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1998

Earth Sciences

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Articles 241 - 270 of 289

Full-Text Articles in Physical Sciences and Mathematics

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer Jan 1998

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer

Journal of the Arkansas Academy of Science

Sections and subsections of the Interior Highlands of Arkansas and Oklahoma are redefined, mapped and briefly summarized. The map was produced to support the Ozark- Ouachita Highlands Assessment (OOHA), being conducted by the USDA Forest Service. It revises the USDA Forest Service map "Ecological units of the eastern United States, first approximation" by Keys et al. (1995) and the earlier maps of the natural divisions of Arkansas (Foti, 1974; Foti, 1976; Pell, 1983) to reflect new knowledge and to achieve consistency with units recognized in Missouri. Four sections (natural divisions) are defined as opposed to the three of the previous …


Inventory Of Sub-Catchments Within The Albany Eastern Hinterland, B Radys Jan 1998

Inventory Of Sub-Catchments Within The Albany Eastern Hinterland, B Radys

Resource management technical reports

The release of the "Salinity Action Plan for Western Australia' in December 996 highlighted the need for catchment scale planning and coordinated actions to reverse salinity trends.

A separate report has been produced for each major catchment area. Each report contains and inventory of all sub-catchments, with information on area, degradation risks and group activities with each catchment.


9. Alteration Of Uppermost Lavas And Volcaniclastics Recovered During Leg 152 To The East Greenland Margin, Mary Anne Holmes Jan 1998

9. Alteration Of Uppermost Lavas And Volcaniclastics Recovered During Leg 152 To The East Greenland Margin, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

During the last stages of the eruption of syn-rift basalts along the East Greenland Margin, debris flows and/or pyroclastic deposits were emplaced at Ocean Drilling Program Sites 915 and 916. The deposits and the tops of the lava flows at Site 918 were altered by subaerial weathering processes as indicated by downhole changes in mineral and chemical composition, and by the mineral paragenesis. Kaolinite and goethite, which form in acidic waters, are abundant at the tops of the weathering profiles and decrease in abundance downward. They are replaced by a smectite-hematite-opal assemblage at the bases of the weathered profiles. Gibbsite …


Calcareous Nannofossil Paleogene Biostratigraphy Côte D'Ivoire-Ghana Marginal Ridge, Eastern Equatorial Atlantic, Samir Shafik, David K. Watkins, Im Chul Shin Jan 1998

Calcareous Nannofossil Paleogene Biostratigraphy Côte D'Ivoire-Ghana Marginal Ridge, Eastern Equatorial Atlantic, Samir Shafik, David K. Watkins, Im Chul Shin

Department of Earth and Atmospheric Sciences: Faculty Publications

Paleogene sections on the Côte d’Ivoire-Ghana Marginal Ridge in the eastern Atlantic Ocean, sampled at three sites during Ocean Drilling Program Leg 159, are shown to have calcareous nannofossil assemblages in distinct packages of (sub)zones separated by hiatuses or barren sediments. The packages are different at each of the sites; all fall within the interval from late Paleocene Zone CP6 to latest Oligocene Subzone CN1a inclusive. Three packages (CP9b–CP11, CP13, and CP19) on the crest of the Marginal Ridge at Site 960, four (CP7–CP9b, CP11, CP13–?CP15, and CP17–CN1a) at nearby Site 959 on the shoulder of the Marginal Ridge, and …


Data Report: Pump Sampling And Sediment Analysis In Support Of The Sensor Insertion System Duck, N.C. April And October, 1997, Grace M. Massey, Carl T. Friiedrichs, Amo De Kruif, Daan C. Rijks Jan 1998

Data Report: Pump Sampling And Sediment Analysis In Support Of The Sensor Insertion System Duck, N.C. April And October, 1997, Grace M. Massey, Carl T. Friiedrichs, Amo De Kruif, Daan C. Rijks

Reports

The objectives of this study were to (i) construct a pumping system, (ii) operate the system and collect samples of suspended sediment across the width of the surf zone during two major field experiments planned for the SIS in 1997, and (iii) analyze the resulting samples for sand concentration, sand size distribution, total percent sand, total percent mud, and organic content. The purpose was to provide a high quality data set of pump samples with which to later test the sensitivity of indirect measurements of suspended sand concentration to the presence of suspended mud. The response of OBSs is known …


