The Marifil Volcanic Complex at Sierra de Pailemán: implications for the Early Jurassic magmatic evolution of the Eastern North Patagonian Region

ABSTRACT

The Sinemurian Marifil Volcanic Complex at Sierra de Pailemán, located in the east part of the North Patagonian Region, Argentina, includes five lithofacies and three volcanic events. The volcanic activity begins with subaerial pyroclastic-fall deposits, massive lapilli tuffs with eutaxitic textures, and subaerial silicic domes’ emplacement. The upper part of the sequence is formed by pyroclastic fall deposits that pass to massive lapilli tuffs and rhyolitic lava flows. These lithofacies indicate the collapse of explosive eruption columns, coeval with small silicic domes’ emplacement, and lava-flows’ eruption. The volcanic episode at Sierra de Pailemán was generated during continuous magmatic activity because no erosional or unconformity surfaces were recognized. The Marifil Volcanic Complex’s age at Sierra de Pailemán is 191.2 ± 1.3 Ma (Sinemurian) and belongs to the V0 phase of volcanism. These rocks are high-K rhyolites, possibly produced by partial melting of the lower crust, promoted by fluids derived from a subducted plate in back-arc settings that change to an intraplate setting. The Lu-Hf isotopes suggest the possibility of magma mixing in the source and recycling or re-melting of a more evolved crust related to subduction zones. The Lower Jurassic magmatic activity in the western North Patagonian Region and the Patagonian Cordillera of Argentina and Chile correspond to continental arcs.

Graphical abstract

KEYWORDS:

• Marifil Volcanic Complex
• Sierra de Pailemán
• North Patagonian Region
• high-K rhyolites

Acknowledgments

This study is part of research projects granted by Universidad Nacional del Sur and CONICET. Prospección geofísica de la Provincia de Rio Negro, Ciclos tectomagmáticos de la República Argentina (grant 24/H060), and Gondwánico y Patagonídico del Macizo Nordpatagónico occidental (grant 24/h121) were granted by the Universidad Nacional del Sur. Análisis de la configuración y evolución geológico–geofísica del sector oriental de la Comarca Nordpatagónica (grant 546) was supported by the ANPCYT-UNS (Agencia Nacional de Promoción Científica y Tecnológica), whereas Significado y evolución de los eventos tectonomagmáticos Gondwánicos y Patagonídicos del norte de Patagonia was granted by CONICET (grant 11220150100184).

We would like to thank Contreras and Catriel families at Sierra de Pailemán, as well as the personnel of the Condor Project.

Special thanks to all the technicians of MultiLab, UERJ for possessing the samples used to obtain the geochronological data and to the technicians and geologists of Laboratorio de Petrotomia, UNS.

We express our appreciation to the anonymous reviewers and Dra. S. Lagorio, for their constructive comments that helped us improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here

Additional information

Funding

This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas [Grant 11220150100184]; ANPCYT-UNS [Grant 546]; Secretaría General de Ciencia y Tecnología, Universidad Nacional del Sur [Grant 24/H060,Grant 24/H121].