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1.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》1999,24(10):913-920
Climatic change in SE Europe can be characterized by the term aridification, which means increasing semi-aridity, manifested in an increase of mean annual temperature and at the same time in a decrease in the yearly precipitation.The paper deals with research results obtained within the framework of the MEDALUS II project (funded by the Commission of the European Communities). The project had the following objectives:
- 1.(i) Assessment of the impact of global change on the climate of the investigated area, including possible future climates.
- 2.(ii) Physical processes of aridification, including studies of groundwater level change, soil moisture profile dynamics, soil development, vegetation change and soil erosion.
- 3.(iii) Land use change, involving research on present land use and suggestions for the future.
- 1.(i) Statistical analysis of climatic oscillations and computer runs of climatic scenarios,
- 2.(ii) Analysis of ground water data, mapping and analysis of soils and vegetation, assessment of present and future soil, and
- 3.(iii) Land capability assessment through ranking environmental conditions according to the demands of the most widely grown arable crops in Hungary.
2.
《Engineering Geology》2001,59(1-2):1-49
Geologic concepts and scientific-technical guidance for the planning-design and construction of engineered works was recognized in Europe by the 1800s and by the early 1900s in North America. This early geologic knowledge and experience provided the rudimentary principles that guided practitioners of the 19th century in serving the emerging projects in western United States. Case studies review the scientific-technical lessons learned and the legacy of geologic principles established in the planning and construction of major civil, mining, and military engineered works in the western states. These contributions to GeoScience knowledge and engineering geology practice include:
- •Tunnels and aqueducts across active fault zones, beneath young volcanic features, groundwater-charged faults, and land subsidence mitigation.
- •Controversial foundation design, Folsom and Auburn dams, Golden Gate Bridge.
- •Protective underground construction chambers, safety dependent geologic setting.
- •Geologic mapping as database management leasing, maintenance railroad trackway.
- •Causeway Great Salt Lake, geo-risks calculated, mitigated ‘as-constructed’.
- •Nuclear powerplants seismic design.
- •Urban Land-Use, on-going processes, acceptable geo-risks.
- •Dwelling Insurance, insuree's responsibilities.
- •Selecting technique/method to mitigate risk, preferably based on extensive database, evaluation of characteristics and historical origin adverse features/conditions that constitute a geo-risk.
3.
The Karkonosze–Izera Massif is a large tectonic unit located in the northern periphery of the Bohemian Massif. It includes the Variscan Karkonosze Granite (about 328–304 Ma) surrounded by the following four older units:
- -Izera–Kowary (the Early Paleozoic continental crust of the Saxothuringian Basin),
- -Ještĕd (the Middle Devonian to Lower Viséan sedimentary succession deposited on the NE passive margin of the Saxothuringian Terrane), out of the present study area,
- -Southern Karkonosze (metamorphosed sediments and volcanics filling the Saxothuringian Basin), out of the present study area,
- -Leszczyniec (Early Ordovician, obducted fragment of Saxothuringian Basin sea floor).
- -formation of the Saxothuringian Basin and its passive continental margin (about 500–490 Ma)
- -Variscan thermal events:
- -regional metamorphism (360–340 Ma)
- -Karkonosze Granite intrusion (328–304 Ma)
- -Late Cretaceous and Neogene-to-Recent hypergenic processes.
4.
Most of the Cu (± Mo,Au) porphyry and porphyry-related deposits of the Urals are located in the Tagil-Magnitogorsk, East-Uralian Volcanic and Trans-Uralian volcanic arc megaterranes. They are related to subduction zones of different ages:
- (1)Silurian westward subduction: Cu-porphyry deposits of the Birgilda-Tomino ore cluster (Birgilda, Tomino, and Kalinovskoe) and the Zeleny Dol Cu-porphyry deposit;
- (2)Devonian Magnitogorsk eastward subduction and the subsequent collision with the East European plate: deposits and occurrences are located in the Tagil (skarn-porphyry Gumeshevskoe etc.) and Magnitogorsk terranes (Cu-porphyry Salavat and Voznesenskoe, Mo-porphyry Verkhne-Uralskoe, Au-porphyry Yubileinoe etc.), and probably in the Alapaevsk-Techa terrane (occurrences of the Alapayevsk-Sukhoy Log cluster);
- (3)Late-Devonian to Carboniferous subduction: deposits located in the Trans-Uralian megaterrane. This includes Late-Devonian to Early Carboniferous Mikheevskoe Cu-porphyry and Tarutino Cu skarn-porphyry, Carboniferous deposits of the Alexandrov volcanic arc terrane (Bataly, Varvarinskoe) and Early Carboniferous deposits formed dew to eastward subduction under the Kazakh continent (Benkala, etc.).
