Heavy metal retention in secondary precipitates from a mine rock dump and underlying soil, Dalarna, Sweden

This study investigates the retention of heavy metals in secondary precipitates from a sulfidic mine rock dump and underlying podzolic soils by means of mineralogical and chemical extraction methods. The rock dump, which is at least 50 years old, consists of a 5–10-cm-thick leached zone and an underlying 110–115-cm-thick accumulation zone. Optical microscopy and electron microprobe analyses confirm that pyrrhotite weathering has proceeded much further in the leached horizon relative to the accumulation horizon. The weathering of sulfides in the leached zone has resulted in the migration of most heavy metals to the accumulation zone or underlying soils, where they are retained in more stable phases such as secondary ferric minerals, including goethite and jarosite. Some metals are temporarily retained in hydrated ferrous sulfates (e.g., melanterite, rozenite). Received: 28 October 1996 · Accepted: 24 February 1997     

江西利山金矿床地质特征及控矿构造

本文较系统地阐述了利山金矿床的各项地质特征，并重点就控矿构造问题进行了总结讨论，认为ＮＷＷ向断裂带严格控制了所有金矿体的产出。ＮＮＥ、ＮＮＷ向断裂与ＮＷＷ向断裂带的交汇部位控制了富矿段的产出。在此基础上初步探讨了矿床成因及找矿方向，这对该地区的找矿评价和开发均具有实际意义     

正态化克立格法在路腊汞矿储量计算中的应用

正态化克立格法是对传统储量计算方法的改革和创新。其计算过程的科学性和计算结果的正确性在路腊汞矿作了探采对比试算，取得了良好的结果。     

Structure of the Mount Raymond transverse zone at the southern end of the Wyoming salient, Sevier fold-thrust belt, Utah

The Mount Raymond transverse zone (MRTZ) forms the east-west-trending boundary between the Wyoming salient of the Sevier fold-thrust belt and the Uinta/Cottonwood arch in north-central Utah. Major faults in the zone dip 40° to 45° north. Our structural analysis indicates that the MRTZ contains both contractional and extensional structures. The contractional structures (thrusts and related folds) initially formed as part of a southeast-verging, northeast-trending thrust system. This system gradually curved and merged to the north with the east-verging Absaroka thrust system in the apex of the Wyoming salient. The contrast in trend between structures in the MRTZ and those in the apex of the Wyoming salient reflects the initial curvature of the salient. This curve formed because the stratigraphic sequence involved in thrusting thinned gradually southward, toward the axis of a proto-Uinta arch. The present east-west trend of the MRTZ developed during Laramide uplift of the Unita/Cottonwood arch, an event which tilted the faults into their present position. Cenozoic crustal extension subsequently reactivated segments of the MRTZ. In sum, the evolution of the MRTZ illustrates how post-thrusting processes can affect the map-view geometry of thrust belts to create transverse zones.     

Geochemical modeling of coal mine drainage, Summit County, Ohio

 Geochemical modeling was used to investigate downstream changes in coal mine drainage at Silver Creek Metro-park, Summit County, Ohio. A simple mixing model identified the components that are undergoing conservative transport (Cl^–, PO₄ ^3–, Ca²⁺, K⁺, Mg²⁺ and Na⁺) and those undergoing reactive transport (DO, HCO₃ ^–, SO₄ ^2–, Fe²⁺, Mn²⁺ and Si). Fe²⁺ is removed by precipitation of amorphous iron-hydroxide. Mn²⁺ are removed along with Fe²⁺ by adsorption onto surfaces of iron-hydroxides. DO increases downstream due to absorption from the atmosphere. The HCO₃ ^– concentration increases downstream as a result of oxidation of organic material. The rate of Fe²⁺ removal from the mine drainage was estimated from the linear relationship between Fe⁺² concentration and downstream distance to be 0.126 mg/s. Results of this study can be used to improve the design of aerobic wetlands used to treat acid mine drainage. Received: 4 June 1996 · Accepted: 17 September 1996     

Accretion and exhumation at a Variscan active margin, recorded in the Saxothuringian flysch

The Saxothuringian flysch basin, on the north flank of the Central European Variscides, was fed and eventually overthrust by the northwestern, active margin of the Tepla-Barrandian terrane. Clast spectra, mineral composition and isotopic ages of detrital mica and zircon have been analyzed in order to constrain accretion and exhumation of rocks in the orogenic wedge. The earliest clastic sediments preserved are of early Famennian age (ca. 370?Ma). They are exposed immediately to the NW of the suture, and belong to the par-autochthon of the foreland. Besides ultramafic (?ophiolite) material, these rocks contain clasts derived from Early Paleozoic continental slope sediments, originally deposited at the NW margin of the Saxothuringian basin. These findings, together with the paleogeographic position of the Famennian clastics debris on the northwestern passive margin, indicate that the Saxothuringian narrow ocean had been closed by that time. Microprobe analyses of detrital hornblendes suggest derivation from the “Randamphibolit” unit, now present in the middle part of the Saxothuringian allochthon (Münchberg nappes). Detrital zircons of metamorphic rocks formed a little earlier (ca. 380?Ma) indicate rapid recycling at the tectonic front. The middle part of the flysch sequence (ca. early to middle Viséan), both in the par-autochthon and in the allochthon, contains abundant clasts of Paleozoic rocks derived from the northwestern slope and rise, together with debris of Cadomian basement, 500-Ma granitoids and 380?Ma (early Variscan) crystalline rocks. All of these source rocks were still available in the youngest part of the flysch (c. middle to late Viséan), but some clasts record, in addition, accretion of the northwestern shelf. Our findings permit deduction of minimum rates of tectonic shortening well in excess of 10–30?mm per year, and rates of exhumation of ca. 3?mm/a, and possibly more.     

义马新安煤矿特大型奥灰突水的治理

采用“上阻、中栏、下堵”的立体堵水方法，封堵了义马新安煤矿1995年11月5日发生的特大型（4257m3／h）奥灰突水通道，解放被淹矿井，堵水效果良好。     

Crustal structure of Dabieshan orogenic belt

The crustal structures ofP velocity and density on the deep seismic sounding profile across the Ilabieshan orogenic belt are presented. There is a 5-km-thick crustal “root” between the Yuexi and Xiaotian where the elevation is highest on the profile. An apparent Moho offset of 4. 5 km beneath the Xiaotian-Mozitan fault marks the paleo-suture of the Triassic collision. A high-velocity anomaly zone at the depth below 3 km beneath the ultra-high pressure (UHP) zone may be correlated to the higher content of UHP metamorphic rocks. Project supported by the National Natural Science Foundation of China and the Joint Earthquake Science Foundation.     

造山带岩浆活动与构造运动关系研究综述

熔体及其活动在造山带的演化中发挥了重要作用。熔体活动发迹了地壳应力作用方式而诱发形成剪切带或断层；熔体活动调整块体间的位移而影响造山带的变形；     

秦岭造山带南北向构造及有关问题的讨论

秦岭造山带具有复杂和长期演化的历史，本文对秦岭造山带的主造山期，结构特征（包括构造单元划分），构造体制和发展演化等进行了综合和讨论。