Reliability of selected procedures of stress inversion and data separation for inhomogeneous populations of calcite twins and striated faults: insights from numerical experiments

In the course of numerical experiments selected algorithms for stress tensor inversion and separation of heterogeneous populations of calcite twins and striated faults were tested. Artificial data sets were created in a manner simulating natural processes. They were composed of data, dynamically compatible with one or two stress tensors and chaotic “noise” imitating natural imperfections. For calcite twins the classical inversion procedure is considered valid, with restrictions regarding a high proportion of chaotic data, when shape ratio of the stress tensor Φ is poorly constrained. The algorithm of Etchecopar (1984 fide Tourneret and Laurent in Tectonophysics 180:287–302, 1990) devised originally for calcite twins has been modified and applied to fault/slip data, facilitating a rejection of incompatible outliers. Two main classes of data separation procedures were tested: separation contemporary with inversion and separation prior to inversion, utilising hierarchical clustering. The separation contemporary with inversion performs moderately but often fails with complex calcite twin sets. The performance of hierarchical clustering is high, but only with a σ ₁ orientation as a similarity criterion—the new strategy introduced in this contribution. For fault/slip data the hierarchical clustering with the right-dihedra construction as the similarity criterion (Nemcok et al. 1999) is satisfactory. Additionally, a new approach is proposed for fault/slip data, utilising principles of the classical algorithm for heterogeneous populations of calcite twins. Validated algorithms for striated faults were successfully applied to a natural data set from the Holy Cross Mts (central Poland).     

多期断层擦痕的硬划分:一种目标函数算法

提出一种基于硬划分的目标函数法 ,它能够识别多期断层擦痕数据。这是通过在Fry(1999)的Sigma空间里对数据内在的线性构造的识别来实现的。与其它的应力反演法不同 ,目标函数法在原理上相对完善。为了检验此方法 ,在设定的应力张量下由ManteCarlo法生成“人工”断层擦痕数据。计算结果表明 ,目标函数法能够很好地识别多期断层擦痕数据。应力估测的准确度取决于断层擦痕数据的误差和不同构造期应力张量之间的相似性。随着断层擦痕数据误差范围的加大 ,应力估测的准确度趋向降低。当断层擦痕数据存在误差时 ,越是相似的设定应力张量 ,其估计准确度也就越低。不同期构造应力的彼此相似往往与构造应力场微妙或细部的时空变化有关。在从多期断层擦痕数据里识别出相似的不同期构造应力上 ,目标函数法有所突破 ,进而有助于深入认识地质构造的形成。     

Groundwater pollution by Cystine manufacturing industrial effluent around the factory

 The pollution potential of Cystine industrial effluents on groundwater pollution is assessed. The results indicate that the Cystine industrial effluent which is partially treated and stored in lagoons contains a high concentration of inorganic solids and soluble organics. The percolation of these effluents caused groundwater pollution impairing the water quality. Received: 20 April 1999 · Accepted: 7 June 1999     

Occurrence, transport, and fate of trace elements, Blue River Basin, Summit County, Colorado: An integrated approach

Received: 24 May 1999 · Accepted: 19 July 1999     

The Long‐Term Robustness and Stability of Consensus Values as Composition Location Estimators for a Typical Geochemical Test Material in the GeoPT Proficiency Testing Programme

Re‐issuing the same test material, its true identity unknown to participants, in two rounds of the GeoPT proficiency testing programme 18 years apart has demonstrated remarkable similarity, and therefore stability, of consensus values independently estimated for over fifty measurands in each round. A comparison of the two data sets, GeoPT5 (AMH‐1) from 1999 and GeoPT41 (ORA‐1) from 2017, shows that corresponding consensus values, rigorously derived by current procedures for complete compatibility, are for the most part statistically indistinguishable when account is taken of their associated uncertainties. Inferences that may be drawn from this exceptional agreement include: (a) the consensus estimation procedure was robust and gave consistent results; (b) overall, the balance of the contributed data was unaffected by significant changes in: (i) the populations of laboratories participating, (ii) the proportions of laboratories producing results by different techniques, (iii) the manner in which systems were calibrated, or (iv) the aspirations of laboratories to attain higher quality results over time; and (c) unsurprisingly perhaps, that the test material itself had remained stable and unchanged during that time. Additionally, a statistical comparison of the original values for AMH‐1 with consensus values derived by current procedures demonstrates that they are also effectively indistinguishable.     

