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In this study we used a multidisciplinary approach, coupling morphological, geological, geochemical, and statistical analyses to investigate the provenance of rhyodacitic and dacitic glass knapped at the Pilauco site (40°34′11" S, 73°06′17" W; 13,570 ± 70–12,540 ± 90 14C year BP) in northwestern Chilean Patagonia. A morphotechnological analysis was performed on the entire lithic assemblage, which is composed of cores, retouched and unretouched unifacial flakes, and small pieces of debitage, some of them closely associated with Notiomastodon aff. N. platensis gomphothere bones. Sixty‐two archeological and geological samples were analyzed by inductively coupled plasma mass spectrometry revealing a wide range of basaltic to rhyodacitic compositions. The archeological knappable dacitic and rhyodacitic glasses were recovered from pebbles deposited mainly on a beach away from the site, as deduced by the presence of minute and dense crescentic percussion marks on the cortexes. Geochemical trace element analysis suggests that the Puyehue–Cordón Caulle Volcanic Complex is the most likely source for the volcanic glass artifacts at Pilauco. The new morphotechnological and provenance record and improved stratigraphic sequences highlight the Pilauco site as an important contribution for the diversity of the South American geoarchaeological context. [ABSTRACT FROM AUTHOR]

The Southern Patagonian Icefield (SPI) lies above an area of slow convergence between Antarctic and South-America plates, where limited seismicity is recorded by global and regional seismic networks. To understand the seismic behavior of this zone, we analyze two years of continuous broad-band data recorded by 27 seismometers, deployed around the SPI. Substantial ice loss coupled with the unusually low viscosity of the underlying mantle is causing a rapid uplift. Our findings indicate that most of the seismicity occurs in the upper crust , likely associated with the (re)activation of regional compressive structures. However, earthquakes immediately beneath the SPI generally are shallower and show normal or strike-slip faulting. We suggest that this activity is promoted as a response to the crustal relaxation after rapid ice removal of SPI. The almost complete absence of interplate and intraslab events is consistent with a locked megathrust fault interface, highlighting the similarity of this region with the Cascadia subduction zone. • Shallow seismicity is observed in the majority in the area of southern Patagonia Icefield. • The inferred stress suggests the solid earth response to mass loss from the icefield as the major cause. • The almost complete absence of interplate earthquakes suggests that the megathrust may be locked. [ABSTRACT FROM AUTHOR]