Influence of a glacial buzzsaw on the height and morphology of the Cascade Range in central Washington State, USA

Analysis of climatic and topographic evidence from the Cascade Range of Washington State indicates that glacial erosion limits the height and controls the morphology of this range. Glacial erosion linked to long-term spatial gradients in the ELA created a tilted, planar zone of 373 cirques across the central part of the range; peaks and ridges now rise ≤600 m above this zone. Hypsometric analysis of the region shows that the proportion of land area above the cirques drops sharply, and mean slopes >30° indicate that the areas above the cirques may be at or near threshold steepness. The mean plus 1σ relief of individual cirque basins (570 m) corresponds to the ∼600-m envelope above which peaks rarely rise. The summit altitudes are set by a combination of higher rates of glacial and paraglacial erosion above the ELA and enhanced hillslope processes due to the creation of steep topography. On the high-precipitation western flank of the Cascades, the dominance of glacial and hillslope erosion at altitudes at and above the ELA may explain the lack of a correspondence between stream-power erosion models and measured exhumation rates from apatite (U-Th/He) thermochronometry.     

BOOK REVIEWS

Books reviewed in this article: USA, Eine Geographische Landeskunde , Vol. I, Der Grossraum in Strukturellem, Wandel, 3rd Ed. Helmut Blume . Introduction to Remote Sensing . James B. Campbell . The Sounds of People and Places: Readings in the Geography of American Folk and Popular Music . George O. Carney , ED. Development and Underdevelopment . John Cole . Mobility and Employment in Urban Southeast Asia: Example from Indonesia and the Philippines . Michael A. Costello , Thomas R. Leinbach , AND Richard Ulack . Soviet Asia: Economic Development and National Policy Choices . Leslie Dienes . The Third World City . David Drakakis -Smith . Scholars' Guide to Washington, DC for Cartography and Remote Sensing Imagery (maps, charts, aerial photographs, satellite images, cartographic literature and geographic information systems). Ralph E. Ehrenberg . Population and Development in the Third World . Allan AND Anne Findlay . The Early Mapping of Hawaii . Gary L. Fitzpatrick . Energetics of Physical Environment: Energetic Approaches to Physical Geography . K. J. Gregory , ED. Wildland Recreation: Ecology and Management . William E. Hammitt and David N. Cole . Agricultural Commercialization and Government Policy in Africa . J. Hinderink AND J. J. Sterkenburg . The Dynamics of American Housing . James W. Hughes AND George Sternlieb . Thailand: Buddhist Kingdom as Modern Nation State . Charles F. Keyes . Resolving Locational Conflict . Robert W. Lake , ED. Lands at Risk in the Third World: Local-level Perspectives . Peter D. Little and Michael M. Horowitz , EDS. Nathaniel Southgate Shaler and the Culture of American Science . David N. Livingstone . Regions: The Economics and Politics of Territory . Ann R. Markusen . Wetlands . William J. Mitsch and James G. Gosselink . Historical Geography: Progress and Prospect . Michael Pacione , ED. Loess and Periglacial Phenomena . Marton P$eacsi and Hugh M. French , EDS. Regional Management of Metropolitan Floodplains, Experience in the United States and Abroad . Rutherford H. Platt , ED. Human Cartography: Mapping the World of Man . Janos Szegö . Atlas of Great Lakes Indian History . Helen H. Tanner , ED. The Botany of Mangroves . P. B. Tomlinson . Urban Spatial Traffic Patterns . Rodney Vaughan . The Night After … Climatic and Biological Consequences of a Nuclear War . Yevgeni Velikhov , ED. Industrial Geography . H. D. Watts . Dictionary of Quotations in Geography . James O. Wheeler and Francis M. Sibley . Vermont Townscape . Norman Wiliams , Jr. , Edmund K. Kellogg and Peter M. Lavigne .     

THE SPATIAL VARIABILITY OF RAINFALL pH IN THE WASHINGTON,D.C METROPOLITAN AREA *

This study evaluated the pH of rain water at 28 sample stations throughout the Washington, D.C. metropolitan area and determined the efficacy of utilizing a volunteer sampling network under a limited budget. Twelve rain events from September 1984 to August 1985 were analyzed. Despite the small number of events sampled, a strong relationship emerged between storm path, pH pattern, and average rainfall pH. A long, overland storm track yielded low rainfall pH and a simple spatial pattern of rain pH, while coastal storms produced relatively higher pH and a pattern with many areas of local variability.     

Late-Quaternary diminution and abundance of prehistoric bison (Bison sp.) in eastern Washington state, U.S.A.

Bison (Bison spp.) occurred in eastern Washington state during the late Quaternary. This area is considered to be peripheral to the center of this taxon's natural range. Bison in the plains east of the Rocky Mountains, the heart of this range, underwent diminution during the late Quaternary, and apparently also did so in other, peripheral areas. A ratio diagram of measurement data derived from eight zooarchaeological collections of bison remains recovered from eastern Washington, in combination with the presence of both sexes and all age classes of individuals, indicate that local bison may have also undergone diminution there. There are, however, a relative paucity of bison remains during the middle Holocene and an apparent 2000-year absence of bison from eastern Washington at this time. As a result, the hypothesis that bison became smaller elsewhere and then immigrated to eastern Washington cannot be falsified. Both the diminution and the fluctuating abundance of bison appear to be responses to forage quality and quantity.     

