The tephra deposits of the large 4.2 ka BP Cerro Blanco eruption in the southern Puna, Central Volcanic Zone, Andes

BAEZ, WALTER ARIEL; AGUSTIN LOBO; JULIO SAAVEDRA; JOSÉ LUIS FERNADEZ TURIEL; JUAN-FERNANDO GALLARDO; NORMA RATTO; JUAN CARLOS CARRACEDO; FRANCISCO-JOSÉ PEREZ TORRADO; MARGARITA OSTERRIETH; MARTA REJAS; ALEJANDRO RODRIGUEZ-GONZALES

Zaragoza

Congreso; PAGE 2017; 2017

World Climate Research Programme.

We present stratigraphical and geomorphological data,physical volcanology, radiocarbon dating, and tephrapetrography and geochemistry data which provideevidence for a major explosive eruption -spreading140 km3 ashes over 440,000 km2- from the southernPuna in NW Argentina. This eruption occurred around4100-4410 years ago in the Cerro Blanco VolcanicComplex. Ash fallout deposits mantled the region up tohundreds of kilometres from the volcano and thickpyroclastic flow deposits ponded the neighbouringvalleys at distances up to 35 km from source. Thiseruption is the biggest documented during the past fivemillennia in the Central Volcanic Zone of the Andes,and possibly one of the largest Holocene explosiveeruptions around the world. Furthermore, we haveidentified two additional eruptions in the region, oneduring the Early-Holocene and other in the Late-Holocene. The recognition of these significant volcanicevents sheds new light on interpretations of theHolocene geological and archaeological records, andoffers an excellent, extensive regionalchronostratigraphic marker for reconstructing Holocene geological history over a wide geographical area of South America.