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Home , Cerro Blanco (volcano), Ignimbrite, Nevado Tres Cruces

EGU2020-5038 The 4.2 ka cal BP major eruption of , Central ICTJA J.L. Fernandez-Turiel1, F.J. Perez-Torrado2, A. Rodriguez-Gonzalez2, N. Ratto3, M. Rejas1, A. Lobo1

¹Institute of Earth Sciences Jaume Almera, ICTJA, CSIC, Barcelona, Spain ([email protected], [email protected], [email protected]) 2 Instituto de Estudios Ambientales y Recursos Naturales (i–UNAT), Universidad de Las Palmas de Gran Canaria (ULPGC), Las Palmas de Gran Canaria, Spain ([email protected], [email protected]) 3 QUECA Universidad de Buenos Aires, Instituto de las Culturas (UBA-CONICET), Facultad de Filosofía y Letras, Buenos Aires, ([email protected])

Introduction Results Conclusions CdP CB BdF The major eruption of Stratigraphic summary Bimodal particle size Geochemistry ● These results change the paradigm of Holo- CB23 the Cerro Blanco Volca- cene volcanism of southern Puna in the Cen- Sub- Sequence Unit Lithofacies and interpretation Mineralogy unit 4410-4150 a cal BP CB 3 nic Complex (CBVC), in Bolsón de BdF1 Alternating layers of moderate-poorly sorted, dacitic glass >> plagioclase, , , 2 tral Volcanic Zone of the Andes (CVZ). Fiambalá and ash. Plinian fall deposit. >> , , , the Central Volcanic titanite BdF Cerro Blanco CB3 4 Alternating layers, 3-30 cm thick, of siliceous sinter. amorphous silica (postcaldera) Deposits of hot springs. ● CBVC generated the largest documented Zone of the Andes, NW ca. b 7820 AP 3 Poorly defined decimetric-scale stratified deposits, poorly glass >> , quartz, biotite, to very poorly sorted, with decimetric angular rhyolitic magnetite, ilmemite >> apatite, allanite- eruption during the past five millennia in the ca. 4200 a cal AP Argentina, dated at blocks in rhyolitic lapilli and coarse ash matrix deposits. , CB 3 Block-and-ash deposits. 2 CVZ and around the world. CB 3 4410–4150 a cal BP, is 2 Poorly to well–defined layers, 3-30 cm thick, white, 4440-4240 a cal BP 2 20 µm ca. 1700 a cal BP rhyolitic lapilli and ash deposits. Fallout and (?) SEM image of distal thin-bedded ash (CB 1 sub-unit) the most important of phreatomagmatic deposits. 2 CB 1 Crystal poor, very vesicular, domes. the three major Holoce- of Cerro Blanco CB2 3 Unstratified, matrix-supported, moderate to poorly sorted glass >> feldspars, quartz, biotite, CB 3 (≈15 km3) ne felsic eruptive events (syncaldera) rhyolitic with clasts dominated by coarse magnetite, ilmenite > clinopyroxene, 2 pumice lapilli. Pyroclastic density current (PDC) deposits. orthopyroxene, amphiboles > allanite- par�culate cored cluster epidote, muscovite, titanite, zircon identified in the sou- 2 Unstratified rhyolitic ash. Plinian fall deposit. core par�cle thern Puna (Fernan- 1 Alternating layers, 1-3 cm thick, some of lapilli and some CdP of ash. Rhyolitic Plinian fall deposit. shell par�cle dez-Turiel et al., 2019). CB1 Poorly stratified lithic-rich . Block-and-ash deposit. glass >> feldspars, quartz, biotite, (precaldera) magnetite, ilmenite Cueros de CdP2 1,2 Unstratified, matrix-supported, moderate to poorly sorted glass >> feldspars, quartz, biotite, Purulla ignimbrite with clasts dominated by coarse pumice lapilli magnetite, ilmenite > apatite, allanite- Two different composi- 70º 60º W 67°50' 67°45' 67°40' W in CdP21 and lithic-rich CdP22. Pyroclastic density current epidote, muscovite, titanite, zircon (PDC) deposits. tions of plagioclases, bio- a NVZ N a Particle size bimodality is interpreted as evidence of particle aggre- tite, and Fe–Ti oxides ob- CdP1 Alternating layers, 1-10 cm thick, some of lapilli and some glass >> feldspars, quartz, biotite, gation in the eruptive plume, forming cored ash clusters that typica- served in the CB2 syn–cal- ENC of ash. Rhyolitic Plinian fall deposit. magnetite, ilmenite > amphiboles, lly break on impact with the ground. The resulting fallout deposit is dera sub–units indicate La Paz a clinopyroxene > apatite, allanite-epidote, CVZ PSBC muscovite, titanite, zircon Plinean fall deposits made up of core particles of hundreds of microns in size and shell mixing of two 1 3 particles of tens of microns in diameter that covered the former. batches during the erup- DRE volume from VOGRIPA-LAMEVE, except for Toba (Costa et al., 2014) and Cerro Blanco CB1-23 (≈170 km ) CB1 tion. 20º S ARGENTINA -Puna Central SVZ CB33 26°45' S Volcanic AVZ CB34 Zone CBC Isopach maps Eruption modelling CB31 ● The 4.2 cal ka Cerro Blanco eruption of mag- 3 RC 65º 60º W Bolivia 55º W a Bolivia a Isopach maps (m) for the nitude 7.0 erupted ~170 km over b CB32 Jujuy Paraguay Cueros de Purulla b CB1-2 fall deposits of