A Geochemical Study Of Marine Sediments From The Mac. Robertson Shelf, East Antarctica: Initial Results And Palaeoenvironmental Implications, Peter N. Sedwick, P. T. Harris, L. G. Robertson, G. M. Mcmurtry, M. D. Cremer, P. Robinson Jan 1998

A Geochemical Study Of Marine Sediments From The Mac. Robertson Shelf, East Antarctica: Initial Results And Palaeoenvironmental Implications, Peter N. Sedwick, P. T. Harris, L. G. Robertson, G. M. Mcmurtry, M. D. Cremer, P. Robinson

OES Faculty Publications

Sediments from the Antarctic continental margin may provide detailed palaeoenvironmental records for Antarctic shelf waters during the late Quaternary. Here we present results from a palaeoenvironmental study of two sediment cores recovered from the continental shelf off Mac. Robertson Land, East Antarctica. These gravity cores were collected approximately 90 km apart from locations on the inner and outer shelf. Both cores are apparently undisturbed sequences of diatom ooze mixed with fine, quartz-rich sand. Core stratigraphies have been established from radiocarbon analyses of bulk organic carbon. Down-core geochemical determinations include the lithogenic components Al and Fe, biogenic components opal and organic …


Phosphorus In The Landscape: Diffuse Sources To Surface Waters. Land And Water Resources Research And Development Corporation. Occasional Paper 16/98, Richard Davis, Anne Hamblin, E O'Loughlin, Nic Austin, R Banens, P Cornish, P Hairsin, M Mcculloch, Phil Moody, J Olley, B Prove, I Smalls, David Weaver Jan 1998

Phosphorus In The Landscape: Diffuse Sources To Surface Waters. Land And Water Resources Research And Development Corporation. Occasional Paper 16/98, Richard Davis, Anne Hamblin, E O'Loughlin, Nic Austin, R Banens, P Cornish, P Hairsin, M Mcculloch, Phil Moody, J Olley, B Prove, I Smalls, David Weaver

All other publications

The National Eutrophication Management Program (NEMP) and Environment Australia convened a workshop to develop a coherent overview of the sources and transport of diffuse phosphorus in Australian catchments based on the latest knowledge. The Land and Water Resources Research and Development Corporation (LWRRDC) and the Murray–Darling Basin Commission (MDBC) jointly fund NEMP. A select group of scientists attended the workshop and developed a coherent statement about phosphorus sources and transport in Australian catchments. The group did not extend this statement to include recommended management practices. This paper reports the findings from the workshop. State governments have developed algal and nutrient …


The Use Of Red Mud/Gypsum To Reduce Water Pollution From Sandy Soils Used For Vegetable Production, Ian Mcpharlin, W. J. Robertson, R. C. Jeffery Jan 1998

The Use Of Red Mud/Gypsum To Reduce Water Pollution From Sandy Soils Used For Vegetable Production, Ian Mcpharlin, W. J. Robertson, R. C. Jeffery

Research Reports

An important domestic and export vegetable industry is located on the sands of the Swan Coastal Plain (SCP) in Western Australia. The total value of the vegetable industry on the SCP was estimated at $90M in 1996/7 or about 50% of the total value of the industry. This vegetable production has been located on good quality sands such as the Spearwood and yellow Karrakatta sands, close to the coast, since the 1950s. However in recent years competition for this land for urban and industrial use has forced vegetable production onto soils with poorer water and phosphorus retention capacity such as …


Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 3 Hunts' Catchment (Frankland), A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr Jan 1998

Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 3 Hunts' Catchment (Frankland), A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr

Resource management technical reports

High water use vegetation systems for salinity control were trialed on an 80 ha catchment located 12 km east of Frankland, Western Australia. The catchment receives about 510 mm annual rainfall and 1525 mm annual evaporation. Development of salinity in the catchment is concentrated in the valley floor. Here the groundwater is extremely saline (3000-4000 mS/m) and piezometric levels are between 1 m below and 1 m above the surface.


Inventory Of Sub-Catchments Within The Wilson Inlet Catchment, B Radys Jan 1998

Inventory Of Sub-Catchments Within The Wilson Inlet Catchment, B Radys

Resource management technical reports

The release of the "Salinity Action Plan for Western Australia' in December 996 highlighted the need for catchment scale planning and coordinated actions to reverse salinity trends.

A separate report has been produced for each major catchment area. Each report contains and inventory of all sub-catchments. with information on area, degradation risks and group activities with each catchment.


Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 : 6. Summary Of All Sites, A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr, Peter J. Tille Jan 1998

Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 : 6. Summary Of All Sites, A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr, Peter J. Tille

Resource management technical reports

The south-western Woolbelt receives annual rainfall between 500-700 mm with long dry summers and cool wet winters. The dominant land use is grazing of Merino sheep for wool productiion, with smaller areas (5-15%) of cropping. All of the catchments selected were affected by salinity, but the extent and severity varied. In all catchments the location of the major expression of salinity was the valley floor.


Optical Digital Fragmentation Measuring Systems -- Inherent Sources Of Error, Norbert H. Maerz, Wei Zhou Jan 1998

Optical Digital Fragmentation Measuring Systems -- Inherent Sources Of Error, Norbert H. Maerz, Wei Zhou

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Automated optical imaging systems of measuring fragmentation are increasingly being used in the mining, comminution, and materials handling industries. These methods have been well received in many of the industries involved. Considering that in many of these applications there are no alternative ways of sizing material, having even a rudimentary measurement of size distributions allows evaluations of explosive, blast design, detonator performance, crusher and milling performance, and material degradation due to transport.

Optical methods have inherent limitations, which reflect on accuracy, precision, and reproducibility of measurement results. This stems from the fact that there are myriads of variables, which affect …


Comparison Of Median Indicator Kriging With Full Indicator Kriging In The Analysis Of Spatial Data, Donna Hill Jan 1998

Comparison Of Median Indicator Kriging With Full Indicator Kriging In The Analysis Of Spatial Data, Donna Hill

Theses : Honours

In the earth sciences, and particularly in the mining of precious metals, data distributions are often strongly positively skewed. When making decisions on the potential profitability of a gold mine, for example, the high values of the distribution are of particular importance. Indicator kriging provides estimates of cumulative distribution functions from which grade tonnage curves may be calculated. Multiple or full indicator kriging requires a semivariogram to be modelled and a kriging system of equations to be solved for each cut off. This can be time consuming and modelling indicator semivariograms at high cut-offs may be difficult because of the …


Resource News-Spring 1998 Jan 1998

Resource News-Spring 1998

Conservation and Survey Division

No abstract provided.


Overview Of The 8th International Symposium On Vulcanospeleology, William R. Halliday Jan 1998

Overview Of The 8th International Symposium On Vulcanospeleology, William R. Halliday

International Journal of Speleology

In February 1998 the 8h International Symposium on Vulcanospeleology was hosted by CEGEA (Cave Exploration Group of East Africa) in Nairobi, Kenya: it was attended by 16 scientists coming from 4 continents. Pre- and Post- Symposium excursions allowed the participants to have an overview on the most important and famous volcanic cave of that area.


Volcanic Caves Of East Africa - An Overview, Jim W. Simons Jan 1998

Volcanic Caves Of East Africa - An Overview, Jim W. Simons

International Journal of Speleology

Numerous Tertiary to recent volcanoes are located in East Africa. Thus, much of the region is made up volcanic rock, which hosts the largest and greatest variety of East Africas caves. Exploration of volcanic caves has preoccupied members of Cave Exploration Group of East Africa (CEGEA) for the past 30 years. The various publications edited by CEGEA are in this respect a treasure troves of speleological information. In the present paper an overview on the most important volcanic caves and areas are shortly reported.


The Cave Exploration Group Of East Africa And Volcanic Caves In Kenya, Michael Declan Kennedy Jan 1998

The Cave Exploration Group Of East Africa And Volcanic Caves In Kenya, Michael Declan Kennedy

International Journal of Speleology

This paper looks at the history of the Cave Exploration Group of East Africa with special reference to the exploration of volcanic caves. It demonstrates that the group has concentrated on two main areas, the Chyulu HiIls and Mt. Suswa, although other areas have also been studied. The Cave Exploration Group of East Africa has had to cope with various problems. The most important of which are related to the socio-economic conditions of a developing country. These problems have not prevented the group from making a valuable contribution to vulcanospeleology.


Lave Caves Of Kilimanjaro. Mawenzi Lava Tubes, Clive Ward Jan 1998

Lave Caves Of Kilimanjaro. Mawenzi Lava Tubes, Clive Ward

International Journal of Speleology

This is the first short report on the exploration of lava tubes in the upper part of Kilimanjaro. The area seems to be extremely interesting from vulcanospeleological point of view.


