thumbnail

Mineralogical map showing the distribution and abundance of gold, scheelite, chalcopyrite, arsenopyrite, minium, and sapphire corundum in heavy-mineral concentrates in the Seward and Blying Sound quadrangles, Alaska

Miscellaneous Field Studies Map 880-G
By:  and 

Links

Abstract

Reconnaissance geochemical and mineralogical sampling was done in the Seward and Blying Sound quadrangles during 1975 and 1976 as part of the Alaska Mineral Resources Assessment Program (AMRAP). These maps show the distribution and abundance of gold, scheelite, chalcopyrite, arsenopyrite, minium and sapphire corundum in heavy-mineral concentrates. 

Heavy-mineral concentrate samples were collected at 525 sites from active channels and, locally, from the interface of streambeds with intermediate- to low-tide beaches. The heavy-mineral concentrates were obtained by panning stream sediments in the field to remove most of the light minerals. The panned samples were sieved though a 20-mesh (0.8 mm) screen in the laboratory, and the minus-20 mesh fraction was further separated with bromoform (specific gravity: 2.86) to remove any remaining light-mineral grains. Magnetite and other strongly magnetic heavy minerals were removed from the heavy-mineral fraction by using a hand magnet. The remaining sample was passed through a Frantz Isodynamic Separator1 and a nonmagnetic fraction was obtained at a setting of 0.6 amperes. A split of this nonmagnetic fraction was examined  for its mineralogic content using a binocular microscope and X-ray diffraction. The nonmagnetic concentrates primarily contain muscovite, sphene, zircon, apatite, rutile, and anatase. Small amounts of other minerals such as gold, scheelite, minium, sapphire corundum, and most sulfides will also be found in this fraction. 

The use of trade names is for descriptive purposes only and does not constitute endorsement of those products by the U.S. Geological Survey. 

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Mineralogical map showing the distribution and abundance of gold, scheelite, chalcopyrite, arsenopyrite, minium, and sapphire corundum in heavy-mineral concentrates in the Seward and Blying Sound quadrangles, Alaska
Series title Miscellaneous Field Studies Map
Series number 880
Chapter G
ISBN 0607803517
DOI 10.3133/mf880G
Year Published 1978
Language English
Publisher U.S. Geological Survey
Description 2 Plates: 37.91 x 33.96 inches and 56.30 x 39.86 inches
Country United States
State Alaska
Other Geospatial Blying Sound Quadrangle, Seward Quadrangle
Scale 250000
Google Analytic Metrics Metrics page
Additional publication details