Description:
The objective of this study has been to determine areas potentially favorable
for oil and gas exploration in southeastern Arizona. Surface geological investigations
in the mountain ranges indicate that a thick sequence of marine sedimentary
Paleozoic and Mesozoic (Cretaceous) rocks was deposited in the Pedregosa basin in
southeastern Cochise County and adjacent shelf areas. According to Wengerd (1962),
Kottlowski (1971), Greenwood (1969), and Greenwood and Kottlowski {1974), these
marine strata deposited in this basin are similar in many aspects to those in
petroleum-productive areas in southeast New Mexico and west Texas. They contain
organic-rich basin facies of rocks that were probable sources for oil and gas. The
margins of the Pedregosa basin offer structural, stratigraphic, unconformity, and
paleogeomorphic traps. However, such adverse factors as the wide thickness variance
of Cenozoic valley fill
(100 feet or less to almost
12,000 feet), very little information
as to the absence
or presence of potentially
petroleum-productive undeformed
Paleozoic and Mesozoic
rocks beneath Cenozoic
rocks in the valleys, and
extensive evidence in the
mountains that the area has
had an extremely complex
geologic history, have discouraged
exploration in the
past.