Luminescence Dating Reveals Multiple Late Quaternary Eruptions at the Soda Lake Volcanic Center, Nevada

Abstract. The Soda Lake volcanic center in western Nevada is the youngest known volcanic system in the state, yet its eruptive history remains poorly constrained because of conflicting stratigraphic interpretations and the limitations of conventional radiometric dating in young mafic volcanic terrains. Here we apply post-infrared infrared stimulated luminescence (post-IRIR) dating to potassium-rich feldspar separates extracted from volcaniclastic sediments and plagioclase phenocrysts extracted from juvenile basalt bombs to directly constrain the timing of eruptive activity using two distinct luminescence resetting pathways: complex eruption- and transport-related resetting of volcaniclastic grains (including variable thermal, optical, and mechanical resetting) and thermal resetting of feldspar phenocrysts within basalt bombs. Single-grain post-IRIR measurements of surge and reworked volcaniclastic deposits indicate eruptions at ~5.5 ka and ~12.5 ka. The ~5.5 ka eruption is further corroborated by plagioclase phenocrysts extracted from basalt bombs associated with the youngest eruptive phase, which yielded statistically indistinguishable ages. Despite contrasting depositional histories and luminescence resetting mechanisms, ages derived from sedimentary and bomb-derived materials are internally consistent, demonstrating that reliable eruption chronologies can be established from multiple components of a volcanic system. More broadly, the results demonstrate that eruption-related luminescence resetting may be preserved in juvenile phenocrysts, volcaniclastic sediments, and potentially xenocrystic materials, substantially expanding the range of datable components available in young mafic volcanic systems. These results resolve long-standing uncertainties regarding the eruptive history of the Soda Lake volcanic center and demonstrate the broader potential of luminescence dating for directly constraining young basaltic volcanism in settings where conventional geochronologic methods are ineffective.