藏南地区金和锑矿床(点)类型及其时空分布特征

本文首次对藏南地区金和锑矿床(点)地质特征、成因类型和空间分布特点进行了总结，对金和锑成矿作用与中新生代构造一岩浆活动的关系进行了论证，对区域地壳演化过程中金和锑成矿动力学机制进行了讨论。该区的金和锑矿床(点)可按容矿围岩划分为：①变质岩为主要容矿围岩矿床(点)，包括金和金一锑矿床(点)；②沉积岩为主要容矿围岩矿床(点)，包括金、锑、金一锑和锑多金属矿床(点)；③火山岩为主要容矿围岩矿床(点)，以金一银矿床为代表。根据金和锑矿床(点)空间分布特点和地质特点，将本区划分为4个矿化集中区：拉昂错一马攸木一帕羊金矿化集中区(A)，然勒金和锑矿化集中区(B)，洛扎一措美锑矿化集中区(C)和邛多江金一锑矿化集中区(D)。各矿化集中区内大多数金和锑矿床(点)与燕山晚期～喜马拉雅早期富碱火成岩具密切时空分布关系，它们是古板块对接碰撞期和碰撞期后大规模构造一岩浆活动的产物。近东西向挤压性和南北向张性断裂交汇部位以及富碱火成岩发育区是寻找金和锑矿床(点)的有利场所。     

裂缝性岩石裂缝扩展的光弹构造物理模拟——以南华北盆地户部寨沙河阶组为例

以南华北盆地户部寨第三系沙河阶组粉砂岩低渗透储层为例,总结了其中发育的5种类型构造裂缝组合,即:①南北向雁形张节理组成的共轭剪节理带;②东西向雁形张节理组成的共轭剪节理带;③缠结状多组剪切构造裂缝;④组合状交切的多组剪切构造裂缝及张裂缝;⑤散状无序排列的构造裂缝。在此基础上,建立光弹性试验构造物理模型,沿现应力场96°方向,均匀地对该模型逐步增加外载力。结果表明,沿各组合裂缝尖端分别形成对称于裂缝走向、且主轴垂直于裂缝的Ⅰ型等色线条纹;对称于裂缝走向、且主轴平行于裂缝走向的Ⅱ型条纹和斜交于裂缝走向的复合型(Ⅲ型)条纹。第①类组合裂缝尖端以Ⅰ型等色线条纹的拉张应力和张剪应力为主;第②类组合裂缝尖端以复合型(Ⅲ型)等色线条纹的挤压应力为主;第③、④和⑤类组合裂缝尖端的应力分布较为复杂。当模型外载荷接近1000kg时,裂缝尖端起裂,并开始发育显微裂缝,而当外载荷达1100-1200 kg时,沿裂缝尖端部位形成宏观裂缝,并开始扩展。5种类型的裂缝组合扩展发育程度由强至弱依次为:①,③,⑤,②,④。其中第①类共轭裂缝组合起裂最早,扩展最快,裂缝间的连通趋势最好,说明规则分布的构造裂缝组合,在垂直于外施加载衙时更易达到连通的目的。     

胜利油田车镇凹陷沙河街组二、三段沉积相

车镇凹陷古近系沙河街组三段上亚段-二段下亚段是较为典型的深断陷型三级层序.层序的发育主要受控于幕式断陷作用,可进一步划分出低位体系域、湖侵体系域和高位体系域.通过岩心观察、薄片镜下鉴定、粒度分析、古生物及遗迹化石分析,并综合利用测井曲线和地震相特征,认为该时期主要发育有扇三角洲、三角洲、近岸水下扇、湖底扇、滨浅湖滩坝等骨架砂体相,以及滨浅湖、半深湖-深湖等沉积相及其亚相.综合考虑物源特征、沉积环境、沉积体系平面展布以及生、储、盖组合关系,认为有利的沉积相带主要是三角洲、扇三角洲前缘、湖底扇、近岸水下扇的中扇和外扇以及滨浅湖中发育的滩坝和砂坝.     

山东省临邑县临盘镇地裂冒喷水油灾害初步分析

1998年7月临邑县临盘镇西十二里村发生地裂冒喷水油灾害：对此次灾害研究认为，灾害发生前地应力已有明显改变，这种改变应是自然因素造成的，油田开发难以直接引发断层的活动。因此，地裂冒喷水、油灾害是因活动性断昙——临邑断层在局部薄弱部位活动而引起的，断层活动使地下流体顺断层涌出地表，是自然地质灾害。灾害的诱发因素是多方面的，其中地面不均衡沉降耦合使得地下应力布不均习，导致在断层的薄弱部位产生应力集中，并引发灾害发生。灾害发生已使得地下不均衡应力得以释放，近期内再次发生灾害的可能性不大。     

淄博市洪山、寨里煤矿地下水串层污染形成原因及防治

淄博市洪山、寨里煤矿区隐伏的奥陶系灰岩裂隙岩溶水污染严重。水质污染突发于矿坑全面闭坑以后，污染范围与矿坑水区一致，地下水污染组份与矿坑水的高含量组份相同。水质恶化主要由矿坑水串层污染所致。在此针对串层污染形成原因及影响因素，提出了防治对策。     

