geothermal resource potential of the safford-san simon basin, arizona

over an inferred decollement in the basement of the Safford basin, they may
have significant permeability and have significant geothermal reservoir
potential.
Basement Structure of the Southern Safford-San Simon Basin
The basement stratigraphy and structure in the southern Safford-San
Simon basin has a different character than the basement of the central and
northern portions of the basin.
Outcrops in the Dos Cabezas and Chiricahua
Mountains reveal a more varied stratigraphy than is observed in the Pinaleno
Mountains or Gila Hountains.
Two structural terranes typify the northern Chiricahua Mountains (Sabins,
1957; and Drewes, 1976). The northern terrane appears in situ or autochthonous.
The other terrane is allochthonous and is thrust over the northern
autochthon.
An early Cretaceous gravel, the Glance Conglomerate, unconformably
overlies Paleozoic rocks on the autochthonous block (Sabins, 1957).
West of
Apache Pass in the Dos Cabezas, the Glance Conglomerate
unconformably overlies
Pennsylvania Horquilla Limestone, while six miles east of Apache Pass, the
Glance Conglomerate overlies the El Paso Formation and Coronado Sandstone
(Sabins, 1957).
The Paleozoic sequence overlies Precambrian Pinal Schist,
gneiss, and granite.
The allochthonous block, formed by the Fort Bowie and Wood Mountain
thrust faults, is correlated on a regional scale by Drewes
(1979) as part
of an extensive crustal plate thrust northward and northeastward in southeast
Arizona and southwest New Mexico called the Hidalgo Allochthon.
In the
study area, Drewes (1976) infers a thrust fault in the subsurface beneath
the southern San Simon basin, which connects the thrust faults at Granite
Gap with those in the northern Chiricahua Mountains. However, it should be
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