Fig. 3: A compilation of isotopic data from igneous rocks, xenoliths and basement located in the southwest United States and northwest Mexico.
From: Porphyry copper formation driven by water-fluxed crustal melting during flat-slab subduction
a, A compilation of Nd isotopes from igneous rocks formed between 140 Ma and present day highlighting the influence of Farallon flat-slab subduction between ~80 and 40 Ma on magma petrogenesis. Range of calculated basement εNd(t) over this period representing younger (~1.1 Ga) mafic lithologies such as the diabase dykes, garnet–clinopyroxene xenoliths and amphibolites with unradiogenic values representing felsic older (~1.4–2.0 Ga) lithologies, including the Proterozoic granites and Pinal Schist. b, Whole-rock Sr–Nd isotopes for biotite ± hornblende and muscovite ± garnet-bearing granites, PCDs, and basement lithologies. Negative εNd(t) suggests all granitoids have unradiogenic signatures and overlap with the ~1.1 Ga diabase dykes, CPTZ xenoliths and Proterozoic basement. They are notably distinct from the juvenile mantle-wedge-derived magmas. 87Sr/86Sr(i) represents the calculated initial 87Sr/86Sr ratio for the rock at time of crystallization. c, Whole-rock two-stage Sm–Nd model age probability density plot for Laramide biotite ± hornblende-bearing granites, muscovite ± garnet-bearing granites, xenoliths, basement and zircon inheritance. d, Hf-in-zircon isotopes from granitic rocks in the southwest United States and northwest Mexico, biotite ± hornblende-bearing granites, muscovite ± garnet-bearing granites, and CPTZ garnet–clinopyroxene xenoliths have overlapping unradiogenic isotopic signatures. Data compiled from sources in Supplementary Table 3.
