Physics
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992pepi...74..109m&link_type=abstract
Physics of the Earth and Planetary Interiors, Volume 74, Issue 3-4, p. 109-126.
Physics
3
Scientific paper
In a relatively brief interval near the Eocene-Oligocene boundary, trachydacite lavas were erupted over an area of about 300 km2 to form the Egan Range Volcanic Complex, in the southern Butte Mountains and adjacent Egan Range of east-central Nevada. The mean radiometric age for this volcanic episode is 34.1 +/- 0.2 Ma, based on whole-rock and biotite K-Ar ages. Detailed comparisons were made between anisotropy of magnetic susceptibility (AMS) and the macroscopic petrofabric at 31 sites. Great variation in flow structures is attributed to complex flow in viscous lava over a surface of considerable relief. The magnetic fabric, as expressed by AMS axes, agrees well with the flow petrofabric. Typically, flow lineations are parallel to K1 and flow foliation is perpendicular to K3, as expected. Extension cracks and joints are normal to K1. Late-stage deformation of pipe vesicles also impressed a measurable magnetic fabric. Because of significant initial dip and complexity of flow fabric, paleohorizontal is not generally demonstrable. Paleomagnetic studies indicate an exclusively normal polarity. The mean in situ characteristic direction is relatively well grouped (D = 350°, I = 52°, α95 = 8°) for 28 selected sites and provides a mean pole at 124°E, 81°N, which is not significantly different from the coeval cratonic reference pole. These results indicate that large Oligocene or younger rotations have not affected this sector of the Basin and Range province. The combination of age and magnetic polarity suggests a correlation with a normal polarity subchron of chron 13 or 15.
Hayatsu A.
MacDonald William D.
Palmer H. C.
No associations
LandOfFree
Egan Range Volcanic Complex, Nevada: geochronology, paleomagnetism and magnetic fabrics does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Egan Range Volcanic Complex, Nevada: geochronology, paleomagnetism and magnetic fabrics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Egan Range Volcanic Complex, Nevada: geochronology, paleomagnetism and magnetic fabrics will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1140714