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2002

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Articles 301 - 330 of 334

Full-Text Articles in Earth Sciences

Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra Jan 2002

Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra

United States Geological Survey: Staff Publications

A new tasselled cap transformation based on Landsat 7 at-satellite reflectance was developed. This transformation is most appropriate for regional applications where atmospheric correction is not feasible. The brightness, greenness and wetness of the derived transformation collectively explained over 97% of the spectral variance of the individual scenes used in this study.


Strontium Isotopic Signatures Of The Streams And Lakes Of Taylor Valley, Southern Victoria Land, Antarctica: Chemical Weathering In A Polar Climate, W. B. Lyons, Carmen A. Nezat, Larry V. Benson, Thomas D. Bullen, Elizabeth Y. Graham, Jesicca Kidd, Kathleen A. Welch, James M. Thomas Jan 2002

Strontium Isotopic Signatures Of The Streams And Lakes Of Taylor Valley, Southern Victoria Land, Antarctica: Chemical Weathering In A Polar Climate, W. B. Lyons, Carmen A. Nezat, Larry V. Benson, Thomas D. Bullen, Elizabeth Y. Graham, Jesicca Kidd, Kathleen A. Welch, James M. Thomas

United States Geological Survey: Staff Publications

We have collected and analyzed a series of water samples from three closed-basin lakes (Lakes Bonney, Fryxell, and Hoare) in Taylor Valley, Antarctica, and the streams that flow into them. In all three lakes, the hypolimnetic waters have different 87Sr/86Sr ratios than the surface waters, with the deep water of Lakes Fryxell and Hoare being less radiogenic than the surface waters. The opposite occurs in Lake Bonney. The Lake Fryxell isotopic ratios are lower than modern-day ocean water and most of the whole-rock ratios of the surrounding geologic materials. A conceivable source of Sr to the system …


Baseline Limnology And Nutrient Study Of Basin Head Lagoon, Prince Edward Island, With Management Implications, Karen Connolly Jan 2002

Baseline Limnology And Nutrient Study Of Basin Head Lagoon, Prince Edward Island, With Management Implications, Karen Connolly

Theses and Dissertations (Comprehensive)

Knowledge of physical and chemical process ongoing within an environment is an important step towards proper environmental management. Basin Head, Prince Edward Island is in the process of becoming a Marine Protected Area (MPA) and therefore a comprehensive management plan will need to be completed. The area contains a unique strain of Irish Moss (Chrondrus crispus Stackhouse) that is an important marine plant used in various industries. A study was conducted during the summer of 2000 to assess the basic physical and chemical conditions within the Basin Head Lagoon and surrounding stream inputs. The purpose of the study was to …


Structural And Sedimentary Characteristics Of The Tsergo Ri Rockslide Breccia, Langtang, Nepal, Himalaya, Mark B. Carpenter Jan 2002

Structural And Sedimentary Characteristics Of The Tsergo Ri Rockslide Breccia, Langtang, Nepal, Himalaya, Mark B. Carpenter

Theses and Dissertations (Comprehensive)

The high magnitude Tsergo Ri landslide (c. 100ka), Langtang Himal, with a volume in excess of 15km^3 and a vertical displacement of more than 1500m remains the largest crystalline rockslide in Nepal Himalaya. The Quaternary landslide affected rocks in gneissic fancies of the High Himalayan Crystalline Sequence adjacent to the Tibetan Sedimentary Series. Depositional characteristics from exhumed transport slope sites were analysed at both the macroscopic and the microscopic scale to investigate (i) localised fracture in terms of orientation and density, and (ii) petrography of slide induced host rock deformation. Fracture orientation analysis indicate the spatial orientation of preexisting discontinuities …


Intra-Annual Variation In The Stable Oxygen And Carbon And Trace Element Composition Of Sclerosponges, P. K. Swart, S. Thorrold, B. Rosenheim, A. Eisenhauer, C. G. A. Harriason, M. Grammer, C. Latkoczy Jan 2002

Intra-Annual Variation In The Stable Oxygen And Carbon And Trace Element Composition Of Sclerosponges, P. K. Swart, S. Thorrold, B. Rosenheim, A. Eisenhauer, C. G. A. Harriason, M. Grammer, C. Latkoczy

