Zircon U-Pb ages and Hf isotopes for the Diablillos Intrusive Complex, Southern Puna, Argentina: Crustal evolution of the Lower Paleozoic Orogen, Southwestern Gondwana margin Agustín Ortiz a, b, * , Natalia Hauser b , Raúl Becchio a ,N  estor Suza ~ no a , Alexis Nieves a , Alfonso Sola a , Marcio Pimentel b , Wolf Reimold b, c, d a GEONORTE - INENCO (Universidad Nacional de Salta e CONICET), Av. Bolivia 5150, A4400FVY, Salta, Argentina b Geochronology Laboratory, Instituto de Geoci^ encias, Universidade de Brasília, 70910 900 Brasília, DF, Brazil c Museum für Naturkunde e Leibniz-Institute for Evolution and Biodiversity Research, Invalidenstrasse 43,10115 Berlin, Germany d Humboldt Universit€ aet zu Berlin, Unter den Linden 6, 10099 Berlin, Germany article info Article history: Received 8 September 2016 Received in revised form 9 August 2017 Accepted 24 September 2017 Available online 27 September 2017 Keywords: Southwestern Gondwana Puna Argentina Lower Paleozoic Orogen Zircon U-Pb geochronology Hf isotopes abstract The evolution of the rocks of the Lower Paleozoic Orogen in Puna, at the Southwestern Gondwana margin, has been widely debated. In particular, the scarce amount of geological and geochemical data available for the Diablillos Intrusive Complex, Eastern Magmatic Belt, Southern Puna, require a further study for new evidence towards the understanding of sources, magmatic processes and emplacement of magmas, in order to better comprehend the crustal evolution in this setting. We present new combined UePb and Hf isotope analyses on zircon by LA-MC-ICP-MS from monzogranite, granodiorite and diorite rocks of the Diablillos Intrusive Complex. We obtained 206 Pb/ 238 U concordant weighted average ages of 517 ± 3 Ma and 515 ± 6 Ma for the monzogranite and diorite, respectively, and a concordant age of 521 ± 4 Ma for the granodiorite. These ages permit to constrain the climax of magmatic activity in the Diablillos Complex around ~515e520 Ma, while the emplacement of the complex took place between ~540 Ma and 490 Ma (representing a ca. 50 Ma magmatic event). Major and trace element data, initial 87 Sr/ 86 Sr values varying from 0.70446 to 0.71278, positive and negative 3 Nd(t) values between þ2.5 and 4, as well as 3 Hf(t) for zircon data between þ 3 and 3 indicate that the analyzed samples represent contaminated magmas. The 3 Hf(t) and the 3 Nd(t) values for this complex specify that these rocks are derived from interaction of a dominant Mesoproterozoic crystalline and/or a metasedimentary source and juvenile mantle-derived magmas, with a T DM model age range of ~1.2e1.5 Ga, with later reworking during lower Paleozoic times. The combined data obtained in this contribution together with previous data, allow us to suggest that the formation of the Eastern Magmatic Belt of the Puna was part of a long-lived magmatic event during Early Paleozoic times. Whereby the granitoids of the Eastern Magmatic Belt formed through intra-crustal recycling at an active continental margin, with minor contributions from juvenile material in the back-arc setting. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction The Neoproterozoic to Early Paleozoic rocks (present-day Eastern Cordillera and Puna) in the Central Andes, NW Argentina (Fig. 1), formed at the Southwestern Gondwana margin. Their evolution has been widely debated and traditionally two orogenic events have been distinguished: the Pampean (Upper Precam- brianeLower Cambrian) and the Famatinian (Upper Cam- brianeLower Silurian) stages involving subduction processes with formation of magmatic arcs, followed by accretion/collision of para- auhocthonous and allochthonous terranes (e. g., Ramos et al., 1986; Ramos, 1988, 2008; Loewy et al., 2004; Rapela et al., 2007; Cordani et al., 2009; Collo et al., 2009; Drobe et al., 2009; Hauser et al., 2011). Due to the lack of evidence and indicators for collisional processes - such as suture zones, presence of ophiolites related to oceanic crust, or high P/low T metamorphism indicative of * Corresponding author. GEONORTE - INENCO (Universidad Nacional de Salta e CONICET), Av. Bolivia 5150, A4400FVY, Salta, Argentina. E-mail address: agustinortiz13@hotmail.com (A. Ortiz). Contents lists available at ScienceDirect Journal of South American Earth Sciences journal homepage: www.elsevier.com/locate/jsames https://doi.org/10.1016/j.jsames.2017.09.031 0895-9811/© 2017 Elsevier Ltd. All rights reserved. Journal of South American Earth Sciences 80 (2017) 316e339