Structural Features in a Brittle-Ductile wax Model of Continental Shear
and Extension

M. L. Johnson ; L. Yarema ; J. N. Brune ; S. G. Wesnousky
(Seismological Laboratory, Center for Neotectonic Studies, and
Geological Sciences, MS -174, University of Nevada Reno,  Reno NV
89557-0141; ph. 702-784-1764; e-mail: mandyj@seismo.unr.edu)
	
	Structural features produced during shearing in continental
environments depend on transitional properties between brittle and ductile
layers.  We used a wax model to simulate the structural response of
continental crust under shear and extension in the presence of a
continuous brittle-ductile transition, and compared the results with
results obtained in previous wax model experiments for extension (Brune
and Ellis, 1997).  The wax models were deformed under various initial
conditions in order to reflect a variety of crustal parameters,
representing several different regions.  All experiments produced
characteristic structural features such as tension cracking, folding,
large scale faulting, and block rotation.  
	Structural features in several of the wax models can be likened to
both regional and local scale faulting found in the Basin and Range
province of North America.   These models suggest that block rotation is a
means of differentiating a simple shear environment from a pure
extensional environment.