Publications
USGS research activities relevant to Alaska have yielded more than 9400 historical publications. This page features some of the most recent newsworthy research findings.
Filter Total Items: 2889
Geology of Seward Peninsula and Saint Lawrence Island
Seward Peninsula (Fig. 1) may be divided into two geologic terranes (Fig. 2) on the basis of stratigraphy, structure, and metamorphic history. The Seward terrane, an area 150 by 150 km in the central and eastern peninsula, is dominated by Precambrian(?) and early Paleozoic blueschist-, greenschist-, and amphibolite-facies schist and marble, and intruded by three suites of granitic rocks. The York
Authors
Alison B. Till, Julie A. Dumoulin
Map and table showing isotopic age data in Alaska
The source of the data reported here is a compilation of radiometric ages maintained in conjunction with the Alaska Mineral Resource Assessment Program (AMRAP) studies for Alaska. The symbol shape plotted at each location is coded for rock type, whether igneous, metamorphic, or other; the color of the symbol shows the geologic era or period for the Sample(s) at each locale. A list of references fo
Authors
Frederic H. Wilson, Nora B. Shew, G.D. DuBois
Blood sampling in juvenile buff-breasted sandpipers: Movement, weight change and survival
The effect of blood sampling on juvenile Buff-breasted Sandpipers (Tryngites subruficollis) was evaluated by comparing movements, mass, and survival of 10 broods (37 chicks) that were bled and eight broods (31 chicks) that were not bled. Blood was sampled from the jugular vein of chicks when they weighed 9.1 ± 0.9 g (x̄ ± SD) on or within 1 d of hatch. Chicks showed few short-term negative effects
Authors
Richard B. Lanctot
Geology of south-central Alaska
South-central Alaska is defined as the region bounded by the Kuskokwim Mountains to the northwest, the basins north of the Alaska Range to the north, the Canadian border to the east, and the Chugach Mountains to the south (Fig. 1). This region, hereafter called the study area, includes the Alaska Range, the Wrangell, Nutzotin, and Talkeetna mountains, the Copper River and the Susitna basins, the n
Authors
Warren J. Nokleberg, George Plafker, Frederic H. Wilson
Geologic framework of the Aleutian arc, Alaska
The Aleutian arc is the arcuate arrangement of mountain ranges and flanking submerged margins that forms the northern rim of the Pacific Basin from the Kamchatka Peninsula (Russia) eastward more than 3,000 km to Cooke Inlet (Fig. 1). It consists of two very different segments that meet near Unimak Pass: the Aleutian Ridge segment to the west and the Alaska Peninsula-the Kodiak Island segment to th
Authors
Tracy L. Vallier, David W. Scholl, Michael A. Fisher, Terry R. Bruns, Frederic H. Wilson, Roland E. von Huene, Andrew J. Stevenson
Using stable isotopes to determine seabird trophic relationships
1. The stable isotopes of nitrogen (δ15N) and carbon (δ13C) were analysed in 22 species of marine birds from coastal waters of the northeast Pacific Ocean. Analyses confirm that stable nitrogen isotopes can predict seabird trophic positions.2. Based on δ15N analyses, seabird trophic-level inferences generally agree with those of conventional dietary studies, but suggest that lower trophic-level or
Authors
Keith A. Hobson, John F. Piatt, Jay Pitocchelli
Use of boreal forested wetlands by Pacific loons (Gavia pacifica Lawrence) and horned grebes (Podiceps auritus L.): Relations with limnological characteristics
Our objective was to determine if the occurrence and abundance of Pacific loons (Gavia pacifica Lawrence) and horned grebes (Podiceps auritus L.) on 123 wetlands of Yukon Flats National Wildlife Refuge in east central Alaska were related to the limnological characteristics of those wetlands. Aquatic bird-wetland use surveys were conducted in conjunction with limnological sampling from May through
Authors
P.J. Heglund, J.R. Jones, L.H. Fredrickson, M.S. Kaiser
Population cage experiments with a vertebrate: The temporal demography and cytonuclear genetics of hybridization on Gambusia fishes
The dynamics of mitochondrial and multilocus nuclear genotypic frequencies were monitored for 2 yr in experimental populations established with equal numbers of two poeciliid fishes (Gambusia affinis and Gambusia holbrooki) that hybridize naturally in the southeastern United States. In replicated "small-pool" populations (experiment I), 1018 sampled individuals at six time periods revealed an init
Authors
Kim T. Scribner, John C. Avise
Foraging ecology as related to the distribution of planktivorous auklets in the Bering Sea
We review recent accounts of the foraging ecologies of five species of small auklets found in the Bering Sea. These birds eat a wide variety of zooplankton and micronekton. Least Auklets Aethia pusilla and Whiskered Auklets A. pygmaea, as far as is known, primarily eat copepods, whereas Created Auklets A. cristatella appear to specialize on euphausiids, at least during the breeding season. The di
Authors
George L. Hunt, Nancy M. Harrison, John F. Piatt
Decline of spectacled eiders nesting in western Alaska
Spectacled eider (Somateria fischeri) populations in western Alaska are now less than 4% of the numbers estimated in the early 1970s. In 1992, an estimated 1721 nesting pairs remained on the Yukon-Kuskokwim Delta. Causes of this rapid and continuing decline of -14% per year are undocumented. Many aspects of spectacled eider biology remain unknown, including their marine foraging habitats, food ite
Authors
Robert A. Stehn, Christian P. Dau, Bruce Conant, William I. Butler
Massive sulfide metallogenesis at a late Mesozoic sediment-covered spreading axis: Evidence from the Franciscan complex and contemporary analogues
The Island Mountain deposit, an anomalous massive sulfide in the Central belt of the Franciscan subduction complex, northern California Coast Ranges, formed during hydrothermal activity in a sediment-dominated paleo-sea-floor environment. Although the base of the massive sulfide is juxtaposed against a 500-m-wide melange band, its gradational upper contact within a coherent sequence of sandstone,
Authors
Randolph A. Koski, Roberta C. Lamons, Julie A. Dumoulin, Robin M. Bouse
Population dynamics of the Laysan and other albatrosses in the North Pacific
Laysan albatrosses (Diomedea immutabilis) are among the most prominent bird species which interact with commercial fisheries in the North Pacific. They are attracted to fishing nets and vessels and feed extensively on animals caught in nets, waste fish, offal, and refuse discarded from vessels. Approximately 17,500 individuals were killed in the five major high seas driftnet fisheries in 1990. Lay
Authors
Patrick J. Gould, Rod Hobbs