Biological Sciences Faculty Publications

This paper presents data to support the presence of (1) intra-annual signals in the chemical composition (δ18O and Sr/Ca) of the skeletons ofsclerosponges from the Bahamas and (2) variable rates of skeletal accretion. These conclusions are based on data obtained by using a microsampling method for the stable oxygen and carbon isotopes in which material was extracted at a resolution of one sample every 34 μm and a laser microprobe which obtained trace element data every 20 μm (Sr, Mg, and Pb). An age model was established using a combination of changes in the concentration of Pb, the …


Seiche Events At The Slave River Delta And Great Slave Lake, Northwest Territories: An Assessment Of Process And Impact, James Tobias Gardner Jan 2002

Seiche Events At The Slave River Delta And Great Slave Lake, Northwest Territories: An Assessment Of Process And Impact, James Tobias Gardner

Theses and Dissertations (Comprehensive)

Seiche events are important hydrodynamic processes that impact the Slave River Delta, during the late summer and autumn. Given the scarcity of previous research on seiche events at river deltas and the physical dimensions and orientation of the Slave River Delta, this location at the southern shore of Great Slave Lake is ideal to study the occurrence and impacts of seiche events at a river delta. Seasonal changes to long-term water level trends and water level variability on Great Slave Lake, correspond to changes to the Slave River flow potentially associated with the impacts of regulation of the Peace River. …


Investigating Spatio-Temporal Variability Of Hydrological Components In The Canadian Rockies (Alberta), Christopher Dennis Hopkinson Jan 2002

Investigating Spatio-Temporal Variability Of Hydrological Components In The Canadian Rockies (Alberta), Christopher Dennis Hopkinson

Theses and Dissertations (Comprehensive)

This thesis addresses two questions related to the broad topic of mountain hydrology: 1) How do interannual hydrological balancee and pathway components vary in complex temperate high mountain environments at various spatio-temporal scales? 2) a) Is it possible, using dedicated hydrological models, for significant errors in simulated runoff components despite good hydrograph recreations (i.e. right results for wrong reasons)? b) If so, what kinds of errors are encountered? The first question was addressed by undertaking a hydrological tracer and hydrometric study at three basin scales (Banff —2200 km2, Lake Louise —400 km2 and the headwaters —30 km2) within the Bow …


Upper Spokane River Model: Model Calibration, 1991 And 2000, Chris Berger, Robert Leslie Annear, Scott A. Wells Jan 2002

Upper Spokane River Model: Model Calibration, 1991 And 2000, Chris Berger, Robert Leslie Annear, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:

• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam. • Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen and nutrient dynamics)

This report evaluates the model calibration and discusses issues relative to that calibration effort. …


Validation Of The Ce-Qual-W2 Version 3 River Basin Hydrodynamic And Water Quality Model, Scott A. Wells Jan 2002

Validation Of The Ce-Qual-W2 Version 3 River Basin Hydrodynamic And Water Quality Model, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

CE-QUAL-W2 Version 3, a 2-D (longitudinal-vertical) hydrodynamic and water quality model for river basins combining both river and stratified river-estuary and lakereservoir flow, is a development product of the Waterways Experiment Station in Vicksburg, MS, USA. With the development and release of any revised or reformulated model codes, significant model validation is required. This includes comparison of model results to simple analytical solutions for hydrodynamics and water quality transport, as well as comparison to laboratory and field data. In this paper, the model is compared to numerous analytical solutions for mass transport (1-D advective mass transport) and hydrodynamics (impulsive wind …


Review Of Soil Conservation Legislation : Carnarvon Horticultural Area, Jean-Pierre Clement Jan 2002

Review Of Soil Conservation Legislation : Carnarvon Horticultural Area, Jean-Pierre Clement

Agriculture reports

Lower Gascoyne Management Strategy The Carnarvon horticultural area has suffered considerable erosion damage following flooding of the Gascoyne River. Factors contributing to the erosion include a move to greater vegetable production, the carrying out of unauthorised earthworks and general confusion about the laws that apply to land management and erosion control. With this context, the purpose of this report is: • to clarify the laws applying to erosion control in the Carnarvon horticultural area; • to identify the public authorities with management responsibility for erosion control; and • to suggest a model by which erosion controls and management responsibilities can …


The Meeting Of Two Microbial Worlds: Geochemistry Of The Sulfate-Methane Interface, Walter S. Borowski, Charles K. Paull, William Ussler Iii Jan 2002

The Meeting Of Two Microbial Worlds: Geochemistry Of The Sulfate-Methane Interface, Walter S. Borowski, Charles K. Paull, William Ussler Iii

EKU Faculty and Staff Scholarship

No abstract provided.