SNOWSHED CONTRIBUTIONS TO THE NOOKSACK RIVER WATERSHED,NORTH CASCADES RANGE,WASHINGTON*

ABSTRACT. Meltwater contributes to watershed hydrology by increasing summer discharge, delaying the peak spring runoff, and decreasing variability in runoff. High‐elevation snowshed meltwater, including glacier‐derived input, provides an estimated 26.9 percent of summer streamflow (ranging annually from 16 to 40 percent) in the Nooksack River Basin above the town of Deming, Washington, in the North Cascades Range. The Nooksack is a major spawning river for salmon and once was important for commercial, recreational, and tribal fishing, and in the past its flow met the demands of both human and aquatic ecosystems. But the river is already legally overallocated, and demand is rising in response to the rapidly growing human population. Variability in snowshed contributions to the watershed is considerable but has increased from an average of 25.2 percent in the 1940s to an average of 30.8 percent in the 1990s. Overall stream discharge shows no significant increase, suggesting that the glaciers are melting, and/or precipitation levels (or other hydrologic factors) are decreasing at about the same rate. If glaciers continue to recede, they may disappear permanently from the Cascades. If that occurs, their summer contribution to surface‐water supplies will cease, and water‐management policies will need drastic revision.     

A comprehensive approach to the study of methane-seep deposits from the Lincoln Creek Formation, western Washington State, USA

ABSTRACT A comprehensive approach using palaeontology, petrography, stable isotope geochemistry and biomarker analyses was applied to the study of seven small methane‐seep carbonate deposits. These deposits are in the Oligocene part of the Lincoln Creek Formation, exposed along the Canyon and Satsop Rivers in western Washington. Each deposit preserves invertebrate fossils, many representing typical seep biota. Authigenic carbonates with δ¹³C values as low as ?51‰ PDB reveal that the carbon is predominately methane derived. Carbonates contain the irregular isoprenoid hydrocarbons 2,6,11,15‐tetramethylhexadecane (crocetane) and 2,6,10,15,19‐pentamethylicosane (PMI), lipid biomarkers diagnostic for archaea. These lipids are strongly depleted in ¹³C (δ¹³C values as low as ?120‰ PDB), indicating that archaea were involved in the anaerobic oxidation of methane. Small filaments preserved in the carbonate may represent methanotrophic archaea. Archaeal methanogenesis induced the formation of a late diagenetic phase, brownish calcite, consisting of dumbbell‐shaped crystal aggregates that exhibit δ¹³C values as high as +7‰ PDB. Clotted microfabrics of primary origin point to microbial mediation of carbonate precipitation. Downward‐directed carbonate aggregation in the seeps produced inverted stromatactoid cavities. Large filaments, interpreted as green algae based on their size, shape, arrangement and biomarkers, imply that deposition occurred, in places, in water no deeper than 210 m.     

Climatic implications of latest Pleistocene and earliest Holocene mammalian sympatries in eastern Washington state, USA

For more than fifty years it has been known that mammalian faunas of late-Pleistocene age are taxonomically unique and lack modern analogs. It has long been thought that nonanalog mammalian faunas are limited in North America to areas east of the Rocky Mountains and that late-Pleistocene mammalian faunas in the west were modern in taxonomic composition. A late-Pleistocene fauna from Marmes Rockshelter in southeastern Washington State has no modern analog and defines an area of maximum sympatry that indicates significantly cooler summers than are found in the area today. An earliest Holocene fauna from Marmes Rockshelter defines an area of maximum sympatry, including the site area, but contains a single tentatively identified taxon that may indicate slightly cooler than modern summers.     

A 14,300-year-long record of fire-vegetation-climate linkages at Battle Ground Lake, southwestern Washington

High-resolution macroscopic charcoal analysis was used to reconstruct a 14,300-year-long fire history record from the lower Columbia River Valley in southwestern Washington, which was compared to a previous vegetation reconstruction for the site. In the late-glacial period (ca. 14,300-13,100 cal yr BP), Pinus/Picea-dominated parkland supported little to no fire activity. From the late-glacial to the early Holocene (ca. 13,100-10,800 cal yr BP), Pseudotsuga/Abies-dominated forest featured more frequent fire episodes that burned mostly woody vegetation. In the early to middle Holocene (ca. 10,800-5200 cal yr BP), Quercus-dominated savanna was associated with frequent fire episodes of low-to-moderate severity, with an increased herbaceous (i.e., grass) charcoal content. From the middle to late Holocene (ca. 5200 cal yr BP to present), forest dominated by Pseudotsuga, Thuja-type, and Tsuga heterophylla supported less frequent, but mostly large or high-severity fire episodes. Fire episodes were least frequent, but were largest or most severe, after ca. 2500 cal yr BP. The fire history at Battle Ground Lake was apparently driven by climate, directly through the length and severity of the fire season, and indirectly through climate-driven vegetation shifts, which affected available fuel biomass.     

Urban migrant women’s everyday food insecurity coping strategies foster alternative urban imaginaries of a more democratic food system

Urban migrant women worldwide utilize a creative combination of food insecurity coping strategies to procure food for themselves and their families. Using in-depth interviews with 72 migrant women in Medellín, Colombia, and Washington, DC, this paper argues that in low-income urban communities these everyday strategies can further their demands for autonomy in determining what foods they produce and consume. Relying on feminist geography and food sovereignty literature, this research explores how migrant women living in poverty rely on informal networks for growing and sharing food, seek out organic, fresh foods, and utilize independent survival strategies to counter exclusionary rhetoric and a food system they view as unhealthy. In doing so, they devise alternative urban imaginaries of a more democratic food system. This research contributes a more nuanced understanding of the food insecurity experiences of urban migrant women.