Lava Caves Of Grande Comore, Indian Ocean: An Initial Reconnaissance, September 1997, Gregory J. Middleton Jan 1998

Lava Caves Of Grande Comore, Indian Ocean: An Initial Reconnaissance, September 1997, Gregory J. Middleton

International Journal of Speleology

What are believed to have been the first speleological investigations in the Comoros Islands were carried out on Grande Comore island between 7 and 13 September 1997. A number of caves were located with the help of local informants and the more significant ones surveyed. Exploration of some caves was not able to be completed. The potential for further significant discoveries is believed to be high.


"Pit Craters", Lava Tubes, And Open Vertical Volcanic Conduits In Hawaii: A Problem In Terminology, William R. Halliday Jan 1998

"Pit Craters", Lava Tubes, And Open Vertical Volcanic Conduits In Hawaii: A Problem In Terminology, William R. Halliday

International Journal of Speleology

Almost from the 1849 publication of the term pit crater, volcanologists have disagreed about the parameters differentiating these features from other vertical volcanic structures. Kaluaiki is a jameo giving entry to Thurston Lava Tube in Hawaii Volcanoes National Park. Long-standing misidentification of it as a pit crater is an example of misunderstandings arising from the lack of a clear definition of pit crater. In general, pit craters are unrelated to lava tube caves genetically, but two special cases are discussed. One probably is genetically related to a rift tube deep below the surface; the other is a complex of a …


The Origin Of Tubular Lava Stalactites And Other Related Forms, Kevin Allred, Carlene Allred Jan 1998

The Origin Of Tubular Lava Stalactites And Other Related Forms, Kevin Allred, Carlene Allred

International Journal of Speleology

Tubular lava stalactites are often found in lava tubes. Field observations, sample analysis, and comparative studies indicate that these are segregations extruded during cooling from partially crystallized lava al about 1,070 - 1,000 °C. Retrograde boiling (gas pressure) within the lava provides a mechanism to expel the interstitial liquid. In addition to tubular lava stalactites, a variety of other lava features can also result, such as lava helictites, lava coralloids, barnacle-like stretched lava, runners, runner channels, and some lava blisters and squeeze-ups.


The 1981 Eruptive Fissure On Mt. Etna: Considerations On Its Exploration And Genesis, Angelo Leotta, Marco Liuzzo Jan 1998

The 1981 Eruptive Fissure On Mt. Etna: Considerations On Its Exploration And Genesis, Angelo Leotta, Marco Liuzzo

International Journal of Speleology

This paper is targeted to an analysis of features common to various fissure caves on Mt. Etna, Sicily. The Authors report the preliminary results of the exploration carried out in the 1981 eruptive fissure, the technical problems met during the exploration, the flow trends and the different courses of the molten material inside the fissure, the particular morphologies. A genetic model is proposed, different from those characterising the lava tube cave genesis, and links are suggested between the various fissures and the main tectonic stress systems operating on Mt. Etna, as well as the morpho-structural conditions of the volcanic edifice …


Chemical Deposits In Volcanic Caves Of Argentina, Carlos Benedetto, Paolo Forti, Ermanno Galli, Antonio Rossi Jan 1998

Chemical Deposits In Volcanic Caves Of Argentina, Carlos Benedetto, Paolo Forti, Ermanno Galli, Antonio Rossi

International Journal of Speleology

During the last Conference of the FEALC (Speleological Federation of Latin America and Caribbean Islands) which was held in the town of Malargue, Mendoza, in February 1997, two volcanic caves not far from that town were visited and sampled for cave mineral studies. The first cave (Cueva del Tigre) opens close to the Llancanelo lake, some 40 kms far from Malargue and it is a classical lava tube. Part of the walls and of the fallen lava blocks are covered by white translucent fibres and grains. The second visited cave is a small tectonic cavity opened on a lava bed …


Tectonic Caves Of Solai In The Kenyan Rift Valley, Robert A. Davis Jan 1998

Tectonic Caves Of Solai In The Kenyan Rift Valley, Robert A. Davis

International Journal of Speleology

Tectonic caves at Solai, Kenya, were explored in 1970. These lie in a complex geological area of the Great Rift Valley in columnar-faulted ignimbrite. Fissures are presumed to have been widened by later tectonic activity -e.g. the major earthquake of January, 1928. The caves and exploration are briefly described. Questions of formation, drainage and possibilities of steam reservoirs are discussed.


