尧峪金铜矿超厚水敏性地层钻进泥浆护壁技术

尧峪金矿区超厚水敏性风化层,在钻进过程中遇到坍塌、掉块、事故频繁发生等问题,采用常规护壁措施并没有取得预想的效果。通过试验应用PAB不分散聚合物泥浆和钾基处理的聚合物泥浆,取得了良好的效果,顺利完成了ZK604孔的钻探施工,为该矿区今后的钻探工作提供了一些可供参考的经验。介绍了该矿区钻探施工的难题以及采取的泥浆技术措施。     

Sedimentary characteristics and provenance of the basal conglomerate of the Late Jurassic-Early Cretaceous Jiaolai Basin,eastern China and their implications for the uplift of the Sulu Orogenic Belt

ABSTRACT

The basal conglomerates (‘Linsishan Conglomerate’, LC, herein) are exposed discontinuously along the northern part of the Sulu Orogenic Belt (SOB) and the southern part of the Jiaobei Terrane. Studying these conglomerates can offer key constrains for the formation age of the Jiaolai Basin and improve our understanding of the uplift and erosional histories of the SOB and Jiaobei Terrane, which are still in great controversy. In Huangyadi section, the LC is characterized as debris-flow deposits, channel deposits, and sheet-flow deposits. However, in Shanjiao section, the LC is changed to sheet-flow and sieve deposits, as well as debris-flow and channel deposits. These deposit characteristics indicate an unstable tectonic setting during initial opening stage of the basin. Based on the data of conglomerate component, palaeocurrent, and debris zircons ages, it can be inferred that the sediments in the Laiyang region were sourced from the Jiaobei Terrane and Northern Sulu Orogenic Belt (NSOB), and the sediments in the Zhucheng and Wulian regions were derived from the Jiaobei Terrane and the Southern Sulu Orogenic Belt (SSOB). Besides, the sediments in the Haiyang and Jimo regions were provided by the NSOB and SSOB, respectively. The significant SHRIMP U–Pb ages of a tuff developing in the LC has been obtained, indicating that 149 ± 2.5 Ma is the oldest age constraint for the Jiaolai Basin. In addition, our result shows that the Latest Jurassic (ca. 149 Ma) may be a critical time; before this time, the Jiaobei Terrane and the SOB experienced a rapid uplift with minimal uplift velocity (~0.9 km/Ma); since then, the Orogen began to collapse and a series of basins formed rapidly in its core, which indicate the tectonic stress regime of the Dabie-Sulu Orogen varied from compressional stress to tensile stress.     

白彦砾岩的形成时代及砾石组构特征分析

通过对白彦砾岩中孢粉取样鉴定及其砾石组构的统计研究,孢粉组合特征显示其形成时代为中侏罗世,并非通常认为的古近纪。砾石组构特征显示为湖滨相或海滨相成因,砾岩中金刚石特征显示出与蒙阴常马金刚石原生矿的相似性。综合分析认为,白彦砾岩形成于中侏罗世鲁西地区单断拉分盆地诞生之前,应为三台组沉积之前的沉积物。白彦砾岩沉积时代的确定,对恢复该区岩相古地理、确定金刚石原生矿的剥蚀与搬运等都具有重要意义。     

南化塘区晚震旦世碳酸盐砾岩层序及其形成机制探讨

作者认为鄂西南化塘区晚震旦世发育的一套碳酸盐砾岩层序,是碳酸盐台地上台隆边缘形成的一种特殊沉积岩相,是古海洋面强烈波动的一种标志。文章从构造学和沉积学方面初步探讨了其建造过程和形成机制。     

四川高县芙蓉山白岩山崩的成因

根据芙蓉山白岩山崩区的环境地质特征、成因，得出白岩山崩是人类与环境没有协调好而酿成的地质灾害的结论。     

Occurrence of gold in hydrothermal pyrite,western Taupo Volcanic Zone,New Zealand

The Taupo Volcanic Zone (TVZ) on the North Island of New Zealand is located above the subducting Pacific slab and hosts hydrothermal systems related to subduction, arc magmatism and crustal extension. In these systems, gold is transported primarily as sulphide complexes, with gold being deposited in response to boiling and mixing of the deep geothermal fluids. Conglomerate cobbles and hydrothermal fumaroles from the upper Retaruke River in the western TVZ are mineralised deposits that have been eroded from the nearby Miocene alluvial sedimentary plateau. Abundant gold-bearing pyrite was precipitated in the conglomerates and fumaroles by late hydrothermal process, primarily occurring as veinlets, disseminations and fine-grained aggregates which consists discrete euhedral microcrystals. Scanning electron microscopy combined with X-ray energy disperses spectroscopy shows that pyrites are commendably affected by late hydrothermal fluids, possibly by the carbonate fluid. Electron probe microanalysis revealed that the pyrite contains 20–120 ppm Au (averaging 60 ppm). Wavelength dispersive spectral elemental mapping suggests that gold is distributed uniformly in pyrite, indicating structurally bound gold (solid solution) in pyrite. Gold mineralisation recognised in the conglomerates and fumaroles demonstrates that the upper Retaruke River is a promising target for future gold exploration.     