Cave Breakdown By Vadose Weathering, R. A. L. Osborne Jan 2002

Cave Breakdown By Vadose Weathering, R. A. L. Osborne

International Journal of Speleology

Vadose weathering is a significant mechanism for initiating breakdown in caves. Vadose weathering of ore bodies, mineral veins, palaeokarst deposits, non-carbonate keystones and impure, altered or fractured bedrock, which is intersected by caves, will frequently result in breakdown. Breakdown is an active, ongoing process. Breakdown occurs throughout the vadose zone, and is not restricted to large diameter passages, or to cave ceilings. The surfaces of disarticulated blocks are commonly coated, rather than having fresh broken faces, and blocks continue to disintegrate after separating from the bedrock. Not only gypsum, but also hydromagnesite and aragonite are responsible for crystal wedging. It …


Arctic Ice Export Events And Their Potential Impact On Global Climate During The Late Pleistocene, Dennis A. Darby, Jens F. Bischof, Robert F. Spielhagen, Steven A. Marshall, Stephen W. Herman Jan 2002

Arctic Ice Export Events And Their Potential Impact On Global Climate During The Late Pleistocene, Dennis A. Darby, Jens F. Bischof, Robert F. Spielhagen, Steven A. Marshall, Stephen W. Herman

OES Faculty Publications

Ice sheets in the North American Arctic and, to a lesser extent, those in northern Eurasia calved large quantities of icebergs that drifted through Fram Strait into the Greenland Sea several times during the late Pleistocene. These icebergs deposited Fe oxide grains (45-250 mum) and coarse lithic clasts >250 mum matched to specific circum-Arctic sources. Four massive Arctic iceberg export events are identified from the Laurentide and the Innuitian ice sheets, between 14 and 34 ka (calendar years) in a sediment core from Fram Strait. These relatively short duration (<1-4 kyr) events contain 3-5 times the background levels of Fe oxide grains. They began suddenly, as indicated by a steep rise in the number of grains matched to an ice sheet source, suggesting rapid purges of ice through Fram Strait, due perhaps to collapse of ice sheets. The larger events from the northwestern Laurentide ice sheet are preceded by events from the Innuitian ice sheet. Despite the chronological uncertainties, the Arctic export events appear to occur prior to Heinrich events.


Dune Morphology Response To Water Level Change, Pinery Provincial Park, Ontario, Canada, Michael C.A. Bitton Jan 2002

Dune Morphology Response To Water Level Change, Pinery Provincial Park, Ontario, Canada, Michael C.A. Bitton

Theses and Dissertations (Comprehensive)

This thesis describes the geomorphological changes to a trough blowout in Pinery Provincial Park's sand dunes. The Park is located on Lake Huron’s southeastern shore where, due to rapid changes in Lake Huron water levels, a study could be completed examining the changes to blowout morphology based on the change in beach sediment supply. The study took place during relative low Lake Huron levels (1999-2000) and was compared to data collected during a period of relative high Lake Huron levels (1994-1995). Field research included erosion pin measurement to monitor and verify morphological change through the throat of the blowout, aeolian …


Stratigraphy And Diagenesis Of The Paleoproterozoic Bushy Park Zinc-Lead Deposit, South Africa, William Daniel Baugaard Jan 2002

Stratigraphy And Diagenesis Of The Paleoproterozoic Bushy Park Zinc-Lead Deposit, South Africa, William Daniel Baugaard

Masters Theses

“The Bushy Park zinc-lead deposit is located in the Northern Cape Province, South Africa. The sulfides are hosted by karst-related breccias that were formed in carbonate shelf deposits of the Neoarchean (2.55 Ga) Campbellrand Subgroup. These rocks are dolomitized completely and silicified partially but have not undergone major metamorphism and thus display remarkable preservation of depositional fabrics. The stratigraphic interval includes the Papkuil and Klippan Formations (> 210 m), a sequence of cyclic microbial laminates interbedded with domed and columnar stromatolites. The Klippan is distinguished from other formations b intense silicification and brecciation. These strata are overlain by the Kogelbeen …


