Fig. 3: Schematic illustration of late Miocene-to-Pleistocene tectonics, climate, and deposition in the Río Iruya catchment.

Pink rectangle indicates the approximate location of the Río Iruya section of this study. a Latest Miocene to mid-Pliocene interval featuring ongoing uplift of the Eastern Cordillera and early stages of foreland development. Largely transverse drainages dominate the depositional system and Río Iruya watershed may not have been directly connected to the eastern Puna Plateau. b Mid-Pliocene-to-Early Pleistocene period characterized by ongoing tectonic uplift in the eastern Cordillera (Sierra Santa Victoria and Sierra Tilcara). The Río Iruya watershed may have been connected to the eastern Puna Plateau based on the strong proportion of Neogene-aged zircons in the sediment. c Hinterland Puna Plateau drainages such as the Quebrada de Humahuaca are fully diverted to the south by sustained range growth and increasing aridification. The Río Iruya may have become disconnected from the Puna Plateau and begun to establish its modern extent based on the near disappearance of Neogene zircons from the sediment.