- (4)Continent-continent collision in Late Carboniferous produced the Talitsa Mo-porphyry deposit located in the East Uralian megaterrane.
5.
Prof. Jean -Claude Vicente 《International Journal of Earth Sciences》1975,64(1):343-394
Hercynian absolute ages obtained from many plutonites and metamorphites of the Sierras Pampeanas compel to consider this polymetamorphic domain rather as an intermediate hinterland and axis of divergent symmetry between the two elementary geosyncline ranges (Cuyanides and Bolivianides) of the south america hercynian orogen. Attempt of Cuyanides paleogeographic organization indice to define during the geosyncline period (Cambrian to Devonian): the Pampean zone which consist of:
- an internal sub-zone (eastern) or pampean s. st. with hinterland significance
- a more external sub-zone (western) or transpampean or Umango sub-zone with intermediate features between eugeanticlinal ridge and eugeosynclinal furrow;
- the Calingasta zone as a typical eugeosynclinal furrow with pelagic-terrigenous ordovician sedimentation and ophiolitic magmatism followed by early silurian than devonian Flyschs;
- the Zonda zone as an external ridge with neritic cambro-ordovician facies and devonian flyschs.
6.
《Comptes Rendus Geoscience》2019,351(5):355-365
Located in northern Niger, the NW–SE Téfidet trough is the western branch of the Ténéré rift megasystem.Here we present a tectono-sedimentary analysis of the Téfidet trough, based on the combined use of satellite imagery, field observations and measures, and available literature. We use these data to analyse the sedimentary facies and the tectonic deformations (faults, folds, basins) in the Téfidet trough, and derive their relative chronology. Doing so, we characterize synrift and postrift deformations and their interactions with sedimentation.Altogether our analyses suggest that the Téfidet trough was affected from the Cretaceous to the Paleogene by three major tectonic periods.
- •The first period was a rifting stage with extension and transtension during the Albian–Aptian times. The mean extension was ∼N60° and dominantly produced NW–SE-trending normal faults, a few strike-slip faults locally associated with small folds with sigmoidal axis and small reverse faults, and progressive unconformities.
- •the second period was also a rifting time, which prevailed during the Upper Cretaceous. The regime was marked by transtensional to extensional tectonics, under a ∼N130° shortening and a ∼N60° trending stretching. The end of this period saw the closure of the Téfidet trough.
- •the third period was a postrift stage. It was characterized by a ∼N70° extensional to transtensional regime during the Oligocene–Pliocene. It mainly produced post-sedimentary extensional faults and fractures and alkaline volcanism. We eventually discuss these deformation phases in relation with the Cretaceous Gondwana breakup and its related rifting events in West and North Africa, and with the subsequent Africa–Europe collision.
7.
《Journal of Asian Earth Sciences》1999,17(5-6):683-702
The Thakkhola–Mustang graben is located at the northern side of the Dhaulagiri and Annapurna ranges in North Central Nepal. The structural pattern is mainly characterised by the N020–040° Thakkhola Fault system responsible for the development of the half-graben. A detailed study of the substrate and the sedimentary fill in several outcrops indicates polyphased faulting:-pre-sedimentation faulting (Miocene), with a mainly NNW–SSE to N–S compressional stress expressed in the substratum by N020–040° and N180–N010° sinistral and N130–140° dextral conjugate strike-slip faults;-syn-sedimentation faulting (Pliocene–Pleistocene), characterised by a W–E to WNW–ESE extensional stress and tectonic subsidence of the half-graben during the Tetang period (Pliocene probably), followed by a doming of the Tetang deposits and a short period of erosion (cf. Pliocene planation surface and unconformity between the Tetang and Thakkhola Formations); the Thakkhola period (Pleistocene) is characterized by a W–E to WNW–ESE extensional stress and a major subsidence of the half graben;-post-sedimentation recurrent extensional faulting and N–S and NE–SW normal faults in the late Quaternary terrace formations.Geodynamic interpretation of the faulting is discussed in relation to the following:
- 1.the geographic situation of the Thakkhola–Mustang half-graben in the southern part of Tibet and its setting in the Tethyan series above the South Tibetan Detachment System (STDS);
- 2.the geodynamic conditions of the convergence between India and Eurasia and the dextral east–west shearing between the High Himalayas and south Tibet;
- 3.the possible relations between the sinistral Thakkhola and the dextral Karakorum strike-slip faults in a N–S compressional stress regime during the Miocene.