Outcrop To Subsurface Stratigraphy Of The Pennsylvanian Hermosa Group Southern Paradox Basin U.S.A., Alan Lee Brown Jan 2002

Outcrop To Subsurface Stratigraphy Of The Pennsylvanian Hermosa Group Southern Paradox Basin U.S.A., Alan Lee Brown

LSU Doctoral Dissertations

Pennsylvanian (Desmoinesian) sedimentary rocks within the Paradox Basin Four Corners area of the western United States afford a unique opportunity to study the development of sedimentary successions in a complex marine to nonmarine depositional setting. The close association of thick intervals of nonmarine fan-delta facies adjacent to and in time equivalent position to marine carbonate-evaporite facies suggests complex relationships between the factors affecting deposition. Development of an effective scheme to differentiate the depositional signatures from within these sedimentary successions is the primary goal of this study. To achieve this goal, two objectives were pursued. The first was to calibrate the …


Modeling The Biogeochemical Cycle Of Selenium In The San Francisco Bay, Shannon L. Meseck Jan 2002

Modeling The Biogeochemical Cycle Of Selenium In The San Francisco Bay, Shannon L. Meseck

OES Theses and Dissertations

Due to recent concerns about selenium toxicity in the San Francisco Bay and the roles of refinery and San Joaquin River inputs on the selenium cycle, the model ECoS 3 (distributed from Plymouth Marine Laboratory, United Kingdom) was modified to simulate the biogeochemical cycle of selenium in the Northern Reach. The model is designed to simulate salinity, total suspended material, phytoplankton concentrations, dissolved selenium and its speciation (selenite, selenate, and organic selenide), and particulate selenium and its speciation (selenite + selenate, elemental selenium, and organic selenide). Actual data from 1999 were used to calibrate the model, while data from other …


In Situ Hydraulic Testing And Water Quality Sampling In The Hyporheic Zone Of The Columbia River, Hanford Reach, Washington, Evan V. Arntzen Jan 2002

In Situ Hydraulic Testing And Water Quality Sampling In The Hyporheic Zone Of The Columbia River, Hanford Reach, Washington, Evan V. Arntzen

Dissertations and Theses

Several chemical and radiological contaminants are present in an unconfined aquifer underlying the U.S. Department of Energy's Hanford Site in southeast Washington State. Hexavalent chromium [Cr(VI)], previously used as an anticorrosive in plutonium production reactors on the shoreline of the Columbia River, is of particular concern because of its conservative nature, toxicity to humans and aquatic life, and proximity to protected salmon spawning habitat. Hydrogeologic data are abundant from the unconfined aquifer, but are lacking from the hyporheic zone through which Cr(VI) is transported into the river. A hydrogeologic study was conducted near one known Cr(VI) plume to determine the …


Using Simulated Annealing In Geostatistics, Wesley Wells Jan 2002

Using Simulated Annealing In Geostatistics, Wesley Wells

Theses : Honours

Simulation methods are now used extensively for estimation and prediction in mining and petroleum industries and also in environmental management. In this thesis we describe the method of simulated annealing and examine in detail the GSLIB implementation algorithm SASJM. In the context of two case studies involving both sample and exhaustive data sets, we demonstrate this algorithm and then investigate the effect on the outcome of varying the different algorithm parameters. We also consider the effect of varying the weighting given in the simulated annealing objective function to the reproduction of each of the sample histogram and semivariogram. For the …


Stable Isotopes Of Carbon As An Invaluable Stratigraphic Tool: An Example From The Cambrian Of The Northern Appalachians, Usa, Bosiljka Glumac, Malkah L. Spivak-Birndorf Jan 2002

Stable Isotopes Of Carbon As An Invaluable Stratigraphic Tool: An Example From The Cambrian Of The Northern Appalachians, Usa, Bosiljka Glumac, Malkah L. Spivak-Birndorf

Geosciences: Faculty Publications

This study illustrates the usefulness of carbon isotopes in stratigraphic interpretations of poorly fossiliferous strata beyond the resolution possible by biostratigraphy. The Upper Cambrian strata of the lower Gorge Formation in northwestern Vermont have been interpreted as highly condensed continental-slope deposits with a hiatus bracketed by the trilobite fauna of the Dunderbergia zone (Steptoean) and the Saukia zone (upper Sunwaptan). This interpretation was based on information from two thin fossiliferous intervals, the occurrence of one of them being unconfirmed in a recent study. Carbon isotopes provide a means for testing this interpretation because marine carbonate rocks deposited during the Steptoean …


