Enterprise Zone, Southwestern Utah: Implications for Initiation of a Major Miocene Transfer Zone
Paleomagnetic results from the eastern Caliente- Enterprise zone, southwestern Utah: Implications for initiation of a major Miocene transfer zone Michael S. Petronis1,*, Daniel K. Holm2, John W. Geissman3, David B. Hacker2, and Billie J. Arnold2 1Environmental Geology, Natural Resource Management Department, New Mexico Highlands University, Las Vegas, New Mexico 87701, USA 2Department of Geology, Kent State University, Kent, Ohio 44242, USA 3Department of Geosciences, University of Texas at Dallas, ROC 21, 800 West Campbell Road, Richardson, Texas 75080-3021, USA ABSTRACT large and statistically signifi cant. For exam- defi ne the CEZ after Axen (1998) as the region ple, site P-18 from the Bauers Tuff yields an encompassing all transverse structures whether The Miocene Caliente-Enterprise zone R = –61.1° ± 5.3° and F = –0.6° ± 5.0°. Rela- or not they include evidence for counterclock- (CEZ) in southwestern Utah (USA) is a tive to the expected Miocene direction, in situ wise vertical axis rotation. Displacement trans- 20–50-km-wide east-northeast–trending left- paleomagnetic data from the Iron Axis lac- fer systems, or accommodation zones, are often lateral transfer zone that displaces north- coliths, specifi cally the Three Peaks laccolith, subvertical fault systems that transfer displace- south–trending crustal blocks of the eastern yield a mean that is discordant in declination, ment from one region of the crust to another Basin and Range Province to the west. Pre- with estimated R = –22.2° and F = –8.8° val- (Moustafa, 1976; Bosworth, 1985, 1986; Lister vious paleomagnetic results from the central ues. These rotation and fl attening estimates, et al., 1986; Rosendahl, 1987; Chapin, 1989; and western CEZ show signifi cant counter- although consistent with the overall data set Faulds et al., 1990; Faulds and Varga, 1998).
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