地球化学块体的方法技术在山东金资源潜力预测中的应用

山东的化探扫面工作已经结束了13a，积累了数十万的化探资料。作者尝试用地球化学块体的方法技术来挖掘这些资料的潜在价值。因此，对山东全省Au的资源潜力进行了预测，确定了圈定山东地球化学块体的下限值为2.5ng／g，圈出了2个地球化学块体和数十个区域异常。统计计算了2个地球化学块体和8个区域异常的参数特征，计算出1000m厚岩块总的Au供应量为419236t，根据所确定的成矿率0.90%来预测500m和1000m深度内这2个地球化学块体和8个区域异常所覆盖的15631km^2的范围内的Au的资源潜力为1249t和2522t。     

中国铜矿资源找矿前景

从中国60年铜矿勘查程度研究入手,分析了铜矿床的产出与勘查程度的空间、强度的内在联系。统计结果表明,铜矿床的规模与勘查程度呈正相关,发现一个大型铜矿床所需要的钻探工作量为(12.5～16)×104m,发现一个中型铜矿床需要的钻探工作量至少为(4.8～5.48)×104m。面积约占中国2/3的中西部地区,铜矿的勘查程度低或极低,查明铜矿床的数量和储量仅占全国的17%和34%,西部地区还具有巨大的找矿潜力。选择勘查程度较低或极低、又具备铜矿成矿地质背景的区域作为铜矿成矿区带,在区带内利用已发现的铜矿床、矿(化)点和可能具有反映铜矿化显示的化探异常等因素圈定找矿远景区。在提高勘查程度就有可能发现更多资源储量的前提下,采用高勘查程度区铜资源储量的特征和参数,对低勘查程度区的铜资源储量进行类比预测,估算全国铜资源潜力为(5591～18483)×104t,其中西部低勘查程度区的潜在铜资源量为(5591～13660)×104t,可发现大型铜矿床30～70个。铜找矿远景区主要分布在西藏冈底斯、班公湖,西南三江,新疆东天山,内蒙古大兴安岭,中东部铜矿山深部及外围。     

缓变型地球化学灾害:特征、模型和应用

“缓变型地球化学灾害”是通过长期积累而存在于土壤或沉积物中的包括重金属和有机污染物在内的环境污染物,因环境物理化学条件(例如温度、pH值、湿度、有机质含量等)的改变减小了环境容量,某种或某些形态的污染物大量地被重新活化和突然释放出来并造成严重生态和环境损害的灾害现象。这种灾害具有明显的特征,其定量数学模型可较完整地概括出环境系统从“干净”到“污染”再到“灾害”的整个过程,可以用于灾害的风险概率评估、预测、灾害爆发轨迹等方面的研究,为土壤污染防治和灾害预警提供了定量研究工具和可供实际采用的基本手段,对当前国土资源调查中的“生态环境地球化学评价”具有重要的借鉴意义。     

用人工神经网络进行空间不完备数据的插补

在地学研究中,特别是区域性资料处理过程中,常常遇到“不完备数据”的问题,即所谓的“数据不全”。在尽量减小估计误差的条件下对缺失数据进行预测或插补,对于充分利用历史资料和已知信息,提高预测质量具有重要意义。利用径向基人工神经网络(RBF)同时具有自组织神经网络和回归网络的优点,可以对缺失数据进行预测。实际区域地球化学数据处理的结果表明,RBF网络对空间不完备数据的建模和预测具有优异的效果。     

一套用来分析构造方位并重点研究脆性构造及古应力分析的数据库系统和程序

为了用不同方法处理不同规模(区域和局部)的构造方位数据,并将其用于形态、年代及机制分析之中,我们精心研制出一套叫做Tector的系统文件和Fotran程序,这套程序已在各研究所的地质、地球物理方面的应用过程中得到不断改进。本篇摘要从应用的角度讨论这套程序,而不讨论这个系统所涉及的在其它文献中已讨论过的具体方法,比如断层滑移数据的反演问题。     

前寒武纪海洋水的成分

前寒武纪海洋水的成分和现在的海洋水是不同的,当时存在缺氧的CO_2~-大气圈是直接的原因。起始时期,矿化度比较低。海水属氯含量较低、磷酸盐较富的氯——重碳酸盐化型水,而且缺乏硫酸盐。硫呈硫化物还原状态。磷酸盐的富集促进了生命的发展。Na~+、Mg~(2+)阳离子与浓度比现在高的Ca~(2+)、Fe~(2+)、Ba~(2+)同时共存。主要演变趋势见图1。     

A Large-Scale Palaeozoic Dextral Ductile Strike-Slip Zone:the Aqqikkudug-Weiya Zone along the Northern Margin of the Central Tianshan Belt,Xinjiang,NW China

The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by "flower" strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269(5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.     

Chemical Indicator of Spinel During Partial Melting and Subsolidus Equilibration of Mantle Peridotite:Experimental Study and Application to Natural Rocks

Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 GPa. The results shows (1) during partial melting, Mg# [=Mg/(Mg+Fe)]and Cr# [=Cr/(Cr-Al)]of spinel increase with an increase in degrees of melting) (2) during subsolidus equilibration, with increasing temperatures, Mg# of spinel increases but Cr# of spinel remains almost unchanged in dunite and increases slightly in Iherzolite and harzburgite. The negative and quasi-linear Mg# -Cr# correlation of spinel represents an isotherm of total non-equilibrium. The same results have been obtained by means of mathematical modelling. It is also proved by Mg# -Cr# correlation of spinel in natural peridotites. As a result of the spinel subsolidus equilibration, only variation of Cr# of spinel is limited, and then Cr# of spinel can be used to estimate the relative degree of melting undergone by host rocks     

新疆阿舍勒铜锌矿床矿石化学组分分带研究及意义

阿舍勒铜锌矿床是近年来发现的大型火山成因块状硫化物矿床之一。由于矿床成矿后遭受构造变质变形作用，使矿体的形态、产状发生了很大变化，所以矿体的分带结构也很难保留该类矿床所具有的理想分带型。因此，研究矿床分带性，对于了解矿床的成矿方式以及确定矿体的分布型式、产出状态、，进而指导找矿预测等方面均具一定意义。     

地幔橄榄岩部分熔融的实验研究——论地幔富硅酸盐流体(熔体)的成因

在0.61 GPa和1.0 GPa条件下,进行了地幔二辉橄榄岩的部分熔融实验,首次探讨了熔体成分在“不同熔融阶段”随部分熔融程度的变化。结果显示,熔体中SiO_2、CaO、Al_2O_3、Na_2O和TiO_2变化趋势在不同熔融阶段不一样。熔体成分在低压下或较高压下相对富SiO_2。幔源富硅酸盐流体(熔体)的成因有多种,但存在于同一地幔橄榄岩捕虏体中、挥发分及碱质含量相近而其他成分不同的基性—中酸性富硅酸盐熔体,是在有地幔C—O—H流体介入或其他交代矿物存在时的原位局部平衡