Nagaur — tertiary interface under Punjab-Haryana semi-desertic plains in western India

The subsurface Nagaur Basin in northwest Haryana and southwest Punjab hosts evaporite sequence, conformably overlain by Nagaur red beds and grey beds. A polymictic conglomerate intervenes the Nagaur sequence and the overlying Tertiary sequence. The focus is on the new finds of (i) distinctive ‘grey beds’ overlying ubiquitous red beds, (ii) ‘Malout conglomerate and grit’ horizon (Palaeocene-Miocene) marking an unconformity over the Nagaur Group (early Cambrian) and (iii) ‘entrapped gas and dried-up leaves/carbonaceous flakes’ in the conglomerate unit and succeeding Tertiary rocks. Palaeoenvironmental significance has been discussed. The Nagaur ‘red beds’ has been likened to ‘continental red beds’ of Schreiber (1978) and ‘reworked red beds’ of Krynine (1949). The ‘grey beds’ are channel fillings, fresh material having been derived from fresh cuttings by streams/rivers following structural grains in the Aravalli landscape where the interfluves provided weathered (oxidised) materials for the red beds. Association of continental red beds and grey beds is known in the Newark Series (Triassic) of the Eastern United States and the Keweenawan ‘late Precambrian’ of the Lake Superior region.     

Pulsating oblate and prolate three-dimensional strains

The progressive ductile deformation of competent spherical inclusions is modeled analytically. Results of this study may help to understand better the limitations connected to geological field methods using competent inclusions for strain analyses. Parameters studied and quantified here are the strain magnitude, the progressive change in inclusion shape, the orientation of the finite strain axes, the frequency of pulsation, and the coupling between the strain ellipticity and viscosity contrast. Competent inclusions develop pulsating apparent strains if the host material is subjected to a component of simple shear and provided time or strain rate is sufficient to complete the strain cycle. The disparity between the strain magnitude inferred from competent viscous inclusions and that undergone by the host rock, increases for larger viscosity between them. The pulsation of the inclusion may suggest zero strain after a strain cycle has been completed, even though strain in the host rock is extremely large. The inclusion will develop pulsating oblate strains if a shortening rate is superposed normal to the plane of pulsation. Conversely, pulsating prolate strains occur if an extension rate is superposed instead of shortening. Stretching lineations outlined by deformed competent inclusions within shear zones beneath collapsing nappe sheets may even point perpendicular to the direction of nappe transport. This finding offers an explanation for the occurrence of mutually perpendicular pebble elongations in nearby locations within the Bygdin conglomerate beneath the Jotun nappe, Norwegian Caledonides.     

安徽省祁东煤矿底砾含水层突水灾害成因与治理技术

文章介绍了皖北煤电集团公司祁东煤矿3222工作面特大突水灾害过程，并根据“四含”水文长观孔水位，突水后水温变化特点、水质化验资料及防水煤岩柱构成，分析出水水源为：第四系“四含”水；导水通道可能为：①采动裂隙沟通风化网络裂隙；②工作面中部存在垂向导水裂缝带，使“四含”水下泻所致。通过对突水性质和水情发展趋势的分析研究，决定采用强制排水、建防水闸墙、水泥浆封盖“四含”和基岩风化带堵出水水源；粘土浆充填固结采空冒裂带的治理方案。实施后，堵水率达100％，仅用102d就恢复了矿井生产，安全撤出了综采支架，取得了良好的经济效益和社会效益。     

内蒙古巴彦诺日公地区构造砾岩特征及其形成机制

通过巴彦诺日公地区1／5万地质填图和重点解剖研究，认为原1／20万区调中所划下元古界阿拉善群大部分岩石组合可与内蒙古中部地区色尔腾山岩群进行对比，且祖宗毛道组三段实际上是一套构造砾岩。在研究该砾岩宏观和微观特征的基础上，认为其形成机制为伸展机制下的构造拆离。