(U‐Th)/He and ⁴He/³He Thermochronology of Secondary Oxides in Faults and Fractures: A Regional Perspective From Southeastern Arizona

Abstract

Hematite and other secondary Fe-and Mn-oxides often precipitate in shallow crustal faults and fractures and reflect episodes of fluid-rock reactions (

Oligocene‐Miocene Exhumation of the Pinaleño Metamorphic Core Complex, Southeastern Arizona: Support for Magmatism and Plate Margin Reorganization as Controls on Regional Exhumation Trends

“…Scoggin, Reiners, et al. (2021) also suggested that the Pinaleño Mountains experienced exhumation and cooling related to Basin and Range extension based on Fe‐oxide (U‐Th)/He (FeHe) dates from the Eagle Pass area that are distributed around ∼10 Ma.…”

“…No comprehensive study of the Pinaleño Mountains exhumation history has been previously undertaken, although thermochronologic data has been reported from the Pinaleño core complex footwall including a whole‐rock (mylonite) K‐Ar date of 28 Ma (Rehrig & Reynolds, 1980), a muscovite 40 Ar/ 39 Ar date of 23.5 Ma and a biotite 40 Ar/ 39 Ar date of 19.8 Ma from an undeformed Relleno suite granite sample (sample PM‐3, Long et al., 1995), two biotite 40 Ar/ 39 Ar ages of 18.5 and 28.6 Ma from mylonite rocks (samples PM‐4 and PM‐6, Long et al., 1995), three AFT dates of 29.2, 25, and 19.6 Ma that decrease with decreasing elevation (Jepson et al., 2021), and Fe‐oxide (U‐Th)/He dates in the range 25–9 Ma (Scoggin, Reiners, et al., 2021). These dates are similar to data from other local core complexes, including the Catalina‐Rincon and Coyote Mountains core complexes (Fayon et al., 2000; Gottardi et al., 2020; Jepson et al., 2022).…”