The Colorado College Alpine Journal is a collection of climbing related stories and articles based on the experiences and adventures of Colorado College alumni and students. Contents for this issue include descriptions of climbs in North America, South America, Africa and Asia.
The Catalyst is the weekly student newspaper of Colorado College. This issue was published January 30, 2009. Page 6 of issue missing. Page 10 of issue incorrectly dated December 30. Pages 2, 3, 4 of issue incorrectly dated 2008.
The Catalyst is the weekly student newspaper of Colorado College. This issue was published April 3, 2009.
The Catalyst is the weekly student newspaper of Colorado College. This issue was published February 27, 2009.
The Catalyst is the weekly student newspaper of Colorado College. This issue was published January 23, 2009.
Poster created for 2nd annual Feminist and Gender Studies Distinguished Alumnae event featuring three Colorado College alumni to be held Thursday, April 9, 2009 in the Edith Kinney Gaylord Cornerstone Arts Building. Sponsored by the Feminist and Gender Studies Program, Colorado College.
Mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana) covers large areas in arid regions of western North America. Climate-change models predict a decrease in the range of sagebrush, but few studies have examined details of predicted changes on sagebrush growth and the potential impacts of these changes on the community. We analyzed effects of temperature, precipitation, and snow depth on sagebrush annual ring width for 1969 to 2007 in the Gunnison Basin of Colorado. Temperature at all times of year except winter had negative correlations with ring widths; summer temperature had the strongest negative relationship. Ring widths correlated positively with precipitation in various seasons except summer; winter precipitation had the strongest relationship with growth. Maximum snow depth also correlated positively and strongly with ring width. Multiple regressions showed that summer temperature and either winter precipitation or maximum snow depth, which recharges deeper soil horizons, are both important in controlling growth. Overall, water stress and perhaps especially maximum snow depth appear to limit growth of this species. With predicted increases in temperature and probable reduced snow depth, sagebrush growth rates are likely to decrease. If so, sagebrush populations and cover may decline, which may have substantial effects on community composition and carbon balance.
The Department of Anthropology Newsletter is an occasional publication issued by the Department and provides news related to its students, faculty and alumni.
After eight years of non-engagement, the new administration and the U.S. Congress, led by a majority in the President’s party, are rapidly developing climate policy legislation. This paper summarizes past efforts to establish a national climate policy in the United States as well as the major forces influencing the current debate. While this debate is largely shaped by domestic considerations, it takes place as the international community moves to agree on a post-Kyoto policy regime in Copenhagen next December. Whether the United States is willing to take strong action will significantly influence the actions of other nations.
The glassy groundmass contains small plagiocase and clinopyroxene crystals, both of which are found as microphenocrysts. Plagioclase grains are variable in size and subhedral in shape. Clinopyroxene phenocrysts are substaniatlly larger, often due to the formation of glomeroporphyroclasts.
The salt-n-pepper groundmass of opaques, pyroxenes, and feldspars appears almost intserstitial due to the high abundance of microphenocrysts. The phenocrystic population is dominated by subhedral plagioclase and, to a much lesser degree, clinopyroxene. Rounded, phenocryst-sized pockets of granular quartz are found throughout the groundmass.
This thin section has a diabasic texture. While the plagioclase has remained relatively unaltered, clinopyroxene has been almost entirely pseudomorphed by serpentine. Anhedral clusters of calcite is found throughout.
Interpenetrating zones of optically-continuous, pebbly-textured olivine, fibrous serpentine, and radiating talc. This thin section has interfingered scaly and fibrous textures.
The groundmass of glass and plagioclase microlites is host to euhedral phenocrysts of three euhedral mineral phases, plagioclase, hornblende, and biotite.
The crystals in this thin section look somewhat out of equilibrium with the melt. The groundmass is microcrystalline and riddled with plagioclase and pyroxenes, as well as glass. Crystals of the phenocryst population are generally subhedral, with rounded corners and irregular twins. The pyroxenes are frequently rimmed by pyroxenes of differing composition. Plagioclase phenocrysts are of differing generations; the first has cloudy, inclusion-rich cores with fresh rims and the second lacks this core. Both may be concentrically zoned. The pyroxenes in particular tend to cluster in glomeroporphyroclasts. The occasional granular aggregate of calcite can be observed in this sample.
The range in grain size for the plagioclase laths in this thin section is continual from the groundmass euhedral microlites to the subhedral phenocrysts. Concentric zoning and sieve textures are common in the plagioclase phenocrysts. Clinopyroxene phenocrysts are also subhedral, commonly twinned, and infrequently clustered in glomeroporhpyroclasts. In addition to plagioclase, the groundmass contains clinopyroxene, opaques, and serpentine.
The least altered phase in this thin section is plagioclase, which forms roughly aligned, variably sized laths that make up both the groundmass, which is dominantly glass, and the phenocryst population. A second phenocryst, clinopyroxene, remains only as inclusions in the calcite pseudomorphs that replaced it. Vesicles, clays, and hematite pseudomorphs are abundant in this thin section.
Western Minerals Inc. calls this sample as 'metasomatised pyroclastics, baked and well indurated, slightly metasomatised.' It is fine-grained and dominated by anhedral quartzofeldspathic phases which vary in size and are peppered with small, equant pyroxenes. Rounded, partially chloritized clusters are scattered throughout.
This thin section consists of several zones. The first, a fine-grained glaucophane schist. The boundaries between individual glaucophane crystals frequently blur. Aggregates of sphene are stretched out lines paralleling the complexly folded foliation. This zone is abruptly cut by a green, omphacite-rich band, bordered on each sided by a greater concentration of sphene. In the third zone, the glaucophane fabric is interleaved with elongate aggregates of omphacite, epidote and sphene.
Subhedral phenocrysts of plagioclase, clinopyroxene, and olivine are squeezed into the fine web of rock that rims the massive vesicles of this scoria. Plagioclase has a sieve texture and is frequently zoned. The corners of most grains are rounded. Both clinopyroxene and olivine are generally equant in shape and olivine is more abundant than the pyroxene. All three phases show some degree of resorption. The groundmass contains moderately-sized crystals of all three phases. This sample is very fresh and unaltered.
Based on grain size, two populations of pyroxenes and plagioclase exist in this sample; the first are the fine-grained, equant crystals of the glassy groundmass, and the second, the subhedral to anhedral phenocrysts visible in handsample. The inconsistently-shaped plagioclase grains are sometimes zoned and frequently contain inclusions of glass.
The groundmass of this porphyritic basalt is predominantly glass with less abundant plagioclase microlites. The most readily-identifiable mineral of the phenocryst population is plagioclase. Of greater abundance are euhedral, opaque pseudomorphs. Rare inclusions of pyroxene are observed within these opaques. Pockets of chalcedony disrupt the otherwise uniform groundmass.
Unoriented plagioclase laths and interstitial glass and clinopyroxene make up the groundmass of this vesicular basalt. Olivine and orthopyroxene microphenocrysts are scattered throughout.