EGU General Assembly 2020
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the Creative Commons Attribution 4.0 License.

The 4.2 ka cal BP major eruption of Cerro Blanco, Central Andes

Jose-Luis Fernandez-Turiel1, Francisco-Jose Perez-Torrado2, Alejandro Rodríguez-Gonzalez2, Norma Ratto3, Marta Rejas1, and Agustin Lobo1
Jose-Luis Fernandez-Turiel et al.
  • 1ICTJA, CSIC, Barcelona, Spain (,,
  • 2Instituto de Estudios Ambientales y Recursos Naturales (i–UNAT), Universidad de Las Palmas de Gran Canaria (ULPGC), 35017 Las Palmas de Gran Canaria, Spain (,
  • 3Universidad de Buenos Aires, Instituto de las Culturas (UBA-CONICET), Facultad de Filosofía y Letras,

The major eruption of the Cerro Blanco Volcanic Complex (CBVC), in the Central Volcanic Zone of the Andes, NW Argentina, dated at 4410–4150 a cal BP, was investigated confirming that is the most important of the three major Holocene felsic eruptive events identified in the southern Puna (Fernandez-Turiel et al., 2019). Identification of pre–, syn–, and post–caldera products of CBVC allowed us to estimate the distribution of the Plinian fallout during the paroxysmal syn–caldera phase of the eruption. Results provide evidence for a major rhyolitic explosive eruption that spread volcanic deposits over an area of about 500,000 km2, accumulating >100 km3 of tephra (bulk volume). This last value exceeds the lower threshold of Volcanic Explosive Index (VEI) of 7. Ash-fall deposits mantled the region at distances >400 km from source and thick pyroclastic-flow deposits filled neighbouring valleys up to several tens of kilometres from the vent. This eruption is the largest documented during the past five millennia in the Central Volcanic Zone of the Andes, and is probably one of the largest Holocene explosive eruptions in the world.

The implications of the findings of the present work reach far beyond having some chronostratigraphic markers. Further interdisciplinary research should be performed in order to draw general conclusions on these impacts in local environments and the disruptive consequences for local communities. This is invaluable not just for understanding how the system may have been affected over time, but also for evaluating volcanic hazards and risk mitigation measures related to potential future large explosive eruptions.

Financial support was provided by the ASH and QUECA Projects (MINECO, CGL2008–00099 and CGL2011–23307). We acknowledge the assistance in the analytical work of labGEOTOP Geochemistry Laboratory (infrastructure co–funded by ERDF–EU Ref. CSIC08–4E–001) and DRX Laboratory (infrastructure co–funded by ERDF–EU Ref. CSIC10–4E–141) (J. Ibañez, J. Elvira and S. Alvarez) of ICTJA-CSIC, and EPMA and SEM Laboratories of CCiTUB (X. Llovet and J. Garcia Veigas). This study was carried out in the framework of the Research Consolidated Groups GEOVOL (Canary Islands Government, ULPGC) and GEOPAM (Generalitat de Catalunya, 2017 SGR 1494).


Fernandez–Turiel, J.L., Perez–Torrado, F.J., Rodriguez–Gonzalez, A., Saavedra, J., Carracedo, J.C., Rejas, M., Lobo, A., Osterrieth, M., Carrizo, J.I., Esteban, G., Gallardo, J., Ratto, N., 2019. The large eruption 4.2 ka cal BP in Cerro Blanco, Central Volcanic Zone, Andes: Insights to the Holocene eruptive deposits in the southern Puna and adjacent regions. Estudios Geologicos 75, e088.

How to cite: Fernandez-Turiel, J.-L., Perez-Torrado, F.-J., Rodríguez-Gonzalez, A., Ratto, N., Rejas, M., and Lobo, A.: The 4.2 ka cal BP major eruption of Cerro Blanco, Central Andes, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5038,, 2020

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Presentation version 1 – uploaded on 18 Apr 2020
  • CC1: Comment on EGU2020-5038, Benjamin Heit, 04 May 2020

    placing the Cerro Blanco eruption between the Campi Flegrei and Santorini sounds extremely suspicious. I think the authors did something wrong in all these calculations. The material collected will never represent such an eruption. I am not sure about the way they collected samples in the filed. Either they ignored the field evidence or have never been in field. Cerro Blanco is rather a small eruption compared to others in the Puna Plateau. I would suggest the authors to re-think what went wrong or we will need to wait until more reliable evidence is presented about the volumes of materials. This data as presented here are biased and make no sense.

    • AC1: Reply to CC1, Jose-Luis Fernandez-Turiel, 04 May 2020

      Many thanks for your interest in our work. However, I am sorry to tell you that your comments have no scientific basis. We do present evidence and, of course, our findings on the 4.2 ka eruption of Cerro Blanco are based on intensive field campaigns carried out over the years in a large area of NW of Argentina. We recommend that you read the article detailing the research carried out on this Holocene eruption of Cerro Blanco ( ) (Fernandez–Turiel J. L. et al., 2019. Estudios Geológicos,  75 (1): e088, 31 pp.). Scientific controversy is stimulating and we are certainly open to discussion, but neglecting work by other colleagues without providing any reason cannot be considered part of a scientific debate. What evidence are you presenting to support your opinion? For example, based on your knowledge of the regional field geology, which Holocene eruptions are greater than Cerro Blanco in the Southern Puna?

