排序方式： 共有15条查询结果，搜索用时 15 毫秒
1.
The largest karst cave discovered in a tunnel during motorway construction in Slovenia’s Classical Karst (Kras) 总被引：1，自引：0，他引：1
Karst researchers of the Karst Research Institute ZRC SAZU are regularly consulted during the planning of Slovenia’s motorways
and invited to observe and monitor construction in the karst areas. More than 350 caves have been discovered in the course
of building 60 km of new motorways over the past decade. Access to the most important caves is preserved by concrete tubes
closed with metal covers at the roadside. The largest cave system in a tunnel, named LC-S647, is almost entirely preserved.
The protection of this cave will serve as a good example for the preservation of natural heritage in the future. Construction
work for the motorway uncovered a high degree of karstification. In particular, the discovery of this cave in the Kastelec
tunnel LC-S647 showed the existence of a major cave system in the geological and speleological past. A number of unconnected
passages have also been found. Caves discovered during highway construction have brought new knowledge about the cavernosity
and the geological history of this part of the karst. 相似文献
2.
<正>Mushroom Mountain karren with predominantly flat tops that formed along the stylolites and bedding planes dictated the special features of this karst landscape.Their features and rock relief clearly reflect the geological conditions and development.The subsoil karren with conical tops dissected by subsoil rock relief were exposed from beneath the soil.Below tree vegetation,the subsoil karren are to a great extent covered by moss and lichen,under which they acquire their characteristic shape.On the bare surface they were reshaped by rainwater that carves flutes and solution pans.The old cave that opens below the top of one of the cones reveals the period before its dissection into hills and cones when this part of the karst aquifer was still deep under the water table. 相似文献
3.
Barbara Vokal-Nemec Janina Szaran Andrzej Trembaczowski Stanislaw Halas Tadej Dolenec Sonja Lojen 《Aquatic Geochemistry》2006,12(3):199-220
Measurements were made of sulphur and oxygen isotope ratios of sulphate in some Slovenian rivers, lakes and tap waters. δ34S ranged from −0.2 to + 13.3‰, δ18O ranged from +4.9 to + 13.6‰, and the sulphate content varied from 0.8 to 41.4 mg/L. Rivers flowing from the Julian Alps
contain a very low amount of sulphate that is leached from a thin horizon of soil by rain. As confirmed by their low δ18O values, these sulphates do not enter the rivers directly in rain, but arise from biochemical cycling in the soil. The low
δ34S of this sulphate indicates that it originates from the oxidation of sedimentary sulphides. The evolution of sulphates along
the river course was investigated for the Sava and Ljubljanica rivers. The variations observed in sulphate from the waters
studied result from variations in the contribution of sulphates of different origin. Downstream the Sava River sulphate is
depleted in the heavy isotopes of both sulphur and oxygen, with δ-values gradually tending toward the δ-values of groundwater
sulphates in the watershed. In contrast, the δ-values of sulphate in the Ljubljanica River are almost constant and similar
to those of sulphate in local groundwater. Introduction of water from Italian and Slovenian mines was recorded in the Soča
River, where the lowest δ34S value of sulphate sulphur (−0.2‰) was observed. In addition, the influence of sulphate from the oxidation of sedimentary
sulphides was recorded in the Sotla River. No evidence was found for introduction of sulphate from factories. 相似文献
4.
Martin KNEZ Tadej SLABE 《《地质学报》英文版》2007,81(1):148-157
Shilin is among the most interesting form of stone forest to occur in karst landscapes. They develop from karren subsoil, and their shapes, entire forests or just individual pillars and their rock relief, depend on the conditions under which they were formed, their location in the karst landscape, and above all on the characteristics of the rock： its composition, stratification, and fissuring. Because of the exceptional characteristics of this karst phenomenon in China, we propose that the term ＂shilin＂ be used in the professional literature for this type of stone forest. 相似文献
5.
