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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Thermal Conditions And Movement Of Rock Glaciers In The North Cascades, Washington, Joseph Goshorn-Maroney
Thermal Conditions And Movement Of Rock Glaciers In The North Cascades, Washington, Joseph Goshorn-Maroney
WWU Graduate School Collection
Rock glaciers are a largely unrecognized phenomenon in the North Cascades. In part this reflects their scarcity there. Additionally, because rock glaciers are widely held to be the product of permafrost conditions, the dearth of literature regarding North Cascade rock glaciers also reflects the notion that active rock glaciers should not exist at all in such temperate mountain ranges. Rock glaciers have been linked to specific air temperature conditions ( < -2°C), and, based on that link, are often used as visual indications of mountain permafrost. The North Cascades, a maritime mountain range with high snowfall and relatively warm climate, are a good location to test the permafrost-rock glacier link. Review of aerial photography and satellite imagery, however, reveals at least ten morphologically active rock glaciers and even more that appear inactive. To test the activity and possible link to permafrost conditions, I selected two of the active-looking rock glaciers for movement monitoring and thermal investigation. Movement monitoring was accomplished by conducting repeat scans with a terrestrial laser scanner; this investigation represents the first attempt to use this technique on rock glaciers in North America. The Craggy Peak rock glacier was shown to be moving downslope at a rate of 5 to 10 cm per year. Movement vectors toward the top of the rock glacier suggested deflation, while vectors toward the toe indicated a slight inflation. Flow toward the top and center of the rock glacier also was faster reflecting the steeper slope while flow toward the toe slowed and vectors radiated out. Movement was not detectable on second rock glacier, Star Peak, due mainly to lack of control points located on and around the scan target. Moreover, lack of a good vantage point at the site limited the scan coverage, inhibiting data processing. Because the North Cascades are a maritime mountain range with climate conditions thought to be too warm and wet to support rock glaciers, I also deployed miniature temperature data loggers in both rock glaciers to record air temperature at the surface and within the rubble. Three logger strings were deployed with three loggers. Each string contained one surface logger, one logger of intermediate depth and one logger that was between 1.5-2.3 meters deep in the rubble (depending on the string). One year of data has revealed that average ground temperature on the rock glaciers is probably near -1 ± 1° C and modeled near-surface air temperature above them is 0.0 ± 1.6° C. Air temperature is marginally to warm to support permafrost, though a more lengthy study period is needed. Thermal exchange during the summer appears to be governed by conductive processes in the form of rain water and solar heating. Moreover, forced convection occurs when wind pumps air into the regolith. During the fall, I document at least one instance where the data loggers capture natural convection when relatively warm air evacuated the regolith. Natural convection occurs when cold air overlays warm air and the subsequent density driven inversion results in warm air escaping into the air and cold air settling into the regolith.
