云南东川因民铜矿金矿化特征及成因初探

因民铜矿发育两种金矿化类型:一是铜矿的伴生金;二是热液构造蚀变岩型。化探样品分析结果显示,金矿化主要赋存于金箔箐断层上、下盘的角砾状蚀变岩内,空间上受岩性和断裂构造的双重控制。邻区拖布卡金矿的成矿地质背景与本区相似,在成矿地质年代上作以类比推测,认为喜马拉雅期是主成矿期。另外通过对光片镜下和化探原生晕样聚类分析研究,发现构造蚀变岩型金矿化具明显的多期多阶段性及热液特征。     

基于已知钻孔的场地类别模糊等值线的建立

对照现行《建筑抗震设计规范》（GB50011-2001）场地类别划分方法,应用模糊数学原理,推导了场地类别的模糊二次评价方法,得出了场地类别的模糊向量和模糊特征周期,实现了场地类别划分的连续化;在此基础上,基于收集到的杭州市254个建筑场地波速钻孔实测资料,通过建立场地类别地质模型,实现了场地类别、特征周期的模糊等值线,与实测资料对比,结果表明：由该模糊等值线得出的建筑场地抗震类别与现行《建筑抗震设计规范》给出的场地类别是统一的,模糊特征周期与规范给出的特征周期基本上是吻合的,该模糊等值线对建筑抗震设计具有指导意义。     

New basin modelling results from the Polish part of the Central European Basin system: implications for the Late Cretaceous–Early Paleogene structural inversion

Combined subsidence and thermal 1D modelling was performed on six well-sections located in the north-western Mid-Polish Trough/Swell in the eastern part of the Central European Basin system. The modelling allowed constraining quantitatively both the Mesozoic subsidence and the magnitude of the Late Cretaceous–Paleocene inversion and erosion. The latter most probably reached 2,400 m in the Mid-Polish Swell area. The modelled Upper Cretaceous thickness did not exceed 500 m, and probably corresponded to 200–300 m in the swell area as compared with more than 2,000 m in the adjacent non-inverted part of the basin. Such Upper Cretaceous thickness pattern implies early onset of inversion processes, probably in the Late Turonian or Coniacian. Our modelling, coupled with previous results of stratigraphic and seismic studies, demonstrates that the relatively low sedimentation rates in the inverted part of the basin during the Late Cretaceous were the net result of several discrete pulses of non-deposition and/or erosion that were progressively more pronounced towards the trough axis. The last phase of inversion started in the Late Maastrichtian and was responsible for the total amount of erosion, which removed also the reduced Upper Cretaceous deposits. According to our modelling results, a Late Cretaceous heat-flow regime which is similar to the present-day conditions (about 50 mW/m²) was responsible for the observed organic maturity of the Permian-Mesozoic rocks. This conclusion does not affect the possibility of Late Carboniferous–Permian and Late Permian–Early Triassic thermal events.     

Coalification in Carboniferous sediments from the Lötschberg base tunnel

Vitrinite reflectance (Rr), proximate analysis and carbon isotope composition (δ¹³C) have been used to characterise coal samples from two zones of Late Carboniferous sediments (Gastern and Ferden) in the Aar massif where they are penetrated by the Lötschberg base tunnel (constructed between 1999 and 2005). Samples are characterised by variable ash yields (21.7–93.9%; dry basis); those with ash yields of less than ~50% and with volatile matter content (V;dry ash-free basis) within the limits 2 < V% ≤ 8 are anthracite. Values of Rr range from 3.89% to 5.17% and indicate coalification to the rank of anthracite and meta-anthracite in both Gastern and Ferden Carboniferous zones. Samples of anthracite and shale from the Gastern Carboniferous exhibit a relatively small range in δ¹³C values (–24.52‰ to –23.38‰; mean: –23.86‰) and are lighter than anthracite samples from the Ferden Carboniferous (mean: –22.20‰). The degree of coalification in the Gastern and Ferden Carboniferous zones primarily depends on the maximum rock temperature (T) attained as a result of burial heating. Vitrinite reflectance based estimates of T range from ~290° –360 °C. For a proposed palaeogeothemal gradient of 25 ° C/km at the time of maximum coalification the required overburden is attributable to relatively thin autochtonous Mesozoic/Cenozoic sedimentary cover of the Aar massif and Gastern granite and deep tectonic burial beneath advancing Helvetic, Ultrahelvetic and Prealpine (Penninic) nappes in Early Oligocene to Miocene.     

