(>69%)、Al2O3(平均为15.89%)、Sr (平均为354×10-6),低Y(平均为12.97×10-6)、Yb(平均为0.95×10-6)含量,轻重稀土强烈分异((La/Yb)N平均为19.8);同时它们有着高Mg#(平均为65)、Cr(平均为107×10-6)、Ni(平均为13×10-6)含量。研究区这些具有埃达克质岩特征的含矿斑岩并非源于俯冲洋壳、底侵或加厚下地壳部分熔融的产物,也不是玄武质岩浆结晶分异的产物,而很可能是拆沉下地壳部分熔融的结果。另一方面,南向俯冲的Slainajap洋壳或班公湖-怒江洋壳的断离也可能诱发板片窗上部的壳幔物质发生部分熔融而形成研究区的含矿斑岩。 相似文献
9.
82年9月至84年8月,浙江北部和平三矿地区投入激电(中梯)测量、激电测深法和磁法以及地球化学土壤测量等方法,对硼矿及多金属矿进行普查。钻孔验证结果表明,据ZK104、ZK105等孔的见矿厚度和品位,预测硼矿体的规模达到小型至中型矿床。物探方法在本区找硼矿中取得明显效果。 相似文献
10.
福建马坑矽卡岩型铁(钼)矿床稀土元素地球化学及地质意义 总被引：1，自引：0，他引：1
马坑铁(钼)矿是一个赋存于莒舟-大洋花岗岩外接触带黄龙组(C2h)灰岩和林地组(C1l)碎屑岩层间构造破碎带中的大型铁矿床。本文利用电感耦合等离子体质谱法(ICP-MS)对马坑的石榴子石、辉石、黄铁矿和磁铁矿矿石的稀土元素(REEs)开展研究。结果表明:石榴子石、辉石和磁铁矿单矿物的稀土分配模式具有相似性,多为轻稀土富集,正铕异常,基本无铈异常,表明其成矿环境为氧化环境,暗示它们之间存在成因联系。矿体附近大理岩和退化蚀变岩稀土元素特征出现规律性变化,表明它们受到岩浆期后热液的交代作用的影响,碎屑岩和褪色辉绿岩提供了部分铁质。 相似文献
11.
作者将奇异谱分析(SSA)引入第四纪古气候变化研究中,收到了较好的效果。奇异谱分析是一种新的时间序列分析工具,它可形成一个单边(向前)滤波器,将原时间序列有效地分解成各个主成分,其滤波系数完全由数据本身决定。由奇异谱分析确定的统计维,给出动力维上界的估计,为非线性动力学研究打下基础。分析表明,在整个第四纪,宝鸡黄土粒度曲线的统计维为19,与深海钻孔V28-239氧同位素分析结果(=18)十分接近;各主成分在地球轨道几何参数各成分中大都能找到对应关系,但均不是线性响应关系;与偏心率、地轴倾斜度和岁差有关的成分分别占46、43和6％左右;其中第一主成分还揭示出与偏心率约0.4Ma周期对应的振荡仅在2.5—1.7和0.7—0.3Ma B.P.出现。 相似文献
12.
从研究激电场频谱特征及充、放电时间特征出发,根据实验观测结果,总结了硫化物矿化体(黄铜矿)及含石墨白云质大理岩等岩性的频谱特征及充放电时间特征,探索到新的定性评价激电异常源参数——频率谱及时间谱、视衰减速度。实践证明,利用频率谱定性评价硫化物矿化体(黄铜矿)与含石墨白云质大理岩激电异常源取得较佳效果。 相似文献
13.
IP找水与DDJ-1型仪器野外数据采集 总被引：7，自引：2，他引：5
用DDJ-1型多功能激电仪对IP法二次场的长延续时段采集,可提高观测数据质量和判断数据采集的可靠性,因而观测到了反映第二层为相对高极化率的三层"K"型极化率曲线. 相似文献
14.