Sedimentologic, Stable Isotopic, And Paleomagnetic Analysis Of Laramide Synorogenic Strata: Unroofing Of The Beartooth Range, Montana And Wyoming, Austin S. Hart
WWU Graduate School Collection
The timing and sequence of Paleogene proximal sediments derived from the rising Beartooth Range of Montana and Wyoming and shed eastward into the western Bighorn Basin have been interpreted differently by earlier workers. Improving our knowledge of the relationships between proximal and distal strata in the western Bighorn Basin will lead to a better understanding of basin development in the northern Laramide Province. The objective of this study is to use petrographic, stable isotopic and paleomagnetic datasets from Beartooth synorogenic deposits in order to address different hypotheses concerning the timing and sequence of sedimentation off the Beartooth uplift. The synorogenic …
Relocation And Analysis Of The 2007 Nechako, B.C., Seismic Swarm: Evidence For Magmatic Intrusion In The Lower Crust, Jesse A. Hutchinson
Relocation And Analysis Of The 2007 Nechako, B.C., Seismic Swarm: Evidence For Magmatic Intrusion In The Lower Crust, Jesse A. Hutchinson
WWU Graduate School Collection
On October 9th, 2007, a seismic swarm, known as the Nechako swarm, began in south-central British Columbia, approximately 20 kilometers west of the Nazko polygenetic cinder cone. After lasting for well over a month, seismic activity tapered off by November 21st, 2007. This study analyzes data from several temporary broadband seismometers deployed by the Geological Survey of Canada near the epicentral locations of initial events from the swarm. Over 4400 events were observed during this period, from which 1048 absolute locations were calculated, with depths ranging from 26-35 kilometers. All of the events recorded by the temporary seismometers were high …
Block Rotation And Magnetostratigraphy Of The Fish Creek-Vallecito Basin, Salton Trough, Ca, Christopher J. Deboer
Block Rotation And Magnetostratigraphy Of The Fish Creek-Vallecito Basin, Salton Trough, Ca, Christopher J. Deboer
WWU Graduate School Collection
The Fish Creek-Vallecito basin (FCVB) is a large Plio-Pleistocene sedimentary basin in the western Salton Trough, CA. The FCVB formed during subsidence along the West Salton Detachment fault and was uplifted and tilted when slip along the West Salton Detachment fault ended and the region became dominated by strike-slip faulting. This study uses paleomagnetism and magnetostratigraphy to determine the timing and rate of rotation of the FCVB. Two hundred and one sites were sampled in the Palm Spring Group of the FCVB. Magnetite and hematite are identified as carriers of remanence, and rock magnetic measurements are consistent with a magnetite …
Gis Investigation Of Scarps On Slide Mountain, Western Whatcom County, Washington, Orion George
Gis Investigation Of Scarps On Slide Mountain, Western Whatcom County, Washington, Orion George
WWU Graduate School Collection
Scarps can form from active faulting and landsliding. Such scarps can be difficult to differentiate in mountainous regions before expensive field work is done. Remote techniques to differentiate between scarps can help focus research time and money on active tectonic scarps. This study utilizes high resolution topographic data derived from light detection and ranging (LiDAR) and a geographic information system (GIS) to analyze geomorphometric differences between landslide headscarps and active tectonic scarps in western Washington. The study is separated into two distinct phases, a GIS mapping phase and a GIS geomorphic analysis phase. The GIS mapping phase focused on mapping …
Magnetic Fabric Analyses Of Ocean Floor Sediments: Characterizing Depositional Processes In The Nankai Trough And Shikoku Basin, Beth Novak
WWU Graduate School Collection
Magnetic fabric analysis was conducted on accretionary prism sediments and on sediments taken from the Shikoku Basin during Integrated Ocean Drilling Program (IODP) Expedition (Exp) 333 in order to characterize the sedimentary processes and depositional mechanisms active along the Nankai Trough. Sedimentary ages, in the form of a magnetostratigraphy, were also determined for these sediments during the course of this study. IODP Exp 333 focused coring efforts off the coast of the Kii Peninsula in Japan on three sites, one site within the Nankai Trough accretionary prism (Site C0018) and two sites seaward of the Nankai Trough in the Shikoku …
Felsic Magmas From Mt. Baker In The Northern Cascade Arc: Origin And Role In Andesite Production, Julie A. (Julie Angela) Gross
Felsic Magmas From Mt. Baker In The Northern Cascade Arc: Origin And Role In Andesite Production, Julie A. (Julie Angela) Gross
WWU Graduate School Collection
Dacitic magmas in volcanic arcs play a critical role in the growth and development of felsic continental crust through mixing to form andesite, or to a lesser extent, by directly adding new crustal material through fractionation of mantle derived basalts. Though dacitic erupted lavas are scarce on Mt. Baker, this study discusses their importance in subsurface processes such as mixing with more mafic magmas, and their potential to add directly to the volume of continental crust. A comprehensive data set (including major, trace, and rare earth element abundances, as well as petrography and mineral chemistry) reveals that the most Sirich, …