A High Resolution Gravity Survey Of The Lake St. Martin Impact Structure, Manitoba, Canada, Christina Davids Jan 2002

A High Resolution Gravity Survey Of The Lake St. Martin Impact Structure, Manitoba, Canada, Christina Davids

Theses and Dissertations

There are roughly 160 known impact craters listed in the Cratering Database (Earth Impact Database, 2002) of these approximately 20% are buried structures. Geophysical methods of investigation are used to study buried impact structures and add to the growing knowledge base of crater properties. Approximately three to five craters are discovered each year, some of which may be identified through gravity anomalies. A high-resolution gravity survey of the Lake St. Martin impact structure, southern Manitoba, Canada, was conducted to further interpret the structure's gravity anomaly. Previous studies have suggested two different crater diameters for Lake St. Martin, one of 23-km …


Salinity In The Classrom, A Resource For Western Australian Schools, Department Of Agriculture, Western Australia, Department Of Education, Western Australia, State Salinity Council, Western Australia Jan 2002

Salinity In The Classrom, A Resource For Western Australian Schools, Department Of Agriculture, Western Australia, Department Of Education, Western Australia, State Salinity Council, Western Australia

Books & book chapters

A Western Australian educational resource for teachers and students of the early, middle and early adolescent phases of learning.

Work is sponsored by Alcoa, Shell, State Salinity Council, Department of Agriculture, Water Rivers Commission.

Contributing authors from the Department of Agriculture are: Gale Bell, David Bicknell, Bruce Radys, Kirsty Chandler and Anne Jones.
Contributing authors from Department of Education WA; Kevin Brady, Michael Burke.
Contributing authors from State Salinity Council; Don Crawford.


Force Balance Along An Inland Tributary And Onset To Ice Stream D, West Antarctica, Stephen F. Price, R. A. Bindschadler, Christina L. Hulbe, Donald D. Blankenship Jan 2002

Force Balance Along An Inland Tributary And Onset To Ice Stream D, West Antarctica, Stephen F. Price, R. A. Bindschadler, Christina L. Hulbe, Donald D. Blankenship

Geology Faculty Publications and Presentations

The transition from inland- to streaming-style ice flow near to and upstream from the onset to Ice Stream D, West Antarctica, is investigated using the force- balance technique. Basal drag provides the majority of the flow resistance over the study area but is substantially modified by non-local stress gradients. Lateral drag increases with distance downstream, balancing ~50-100% of the driving stress at the onset. Longitudinal stress gradients (LSG) are also found to be significant, an observation that distinguishes ice flow in this region from the inland- and streaming-flow regimes that bound it, in which LSG are usually negligible. LSG decrease …


Barium And Lithium In Foraminifera: Glacial-Interglacial Changes In The North Atlantic, Jenney M. Hall Jan 2002

Barium And Lithium In Foraminifera: Glacial-Interglacial Changes In The North Atlantic, Jenney M. Hall

LSU Doctoral Dissertations

The trace element content of calcareous foraminifera provides a powerful tool to the study of glacial-interglacial changes in the physical and chemical properties of the ocean. Foraminifera incorporate barium in direct proportion to its concentration in seawater. Using barium as a nutrient proxy, Ba/Ca in benthic Planulina wuellerstorfi is used to reconstruct changes in thermocline ventilation and mid-depth circulation in the North Atlantic during the last glacial and deglacial time. Rivers are concentrated in barium compared to surface seawater. Therefore, barium in planktonic Neogloboquadrina pachyderma is used to identify deglacial meltwater in the Arctic Ocean. Foraminiferal Li/Ca was analyzed to …


A New Occurrence Of Archaeoscyphia Pulchra (Bassler) From The Ordovician Of Western Canada, J. Keith Rigby, Godfrey S. Nowlan, Peter A. Rowlands Jan 2002

A New Occurrence Of Archaeoscyphia Pulchra (Bassler) From The Ordovician Of Western Canada, J. Keith Rigby, Godfrey S. Nowlan, Peter A. Rowlands

Faculty Publications

A few specimens of the ornate anthaspidellid demosponge, Archaeoscyphia pulchra (Bassler), have been collected from the Lower Ordovician Outram Formation or Skoki Formation, from a saddle at the head of South Rice Brook in northeastern British Columbia. This is the first report of the flanged-appearing annulate, steeply obconical sponge in western Canada, although it has been reported from the Mingan Islands of Quebec and was initially described from Nevada, in the western United States. The taxon has also been reported as other species of Archaeoscyphia from Ordovician rocks of Missouri and from the San Juan region of Argentina.