Hydrochemistry of pampasic ponds in the lower stream bed of Salado River drainage basin, Argentina

Received: 3 May 1999 · Accepted: 13 July 1999     

Hydrochemical and stable isotope assessment of tailings pond leakage, Nickel Plate Mine, British Columbia

Received: 19 April 1999 · Accepted: 19 July 1999     

A groundwater survey of the greater Durban area and environs, Natal, South Africa

Received: 15 June 1999 · Accepted: 30 August 1999     

Upper Neoproterozoic–Lower Cambrian sedimentary successions in the Central Iberian Zone (Spain): sequence stratigraphy, petrology and chemostratigraphy. Implications for other European zones

2 O₃, TiO₂, Zr, and Nb abundances in shales from all the units, strongly suggest a gradual compositional change within this sedimentary succession. Together with the petrological data, the chemical results do not reveal any obvious coeval volcanic contribution to the sediments. On the basis of the chemical data, a comparison is made with other European zones containing detrital sediments composed of reworked crustal components. Received: 4 January 1999 / Accepted: 1 December 1999     

On estimating the earthquake-induced changes in hydrogeological properties of the Choshuishi Alluvial Fan, Taiwan

The hydrological response of the Choshuishi alluvial fan to the 1999 Chi-Chi earthquake shows that the earthquake did impact the aquifer. The possible earthquake-induced changes in hydrogeological properties were investigated in this study. First, contour maps of the hydrologic anomaly, seismic factors, and vertical ground-surface displacement were compared qualitatively. Bulls eye patterns were found on the contour maps of hydraulic conductivity, coseismic groundwater-level change and vertical ground-surface displacement but did not occur with other seismic factors. The more permeable zones of the aquifer were found to coincide with the locations of greater vertical ground-surface displacement and coseismic groundwater-level change in the 1999 Chi-Chi earthquake. This indicates that the change of the hydrogeologic properties of Choshuishi alluvial fan due to the 1999 Chi-Chi earthquake may have mainly occurred in the highly permeable zones. Fractal, cross semivariogram and cross correlogram analyses were performed to quantitatively measure the persistency, variability and similarity, respectively, of spatial hydrologic response, seismic factors and hydraulic conductivity. The groundwater-level change, earthquake intensity, and vertical ground-surface displacement were found to show antipersistent tendencies while other factors showed the opposite. Higher correlations were found between hydraulic conductivity and groundwater-level change in aquifers 2–1 and 2–2, and between hydraulic conductivity and vertical ground-surface displacement in aquifer 3. Changes in porosities and hydraulic conductivity were evaluated in the main aquifers of the Choshuishi alluvial fan based on the data of hydrologic anomaly and the vertical ground-surface displacement. While both approaches show that the 1999 Chi-Chi earthquake has impacted the Choshuishi alluvial fan by reducing its porosity and hydraulic conductivity, these changes were not significant relative to natural variation in hydraulic conductivity.This revised version was published in May 2005 with correction to the rubric.     

