Tectonomagmatic evolution of southwestern Laurentia: Insights from zircon U-Pb geochronology and hafnium isotopic composition of the Red Bluff Granite Suite, west Texas, USA

Abstract We provide laser ablation–multicollector–inductively coupled plasma–mass spectrometry (LA-MC-ICP-MS) and high-precision chemical abrasion–isotope dilution–thermal ionization mass (CA-ID-TIMS) U-Pb ages Hf isotopic compositions of zircons from the Red Bluff Granite Suite mafic dikes in Franklin Mountains El Paso, Texas, USA. Granitoids exposed were previously divided into five magmatic stages based on cross-cutting relationships. Major trace element showed that these granitoids are ferroan, alkaline, A2 type. Homogeneity whole-rock geochemistry suggests granite genetically related share similar petrogenetic histories. Weighted mean zircon 206Pb/238U dates older stage 1 alkali-feldspar quartz syenite 2 1112.36 ± 0.35 1112.46 0.37 Ma, respectively. The weighted εHf(t) values varying +5.3 to +7.2 those other regional ca. 1.1 Ga rocks throughout southwestern Laurentia. Geochemical characteristics, petrological modeling, enriched composition suggest fractional crystallization a basaltic magma was produced by melting an mantle reservoir. However, inheritance 1.3 1.26–1.15 consistent with minor contribution felsic crustal basement. Our data geology post-collisional slab break-off facilitated asthenospheric upwelling partial mantle, possibly subcontinental lithospheric extending Llano Uplift, southeast California northwest. Magma thus generated upon differentiation ferroan A-type granitoids.