利用井中三分量磁测异常垂直分量及水平分量模差对旁侧异常进行二维拟合计算推断解释

利用井中三分量磁测异常垂直分量ΔZ及合理利用水平分量模差ΔH’值对旁侧异常进行二维拟合反演计算,从而对异常进行推断解释,能有效解决井中旁侧磁性体的赋存情况。该方法用于寻找深部磁性矿体准确性高,地质效果显著。     

在井中磁测工作中利用水平模差找盲矿

在磁性矿区,井中磁测已得到广泛应用.但是我们所使用的井中三分量磁测的仪器定向精度较差,使水平分量出现某些无法解释的“假异常”,特别是在垂直孔中无法整理水平分量的磁异常.因此,在以往的解释工作中,只能单独利用一条垂直分量的曲线进行解释.我们知道,磁场不仅有大小,而且有方向.单个垂直分量对磁异常反映是不全面的,它往往会丢失某些有意义的“磁异常”.为了能够全面地反映异常特征而又不出现“假异常”.目前比较可靠而又行之有效的方法是:以垂直磁异常△Z沉曲线为主,结合水平模差△H′曲线进行解释.例如,当钻孔经过磁测之后要判断井底是否还有矿体存在.此时,我们不能只利用△Z曲线的“开口”异常;而     

运用定量解释方法剖析磁异常——以大板金矿区C6磁异常为例

运用定量解释方法对大板金矿区C₆磁异常进行剖析,查明异常原因,说明在特定条件下,根据物理场特征比较,运用定量解释方法搞清异常体的空间赋存状态(形状、产状、埋深),可以区分矿异常与非矿异常.此外,通过实际应用效果比较,对高磁适用的几种简便、快速的定量解释方法进行了评价,证明三角系解释法是一种简捷、实用、值得推广的方法.     

地面综合物化探方法在航磁异常查证中的应用——以易家湾地区航磁异常为例

在钦杭成矿带湖南省衡山县易家湾初步圈定的航磁异常基础上,通过地面高精度磁测、激电测量、化探测量等综合方法,对航磁异常进行了查证、综合解释及效果评价,提高了航空物探异常解释的科学性和精确性,为该区进行全面的异常分析、评价和进行矿产资源预测提供了借鉴.     

根据实测重力异常换算质体磁异常

为了进行重磁异常对比和综合解释,也为了简化磁异常和场沅位置的关系,人们常常把磁异常转换为磁性体重异常。这方面已发表了很多文章。而将实测重力异常转换为质体沿某一方向磁化时的垂直磁场强度异常,则很少为人所注意。其实,这种转换除能进行重磁异常对比和综合解释以外,还可以起到消除或减弱重力区域异常、突出局部异常的作用。下面将介绍这种转换的原理和方法。     

磁异常矢量倾角法及Za/Ta2、Ha/Ta2比值法

本文提出一种利用磁异常失量倾角这个参量对二度磁异常作定量解释的方法。矢量倾角是T_a(由Z_a、H_a所合成)与测线所夹的角度,其特征可以由其正切即Z_a/H_a值所反映。     

井中三分量磁测数据转换及绘图软件的设计和实现

研究了井中三分量磁测数据转换和绘图的方法,针对轴向系统磁力仪,推导了斜井的三分量磁测原始数据转换公式;基于面向对象的程序设计思想,采用VB 2005开发了一套井中三分量磁测数据转换及绘图软件;利用实际资料对软件进行了综合测试,结果表明,该软件能够快速有效地进行井中三分量磁测数据转换,并根据解释上的需要精确地绘制ΔZ曲线图、ΔH矢量图等磁异常图,完成了井中三分量磁测数据的计算机自动转换及绘图的功能,具有一定的应用前景。     

物探综合方法在吉林省安口镇金矿应用效果

本文着重论述了地球物理勘查方法在吉林省安口镇金矿勘查过程中,从己知区物探方法有效性的确定,到在未知区物探综合异常(视极化率ηs异常,视电阻率ps异常,磁测△Z异常、土壤Au测量异常)解释的应用效果。并用典型矿段的物化采异常特征,建立了地球物理方法在该区找矿模式。     

判别解释法区分磁异常

判别解释法区分磁异常是利用磁性矿床和磁性岩体上的电磁异常特征和表征航磁与航电异常相互关系的相关系数作为特征参数,建立线性判别函数,按一定的运算规则将多变量变成一个新的单变量,并以它作为判别指标,对未知磁异常进行综合评价分类.通过对八个磁异常十三条测线的计算所得的判别值进行判别解释,表明了方法是有效的,能够客观、快速、正确地对磁异常进行综合评价分类.     