      • CC2: Reply to AC1, Benjamin Heit, 04 May 2020

        dear autor, I worked on Cerro Blanco seismology  myself and have contacted local volcanologists and volcano scientists from the US and Germany to learn about the explosivity and volumes related to this 4.2 ka eruption. I think there is no discussion about this. You are saying this is among the top 3 eruptions in the world!!! We are discussing here your data. And, yes you are right, there are no other eruptions in the southern Puna of this category in the Holocene. I was thinking  about Mio-Pliocene.

        coming back to your data, if you really want to know, I am saying something in YOUR DATA IS WRONG and CAN NOT BE REAL as you place this small eruption above other like Tambora . I can not imagine why you are suggesting such a big volume of material for the Cerro Blanco eruption other than samples that were not properly taken in the field. 

        You are saying that my opinion cannot be considered part of a scientific debate. You are referring to your own paper to support this data,...really? you are citing your own work as to say !this has been done properly? this is not scientific at all. Do you have any other results from other colleagues?

        a proper peer-reviewed paper, I just found online (published on JSAMES) analized the same material as you did and came to the conclusion:

        An important unresolved issue for the CB eruption is it volume. The currently estimated volume of 83 km3 (DRE) by Fernando-Turiel et al. (2019) is inconsistent with the size of the Cerro Blanco caldera and to date the over thickening of the distal ash by local rework is poor assessed. (sic)

        If you think you are fine and sure about your data, please prove me wrong and go publish this properly in a well stablished journal. One more question, did you ever try to talk to local volcanogists that have been working  and producing papers, master and PhD thesis in the Puna for decades? Have you got local universities involved in your project? I can't believe anyone will support this idea nor there is such kind of data.


        • AC2: Reply to CC2, Jose-Luis Fernandez-Turiel, 04 May 2020

          We are referring to our own work on the recent eruption of Cerro Blanco ( ) because the current poster presentation is based on that work. We have not found any other article fully supporting our view, as it is often the case when scientists present something really new. The discovery of the ash fall deposits of the recent Cerro Blanco eruption allowed us to estimate the age and volume of the eruption. These findings generated a heated discussion on both topics. The age debate seems settled (4.2 cal ka), while the discussion on the volume continues for some people, who always express opinions but never present data.

          In relation to some of your assertions, it is important to clarify some points. We do state that Cerro Blanco generated the largest documented eruption during the past five millennia in the Central Volcanic Zone and around the world but we have never said that this eruption is among the top 3 eruptions in the world. Your statement “You are saying this is among the top 3 eruptions in the world!!!” is thus a fake argument, beyond any honest debate.

          Regarding your comments “something in YOUR DATA IS WRONG and CAN NOT BE REAL” and “samples that were not properly taken in the field”, we want to emphasize that we presented our data in the afore-mentioned article and in related datasets, both can be verified in Open Access following FAIR ("findable, accessible, interoperable, reproducible") standards. What about your data?

          The JSAMES paper (Báez et al., 2020. Eruptive style and flow dynamics of the pyroclastic density currents related to the Holocene Cerro Blanco eruption (Southern Puna plateau, Argentina), Journal of South American Earth Sciences, 98, 102482, ) that you mention but of which you do not provide the reference (against elementary scientific etiquette) , focuses on the pyroclastic density currents related to the Holocene Cerro Blanco eruption, but not to the ash fall deposits of this eruption. Therefore, that article did not “analyzed the same material as you did”, a second  false asserion of yours. In our view, the conclusion that you mention from that work is not supported by any kind of data.

          Last but not least, local and no-local scientists were involved in the project. Preliminary, intermediate and final results, such as those shown here, on the discovery of the Cerro Blanco eruption have been presented at national and international congresses since 2013 (EGU, AGU, CGA, CGE, etc.) as well as invited conferences (e.g., Universidad Nacional de Tucumán, Universidad Nacional de Buenos Aires, Museo de La Plata, etc.). The discussion has always been open and it will continue being open to constructive debate.

          • CC3: Reply to AC2, Benjamin Heit, 05 May 2020

            I accept criticism, but telling that I spread fake words is indeed unacceptable. So, please tell me just one thing. You show in your conclusions the biggest eruptions in the last five millennia and place Cerro Blanco on the third place. Among nine of the biggest eruptions in the world!!!! you are showing this in your conclusions! The Cerro Blanco has a volume of 83.5 km3 according to your own figure and I consider this statement misleading and deceptive. At the beginning I just thought there was a mistake in your data but now I see there is a chance that you just didn’t make a mistake. As I said before, your conclusions are misleading. This would be fake, by the way, fake is the word some politicians use to discredit any kind of criticism. You have been working on this data since 2013 and you still consider they are new, this is what happens in the Andes...the more you wait, the more the ashes are blown by the wind and the rain does the rest: if you go now again to the field, you will be able to obtain maybe 100 km3 and place your data above or at least near to those of Toba!. With all due respect, I have never heard of the journal where you published this data in, where you are by the way, PART OF THE ADVISORY COUNCIL/EDITORIAL BOARD!. Again, please prove me wrong! I will love to see your results published in a proper peer-reviewed journal. I imagine many volcanologists will enjoy your manuscript and will be happy to review your data.

            • AC3: Reply to CC3, Jose-Luis Fernandez-Turiel, 05 May 2020

              The figure of spheres of volumes compares the volume of the Cerro Blanco eruption with other well-known eruptions, just to show its large volume. It is not an exhaustive representation of all past eruptions.

              Regarding the rest of your reply, I believe we are in a loop, we provide results and you provide disqualifications. I refer to our first answer, “neglecting work by other colleagues without providing any reason cannot be considered part of a scientific debate”. Please, we hope that if you want to follow this thread you will focus on the debate on scientific issues related to the Cerro Blanco eruption. Actually, there are many exciting topics of debate and of great interest to many different disciplines in connection with this eruption. Let's not waste time on sterile debates. Once again, thank you for your interest in our work.