Environmental geology in Thailand – programs and strategies

 The paper describes the activities and objectives of the Department of Mineral Resources in the field of environmental geology. This approach is still a comparatively new for Thailand and presently comprises different programs: environmental geology for regional planning, seismic hazards, flooding/landslides, coastal management and geosites conservation. The Environmental Geology Section of the Department is the relevant administrative unit. The technical work and the related documentations focus on rising public awareness and integration of geo-information into land-use planning and land development. Received: 23 April 1999 · Accepted: 8 June 1999     

冻融模型相似性分析及试验验证

为提高冻融模型与原型的相似程度,提出冻结指数相似比和实验室修正系数的概念及计算方法。以哈尔滨地区黄土为试验材料,将该地区2010–2012年3年日平均气温进行线性简化,基于含相变热传导的微分方程基础上,采用相似理论,在几何、温度和时间比尺约束下对密度为1.60 g/cm3、含水率为20 %的试样进行冻融循环模型试验,确定实验室修正系数K值为1.13,得到冻结指数相似比CI为1:102.5。对冻融阶段温控历时进行优化,进行冻融循环模型试验。通过对比可知,优化后模型的最大冻深值为21.33 cm,与模型预定值20 cm相差仅6.5 %;优化后冻融模型弥补了太阳辐射对冻深的影响,一个冻融周期由108.14 h减少为84.53 h。以实验室修正系数K和冻结指数相似比CI优化冻融过程的各温控阶段历时合理,显著提高了冻融模型的最大冻深和冻融过程在几何比尺和时间比尺上的相似度。     

Geochemical analyses of geological layers and groundwater flows

X-ray fluorescent spectroscope analysis easily finds ratios of geochemical elements in soil. Applying the method of ratio matching to measured ratios, the classification of geological layers, and the flow directions of groundwater can be determined. This method is applied to three hill slopes in Japan and the results are in good agreement with the observations and measurements of soil cores obtained by drilling. The classification of geological layers is found to be quantitatively connected with the rates of organic matter in soil cores. Received: 5 February 1999 · Accepted: 7 September 1999     

Fracture void structure: implications for flow, transport and deformation

 This review focuses on studies of flow, transport and deformation processes at a scale of a single discontinuity. The paper provides an evaluation of: (1) various methods suggested for geometrical characterization of void structure; and (2) theoretical and practical problems arising from significant differences between the actual geometry of fracture void structure and its parallel plate representation. The use of an equivalent aperture concept is shown to be seriously misleading in: (a) evaluation of flow regime, and hence selection of appropriate flow laws; (b) correlating tracer and hydraulic tests, and assessment of solute transport properties; and (c) relating hydraulic and mechanical apertures, and predicting influence of stress perturbation and deformability. Received: 2 August 1999 · Accepted: 30 November 1999     

An investigation of the environmental loads of Shei-Pa National Park in Taiwan

 Recreation is one of the functions of national parks. Nevertheless, heavy tourism has started to impose serious problems on the maintenance of some national parks in Taiwan. This study has tried to survey as well as calculate the impact problems resulting from park tourism in terms of environmental loads. A simple method is proposed to calculate the quantity of environmental loads. Only visitor information from questionnaires and per capita data are needed in the calculation process. Shei-Pa National Park was taken as an example. The water demand, the electricity used and the various forms of the environmental loads, including wastewater and solid waste discharge, were all surveyed and calculated on a per capita basis. Received: 21 July 1999 · Accepted: 8 November 1999     

Colour origin of upper cretaceous pelagic red sediments within the Eastern Pontides, northeast Turkey

 Characteristic samples of Upper Cretaceous pelagic red sediments from different parts of the Eastern Pontides (NE Turkey) have been investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy coupled with energy dispersive analyses (SEM/EDAX). The red sediments are composed of limestone and muddy limestone, and characterized by abundant planktonic foraminifers. Hematite content ranges from 0.5 to 3.0 wt.%. Electron microscope observations suggest that the hematite pigment has a diagenetic origin. The red colour is due to presence of hematite pigment, and indicates oxidizing conditions during early diagenesis in a relatively deep marine environment. Received: 4 January 1999 / Accepted: 8 July 1999     