应用重磁方法勘查铁矿的效果--以辽宁建昌县马道铁矿为例

文章运用重磁方法以辽宁建昌县马道铁矿找矿为例,说明了重磁法的找矿效果,特别指出重力、磁法的科学组合是勘查评价铁矿、区分磁异常性质、寻找富铁矿的有效综合找矿方法。通过对一磁异常进行重新解释和评价,最终验证该异常为一大型鞍山式沉积变质磁铁矿引起的。同时说明GIS、MRAS计算技术模拟、判别分析等现代先进勘探技术的综合运用,是在老矿山的深部和外围铁矿勘查过程中的重要手段。因此,在对危机矿山的研究中,对如何加深地球物理异常的解释和评价等问题,应予以高度重视。     

An algorithm for finding composition,molar volume and isochors of CO2-CH4 fluid inclusions from Th and Tfm (for Th < Tfm)

A modified Redlich-Kwong equation of state is used to calculate the solubility of CO₂ in methane at various temperatures and pressures. From the solubility of CO₂ in CH₄ at the triple point and at final melting (T_h < T_fm), and the molar volume of solid CO₂, the volume of solid at the triple point, and the molar volume of the inclusion can be calculated using a mass balance. The pressure at the melting point is calculated from the equation of state.The algorithm predicts composition, molar volume, pressure at final melting and the isochor pressure (for a given temperature of trapping) for CO₂-CH₄ fluid inclusions for the case T_h < T_fm, given T_h, T_fm and experimental data on P_h and d_co2 (solid) at T_h.     

K-H3OFe3(SO4)2(OH)6铁矾的XRD研究

根据X射线衍射(XRD)分析发现: A Fe₃(SO₄)₂(OH)₆(A=K⁺、H₃O⁺)系列铁钒的XRD数据十分相近,难以用XRD区别,需通过能谱(EDS)辅助分析,才能区分此类铁矾。另外,此类铁矾的003和107面网间距d随K⁺含量增大而增大,且呈一元三次方程的关系;而033和220面网间距d随K⁺含量增大而减小,呈一元二次方程的关系。对该现象从铁矾晶体结构方面进行解释:K⁺、H₃O⁺离子位于较大空隙中,且沿着Z轴方向排列,当K⁺、H₃O⁺离子之间相互替换时,会导致该铁矾晶体结构在Z轴方向有较明显的变化。     

Actinide crystal-liquid partitioning for clinopyroxene and Ca3(PO4)2

Using fission and alpha track radiography techniques, we have measured partition coefficients (D) for the actinide elements Th, U and Pu between diopsidic clinopyroxene, whitlockite [β-Ca₃ (PO₄)₂] and silicate liquid at 20kbar. Equilibrium partitioning at the crystal-liquid interface is assumed, and corrections for actinide zoning have been applied to the measured D values. Reproducibility for both actinide and minor element D values is carefully examined as a criterion for crystal-liquid interface equilibrium. The data are mostly compatible with interface equilibrium except for experiments at high cooling rates ( ? 30 deg/hr). Partition coefficients for Th/U/Pu of about 0.002/0.002/0.06 are measured for clinopyroxene and 1.2/0.5/3.4 for whitlockite. At an oxygen fugacity of 10^?8.5, Pu is much more readily incorporated into the crystalline phases than is U or Th because of the importance of trivalent Pu. The D_Pu(cpx) is similar to D(cpx) of the light rare earths supporting the concept of Pu/(rare earth) dating.     

异构比φiC4 /φnC4 和φiC5 /φnC5 的石油地质意义

同分子量的正构烷烃和异构烷烃存在着物理化学性质差异,在运移过程中受围岩的物理化学性质及其它外部因素的影响必然产生分异效应,从而使二者在空间分布上具有一定的特征和规律,异构比指标可以在一定程度上反映出这种特征和规律性。用异构比φ_iC4 /φ_nC4 和φ_iC5 /φ_nC5 指标可以判断有机质的成熟度,研究轻烃运移的途径、方向、生成环境及轻烃的生物降解。     

Seawater temperature proxies based on DSr, DMg, and DU from culture experiments using the branching coral Porites cylindrica