Pacific Ocean 2 3 Salta Nevado de Tres Cruces CBVC: (a) showing up to Formosa ~500,000 km , and ~15 km ignimbrites. Cerro Blanco CB23 CB22 Argentina 25º the inferred area of 0.10 Uruguay Volcanic Complex Chile Atlantic Ocean m isopach, and (b) in the 26°50' CB116 Chaco Paraguay 27 km 30º Source: Esri, DeLorme, USGS, NPS; Source: Esri, DigitalGlobe, 1 0.80 0.80 sampled area indicating 10 cm 1 0.60 0.50 ● The ash deposits of this eruption are exten- 0 5 km 23.6 m - Tucumán 0.40 Misiones GeoEye, Earthstar, Geographics, CNES/Airbus DS, USDA, USGS, 0.30 Catamarca the measured thickness. AeroGRID, IGN, and the GIS User Community 0.20 CB118 b 0.10 (c) Semi–log plot of thic- Santiago del Estero sive regional chronostratigraphic markers in CB114 Corrientes 5 CB 2 22 km 1/2 2 34 km - 12.5 m kness vs. (area) shows 0 500 Brazil 11.4 m - La Rioja

Not to scale the best fit model (Wei- Laguna Mar Santa Fe

km 30º S South America, and the cryptotephra for the Santiago Chiquita Buenos Aires Sources: Esri, USGS, NOAA b CB47 0 bull) for isopach adjust- CB22 2.0 m 196 km San Juan Uruguay CB31 Córdoba Entre Ríos ment. 68º 67º 66º 65º 64º W Fig. 12d 0 100 200 South Hemisphere. CB 1 CB46 km 2 CB45 San Luis Sources: Esri, USGS, NOAA CB21 Mendoza b Southern Puna Salta Bolsón de Fiambalá sequence reworked 1.5 200 km 208 km b 0.10 c 26º S Cafayate Cerro Blanco sequence 0.08 Antofagasta 0.20 Cueros de Purulla sequence de la Sierra 0.30 ● Further interdisciplinary research should be CB1 1.0 Tolombón CB22 Cafayate CB 2 CB44 Antofagasta Eruptive center 2 de la Sierra 204 km 0.40 thickness (m) ARGENTINA CdP CB 1 CB 1 0.50 performed to analyse impacts in local environ- El Peñón CB33 2 0.30 2 0.5 CB40 CHILE Tucumán 0.60 CB01 0.50 Santa María 169 km 0.80 sqrt (area) (km) 155 km 169 km 204 km 204 km 0.30 1 0.80 Tafí del Valle 11 km 0.50 0.60 100 Calchaquí Valleys 1.82 ments and local communities. CB34 0.20 Tafí del Valle 0.32 CBVC 0.35 0.68 1 2.38 0.0 0.57 1 Santiago 0.60 San Miguel de 0.20 1 1.50 CB32 0.60 27º Las Papas 0.40 Tucumán del Estero 2 m 0.34 NTC CB50 1 CB39 CB54 2 Catamarca CB37 200 km p (deposition > 1 kg/m Termas de 164 km 370 km 0.40 Bolsón de 0 155 km CB38 Fiambalá Aguilares Río Hondo CB 2 11,000 daily eruptive events 2 155 km CB41 Fiambalá CB53 Santiago 0.15 0 50 0.20 del Estero (~30 of wind data) Fiambalá 172 km 338 km References km Santiago del Estero 0.10 La Rioja Modelled with Tephra2 0 50 100 Fernandez–Turiel, J.L., Perez–Torrado F.J., Rodriguez–Gonzalez A., Saavedra J., km Plume height 27,000 m (a) volcanic centres in the Andean Central Volcanic (a) Cerro Blanco Volcanic Complex showing El Niño 208 km Carracedo J.C., Rejas M., Lobo A., Osterrieth