Description:
Recently completed studies of neotectonic (ie., latest PlioceneQuaternary)
deformation in Arizona provide new data that, when combined
with regional geophysical and geological characteristics, assist in
evaluation of the numerous interpretations proposed to date for Basin and
Range tectonism. Basin and Range tectonism, sensu strictu, is hereby
restricted to the post mid-Miocene (~15 m.y.B.P.) extensional block
faulting event that produced the present valley and range topography.
This tectonic interval may be distinguished in Arizona from earlier
Oligocene-mid Miocene deformation and volcanism based on regional variations
in stratigraphy and structural style.