... Ordovician quartzites and hornfelses, near their contact with the Cretaceous Aguilar granite. The orebodies are stratigraphically conformable with the siliciclastic rocks and parallel to the contact metamorphic halo of the granite, in the pyroxene-hornblende and albite-epidote hornfels facies.The ores...

... ( Fig. 10F ; mean 206 Pb/ 238 U age, 95% confidence, n = 26), but a biotite K-Ar age was 23.6 ± 1.1 Ma ( Table 1 ). We did not study the Bella Esperanza granodiorite that was dated by Housh and McDowell (2005) , but their isotopic data are referred in the Discussion. Granites are part of the El...

... in Arizona recently have been characterized at a reconnaissance level: the Miami Inspiration system associated with the Schultze Granite, the Sierrita-Esperanza system associated with the Ruby Star Granodiorite, the Ray system associated with the Granite Mountain pluton, and the Kelvin-Riverside system...

... Ar/ 39 Ar geochronology of igneous and hydrothermal minerals. The Patagonia Mountains consist of Precambrian, Paleozoic, and Mesozoic sedimentary, granitic, and volcanic rocks, Laramide volcanic rocks, and a core of Laramide intrusions that comprise the Patagonia Mountains batholith. Laramide igneous...

... is located ~40 km southwest of Tucson on the eastern side of the Sierrita Mountains ( Fig. 1 ). Porphyry mineralization at Sierrita-Esperanza is related to phases of the 64 to 58 Ma Ruby Star granodiorite, a composite pluton that intruded Proterozoic metamorphic and granitic rocks, Paleozoic sedimentary...

... for determination of age using cosmogenic radionuclide techniques, as even modest surface erosion removes the accumulation of the cosmogenic radionuclides and causes significant underestimate of age. This study documents the effects on three large granitic boulders following the Esperanza Fire of 2006 in southern...

...-Gutiérrez et al. (1999) , merge the Xayacatlán and Esperanza granitoids units into the Piaxtla Group just based on the HP overprinting metamorphism. Consequently, they regard it as unnecessary to specify which unit they are referring to—determined age or geologic relationship; therefore, they ambiguously...

... ( Talavera-Mendoza et al., 2006 ). There are no constraints for its minimum age. The Esperanza suite is one of the most conspicuous assemblages of the complex and includes augen gneisses whose granitic protolith has an Early Silurian crystallization age (442 ± 5 to 440 ± 14 Ma; U/Pb; Ortega-Gutiérrez...

... exposures are probably those in the Esperanza quarry in the southern part of the Vredefort dome ( Figs 2 and 3 ). The main rock type at Esperanza is a uniform and homogeneous, medium-grained granite cut by occasional subvertical veins of pegmatite up to around 10 cm thick. The joints and fractures...

...Giovanni O. Cecioni ABSTRACT The Departamento Ultima Esperanza is an ideal place to test the relationship between orogeny and sedimentation, as well as the probable causal relation between orogeny and glaciations. In this study, the presence of sediments with facies of the orogenic Flysch, “Macigno...

... element data ( Rapela & Caminos 1987 ). Also in the northern part, the La Esperanza plutonic complex includes the unfoliated, high-K, calc-alkaline Prieto granodiorite and Donosa granite ( Llambías & Rapela 1984 ; Martínez Dopico et al. 2013 ). The Prieto granodiorite is the largest...

... in sierras of Guatemala. 1 , Santa Rosa ( Dollfus and de Montserrat, 1868 ); 2 , Santa Rosa ( Vinson, 1962 ); 3 , Tactic ( Walper, 1960 ); 4 , Sacapulas (Bohnenberger, 1966); 5 , Chicol ( Anderson et al. , 1973 ); 6 , Esperanza ( Anderson et al. , 1973 ); 7 , Grupera ( Thompson and Miller, 1944...

... the schists, slates, limestones, granites, etc., which have been termed the basal complex. 7 They are of unknown age, possibly including Paleozoic rocks, and with them, for convenience in maintaining the structural grouping, are included the serpentines which are probably of Cretaceous age. The second...

... crystalline basement locally exposed in the Murphy Inlier and Kalkadoon–Leichhardt Belt between the western and eastern successions ( Fig. 1a ). This basement has been widely intruded by 1870–1820 Ma granites ( Blake 1987 ; Etheridge et al. 1987 ; Huston et al. 2012 ; Blaikie and Kunzmann 2020...

... in one sample from the Nueva Esperanza vein (27º20′43″ S, 66º23′17″ W, 3290 m osl), one of the veins in the Capillitas mine ( Fig. 1 ). This vein strikes N80ºE, dips 45ºS, is approximately 100 m long, 0.30 m thick, and is hosted in granite. It is mainly composed of sphalerite, pyrite, tennantite...