Structural control of ore deposition at Kasaan Peninsula, southeastern Alaska

L.A. Warner; E. N. Goddard

doi:10.1029/tr027i005p00712

Home/Archive/USGS

USGS · 70220484

Structural control of ore deposition at Kasaan Peninsula, southeastern Alaska

L.A. Warner·E. N. Goddard

View original source ↗Export metadata ↓

Abstract

Copper‐bearing magnetite deposits and associated copper deposits at Kasaan Peninsula , Prince of Wales Island, southeastern Alaska , have been known for many years and have been mined to some extent for their copper content. At the beginning of World War II, the development of war industries in the Pacific northwest focused attention on the deposits as possible sources of iron ore . From 1942 through 1944 the United States Geological Survey made detailed studies of most of the ore deposits and at a few of the more promising localities diamond‐drilling operations were carried on by the United States Bureau of Mines. The deposits are for the most part small and irregular but of relatively high grade. The chief ore minerals are magnetite, pyrite, and chalcopyrite, and the gangue consists largely of skarn minerals, including garnet, epidote, diopside, and hornblende. The deposits are presumably of pyrometasomatic origin, but whereas deposits of this type are commonly replacement bodies in limestone, at Kasaan Peninsula limestone seemingly was a poor host rock for the ore.

Explore related subjects

Article

Source-reported bounding extent: 55.42277902267131° to 55.67138928829547° latitude; -132.5775146484375° to -132.0721435546875° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

L.A. Warner, E. N. Goddard. 2014-08-18. Structural control of ore deposition at Kasaan Peninsula, southeastern Alaska. https://doi.org/10.1029/tr027i005p00712

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Floral resource availability and surrounding land cover influence bumble bee community composition in an agricultural landscape

Agricultural intensification and the loss of floral resources are suspected factors in bumble bee declines in North America. Understanding the effects of land use on bumble bee communities at the local and landscape scale is important to support conservation efforts. We surveyed 55 prairie and grassland sites in a highly agricultural landscape in 2023 and 2024. We used a multispecies occupancy model to estimate effects of site characteristics on both community-level and species-level occupancy probability. We also evaluated the relationship between species richness and the land cover within 1.6 km of sites. We detected 13 species of bumble bees, including four that are threatened or endangered. Bumble bee community occupancy probability was positively associated with local plant diversity ( β = 0.545, 95% CRI: 0.0293, 1.22) and was generally higher in more forested landscapes ( β = 0.530, 95% CRI: −0.0727, 1.24), but this varied greatly among species. Species richness was significantly lower at sites with high corn/soybean land cover (Spearman's rank correlation coefficient ρ = −0.318, 95% CRI: −0.570, −0.0705) and significantly greater at sites with high forest cover within 1.6 km ( ρ = 0.491, 95% CRI: 0.273, 0.687). Maintaining sites with a continuous availability of flowering plants during bumble bee foraging periods within proximity to forests may be an effective means of sustaining diverse bumble bee communities in highly agricultural landscapes.

Iowa↗

USGS2026

Seismoacoustic analysis of possible vent-drying sequence during phreatomagmatic activity on 13 July 2021 at Semisopochnoi Island, Alaska

Pulse-like infrasound accompanying volcanic phenomena sometimes suggests interaction with water at the crater. We focus on pulse-like infrasound observed at Semisopochnoi Island in the Aleutian Arc, Alaska, during the phreatomagmatic activity on 13 July 2021. Overflight observations confirmed a small, ephemeral water lake on the crater floor in June 2021. We examined temporal variations in pulse-like infrasound activity, seismoacoustic amplitudes, and spectral characteristics. Pulse-like infrasound activity gradually became intermittent and waned at the end of the day. Seismic-infrasonic amplitude ratio decreased, while the infrasound frequency index increased with time. These results suggest less interaction with water due to drying out of the vent. Satellite observations also show increased ground surface temperatures inside the crater from 13 to 14 July. Numerical simulation suggests a significant topographic effect on the waveform and spectrum of the pulse-like infrasound, which should be considered before interpreting the source process.

Alaska↗

USGS2025

Fitness consequences of parasitism in a changing world: A case study with bird blow flies and sagebrush songbirds

Host–parasite interactions increasingly are influenced by human-induced rapid environmental change (HIREC), and the fitness effects of parasitism may be compounded or exacerbated by host traits and/or exposure to additional extrinsic stressors associated with HIREC. Potential interactions between parasitism and different stressors associated with environmental change, however, remain poorly understood for most systems. We examined how parasitism by bird blow flies ( Trypocalliphora braueri ), ambient weather conditions and habitat disturbance jointly affected offspring traits and juvenile mortality for two declining species of sagebrush songbirds (Brewer's Sparrow, Spizella breweri ; and Sage Thrasher, Oreoscoptes montanus ) in Wyoming, USA. We evaluated two alternative hypotheses: that parasitism could act (i) in an independent and additive manner with temperature and habitat alteration ( Multiple Stressors Hypothesis ) or (ii) synergistically to exacerbate the effects of temperature and habitat alteration ( Parasitism-HIREC Interaction Hypothesis ) on offspring traits and juvenile mortality. We assessed morphometric traits of nestlings and survival of fledglings in relation to parasite loads, temperature and habitat disturbance associated with natural gas development to test these hypotheses. Higher parasite loads and colder temperatures were associated with different effects for nestlings of each host species, reducing tarsus and wing chord length for Brewer's Sparrow and increasing mass for Sage Thrasher. Despite differences in the effect of parasitism on nestling traits, post-fledging mortality risk for both species increased with higher parasite loads. The effects of parasitism and temperature mainly were additive, with limited evidence that weather exacerbated the effects of parasitism. Habitat disturbance had a weak positive effect on nestling tarsus length and post-fledging survival probability for Brewer's Sparrow. Although parasitism rarely results in direct mortality of hosts, parasites can nonetheless exert considerable fitness consequences, especially when combined with extrinsic stressors associated with human-induced environmental changes.

Wyoming↗