Nina Daneu Aleksander Rečnik Takashi Yamazaki Tadej Dolenec 《Physics and Chemistry of Minerals》2007,34(4):233-247
The atomic scale structure and chemistry of (111) twins in MgAl2O4 spinel crystals from the Pinpyit locality near Mogok (Myanmar, formerly Burma) were analysed using complementary methods
of transmission electron microscopy (TEM). To obtain a three-dimensional information on the atomic structure, the twin boundaries
were investigated in crystallographic projections
and
Using conventional electron diffraction and high-resolution TEM (HRTEM) analysis we have shown that (111) twins in spinel
can be crystallographically described by 180° rotation of the oxygen sublattice normal to the twin composition plane. This
operation generates a local hcp stacking in otherwise ccp lattice and maintains a regular sequence of kagome and mixed layers. In addition to rotation, no other translations are present
in (111) twins in these spinel crystals. Chemical analysis of the twin boundary was performed by energy-dispersive X-ray spectroscopy
(EDS) using a variable beam diameter (VBD) technique, which is perfectly suited for analysing chemical composition of twin
boundaries on a sub-nm scale. The VBD/EDS measurements indicated that (111) twin boundary in spinel is Mg-deficient. Quantitative
analyses of HRTEM (phase contrast) and HAADF-STEM (Z-contrast) images of (111) twin boundary have confirmed that Mg2+ ions are replaced with Be2+ ions in boundary tetrahedral sites. The Be-rich twin boundary structure is closely related to BeAl2O4 (chrysoberyl) and BeMg3Al8O16 (taaffeite) group of intermediate polysomatic minerals. Based on these results, we conclude that the formation of (111) twins
in spinel is a preparatory stage of polytype/polysome formation (taaffeite) and is a result of thermodynamically favourable
formation of hcp stacking due to Be incorporation on the {111} planes of the spinel structure in the nucleation stage of crystal growth. The
twin structure grows as long as the surrounding geochemical conditions allow its formation. The incorporation of Be induces
a 2D-anisotropy and exaggerated growth of the crystal along the (111) twin boundary. 相似文献
6.
Slovenia's main military training area at Poček is located in the mountainous Javorniki Watershed. This is a karstic district
without surface drainage or river valleys. The typical landscapes are conical hills and plateaus with many dolines. The lithology,
tectonic structure and speleological data indicate a typical karst aquifer with underground water moving rapidly through fissures
and conduits. Little attenuation occurs in such conditions and as a result there is a high risk of pollution. Tracer tests
have shown that a significant proportion of the water recharging the Malni and Vipava springs comes from the vicinity of the
military training area. As a result any polluting activities taking place within the military training area are likely to
affect the two springs. This is a very serious matter as the springs have been developed to provide the water supply for the
population of south-western Slovenia.
Received: 20 April 1998 · Accepted: 24 August 1998 相似文献
7.
Martin Knez Janja Kogovšek Hong Liu Janez Mulec Metka Petrič Nataša Ravbar Tadej Slabe 《Environmental Earth Sciences》2012,67(1):273-283
In Kunming area (6.8 mio population), two big interventions are in progress: construction of a new airport, the 23 km2 area of which will extend across karst terrain northeast of the city, and extensive uptake of water from karst aquifers for drinking and agricultural use. In the study, an interdisciplinary approach was utilized to demonstrate the need for holistic karstology studies prior to performing extensive interferences in the karst environment. This study included survey of surface karst features and microscopic analyses of rock samples in the area of the new airport location, accompanied by hydrogeological studies and microbiological analyses of two karst drinking water sources in its vicinity (Qinglongdong, Huanglongdong). Results showed the specific characteristics of the subsoil stone forest that indicated a high level of karstification. The direction and characteristics of groundwater flow from the sinking Qiaotou Stream at the margin of the new airport area toward the Huanglongdong Spring were defined with a single tracer test. Additional information about hydrogeological characteristics of the karst aquifer was obtained by individual measurements of physical and chemical parameters of the springs and sinking stream. Selected chemical and bacteriological parameters showed substantial pollution of both springs due to various types of human activities in the catchments. The results of the study pointed to the necessity of taking immediate measures for the springs’ protection and showed the importance of interdisciplinary research when planning anthropogenic activities in the karst. 相似文献
8.
