Abstract Today we will be in the Early Proterozoic metavolcanic terrane between Prescott and Jerome, Arizona. This part of Arizona has been one of the major metal producers in the state, not only for base- and precious-metals from Proterozoic deposits, but also for metals from deposits of Laramide and Tertiary age. During the morning we will visit what was considered, until a few years ago, to be an atypical Early Proterozoic massive sulfide deposit at the Iron King mine, near Prescott. There, the regional geologic setting of the Prescott-Jerome are will be discussed, and specific details concerning alteration, mineralization, and metal concentrations of massive sulfide deposits in Arizona will be summarized. Hopefully, the outcome of this summary will be the recognition that, in Arizona, there are different types of massive sulfide deposits: 1) classic base-metal-rich deposits having massive and stringer ore and a well-defined chloritic alteration pipe (United Verde mine in the United Verde district; Bruce mine in the Old Dick district; 2) base-metal-poor deposits that lack stringer ore but that display chloritic alteration zones (Iron King mine in the Big Bug district; and 3) base-metal-poor deposits that lack massive ore and chloritic alteration pipes, but that are characterized by sericitic and aluminosilicate-type alteration (Copper Queen mine in the Agua Fria district; Zonia mine in the Zonia district; Bell Ranch and Huron-Montezuma prospects in the Agua Fria district). End members of the three types are not as common as deposits that share some characteristics of all three. The morning and afternoon

Abstract The Ardmore district displays a thick Paleozoic section, essentially complete from Upper Cambrian to lower Permian, with some older and younger rocks, all exposed in a small area of varied structure and remarkable orogenic history; though of modest topographic relief. For any geologist wishing a good general picture of North American geology, it is one of the indispensable areas for him to see. Because of its exposures of scores of strata which produce oil within a few miles of these outcrops, it is an especially classic area for petroleum geologists. It is also much used by college classes for an introduction to field problems.