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dc.date.accessioned 2023-04-25T18:53:28Z
dc.date.available 2023-04-25T18:53:28Z
dc.date.issued 2017
dc.identifier.uri http://sedici.unlp.edu.ar/handle/10915/152123
dc.description.abstract This work provides new petro-geochemical and isotopic information to constrain the crustal evolution of the Precambrian Cerro La Ventana Formation. The Rb–Sr, Sm–Nd, Pb–Pb, and U–Pb isotopic data obtained as well as their petrological and geochemical features are reported. These data are useful to discuss relationships with equivalent Mesoproterozoic units located along the Cuyania terrane in the proto-Andean Gondwana margin. The type section of the basement rocks of the Cerro La Ventana Formation is located in the south-eastern part of the San Rafael Block, Mendoza Province known as Leones-Ponón Trehué-La Estrechura region. Equivalent crustal fragments are also included in this basement, such as ductile-deformed rocks of the El Nihuil Mafic Unit that are intruded by Ordovician undeformed dolerites. The basement exposed along the type section corresponds to a metamorphosed volcano-plutonic complex with hardly any sedimentary protolith. Main rocks are tonalites and foliated gabbros and quartz diorites that pass to amphibolites, and minor granodioritic–dioritic orthogneisses, with abundant angular microgranitoid enclaves now deformed and stretched intruded in mafic to felsic metavolcanics with porphyritic relic textures. The studied samples classified as tonalites and some close to the field of granodiorites following a calc-alkaline trend. Gabbroic samples from the El Nihuil mafic unit show a more tholeiitic signature. The bulk of samples from the Cerro La Ventana Formation plot within the field of metaluminous rocks; although a few are in the peraluminous field. Main groups of samples plot as low-Al TTD field; however, some of them show high Sr/Y ratios which are typical of high-Al TTD. The Mg#/K ratio is higher in the Cerro La Ventana Formation compared with Las Matras TTG series suggesting a minor differentiated grade for the first one. The chondrite-normalized REE diagrams for Leones samples have Eu anomalies rather positive and gabbros from El Nihuil region display patterns with positive Eu anomalies typical of plagioclase-rich igneous rocks. The Rb–Sr data defined an isochron with 1148 ± 83 Ma, initial 87Sr/86Sr = 0.70292 ± 0.00018. The low initial ratio is indicative of a slight evolved Mesoproterozoic source. An acceptable isochron was obtained using Sm–Nd methodology indicating an age of 1228 ± 63 Ma. The model ages (TDM) are in the range 1.23–1.64 Ga with εNd(1200) in between −0.94 and +4.7 recording a ‘depleted’ source, less evolved than CHUR for the time of crystallization. In a 207Pb/204Pb diagram the samples plot similarly to rocks from the basement of Cuyania Terrane (Pie de Palo Range and crustal xenoliths) showing a distinctive non-radiogenic signature. The tonalitic lithofacies located at the Leones River type section was chosen for zircon U–Pb TIMS dating and the obtained crystallization age was 1214.7 ± 6.5 Ma. The in situ U–Pb (LA-ICP-MS) zircon data done in two different laboratories on samples from El Nihuil mafic unit (tonalitic orthogneisses) plotted in a Concordia diagram, record an intercept at 1256 ± 10 Ma and in Tera-Wasserburg diagram an age of 1222 ± 6.9 Ma. With these isotopic data we confirm the Mesoproterozoic age for the basement of the San Rafael Block. The obtained ca. 1.2 Ga is quite similar to those belonging to the basement of other regions from the Cuyania allochthonous terrane. en
dc.format.extent 19-58 es
dc.language en es
dc.publisher Springer es
dc.relation.ispartof Springer Earth System Sciences es
dc.subject Cuyania terrane es
dc.subject San Rafael Block es
dc.subject Cerro La Ventana Formation es
dc.subject Mesoproterozoic basement es
dc.subject Geochemistry es
dc.subject Geochronology es
dc.title The Mesoproterozoic Basement at the San Rafael Block, Mendoza Province (Argentina): Geochemical and Isotopic Age Constraints en
dc.type Libro es
sedici.identifier.other doi:10.1007/978-3-319-50153-6_2 es
sedici.identifier.isbn 978-3-319-50153-6 es
sedici.creator.person Cingolani, Carlos Alberto es
sedici.creator.person Basei, Miguel A. S. es
sedici.creator.person Varela, Ricardo es
sedici.creator.person Llambías, Eduardo Jorge es
sedici.creator.person Chemale Jr., Farid es
sedici.creator.person Abre, Paulina es
sedici.creator.person Uriz, Norberto Javier es
sedici.creator.person Marques, Juliana es
sedici.subject.materias Geología es
sedici.description.fulltext true es
mods.originInfo.place Centro de Investigaciones Geológicas es
sedici.subtype Capitulo de libro es
sedici.rights.license Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
sedici.rights.uri http://creativecommons.org/licenses/by-nc-sa/4.0/
sedici.contributor.compiler Cingolani, Carlos Alberto es
sedici.relation.bookTitle Pre-Carboniferous Evolution of the San Rafael Block, Argentina es


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