Browsing by Author "Schimmelpfennig, Irene"
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Item Restricted In situ cosmogenic 3He and 36Cl and radiocarbon dating of volcanic deposits refine the Pleistocene and Holocene eruption chronology of SW Peru(Springer, 2019-11-07) Bromley, Gordon R. M.; Thouret, Jean-Claude; Schimmelpfennig, Irene; Mariño, Jersy; Valdivia, David; Rademaker, Kurt; Vivanco Lopez, Socorro del Pilar; ASTER Team; Aumaître, Georges; Bourlès, Didier; Keddadouche, KarimConstraining the age of young lavas, which generally fall outside the effective range of traditional geochronology methods, remains a key challenge in volcanology, limiting the development of high-resolution eruption chronologies. We present an in situ cosmogenic ³He and ³⁶Cl surface-exposure chronology, alongside new minimum-limiting ¹⁴C ages, documenting young eruptions at five sites in the Western Cordillera, southern Peru. Four ³He-dated lavas on the Nevado Coropuna volcanic complex (hitherto thought to be dormant) indicate that the central dome cluster is young and potentially active; two Holocene lavas on the easternmost dome are the youngest directly dated lavas in Peru to date. East of Coropuna, lava domes and block-lava flows represent the most extensive output to date of Nevado Sabancaya, one of Peru’s most active volcanoes. Two ³He measurements confirm the Holocene age of these deposits and expand the chronology for one of the youngest major lava fields in Peru. ³⁶Cl surface-exposure ages from the Purupurini dome cluster and Nevado Casiri document middle-late-Holocene episodes of effusive activity, while basal ¹⁴C ages from a lavadammed wetland constrain an effusive eruption at Mina Arcata, north of Coropuna, to the late-glacial period. These new data advance the recent Western Cordillera volcanic record whilst demonstrating both the considerable potential and fundamental limitations of cosmogenic surface-exposure methods for such applications.