邢东矿井构造特征及应力应变场分析

邢东矿井位于太行山隆起带与华北沉陷带的过渡带,通过区域构造应力-应变场分析,本区先后经历了由挤压-拉张的变形过程,变形强度由弱到强。海西期构造应力影响较弱,印支期-中燕山期构造应力作用较为强烈,形成了大量的挤压结构面和压缩构造．燕山晚期-喜山期是构造形成的最终阶段,以拉张伸展变形为主,现今的多数正断层的断裂结构面仍保存有先期的挤压结构面特征。区内构造以断裂构造为主要形式,断层组合形式多样,这些构造形成期次不同,北西向断裂对北东向断裂具有限制作用。     

松辽盆地宋芳屯油田扶杨油层孔隙结构及其影响因素

通过镜下观察,宋芳屯油田扶杨油层孔隙类型较多,以粒间孔为主。细管压力曲线上看,曲线较陡,分选差,孔隙结构特征参数总体上较差,与孔隙度、渗透率有一定的关系,大的孔隙对渗透率的贡献最大。扶杨油层的孔隙结构较复杂主要由于成岩作用影响,压实作用使孔隙空间显著缩小,胶结作用和自生粘土矿物生长使孔隙进一步缩小和复杂化,后期的溶蚀作用使孔隙空间增加。     

中强地震前后能量分布的自仿射特性

根据简化的地震波传播理论,“漫化”地震能量在空间的分配,减弱能量空间分布概率的极端情形及消除统计域为“空”的情形,由此构造类似于二维ｆＢｍ的地震能量空间分布概率曲面。与起伏不平的地形相似,由于基在水平方向及垂直方向的变化不是等比例的,因而这一分形曲面可能是统计自仿射的。     

我国高碘卤水分布规律及其形成

根据国内外大量实际资料,从碘的分布情况及其所处的地质条件,结合石油和天然气形成过程、油气藏类型及其分布特点,探讨高碘卤水分布的规律及其形成条件,在此基础上指出了我国的找碘方向。     

城市化过程中土地征用风险表征及对策

从土地征用基本概念和基本特征着手，描述了土地征用的主要风险，其表现为土地征用权力滥用、侵害失地农民的权益、诱发集体土地黑市、诱发社会矛盾等方面。分析了产生风险的“公共利益需要”缺乏明确界定、土地征用的补偿标准偏低或滞后、土地征用及相关制度不健全或存在缺陷等主要原因。提出了控制与规避风险的对策与措施：严格限定公益性用地范围，提高征地补偿标准，扩大补偿范围，完善相关制度，严格土地征用程序。     

四川省康定县滑坡灾害发育特征与形成条件

康定县地处四川盆地西缘山地及青藏高原过渡地带。县域内地势险峻,地形切割强烈,地层与地质构造复杂,新构造运动强烈,地震活动频繁。加之降水充沛,致使山地灾害十分发育,其中滑坡灾害占山地灾害的38.32%。通过搜集资料及现场调查,概述了该县县域内滑坡灾害的分布;从行政区划、自然地理及灾害规模等3方面统计分析了滑坡灾害的发育现状;从地形地貌、地层岩性、地质构造、降雨、地震活动、人类工程活动等方面总结了滑坡灾害的形成条件,并提出防治对策与措施,力求有效地预防与减少滑坡灾害的发生。