8.
Dr. G. Wessely 《International Journal of Earth Sciences》1990,79(2):513-520
The exploration for hydrocarbons in the deepest tectonic »floor« underneath the Vienna basin with depths of 6.5–8.5 km, was undertaken between 1977 and 1985 and based on several important conditions: -The assumption that an autochthonous sedimentary cover lies upon the Crystalline Basement (Bohemian massif) below the Neogene basin infill and the Alpine-Carpathian nappes. -Expressed high zones exist within the Vienna basin with exploration targets at depths reachable by drilling. -The significant accumulation of oil- and gasfields m shallower position over the area of interest. As a result of the 4 deep wells drilled for the abovementioned targets more information has been acquired concerning the stratigraphy, facies distribution and depth positions of the autochthonous Jurassic, Upper Cretaceous and Tertiary Molasse along the Eastern flank of the Crystalline basement spur of the Bohemian Massif. The allochthonous, Waschberg- und Flyschzone, both Alpine-Carpathian units underneath the Vienna basin, have been penetrated by these wells for the first time and the overthrust of the Calcareous Alps over the Flysch nappes has been proven (well Aderklaa UT1). Additional information about Neogene sedimentation and faulting was obtained. Drilling results made it possible to get a more comprehensive picture of the 3 tectonic »floors« of the Vienna basin, m detail represented by the Zistersdorf and Aderklaa profiles. Thick basin marls of the Upper Jurassic represent a large source potential for hydrocarbons. The favourable reservoir layers, detected in the Mesozoic sections of the foreland area have not been encountered here till now. A high supply of free hydrocarbons within the deepest floor must be assumed on the basis of many oil and gas shows, a major gas kick in Zistersdorf ÜTla and a limited oil production from a fractured zone along a thrustline in the Maustrenk ÜTla well, both occurring in an overpressured environment. 相似文献
9.
《Applied Geochemistry》2005,20(2):261-274
Very low concentrations of total S, mainly sedimentary sulphides, were quantitatively extracted from Quaternary sands of the Elbe Basin, using HNO3, Br2 and HCl, to distinguish 3 aquifer zones:
- •an upper aerobic section, containing low concentrations (only a few ppm) of non-sulphidic S compounds,
- •the central and lower part of the aquifer, dominated by 34S-depleted sedimentary Fe sulphides, formed by reduction of infiltrating SO4, derived from groundwater recharge, and
- •the lowest 5–10 m of the aquifer, containing high concentrations of 34S-enriched sulphides.
10.
Prof. Dr. G. Haase Dr. L. Händel Dr. Chr. Nagel Dr. Chr. Opp Dr. R. Zierath 《GeoJournal》1990,22(2):153-165
Problems of landscape and resource protection resulting from the intensification of land-use can be mastered only by intersectoral planning and a land management considering (landscape-)ecological principles right from the beginning. In the district of Leipzig ecological studies in the '80ies have focussed on:
- Determination of the regional pattern of atmospheric immissions;
- Registration of heavy metals in soil and vegetation;
- Soil compaction, soil erosion;
- Study of stress indicators in the aeration zone and in the top-most aquifer in order to examine barrier effects in the percolation process.
11.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(9-11):731-735
The seismic wavefield associated to the ongoing eruptive activity at Stromboli volcano (Italy) is investigated using data from two small-aperture, short-period seismic arrays deployed on the northern and western flanks, located at about 1.7 km from the active craters. Two distinct approaches are used to analyze the recorded signals:
- 1.1) the zero-lag cross-correlation method is used to analyze the explosion quakes data, to estimate slowness and backazimuth as a function of lapse time;
- 2.2) multiple filter technique and phase matched filtering are used to estimate Rayleigh wave dispersion, to obtain a shallow velocity model of the two sites.
12.
This paper discusses the history and application of in situ recovery (ISR) to a wide variety of metals. The increasing application of ISR may provide an important method to address a key issue for the mining industry, namely the cost of production.ISR transfers a significant proportion of hydrometallurgical processing to mineralised bodies in the subsurface to directly obtain solutions of metals of interest. As a result, there is little surface disturbance and no tailings or waste rock are generated at ISR mines. However, for ISR to be successful, deposits need to be permeable (either naturally or artificially induced), and the metals of interest readily amenable to dissolution by leaching solutions in a reasonable period of time, with an acceptable consumption of leaching reagents.The paper discusses the following aspects of ISR:
- •History. ISR for uranium was introduced in 1959 in the USA, and subsequently applied in many countries over last 50 years, particularly in the USSR. The share of uranium mined by ISR reached 51% of world production in 2014, and the capacity of ISR mining of uranium is now comparable with that from conventional uranium mines.