In order to investigate the incorporation of Sr, Mg, and U into coral skeletons and its temperature dependency, we performed a culture experiment in which specimens of the branching coral (Porites cylindrica) were grown for 1 month at three seawater temperatures (22, 26, and 30 °C). The results of this study showed that the linear extension rate of P. cylindrica has little effect on the skeletal Sr/Ca, Mg/Ca, and U/Ca ratios. The following temperature equations were derived: Sr/Ca (mmol/mol) = 10.214(±0.229) − 0.0642(±0.00897) × T (°C) (r² = 0.59, p < 0.05); Mg/Ca (mmol/mol) = 1.973(±0.302) + 0.1002(±0.0118) × T (°C) (r² = 0.67, p < 0.05); and U/Ca (μmol/mol) = 1.488(±0.0484) − 0.0212(±0.00189) × T (°C) (r² = 0.78, p < 0.05). We calculated the distribution coefficient (D) of Sr, Mg, and U relative to seawater temperature and compared the results with previous data from massive Porites corals. The seawater temperature proxies based on D calibrations of P. cylindrica established in this study are generally similar to those for massive Porites corals, despite a difference in the slope of D_U calibration. The calibration sensitivity of D_Sr, D_Mg, and D_U to seawater temperature change during the experiment was 0.64%/°C, 1.93%/°C, and 1.97%/°C, respectively. These results suggest that the skeletal Sr/Ca ratio (and possibly the Mg/Ca and/or U/Ca ratio) of the branching coral P. cylindrica can be used as a potential paleothermometer.     

Solubility of pyromorphite Pb5(PO4)3Cl-mimetite Pb5(AsO4)3Cl solid solution series

Pyromorphite Pb₅(PO₄)₃Cl and mimetite Pb₅(AsO₄)₃Cl are isostructural minerals with apatite. Due to their high environmental stability, they have gained considerable attention as metals sequestration agents in water treatment and contaminated soil remediation. Pyromorphite and mimetite can form a continuous solid solution series in near-Earth surface environments. Precipitation of the end members and intermediate members of the series is likely to occur in the areas where the cost-effective in situ immobilization reclamation method, based on phosphate amendments, is applied. In contrast to the widely studied thermodynamic parameters of pyromorphite and mimetite, knowledge of the thermodynamics of their solid solutions is sparse. To supplement the data, a number of compounds from the pyromorphite-mimetite series were synthesized at room temperature using a method to simulate the conditions in the near-Earth surface environments. Afterwards, batch dissolution and dissolution-recrystallization experiments of seven synthesized precipitates were conducted at 25 °C, pH = 2 and in a 0.05 M KNO₃ background electrolyte. The experiments were carried out for a period of 6 (dissolution) and 14 (dissolution-recrystallization) months. A plateau in the [Pb] evolution patterns was used to determine equilibrium. All seven dissolutions were congruent, and the ionic activity products (IAP) of the minerals from the pyromorphite-mimetite solid solution series were calculated based on the dissolution reaction: . The IAPs for pyromorphite and mimetite exhibit a significant difference in values over three orders of magnitude between approximately 10⁻⁷⁹ for pyromorphite and approximately 10⁻⁷⁶ for mimetite. The series appeared to be ideal, and Lippmann and Roozboom diagrams were used for better understanding of its thermodynamics. The results indicated a strong tendency of pyromorphite to partition into the solid phase in the series, which explains some of the naturally observed phenomena. The improvement of the lattice stability of the mimetite due to isostructural phosphate substitutions in anionic sites was observed. The thermodynamic data reported in this study supplement existing databases used in geochemical modeling.     

The bearing of the system CaMgSi2O6CaAl2SiO6CaFeAlSiO6 on fassaitic pyroxene

The system CaMgSi₂O₆CaAl₂SiO₆CaFeAlSiO₆ has been studied in air at 1 atm. The phase assemblage at subsolidus temperatures in the CaMgSi₂O₆-rich portion is Cpx + An + Mel and that in the CaMgSi₂O₆-poor portion Cpx + An + Mel + Sp. At subsolidus temperatures the sigle-phase field of clinopyroxene increases with an increase in the CaFeAlSiO₆ component of the system. The Al₂O₃ content of clinopyroxene, however, continues to increase beyond the single-phase field and attains at least 16.04 wt.% Al₂O₃ with 3.9 wt.% Fe₂O₃. The stability field of fassaite in the system over a range of pressures and oxygen fugacities has been estimated from data in the literature as well as the present data. The CaFeAlSiO₆ content of fassaite is dependent on oxygen fugacity, but is not influenced by pressure. The stability field is strongly influenced by oxygen fugacity at low and high pressure, and decreases with decreasing oxygen fugacity. Clinopyroxenes in both volcanic and metamorphic rocks from various localities, when plotted on the CaMgSi₂O₆CaAl₂SiO₆CaFeAlSiO₆ triangle, show that there is no compositional gap between diopside and fassaitic pyroxene in metamorphic rocks, and that the fassaitic pyroxene in alkalic rocks becomes richer in both CaAl₂SiO₆ and CaFeAlSiO₅ components as crystallization proceeds. These results agree with those obtained in the experimental study.