The Sierra de Macon, Plutonic expression of the Ordovician magmatic arc, Salta Province Argentina

Revealing the continental margin of Gondwana: the Ordovician arc of the Cordón de Lila (northern Chile)

“…Several authors have evaluated the palaeogeographic position of the CISL and the Quebrada Grande Formation and suggested that they could have formed close and associated to the 'Faja eruptiva de la Puna Occidental' (Niemeyer 1989;Coira et al 1999;Poma et al 2004), synonym to the Puna-Famatina arc (Bahlburg and Hervé, 1997;Pankhurst et al, 1998;. It has been also stated that the CISL could belong to Sun and McDonough (1989).…”

“…The drastic decrease of volcanic activity coincides in time with the depositional evolution in the Cordón de Lila, where the Quebrada Grande Formation (Upper Arenigian-Lower Llanvirnian) is not directly affected by volcanism. Arc-related granites intruded throughout the Lower to Middle Ordovician (Kleine et al 2004;Poma et al 2004) the volcano-sedimentary successions.…”

“…b Ternary provenance diagrams from Bhatia and Crook (1986); A oceanic arc, B continental arc, C active continental margin, D rifted/passive margin find the same results as in Niemeyer (1989) and are therefore not shown. Fractionated Ordovician plutonic and volcanic rocks of Arenigian age in the Puna point as well to an arc environment (Hanning 1987;Bahlburg 1990;Bock et al 2000;Kleine et al 2004;Poma et al 2004;Zimmermann and Bahlburg 2006). The rhyolites in the Cordón de Lila are tested regarding their possible arc affinity in the wellestablished binary plots after Pearce et al (1984).…”

Geoquímica, dataciones U-Pb SHRIMP sobre circón e isótopos de Hf del magmatismo gondwánico en el NW de Argentina: petrogénesis e implicancias geodinámicas.

“…The Pampean magmatism is restricted to the Eastern Cordillera (Cañani, La Quesera and Chañi units) (Omarini et al, 2008) and the Famatinian magmatism (Bahlburg et al, 2009) includes both the Faja Eruptiva de la Puna Occidental magmatic arc (Poma et al, 2004) and the Faja Eruptiva de la Puna Oriental back-arc magmatism (Coira, 2008;Zappettini, 2008).…”

Evidence of Early to Middle Ordovician arc volcanism in the Cordillera Oriental and Altiplano of southern Peru, Ollantaytambo Formation and Umachiri beds

“…It similarly remains undecided whether they formed in an arc environment. However, in view of the presence and orientation of the Famatina-Puna arc system in northwestern Argentina and northern Chile (Rapela et al, 1992;Bahlburg and Hervé, 1997;Bahlburg, 1998;Poma et al, 2004), it is permissible to assume that the Arequipa Massif intrusives represent a northward continuation of this arc (Fig. 8).…”