M., Carrizo J.I., Esteban G., Gallardo Zone (data from Global Volcanism Program); NVZ, Northern (ENC), Pie de San Buenaventura Caldera J., Ratto N., 2019. The large eruption 4.2 ka cal BP in Cerro Blanco, Central Vol- Volcanic Zone; CVZ, Central Volcanic Zone; SVZ, Southern Vol- (PSBC), Robledo Caldera (RC), and Cerro Blanco Cal- canic Zone, Andes: Insights to the Holocene eruptive deposits in the southern canic Zone; and AVZ, Austral Volcanic Zone. (b) Studied sec- dera (CBC); (b) stratigraphic units in the Cerro Puna and adjacent regions. Estudios Geologicos, 75, e088. http://estudios- Secondary thickening We hypothesized that secondary tions and eruptive centres (CdP, Cueros de Purulla; CBVC, Blanco Volcanic Complex. vent geol.revistas.csic.es/index.php/estudiosgeol/article/view/982/1200 PDC deposits fall deposits thickening is related to the effect of Cerro Blanco Volcanic Complex; NTC, ). south of Cerro Blanco east of Cerro Blanco the topographically induced turbu- CB 2 Costa A., Smith V.C., Macedonio G., Matthews N.E., 2014. The magnitude and 50 cm 2 lences in the disaggregation, e.g., CB 1 impact of the Youngest Toba super-eruption. Frontiers in Earth Science, 2. 2 the breaking of lee waves, genera- reworked topsoil - light brown silt to sand, or stony dating sample ted by winds passing over elevated 25 CB 2 palaeosol CB54 topography beneath the eruption 2 section number and distance to vent Acknowledgements 370 km plume, and to a minor effect of ups- 1.0 m deposits 0 Financial support was provided by the ASH and QUECA Projects (MINECO, CGL2008–00099 and CB 2 lope moisture transport by easterly 2 4880-4780 a cal BP colluvial deposits CB 3 ignimbrite 2 atmospheric flow. CBVC, Cerro CGL2011–23307). We acknowledge the assistance in the analytical work of labGEOTOP 0.5 CB21 alluvial deposits CB22 unstratified ash Blanco Volcanic Complex, CdP, Geochemistry Laboratory (infrastructure co–funded by ERDF–EU Ref. CSIC08–4E–001) and DRX Cerro Blanco Caldera - 5 km diameter Laboratory (infrastructure co–funded by ERDF–EU Ref. CSIC10–4E–141) (J. Ibañez, J. Elvira and peat and silt lacustrine deposits CB21 alternating layers of lapilli and ash Cueros de Purulla, NTC, Nevado Tres 208 km 200 km 200 km 370 km 0 Cruces. S. Alvarez) of ICTJA-CSIC, and EPMA and SEM Laboratories of CCiTUB (X. Llovet and J. Garcia Veigas), and J. Cortés in communication.

How to cite: Fernandez-Turiel J. L., Perez-Torrado F. J., Rodriguez-Gonzalez A., Ratto N., Rejas M., Lobo A., 2020. The 4.2 ka cal BP major eruption of Cerro Blanco, Central Andes. EGU General Assembly 2020, 4-8 May, Vienna, Austria. EGU2020-5038. https://doi.org/10.5194/egusphere-egu2020-5038.