Age and chemistry of Tertiary volcanic rocks in north-central Arizonaand relation of the rocks to the Colorado plateaus

Abstract

During late Miocene (14.8 m.y.) to early Pliocene (10.1 m.y.) time,local latite and widespread basaltic flows accumulated with associatedcontinental sedimentary deposits in north-central Arizona. Some ofthese rocks were displaced and tilted by normal faults, and newdrainage, now occupied in part by basalt flows of late Pliocene age(average 5 m.y., maximum of 6 m.y.), was established at the southernmargin of the Colorado Plateaus. The time of faulting and uplift ofthe Colorado Plateaus in this region is thus bracketed between about10.1 and 6 m.y. ago.

33 samples from this reference