Abstract: There were huge life and property losses during the Ms8.0 Wenchuan earthquake on May 12, 2008. Strain fluctuation curves were completely recorded at stress observatory stations in the Qinghai-Tibet plateau and its surroundings in the process of the earthquake. This paper introduces the geological background of the Wenchuan earthquake and the profile of in-situ stress monitoring stations. In particular, data of 174 earthquakes (Ms4.0-Ms8.5) were processed and analyzed with various methods, which were recorded at the Shandan station from August 2007 to December 2008. The results were compared with other seismic data, and further analyses were done for the recoded strain seismic waves, co-seismic strain stepovers, pre-earthquake strain valleys, Earth’s free oscillations before and after the earthquake and their physical implications. During the Wenchuan earthquake, the strainmeter recorded a huge extensional strain of 70 seconds, which shows that the Wenchuan earthquake is a rupture process predominated by thrusting. Significant precursory strain anomalies were detected 48 hours, 30 hours, 8 hours and 37 minutes before the earthquake. The anomalies are very high and their forms are very similar to that of the main shock. Similar anomalies can also be found in strain curves of other shocks greater than Ms7.0, indicating that such anomalies are prevalent before a great earthquake. In this paper, it is shown that medium aftershocks (Ms5.5-6.0) can also cause Earth’s free oscillations. Study of free oscillations is of great significance to understand the internal structure of the Earth and focal mechanisms of earthquakes and to recognize slow shocks, thus providing a scientific basis for the prevention and treatment of geological disasters and the prediction of future earthquakes. 相似文献
15.
L. A. Yakovina G. A. Polinovskii Ya. V. Pavlenko M. K. Kuznetsov 《Astronomy Reports》2017,61(1):53-69
The evolutionary status of the bright peculiar carbon giant TU Gemis fairly uncertain. The possibility that this is aCH star—aGalactic halo star with characteristic chemical-composition anomalies—is considered. Unfortunately, data on the atmospheric chemical composition of TUGem are relatively few and are ambiguous. The results of an analysis of a moderate-resolution optical and near-infrared spectrum of TU Gem obtained on the 2-m telescope of Terskol Peak Observatory (Northern Caucasus) is presented. The atmospheric parameters of TU Gem T eff = 3100 K, C/O = 1.10, and [N/Fe] = 0.0 for the derived metallicity [Fe/H] = 0.0 are taken from [1]. The abundances of Na, Mg, Ca, Ti, and Cr are estimated to be normal or slightly enhanced, and the lithium abundance is log N(Li) = +0.1. The abundances of s-process elements are substantially enhanced in the atmosphere of TU Gem, namely, [s/Fe] ≈ 2, for both light and heavy s-process elements. The range of uncertainty in [Fe/H] is 0.0?0.3, and the uncertainties in other estimates are Δ[M/Fe]≈ ±0.3 and Δ[s/Fe] = ±0.5. The results show that TU Gem is an anomalous carbon giant, but not a CH star. 相似文献
16.
We determine detailed 3-D Vp and Vs structures of the crust and uppermost mantle beneath the Kyushu Island, southwest Japan, using a large number of arrival times from local earthquakes. From the obtained Vp and Vs models, we further calculate Poisson’s ratio images beneath the study area. By using this large data set, we successfully image the 3-D seismic velocity and Poisson’s ratio structures beneath Kyushu down to a depth of 150 km with a more reliable spatial resolution than previous studies. Our results show very clear low Vp and low Vs anomalies in the crust and uppermost mantle beneath the northern volcanoes, such as Abu, Kujyu and Unzen. Low-velocity anomalies are seen in the mantle beneath most other volcanoes. In contrast, there are no significant low-velocity anomalies in the crust or in the upper mantle between Aso and Kirishima. The subducting Philippine Sea slab is imaged generally as a high-velocity anomaly down to a depth of 150 km with some patches of normal to low seismic wave velocities. The Poisson’s ratio is almost normal beneath most volcanoes. The crustal seismicity is distributed in both the high- and low-velocity zones, but most distinctly in the low Poisson’s ratio zone. A high Poisson’s ratio region is found in the forearc crustal wedge above the slab in the junction area with Shikoku and Honshu; this high Poisson’s ratio could be caused by fluid-filled cracks induced by dehydration from the Philippine Sea slab. The Poisson’s ratio is normal to low in the forearc mantle in middle-south Kyushu. This is consistent with the absence of low-frequency tremors, and may indicate that dehydration from the subducting crust is not vigorous in this region. 相似文献