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Density and magnetic susceptibility values for rocks in the Talkeetna Mountains and adjacent region, south-central Alaska

Open-File Report 2003-268
By:  and 
https://doi.org/10.3133/ofr03268

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Abstract

This report presents a compilation and statistical analysis of 306 density and 706 magnetic susceptibility measurements of rocks from south-central Alaska that were collected by U.S. Geological Survey (USGS) and Alaska Division of Geological and Geophysical Surveys (ADGGS) scientists between the summers of 1999 and 2002. This work is a product of the USGS Talkeetna Mountains Transect Project and was supported by USGS projects in the Talkeetna Mountains and Iron Creek region, and by Bureau of Land Management (BLM) projects in the Delta River Mining District that aim to characterize the subsurface structures of the region. These data were collected to constrain potential field models (i.e., gravity and magnetic) that are combined with other geophysical methods to identify and model major faults, terrane boundaries, and potential mineral resources of the study area. Because gravity and magnetic field anomalies reflect variations in the density and magnetic susceptibility of the underlying lithology, these rock properties are essential components of potential field modeling. In general, the average grain density of rocks in the study region increases from sedimentary, felsic, and intermediate igneous rocks, to mafic igneous and metamorphic rocks. Magnetic susceptibility measurements performed on rock outcrops and hand samples from the study area also reveal lower magnetic susceptibilities for sedimentary and felsic intrusive rocks, moderate susceptibility values for metamorphic, felsic extrusive, and intermediate igneous rocks, and higher susceptibility values for mafic igneous rocks. The density and magnetic properties of rocks in the study area are generally consistent with general trends expected for certain rock types.

Suggested Citation

Sanger, E.A., Glen, J., 2003, Density and magnetic susceptibility values for rocks in the Talkeetna Mountains and adjacent region, south-central Alaska: U.S. Geological Survey Open-File Report 2003-268, Report: ii, 42 p.; Data File, https://doi.org/10.3133/ofr03268.

ISSN: 2331-1258 (online)

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Density and magnetic susceptibility values for rocks in the Talkeetna Mountains and adjacent region, south-central Alaska
Series title Open-File Report
Series number 2003-268
DOI 10.3133/ofr03268
Year Published 2003
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description Report: ii, 42 p.; Data File
Country United States
State Alaska
Other Geospatial Talkeetna Mountains
Additional publication details