A primary platinum occurrence in the Freetown Layered Intrusion, Sierra Leone

The primary source of the alluvial platinum-group minerals (PGM) of the Freetown Layered Intrusion, Sierra Leone, has been unknown since their discovery 70 years ago. This is a report on work in progress to establish a primary occurrence related to the igneous layering. New whole-rock major and minor element analyses and precious metal assays show that at key horizons there is a significant change in the silicate mineral compositions and in Cu, Cr and Ni, as well as in Pt and Pd, comparable to those encountered in other PGM-bearing layered intrusions. Anomalous (0.1 to 0.4 g/t) Pt levels occur in pyroxene troctolites, which maintain these levels along strike. Received: 30 July 1999 / Accepted: 2 December 1999     

Vegetation recovery and landscape change assessment at Chiufenershan landslide area caused by Chichi earthquake in central Taiwan

This study discusses vegetation recovery and land cover change with reference to the Chiufenershan landslide, a major disaster caused by the Chichi earthquake, 21 September 1999. Image classification technology, landscape indicators from multi-temporal remotely sensed data and a field survey provide the data. Image differencing methods and threshold values coupled with pre- and post-quake satellite images were used. Multi-temporal images in combination with various vegetation indices were drawn on to classify land cover patterns and discuss differences and suitability of indices. Landscape indicators and field investigations fed into an investigation of vegetation recovery and landscape change. The study results show that the best image classification system is original wavebands coupled with a cropping management factor index (CMFI). The land cover analysis shows that areas of forest and grass are increasing and areas of landslide are decreasing. From the field investigation, because the left and right sides of the landslide area were not disturbed by the earthquake, their calculated similarity index is the highest (30.08%). Miscanthus floridulus is the most dominant pioneer plant at the landslide collapse area with an importance value index (IVI) of 63.6%.     

喀斯特峰丛节齿藓类生态分布及其环境因子影响研究

为探寻喀斯特峰丛节齿藓类（Arthrodontae mosses）的生态分布规律及环境因子的影响,选择贵阳市思雅河3座典型喀斯特峰丛为研究对象,利用藓类综合优势比、Sorenson相似性指数及RDA对节齿藓类的生态分布及环境因子影响进行分析。结果表明:3座喀斯特峰丛上共发现节齿藓类植物11科、26属、74种,其中顶蒴单齿藓26种,顶蒴双齿藓21种,侧蒴双齿藓27种。Ⅰ号峰丛以侧蒴双齿藓为主,综合优势比为100%,Ⅱ号、Ⅲ号峰丛则以顶蒴单齿藓为主,综合优势比分别为81.80%、69.75%。节齿藓类在喀斯特峰丛上的分布在坡底以侧蒴双齿藓为主,其综合优势比为97.06%,坡中、坡顶以顶蒴单齿藓为主,其综合优势比分别为86.23%、90.76%。坡中和坡顶的顶蒴单齿藓物种相似性指数最高,为27.91%;坡中和坡顶的侧蒴双齿藓物种相似性指数最低,为11.63%。光照强度和环境温度是影响顶蒴单齿藓类分布的主要因子,侧蒴双齿藓类的分布则主要受到相对湿度的强烈影响;而顶蒴双齿藓类的分布主要受海拔影响。      

Pit lakes: their characteristics and the potential for their remediation

 Pit lakes form when open-pit mining operations are discontinued and dewatering ceases. The increase in open-pit metal mining since the 1970s will lead to the formation of numerous pit lakes over the next 50 years. Many of these lakes will develop acid sulfate conditions with high levels of dissolved metals. Approaches to remediation of these conditions that have been recommended include the addition of lime or other alkaline materials and the stimulation of sulfate-reducing bacteria. However, prevention rather than remediation is probably the preferable approach. Measures to prevent oxidation of mining waste and wall rocks, including measures to fill pits quickly with water, to inhibit the activity of acidophilic sulfur-oxidizing bacteria, and to promote anoxic conditions at the lake bottoms may minimize the formation of acids and dissolved metals. Received: 26 August 1999 · Accepted: 29 October 1999