Spelling suggestions: "subject:"mountain.""
81 |
Glaciological studies in the St. Elias Range, CanadaRigsby, George P. Sharp, Robert P. January 1950 (has links)
Thesis (Masters)--California Institute of Technology, 1950. / Title from home page (viewed 04/27/2010). Includes bibliographical references.
|
82 |
Quartz-feldspar-carbonate bodies of the Carrizo Mountains, TexasLoidolt, Lawrence Henry, 1943-, Loidolt, Lawrence Henry, 1943- January 1970 (has links)
No description available.
|
83 |
Snow glide and full-depth avalanche occurrence, Cascade Mountains, British ColumbiaClarke, Jennifer A. January 1900 (has links)
Snow glide is the translational slip of the entire snow pack over a sloping ground surface. It is
thought that rapid rates of snow glide precede the release of full-depth avalanches. The nature
of avalanches that release at the ground makes them difficult to predict and difficult to control
using explosives. The aim of this research is to determine the relationship between rapid snow
glide and full-depth avalanche occurrence and to examine climate factors affecting both
processes. Data collected from an instrumented site along the Coquihalla Highway in the
Cascade Mountains of British Columbia were used for analysis during two winter seasons (1992-93, 1993-94).
Glide is influenced by the nature of the interaction between the roughness of the ground and the
snow pack, and by the distribution of water at the interface. The presence of water at the
interface affects the material properties of snow and the friction conditions. The impact of freewater
on glide is influenced by the volume and rates of water input. Higher glide rates and fulldepth
avalanche release are the almost immediate responses to contributions of free-water. The
data show that the most significant contributor is rainfall, which is common in the study area
throughout the winter season. The supply of free-water from snow melt due to radiative and
thermal sources of energy become more significant in the spring.
Water inputs increase the thickness of the saturated layer at the base of the snow pack, allowing
greater amplitudes of roughness to be overcome. By drowning or partially drowning the
roughness elements, a thin film of water reduces the shear resistance of the snow pack to
downslope movement. Inputs of water at rates higher than transmissions rates will increase pore
pressures and decrease shear stress encouraging further downslope movement. Failure of the
snow pack at the ground is translational, most often occurring 12-24 hours after a rainfall event,
but sometimes much later when avalanche release would not be expected.
Although there is no threshold glide velocity associated with avalanche release, it can be
concluded that snow glide is a good indicator of active periods of full-depth avalanche
occurrence. However, results from this study show that rainfall rates and snow melt rates may
be more accurate predictors of avalanche occurrence in the study area. / Arts, Faculty of / Geography, Department of / Graduate
|
84 |
Cenozoic thermal and tectonic history of the Coast Mountains of British Columbia : as revealed by fission track and geological data and quantitative thermal modelsParrish, Randall Richardson January 1982 (has links)
Fission track dating of zircon and apatite has been used to determine the Cenozoic uplift history of the British Columbia Coast Mountains from 50°-55°N. 115 dates were obtained from rocks of variable geographic location and altitude, and the resulting date pattern constrains the movement and deformation of the fission track retention isotherms (175°C for zircon, 105°C for apatite) within the crust.
Because date-altitude correlations (apparent uplift rates) cannot always be used confidently to estimate actual rates of uplift, a finite difference numerical scheme was formulated to construct models of heat flow, uplift, denudation, and cooling that satisfy not only fission track dates, but also present heat flow, other isotopic dates, geologic considerations, and fission track-derived estimates of paleo-geothermal gradient. In most cases, apparent uplift rates derived from apatite date-altitude correlations are very close to modeled rates of uplift. Zircon-derived apparent rates, however, often exceed modeled rates and reflect post-orogenic cooling a,nd relaxation of isotherms. The relationship of the movement of isotherms to rates of uplift and fission track-derived apparent uplift rates is quantified and discussed.
Orogenic rapid cooling and uplift occurred from Cretaceous to Eocene time in most of the Coast Mountains. Rates during orogenic uplift were near 1.0 km/Ma, causing
setting of K-Ar clocks in biotite and hornblende. Uplift rates during the middle Cenozoic ranged from 0.2 km/Ma in the axial region of the mountains between 52° and 55°N to less than 0.1 km/Ma south of 52°N. The moderate rates north of 52°N were likely the result of gradual erosion of crust thickened during Eocene orogeny. A thermal origin for this northern uplift is not likely. Rates of uplift south of 52°N were low despite arc-related volcanic activity during the Oligocene and Miocene.
Accelerated uplift in the Late Miocene near Bella Coola-Ocean Falls was probably the result of passage of the transverse Anahim Volcanic Belt or hotspot beneath the area about 10 Ma ago, after which uplift slowed.
Rapid Pliocene-Recent uplift south of 52°N at rates of up to 0.75 km/Ma elevated a broad region creating the present southern Coast Mountains and deforming 7-10 Ma lavas erupted on the mountains' east flank. It is suggested that this uplift resulted from thermal expansion in the mantle related to a westward jump in the locus of late Neogene arc volcanism. The extent of this rapid Pliocene-Recent uplift correlates with the area above the Juan de Fuca-Explorer subducted slab and confirms a relation between continental uplift and plate tectonic setting. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
|
85 |
Geology of Scott Glacier and Wisconsin Range areas, Central Transantarctic Mountains, Antarctica /Minshew, Velon H. January 1967 (has links)
No description available.
|
86 |
Stratigraphy and structure of the Palen Formation, Palen Mountains, southeastern CaliforniaLeVeque, Richard Alan January 1981 (has links)
No description available.
|
87 |
Exploration characteristics of native copper mineralization in the Silver Bell andesite at Las Guijas, Pima County, ArizonaHirt, William Carl January 1978 (has links)
No description available.
|
88 |
Geomorphology of the Box Canyon Drainage Basin, Santa Rita Mountains, Pima County, ArizonaVan Fleet, John Milton, 1948- January 1973 (has links)
No description available.
|
89 |
Structure and petrography of the Bullock Canyon-Buehman Canyon area, Pima County, ArizonaRaabe, Robert George, 1925- January 1959 (has links)
No description available.
|
90 |
OAK FUELWOOD VOLUME ESTIMATION IN THE HUACHUCA MOUNTAINS OF ARIZONA (EMORY OAK)Dueñez, Ricardo Luis, 1954- January 1987 (has links)
No description available.
|
Page generated in 0.051 seconds