Fig. 6: Spatial-temporal tectonic–magmatic–mineralization relationships along the CPTZ supporting a flat-slab subduction and crustal anatexis PCD model for Arizona.
From: Porphyry copper formation driven by water-fluxed crustal melting during flat-slab subduction
a, Ages of volcanism, PCDs, shortening and extension, crustal anatexis, Orocopia Schist (ORS) metamorphism and muscovite ± garnet magmatism projected onto a northwest–southeast striking line (X–X’; Fig. 2b) along the CPTZ with a swath of 400 km. Error bars representing 2σ age uncertainties are less than the size of each data point. Dashed bars represent the inferred duration of contractional deformation or metamorphism based on nearby cross-cutting relations and structural constraints (Supplementary Table 1). b, Pre-Laramide orogenesis (~90–75 Ma) is associated with steep subduction and arc magmatism/ volcanism in western Arizona and California. c, Peak Laramide orogenesis (~75–55 Ma) flat-slab subduction shuts off the mantle wedge, resulting in the termination of arc volcanism and increased end-loading causing crustal thickening and anatexis. Geological features: (1) Orocopia Schist (Farallon Plate) 0.8–1.3 GPa and 660 °C, ~70–65 Ma; (2) Hercules thrust (top south-southwest), ~85–71 Ma; (3) Harcuvar and Harquahala mountains migmatites 0.75 GPa and 750–780 °C, ~73–60 Ma; (4) Tank Pass and Browns Canyon muscovite ± garnet-bearing granites (cuts Hercules thrust), ~79–70 Ma; (5) northwest Arizona PCDs, ~73–68 Ma (Bagdad, Mineral Park, Diamond Joe, Copper Basin, Crown King); (6) Coyote Mountains Pan-Tak muscovite ± garnet-bearing granite, ~58 Ma, which intruded syn-Baboquivari thrusting (top east-northeast); (7) southeast Arizona PCDs, ~72–56 Ma (for example, Ray, Resolution, Globe–Miami, San Manuel, Copper Creek, Sierra Rita, Texas Canyon, Morenci and Safford); (8) Galiuro Mountains thrusts (top east-northeast), ~73–60 Ma; (9) Santa Catalina Mountains Wilderness and Pinaleño muscovite ± garnet-bearing granites, ~58–50 Ma; (10) ’Maricopa thrust’ syn-Wilderness granites (top west-southwest), ~58–50 Ma; (11) water-saturated melting of ~1.7–1.1 Ga mafic lower-crustal source between ~75 and 55 Ma; (12) CPTZ garnet–clinopyroxene xenoliths, ~150 Ma and 75 Ma. Positions (i), (ii) and (iii) represent particle positions on the subducting Farallon slab. SCLM, subcontinental lithospheric mantle.