T. Slabe 《Environmental Geology》1997,32(3):186-190
Major motorway construction is taking place in Slovenia. Almost half the country is karst and many of the new roads are in
such terrain. Karst specialists are involved in road design. They explore underground karst systems and suggest how best to
preserve the most important ones. These experts also provide advice on ways of protecting karst groundwater and on aspects
of road construction in karst. The karst features encountered during construction provide valuable information about the development
of karst systems.
Received: 8 April 1996 · Accepted: 4 February 1997 相似文献
9.
Depositional history of the Miocene Lake Sinj (Dinaride Lake System,Croatia): a long-lived hard-water lake in a pull-apart tectonic setting 总被引：1，自引：0，他引：1
Oleg Mandic Davor Pavelić Mathias Harzhauser Jožica Zupanič Doris Reischenbacher Reinhard F. Sachsenhofer Neven Tadej Alan Vranjković 《Journal of Paleolimnology》2009,41(3):431-452
Early Miocene transpressional wrenching yielded a series of NW–SE-elongated pull-apart basins in the Dinarides of Croatia
and Bosnia and Herzegovina. They accommodated a huge lake system that gave rise to spectacular endemic mollusk radiation.
Lake Sinj, moderately sized at 342 km2, flooded the south-westernmost basin of this system. Due to the karstic environment, the hard-water, alkaline, long-lived
lake developed a sediment infill with an average thickness of 370 m, dominated by authigenic limestone. The studied section
represents the upper third of the basinal infill and provides detailed insights into the critical period of the lake and of
the basinal evolution during the final stages of its filling. It comprises two large-scale, shallowing-upward cycles, both
starting with fossil-poor limestones, gradually passing into coal-bearing carbonate rocks and coal seams. The fossil-poor
intervals are interpreted as phases of repetitive acidification events due to changing lake level, which induced periodic
drying and flooding of the uppermost littoral zone inhabited by starfruit (Damasonium) meadows. The flooding of the aerated, limy mud plain introduced H+ ions from organic-matter decay reactions into the shallow
lake. This decreased its pH level, with catastrophic consequences for its biota. The ecosystem then stabilized during the
orbitally-forced, dry climate phases. Based on the mollusk record, streams still influenced the marginal lake environment
and rich organic-matter production created swamps and mires. The onset of mollusk radiation in the section correlates with
stabilized lake alkalinity, as indicated by the disappearance of starfruits, ongoing authigenic carbonate production and by
coal seams representing textbook examples for coal formation in alkaline environments. The inferred basinal setting fits well
with the pull-apart basin model, pointing to the presence of an extended shallow ramp in front of a steep, fault-induced hillside
of the hinterland. 相似文献
10.
Speleogenesis of Selected Caves beneath the Lunan Shilin and Caves of Fenglin Karst in Qiubei, Yunnan 总被引：2，自引：1，他引：1
Yunnan is famous for its attractive karst landscapes especially shilins, fengcong and fenglin. The development of caves beneath the shilins in the vicinity of Lunan is closely connected with the formation of shilins. Most of the waters percolating through shilins run through the caves beneath them and are responsible for their formation. The study of cave speleogenesis deepens knowledge about both the development of shilins and karst structure. In the vicinity of the Lunan Shilin, speleological, morphological and structural geological studies of four karst caves have been accomplished. At Puzhehei, Qiubei, which is characterised by numerous fenglin, fengcong and caves, speleological and morphological studies have been performed. Cave sediments for paleomagnetic analyses have been taken from all studied areas (samples CH 1-9). Karst caves in SE Yunnan are probably much older than the age of the cave sediments (<780,000 years B.P.). The studied areas are located in the vicinity of the Xiaojiang fault (N-S 相似文献