36-1 Structural Architecture of the Cananea Porphyry Copper District

Session: Cordilleran Mineral Systems: Interdisciplinary Perspectives on Critical Metal Ore Deposits (Posters)

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Abstract:

We present a new structural map and seriated cross sections of the world-class Cananea porphyry copper District, northern Sonora, Mexico. Integrated field mapping, structural analysis, and reinterpretation of existing geological data provide new constraints on the geometry of magmatic intrusions. Our results indicate that the precursor Cuitaca Batholith was emplaced with a broadly subhorizontal roof, largely parallel to the stratification of the Tarahumara Formation. In contrast, the economically significant porphyry copper intrusions were emplaced as steep to near-vertical bodies that cut across the batholithic roof and the volcanic–sedimentary host rocks. The structural architecture of the district is dominated by the María Fault, a major N-S west-dipping normal fault that defines the western margin of the range where several deposits (Mariquita, María, and Buenavista del Cobre) are exposed. This fault was active during the Basin and Range extension and accommodated the approximately 15° eastward tilting of its footwall. This tilting played a fundamental role in exhuming and exposing a crustal section through the magmatic–hydrothermal system. As a consequence of this differential uplift and rotation, individual deposits within the Cananea district currently expose distinct paleodepths. This explains the marked variations in alteration styles, mineralization characteristics, and erosion levels observed across the district, despite their close spatial association. Our new structural model provides a coherent framework linking intrusion geometry, fault kinematics, and erosion history. These results have important implications for exploration, highlighting the role of large-scale extensional structures in controlling exposure levels and preservation of porphyry systems. The model offers predictive criteria for targeting concealed mineralization both within the Cananea district and in analogous extensional terranes worldwide.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3, 2026

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