Subsidence Hazards In Different Types Of Karst: Evolutionary And Speleogenetic Approach, Alexander Klimchouk Jan 2002

Subsidence Hazards In Different Types Of Karst: Evolutionary And Speleogenetic Approach, Alexander Klimchouk

International Journal of Speleology

The typology of karst, based on distinguishing the successive stages of general hydrogeological evolution, between which major boundary conditions and the overall circulation pattern change considerably, gives a natural clue, properly to classify and tie together karst breakdown settings, speleogenetic styles and breakdown development mechanisms. Subsidence hazards vary substantially between the different karst types so that classifying individual karst according to typology can provide an integrated general assessment. This provides a useful basis for selection and realization of region- and site-specific assessment schemes and management strategies. Intrastratal karst types, subjacent karst in particular, are most potent in generating subsidence problems. …


The Engineering Classification Of Karst With Respect To The Role And Influence Of Caves, Tony Waltham Jan 2002

The Engineering Classification Of Karst With Respect To The Role And Influence Of Caves, Tony Waltham

International Journal of Speleology

The engineering classification of karst defines various complexities of ground conditions, in terms of the hazards that they provide to potential construction. Karst is divided into five classes (from immature to extreme). The three key parameters within the classification are caves (size and extent), sinkholes (abundance and collapse frequency) and rockhead (profile and relief). As one component of karst, caves are a hazard to foundation integrity, though natural surface collapses over caves are extremely rare. A cave roof is normally stable under engineering loading where the roof thickness is greater than 70% of the cave width. Construction can proceed over …


Karst Breakdown Mechanisms From Observations In The Gypsum Caves Of The Western Ukraine: Implications For Subsidence Hazard Assessment, Alexander Klimchouk, Vjacheslav Andrejchuk Jan 2002

Karst Breakdown Mechanisms From Observations In The Gypsum Caves Of The Western Ukraine: Implications For Subsidence Hazard Assessment, Alexander Klimchouk, Vjacheslav Andrejchuk

International Journal of Speleology

The term karst breakdown is employed in this paper to denote the totality of processes and phenomena of gravitational and/or hydrodynamic destruction of the ceiling of a karst cavity and of the overlying sediments. It refers not only to the existence of a surface subsidence (collapse) feature but, first of all, to the “internal” (hidden in the subsurface) structures that precede development of a surface form. This study reports and discusses the results of direct mapping and examination of breakdown structures in the gypsum karst of the Western Ukraine, at the level of their origin, i.e. in caves. The accessibility …


Collapse Dolines And Deflector Faults As Indicators Of Karst Flow Corridors, France Šušteršič Jan 2002

Collapse Dolines And Deflector Faults As Indicators Of Karst Flow Corridors, France Šušteršič

International Journal of Speleology

The paper concerns collapse dolines, which appear to be one of the best-defined surface karst phenomena. Despite this appearance, one may find quite different views in the literature, and some of the aspects of their morphogenesis have been overlooked completely. Among these aspects the most obvious is the question of the ongoing development of the closed depression. Five of the most common collapse doline types found in Slovenia are considered in terms of general systems theory, leading to a conclusion that cave roof collapse remains the crucial event in a collapse doline’s development. However, the collapse event itself may be …


Stability Appraisal Of The Medvedova Konta Pothole, Jože Kortnik Jan 2002

Stability Appraisal Of The Medvedova Konta Pothole, Jože Kortnik

International Journal of Speleology

Until 1956 the underground details of areas around Pokljuka were practically unknown due to the area’s non-karstic outward appearance. However, the presence of karst phenomena on this Alpine plain is undoubtedly indicated, primarily by the absence of a surface drainage network. A mathematical model was made of the Medvedova konta pothole, in which two different sets of material properties were used, corresponding to the Triassic limestone that forms the bedrock under the greater part of Pokljuka. The model simulates the gradual thinning of the ceiling of the underground hall, from the surface downwards, until its collapse. The paper presents a …