不同干燥方法对重塑膨润土压汞试验用土样的影响试验研究

采用风干法、烘干法和冻干法分别对不同含水率的重塑膨润土进行干燥制样,利用压汞试验得到的累积进汞量曲线,对重塑膨润土进行了孔隙尺度划分,根据测试结果对土样孔隙尺度分布特征进行了定量分析。试验结果表明：采用风干法、烘干法和冻干法干燥制样后土体孔隙分布存在较大的差异性,土样的含水率越高,差异越明显;风干法、烘干法干燥土样会引起孔隙收缩,导致土体微孔隙特征的变化,冻干法不会引起孔隙收缩,因而不会导致土体微孔隙特征的变化。由此得出了干燥重塑膨润土制备压汞试验用土样最好的干燥方法是冻干法这一结论     

Geochemistry,Zircon U–Pb Analysis,and Biotite 40Ar/39Ar Geochronology of the Maoling Gold Deposit,Liaodong Rift,NE China

The Maoling gold deposit is located in the southwestern part of the Liaodong rift, NE China, and has estimated reserves of 25 t. In this paper we present the results of an investigation into the geochronology and geodynamic mechanisms of igneous activity and metallogenesis within the Maoling gold deposit. New zircon U–Pb age data, biotite ⁴⁰Ar/³⁹Ar age data, whole‐rock geochemistry, and Hf isotopic analyses are presented in order to constrain the petrogenesis and mineralization of the deposit. Zircon U–Pb dating of the Wolongquan biotite monzogranite and Maoling biotite granite yielded mean ages of 194.0 ± 1.1 Ma and 196.1 ± 1.1 Ma, respectively. All the granites are characteristically high‐K calc‐alkaline, enriched in light rare earth elements and large ion lithophile elements, and depleted in high field strength elements, which is consistent with the geochemical characteristics of arc‐type magmas. The Hf isotope characteristics indicate that the granites formed by partial melting of early Paleoproterozoic crustal material. In addition, biotite ⁴⁰Ar/³⁹Ar dating indicates that the Maoling gold deposit formed at 188.9 ± 1.2 Ma, implying that the mineralization was related to both the granite intrusions. Taking into account previous data on S–Pb–O–H isotopes and our new age data, the Maoling deposit can be classified as an intrusion‐related gold deposit. Taking into account the geology of the study area and adjacent regions, we propose that the Maoling gold deposit and its associated granitic intrusions formed in a geodynamic setting that was dominated by subduction of the Paleo‐Pacific Plate beneath the Eurasian continent.     

Gold Deposits in the Sanandaj–Sirjan Zone: Orogenic Gold Deposits or Intrusion‐Related Gold Systems?

Most of the known large gold deposits in Iran are located along the Sanandaj–Sirjan Zone, western Iran, which hosts a wide range of gold deposit types. Gold deposits in the belt, hosted in upper Paleozoic to upper Mesozoic volcano‐sedimentary sequences of lower greenschist to lower amphibolite metamorphic grade, appear to represent mainly orogenic and intrusion‐related gold deposit types. The largest resource occurs at Muteh, with smaller deposits/occurrences at Zartorosht, Qolqoleh, Kervian, Qabaqloujeh, Kharapeh, and Astaneh. Although a major part of the gold deposits in the Sanandaj–Sirjan Zone are related to metamorphic devolatilization, some deposits including Muteh and Astaneh are related to short‐lived disruptions in an extensional tectonic regime and are associated with magma generation and emplacement. The age of gold ore formation in the orogenic gold deposits is Late Cretaceous to Tertiary, reflecting peak‐metamorphism during regional Cretaceous–Paleocene convergence and compression. The Oligocene to Pliocene age of most intrusion‐related gold systems is consistent with the young structural setting of the gold ore bodies; these deposits are sequestered along normal faults, correlated with Middle to Late Tertiary extensional tectonic events. This relationship is comparable to the magmatic‐metallogenetic evolution of the Urumieh‐Dokhtar magmatic arc, where the number of different types of gold‐copper deposits and the magnitude of the larger ones followed development of a magmatic arc. The appropriate explanation may be related to two different stages of gold mineralization consisting of a first compressional phase during the Late Cretaceous to Early‐Middle Tertiary, which is related to orogenic gold mineralization in the Qolqoleh, Kervian, Qabaqloujeh, Kharapeh, and Zartorosht deposits, and the extensional phase during the Eocene to Pliocene that is recognized by young intrusion‐related gold mineralization in the Muteh and Astaneh deposits.     

关于“小岩体为什么有利于成矿”的探讨

2012年在西安召开了一次学术会议,系统地总结了小岩体成大矿的现象和理论。笔者从另一个方面探讨小岩体成矿的理论问题．但是仅涉及与花岗岩有关的小岩体成矿问题,不涉及镁铁和超镁铁质小岩体成矿的问题。关于岩体与成矿的关系,可以从3个层面上去探讨：第一个层面是小岩体成大矿。小岩体成大矿是事实,也是特殊的事实。绝大多数小岩体不成矿,少数小岩体成小矿,个别小岩体成大矿。第二个层面是小岩浆大流体成矿,基本思想是：小岩浆无流体不成矿,小岩浆有小流体成小矿,小岩浆有大流体成大矿。因此,笔者认为成矿的根本在于流体的大小。第三个层面是流体成矿。如果不考虑岩体的因素,只要有大流体即可成大矿。文中指出,从小岩体成大矿,到小岩浆大流体成矿,到流体成矿。表明成矿的本质在流体,无流体不成矿,有流体才可能成矿。流体是成矿的必要条件．温度是成矿的充分条件,二者缺一不可,只有满足了这两个条件才能成矿。     