Hollow Volcanic Tumulus Caves Of Kilauea Caldera, Hawaii County, Hawaii, William R. Halliday Jan 1998

Hollow Volcanic Tumulus Caves Of Kilauea Caldera, Hawaii County, Hawaii, William R. Halliday

International Journal of Speleology

In addition to lava tube caves with commonly noted features, sizable subcrustal spaces of several types exist on the floor of Kilauea Caldera. Most of these are formed by drainage of partially stabilized volcanic structures enlarged or formed by injection of very fluid lava beneath a plastic crust. Most conspicuous are hollow tumuli, possibly first described by Walker in 1991. Walker mapped and described the outer chamber of Tumulus E-1 Cave. Further exploration has revealed that it has a hyperthermic inner room beneath an adjoining tumulus with no connection evident on the surface. Two lengthy, sinuous hollow tumuli also are …


Sheet Flow Caves Of Kilauea Caldera, Hawaii County, Hawaii, William R. Halliday Jan 1998

Sheet Flow Caves Of Kilauea Caldera, Hawaii County, Hawaii, William R. Halliday

International Journal of Speleology

Terminal lobes of sheet flows of pahoehoe lava sometimes form three-dimensional nests, initially separated by partitions consisting of accreted "skins” of each lobe. Melting breaks down these partitions, forming a uniform flow unit. In Kilauea Caldera we have found and mapped sizable drained cavities in low-slope sheet flows. Their general pattern includes three-dimensional nests, with partially melted septa evident in some examples. Christmas Cave is the most extensive found to date, with 632 meters surveyed on two levels. It is located at the lower end of an inflated sheet flow tongue which underwent local deflation as a result of drainage …


Lava Tube Remelt By Radiant Heat And Burning Gasses, Kevin Allred Jan 1998

Lava Tube Remelt By Radiant Heat And Burning Gasses, Kevin Allred

International Journal of Speleology

Some volcanologists assume that interior surfaces of hot lava tubes can commonly be remelted by burning gases and radiant heat. Pending further data, this appears to be unlikely.


Paleosols As Holocene Proxy Climate Indicators, Mclean County, North Dakota, Deborah L. Beck Jan 1998

Paleosols As Holocene Proxy Climate Indicators, Mclean County, North Dakota, Deborah L. Beck

Theses and Dissertations

An exposure with 15 buried A-horizons near Douglas Creek, Lake Sakakawea, central North Dakota, has provided an excellent opportunity for paleoclimate reconstruction. Analyses included texture, stable carbon, radiocarbon, pollen, and phytoliths. The variations in these properties between individual soil horizons served to reconstruct the former environments of each soil horizon.

The paleosols were developed in a sequence of deposits in a mile-long tributary to the Missouri River. The soils are in a shallow valley fill exposed by wave action along the north shore of Lake Sakakawea. The 1996 exposure was up to 4m high and 51.5m wide. There were up …


Gravity Drainage Prior To Cake Filtration, Scott A. Wells, Gregory K. Savage Jan 1998

Gravity Drainage Prior To Cake Filtration, Scott A. Wells, Gregory K. Savage

Civil and Environmental Engineering Faculty Publications and Presentations

During the initial stages of a Buchner funnel or specific resistance test, gravity drainage occurs prior to application of the pressure differential. Some allow time for a small cake to form by gravity drainage. Filtrate data from the gravity drainage period can be used to determine constitutive properties of the cake under a hydrostatic pressure gradient. The constitutive properties that define the structure of the cake include the permeability and porosity as functions of the applied stress. Equations governing the drainage rate during a gravity filtration experiment assuming a constant and a non-constant average cake permeability and cake porosity were …


Modeling Density Currents In Circular Clarifiers, Scott A. Wells, David M. Laliberte Jan 1998

Modeling Density Currents In Circular Clarifiers, Scott A. Wells, David M. Laliberte

Civil and Environmental Engineering Faculty Publications and Presentations

Design of sedimentation tanks for solid-liquid separation is often dependent on assuming ideal flow conditions. But the geometry of the tank and density currents as a result of temperature and suspended solids influences the fluid mechanics of the tank and can result in significant deviations from ideal flow.

A two-dimensional radial flow model was proposed which incorporated the effect of density currents resulting from temperature and suspended solids differentials within the tank. The numerical model predicted the steady-state, layer-averaged radial flow and layer depth.

The model solution and field data showed that the momentum and suspended solids of the inflow …