- •Commodities. A review of the use of ISR for mining other commodities, namely copper, gold, nickel, scandium, rhenium, rare earth elements, yttrium, selenium, molybdenum, and vanadium. ISR for copper was introduced in the 1970s and there were several successful natural tests and mines. Scandium, rhenium, rare earth elements, yttrium, selenium, molybdenum, and vanadium were mined in pilot tests as by-products of uranium extraction. ISR of gold, copper, nickel, rare earth elements and scandium has been successfully developed over recent years. The paper discusses other commodities that have potential to be mined using ISR.
- •Applicability of ISR is addressed by a discussion of the features of mineralisation that need to be considered during different stages of ISR projects. Permeability,1 hydrogeological conditions and selective leachability are the most critical parameters for ISR, and must be defined in the evaluation and exploration stages. Morphology and depth of mineralisation, thicknesses and grades, distribution of mineralisation, presence of aquicludes, and environmental conditions are also important factors for ISR projects.
- •Environmental issues. ISR allows the extraction of mineralisation with minimal disturbance to existing natural conditions. In contrast to underground and open pit mining, there are smaller volumes of mining and hydrometallurgical effluents that require management. Clearly contamination of groundwater by ISR reagents is the critical aspect requiring management during an ISR operation. Control of leaching in ISR operations and various ways of cleaning aquifers are discussed in the paper.
- •Economics. ISR operations deliver a range of benefits including lower CapEx costs for mine development, processing plant and infrastructure. ISR enables production to start at low capital cost and then a modular increase in production, as well as very flexible production capacity. The costs of ISR for different commodities (copper, gold, nickel, scandium, rhenium, rare earth elements, yttrium, selenium, molybdenum, vanadium) are discussed, with economic parameters for uranium production from ISR and conventional provided for comparison. The CapEx, OpEx and common cut-off grades for ISR for different commodities are discussed.
- •Exploration, resource estimation and the development of ISR projects require a number of different approaches compared to conventional mining projects. These criteria and the necessary methodology for resource estimation for ISR projects are described in the article.
13.
14.
R. Catalano B. d'Argenio C. B. Gregor A. E. M. Nairn G. Nardi P. Renda 《International Journal of Earth Sciences》1984,73(2):577-598
The Mesozoic lavas and minor intrusions in the thrust sheets of western Sicily have the following characteristics:
- The lavas in the Triassic Mufara Formation in the north were broken into fragments which rotated independently within the incompetent strata that enclose them. This behavior is characteristic of igneous rocks found within the more internal (northerly) thrust units.
- The Jurassic lavas in the more external (southerly) units have consistent directions which agree with those of the Ammonitico Rosso limestones in the same zone and lie about 30° clockwise from those of coeval autochthonous formations in Tunisia.Schult's presumed Cretaceous directions from Custonaci on the north coast (similar to those found in the Cretaceous Scaglia Rossa at Terrasini to the east byChannel et al., 1980) are rotated still more (140°) with respect to those of the autochthonous Iblean platform of SE Sicily. These differences are believed to reflect rotation of the thrust sheets during tectonic transport in Cenozoic times, the internal units being the most strongly rotated.
- All the igneous rocks are highly altered: generally the original mineralogy cannot be completely determined. Relative abundances of some of the less mobile elements (Ti, Sr, Y) suggest that they are intraplate basalts.
15.
《Applied Geochemistry》1999,14(7):861-871
To support and help hydrochemical evaluation a multivariate mathematical tool named M3 (Multivariate Mixing and Mass balance calculations) has been created within the Äspö Hard Rock Laboratory Research Programme. The computer code can be used to trace the origin of the groundwater and calculate the mixing portions and mass balances from ambiguous groundwater data. Groundwater composition data used traditionally to describe the reactions taking place in the bedrock can now be used to trace the effect from present and past groundwater flow with increased accuracy. The M3 model consists of the following 3 steps:
- •Multivariate analysis, called Principal Component Analysis (PCA) is used to summarise the information from the data set. The summarised information shown in the PCA plots is used for finding relationships, patterns, extreme waters and for further M3 modelling.
- •From the PCA plot mixing calculations are used to calculate the effect of the groundwater mixing on the obtained groundwater composition. This so-called ideal mixing model is used to calculate the mixing proportions given in %, for all the groundwater samples.