山东省大盛群孢粉组合及其年代地层意义

大盛群为一套陆相碎屑沉积岩系 ,其中的孢粉化石可以归纳为 Schizaeoisporites- Ephedripites- Tricolpites(SET)组合 ,希指蕨孢属 Schizaeoisporites、克拉梭粉属 Classopollis、麻黄粉属 Ephedripites及隐孔粉属 Exesipolle-nites为优势属群 ,两气囊花粉个别出现 ,以早期被子植物花粉大量出现为特征 ,主要为三沟型被子植物花粉。该组合的地质时代确定为塞诺曼—土伦期     

Origin of Gold—Bearing Fluid and Its Initiative Localization Mechanism in Xiadian Gold Deposit,Shandong Province

The composition of quartz inclusions and trace elements in ore indicate that gold-bearing fluid in the Xiadian gold deposit,Shandong Province,stemmed from both mantle and magma,belonging to a composite origin.Based on theoretical analysis and high temperature and high pressure experimental studies,gold-bearing fluid initiative localization mechanism and the forming environment of ore-host rocks are discussed in the present paper.The composite fluid extracted gold from rocks because of its expanding and injecting forces and injecting forces and flew through ore-conducive structures,leading to the breakup of rocks.The generation of ore-host faults and the precipitation of gold-bearing fluid occurred almost simultaneously.This study provides fur-ther information about the relationships between gold ore veins and basic-ultrabasic vein rocks and intermediate vein rocks,the spatial distribution of gold ore veins and the rules governing the migration of ore fluids.     

Constraints on the application of carbon isotope thermometry in high- to ultrahigh-temperature metamorphic terranes

Nine marble horizons from the granulite facies terrane of southern India were examined in detail for stable carbon and oxygen isotopes in calcite and carbon isotopes in graphite. The marbles in Trivandrum Block show coupled lowering of δ¹³C and δ¹⁸O values in calcite and heterogeneous single crystal δ¹³C values (? 1 to ? 10‰) for graphite indicating varying carbon isotope fractionation between calcite and graphite, despite the granulite facies regional metamorphic conditions. The stable isotope patterns suggest alteration of δ¹³C and δ¹⁸O values in marbles by infiltration of low δ¹³C–δ¹⁸O‐bearing fluids, the extent of alteration being a direct function of the fluid‐rock ratio. The carbon isotope zonation preserved in graphite suggests that the graphite crystals precipitated/recrystallized in the presence of an externally derived CO₂‐rich fluid, and that the infiltration had occurred under high temperature and low f_O2 conditions during metamorphism. The onset of graphite precipitation resulted in a depletion of the carbon isotope values of the remaining fluid+calcite carbon reservoir, following a Rayleigh‐type distillation process within fluid‐rich pockets/pathways in marbles resulting in the observed zonation. The results suggest that calcite–graphite thermometry cannot be applied in marbles that are affected by external carbonic fluid infiltration. However, marble horizons in the Madurai Block, where the effect of fluid infiltration is not detected, record clear imprints of ultrahigh temperature metamorphism (800–1000 °C), with fractionations reaching <2‰. Zonation studies on graphite show a nominal rimward lowering δ¹³C on the order of 1 to 2‰. The zonation carries the imprint of fluid deficient/absent UHT metamorphism. Commonly, calculated core temperatures are > 1000 °C and would be consistent with UHT metamorphism.     

山东省胶莱盆地东北缘宋家沟金矿地质特征及其成因初探

山东省宋家沟金矿位于胶莱盆地东北缘 ,产于莱阳群林寺山组断裂破碎带中。牟—即断裂带为切割莱阳群的断裂 ,对金矿起控制作用。早白垩纪晚期的火山—岩浆活动为深部含金热液的运移提供了通道 ,并在其有利的构造部位沉淀成矿。稀土元素特征和氧、硫同位素特征亦说明宋家沟金矿的物质来源以深源为主 (幔源及下地壳中的金 ) ,是早白垩世晚期的火山—岩浆活动作用的结果。     

Timing of Fracture Formation and Duration of Mineralization at the Hishikari Deposit, Southern Kyushu, Japan

Abstract. The Hishikari epithermal gold deposit consists of the Honko-Sanjin zone and Yamada zone. On the basis of observed crosscutting relationships of veins, vein system in the Hishikari deposit was classified into the early and late veins. They differ from orientation, width, control by unconformity, the amount of displacement and structural features, but have similarity in gold grade and Au/Ag ratios. K-Ar ages are presented for the classified veins to clarify timing of fracturing and duration of mineralization.
Age determination revealed that the early veins in the Honko-Sanjin zone range from 0.86 to 1.11 Ma and that the late veins range from 0.73 to 0. 84 Ma. The economically most important mineralization in the Hishikari deposit occurred around 0.90 Ma in a very short period (about 0.05 million years).
The distribution of mineralization age in the whole Hishikari deposit, occurrences of slickensides and ground water temperatures imply that mineralization lasted longer in the southern part of the deposit. As compared the early veins with late veins, structural changes including width, strike, dip and vein characteristics occurred at around 0.85 Ma.