疏浚淤泥流动固化土的压汞试验研究

采用压汞法对疏浚淤泥流动固化土进行了微观孔隙结构的研究,分析了固化土的孔隙体积及入口孔径分布特征与固化材料掺量及固化土龄期的关系,并将微观试验结果与固化土的物理指标和强度特性进行了比较。结果表明,采用压汞法研究疏浚淤泥流动固化土的微观孔隙空间分布是成功的,压汞试验得到的微观孔隙特征与众多学者通过宏观力学试验得出的强度规律是一致的,微观结构试验能够很好地解释宏观物理力学性状。随着固化材料掺量的增加和龄期的增长,淤泥固化土的孔隙体积和D50孔径明显减小,入口孔径分布特征亦发生了相应变化。所得流动固化土的入口孔径主要分布在0.01～10 ?m之间,最大分布孔径在0.5～2 ?m之间。     

Thermal alteration of coal in the Khasyn coalfield, Magadan region, Russia

The Early Cretaceous coal deposits of the Khasyn coalfield are intruded by Palaeogene diabase dikes. The coal has vitrinite reflectance values of 2.0–2.5% R_o, and characteristics of normal anthracite at some distance from the dikes, but at direct contact with the dike two morphological coal varieties occur: coal inclusions in the diabase dike and dispersed carbonaceous matter within the dike rock. Both types of coaly matter have properties typical of anthracites: strong anisotropy, altered internal structure and high vitrinite reflectance values ranging from 3.8 to 5.5% R_o. The X-ray diffraction measurements of the interplanar spacing d(002) and the crystallite sizes Lc and La show rather similar values for coal inclusions in the dike and dispersed carbonaceous matter. The additional reflection at 3.37 Å, corresponding to semi-graphite admixture, occurs in the coal and carbonaceous matter inside the dike and is absent in the natural coal outside the dike.     

Effects of geology and human activity on the dynamics of salt-water intrusion in three coastal aquifers in southern Spain

 Mathematical modelling of salt-water intrusion processes in three aquifers on the southern coast of Spain (Río Verde, Río Vélez and Castell de Ferro) reveals that, although all three systems are subject to the same climate and seasonal over-exploitation, geological and human factors have very different effects on the dynamics of contamination. In the Río Verde aquifer, the most important influence is the high volume of extractions occurring during the dry season; in Río Vélez, the intrusion is strongly controlled by infiltration of water from the river to the aquifer, and, in the Castell de Ferro system, an intensely karstified carbonate massif lying in contact with both the sea water and the detrital aquifer represents the main entrance point for influx of sea water and subsequent washing of the aquifer. We have undertaken a mathematical simulation of various possible measures to counteract intrusion, according to the specific characteristics of the process in each aquifer. These measures include artificial recharge, use of natural recharge from the river as a hydraulic barrier, and the construction of a low-permeability barrier. Received: 5 December 1995 · Accepted: 12 April 1996     

关于侵入岩体中金矿床成因研究若干问题的讨论

各时代、不同类型侵入岩中的金矿床是金矿的主要类型。关于金矿床与岩体的成因关系目前尚存在不同的看法，但传统的岩浆热液成因观点仍居统治地位，其原因往往在于不少研究者把岩液热液成因当成了固定模式应用于具体矿床的研究，而不是建立在综合研究的基础之上。本文结合近年来金矿的研究进展，强调侵入岩中金矿床的研究的研究要综合考虑成岩成矿的时代与时差，成矿流体和成矿物质的来源等各方面因素。金矿床定年的进展研究表明，矿     

云南祥云马厂箐富碱斑岩体的地球化学特征及其形成的构造环境

云南祥云马厂箐岩体处于扬子板块西缘与NW向的金沙江—哀牢山深大断裂带东侧交汇部位,属于哀牢山—金沙江富碱侵入岩带的组成部分。马厂箐岩体主要为花岗斑岩、二长斑岩和正长斑岩,岩体化学成分具有富碱、富铝和高钾的特点。岩石富集大离子亲石元素(Rb、Sr、Ba、Th和U)和轻稀土元素(LREE)、相对亏损高场强元素(Ta、Nb和Ti),且Ta、Nb和Ti具TNT负异常;LREE/HREE值为8.04～23.99,δEu值为0.72～0.88,负Eu异常不明显;n(87Sr)/n(86Sr)值范围为0.7072～0.7086,均值为0.7080,高于原始地幔现代值0.7045;n(143Nd)/n(144Nd)值范围为0.5121～0.5124,均值0.5123,低于原始地幔现代值0.512638;ISr值范围为0.7061～0.7075,均值为0.7070;εNd值范围为(3.1～(10.2,均值为(6.8。马厂箐岩体既不属于传统的含碱性暗色矿物的碱性岩类,也不同于典型的A型花岗岩,应属于富碱侵入岩类;岩体的岩浆起源于壳—幔物质混合的一种所谓EMⅡ型富集地幔源;其壳幔混合特征,主要是俯冲进入上地幔的地壳物质与地幔物质发生了源区混合作用的结果;形成于碰撞后的板内构造环境。     

Was the Panzhihua Large Fe-Ti Oxide Deposit,SW China,Formed by Silicate Immiscibility?

The Panzhihua mafic intrusion, which hosts a world-class Fe-Ti-V ore deposit, is in the western Emeishan region, SW China. The formation age(～260 Ma), and Sr and Nd isotopes indicate that the Panzhihua intrusion is part of the Emeishan large igneous province and has little crustal contamination. To assess ore genesis of the Panzhihua Fe-Ti-V ore deposit, two different models have been provided to explain the formation, namely silicate immiscibility and normal fractional crystallization. Silicate...