- •The final step in M3 calculations is the mass balance calculations. Deviations from the ideal mixing model are used to trace the sources and sinks of elements, given in mg/l, which can be due to mass balance reactions.
16.
英吉苏中新生代凹陷是在古生代逆冲推覆构造背景之上发育起来的背驮式前陆盆地。盆地的沉积作用和变形作用严格受基底参与的逆冲断层的控制。中新生代构造由北向南可划分七个带：北部斜坡带；群克─新开屏背斜带；英北向斜带；阿拉干背斜带；英南向斜带；古城墟斜坡带和罗布庄断凸带。叠瓦式逆冲断层、冲起构造、构造三角带、断展褶皱和披覆构造是英吉苏凹陷的主要变形样式。自三叠纪以来，不同时期的沉积中心自造山带向前陆方向迁移。 中新生界变形的动力学和运动学是与塔里木板块南缘活动大陆边缘的板块拼贴事件和壳内拆离缩短作用有关。 相似文献
17.
扎格罗斯褶皱冲断带是扎格罗斯碰撞造山带的前陆褶皱冲断带,也是波斯湾周缘前陆盆地的楔顶带,自北东到南西垂直于构造线方向可分为高扎格罗斯冲断带和扎格罗斯简单褶皱带;自北西到南东沿构造线方向可分为洛雷斯坦区(Lorestan)、迪兹富勒湾区(Dezful Embayment)和法尔斯区(Fars)。扎格罗斯褶皱冲断带的形成始于晚白垩世阿拉伯板块的洋壳向北俯冲到欧亚板块之下,褶皱冲断构造从北东部缝合带向南西方向伸展,并在上新世基本定型。本文选取了横切扎格罗斯褶皱冲断带的3条地质剖面和两条局部地震剖面进行构造变形分析。剖面分析显示研究区垂向上由一条大滑脱面将扎格罗斯褶皱冲断带剖面分为上、下两个构造层;褶皱冲断变形从北东到南西向由强变弱。研究区发育走滑、挤压和拉张3种构造变形,挤压构造变形占主导地位。挤压构造变形又包括滑脱褶皱、断展褶皱、断弯褶皱和双重构造等。 相似文献
18.
Dr. Barbara Theilen-Willige 《International Journal of Earth Sciences》1982,71(1):318-327
The following facts have supported the origin of the Araguainha circular structure in Central Brazil by a meteoritic impact:
- the almost circular contour
- the impact-morphologic sequence including a central uplift, ring walls and a basin rim of escarpments
- outcrops of suevites and mixed breccias
- the evidence of shock metamorphism
- the presence of shatter cones, and
- negative anomalies of the total intensity of the magnetic field at the center of the ring structure.
19.
Alexander A. Godovikov George C. Kennedy 《Contributions to Mineralogy and Petrology》1968,19(2):169-176
Prior experimental work has shown that in the laboratory the mineralogy of eclogites is sensitive to the ratio of CaO ∶ MgO ∶ FeO and that the reaction pyroxene + kyanite?garnet + quartz proceeds to the right at high pressures in rocks rich in magnesium and to the left in rocks rich in calcium and iron. Typical basalts crystallized at high pressure never contain kyanite. The chemistry and mineralogy of a large number of naturally occurring eclogites show they belong to three classes.
- Kyanite-free magmatic eclogites, rich in magnesium, from:
- kimberlites
- dunites and serpentinites.
- Kyanite-bearing eclogites and grosspydites rich in CaO and low in FeO with intermediate MgO from:
- kimberlites
- gneisses.
- Kyanite-free eclogites of metamorphic origin rich in iron with low magnesium and intermediate amounts of calcium from:
- glaucophane schists
- gneisses.
20.
The Brazilian state of Goiás and parts of Mato Grosso represent the centre of the Brazilian shield, between the Guaporé craton in the west and the São Francisco craton in the east. In contrast to opinions before, early Precambrian gneisses and migmatites form only small parts of the shield complex whereas middle and late Precambrian sequences dominate. From tectonic position, an eugeosynclinal central zone can be distinguished accompanied by younger miogeosynclinal series to the east and west. The ultrabasic massifs of Goiás can be differentiated into following types:
- alpinotype serpentinised dunites and peridotites,
- gabbro-pyroxenite-peridotite associations,
- pyroxenite-metagabbro associations,
- dunite-pyroxenite-alkalisyenite associations,
- lamprophyre dykes.