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During our explorations in search of fossils, we obviously favor sedimentary rocks; I invite you to follow me with my wife in search of fossils… in volcanic rocks! (only observation without sampling) In the center of the volcanic massif of Cantal (central France), we explored a not very accessible valley where outcrop deposits of breccias of dense pyroclastic flows, in search of fossil woods of Villafranchian age (upper Pleistocene). According to an old reference (conference , 1969) one can find: “sometimes tree trunks inclined in all directions and sometimes branches. They are black, it is charcoal, produced by combustion in the absence of oxygen. After their reduction in carbon, certain woods underwent a strong fumarolic activity with silicification in opal cristobalite, generally respecting the vegetal structures.” By anatomical study in microscopy, 5 genera have been identified: Cedroxylon, Piceoxylon, Cornoxylon, Fagoxylon, Ulmoxylon. They suggest a temperate or mountain type climate. The conservation of carbonized organic matter indicates that the rock emplacement temperature must have been relatively lower than at the volcanic magma exit point estimated at 900°C according to mineralogy. The pyroclastic flow therefore destroyed a forest by descending the slope of the volcano while cooling. Let us now see in some photos what we discovered with wonder: 2 fossiliferous sites, the first with only one vertical trunk in an overhanging cliff, the second with multiple trunks preserved or hollowed out and branches on the bank of the river (without signs of silicification on these 2 sites found about 300 meters apart). There must therefore still be other nearby sites, but the difficult access to the site probably keeps them out of sight.

The 20th Century's Greatest Volcanic Eruption: Mt Katmai 100 Years Later, USGS, July 2, 2012 https://www.youtube.com/watch?v=7nOSLGSsb1s Mount Katmai description and information, Alaska Volcano Observatory - below web pages have PDFs of papers https://avo.alaska.edu/volcanoes/volcinfo.php?volcname=Katmai https://avo.alaska.edu/volcanoes/activity.php?volcname=Katmai&eruptionid=494 Some PDFs of papers are: Carrara, A., Burgisser, A. and Bergantz, G.W., 2020. The architecture of an intrusion in magmatic mush. Preprint, eartharxiv-org https://eartharxiv.org/hc4px/ Eichelberger, J.C. and Izbekov, P.E., 2000. Eruption of andesite triggered by dyke injection: contrasting cases at Karymsky Volcano, Kamchatka and Mt Katmai, Alaska. Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 358(1770), pp.1465-1485. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.548.7200&rep=rep1&type=pdf Tibaldi, A. and Bonali, F.L., 2017. Intra-arc and back-arc volcano-tectonics: Magma pathways at Holocene Alaska-Aleutian volcanoes. Earth-Science Reviews, 167, pp.1-26. https://www.academia.edu/35709811/Intra-arc_and_back-arc_volcano-tectonics_Magma_pathways_at_Holocene_Alaska-Aleutian_volcanoes http://unimib.academia.edu/AlessandroTibaldi Ward, P.L. and Matumoto, T., 1967. A summary of volcanic and seismic activity in Katmai National Monument, Alaska. Bulletin Volcanologique, 31(1), pp.107-129. https://ozonedepletiontheory.info/Papers/Ward1967KatmaiVolcanoes.pdf Yours, Paul H.

Volcanoes’ Deadly Pyroclastic Flows Surf on Air to Achieve Super Speed After an eruption, DIY cushions of gas help searing torrents of gas, ash, and rock spread miles from their source within a matter of minutes. Kathrine J. Wu., LPB, April 8, 2019 https://www.pbs.org/wgbh/nova/article/volcano-pyroclastic-flows-surf-on-air/ Pyroclastic Flows May Spread Swift Death on a Cushion of Air Ryan F. Mandelbaum, GIZMODO, APril 8, 2019 https://gizmodo.com/pyroclastic-flows-may-spread-swift-death-on-a-cushion-o-1833888985 Pyroclastic flows: The secret of their deadly speed, Nature Video https://www.nature.com/articles/d41586-019-01145-2 https://www.youtube.com/watch?v=hvuP7kuX7Dk The paper is: Gert Lube, Eric C. P. Breard, Jim Jones, Luke Fullard, Josef Dufek, Shane J. Cronin and Ting Wang, 2019, Generation of air lubrication within pyroclastic density currents. Nature Geoscience. Article | Published: 08 April 2019 https://www.nature.com/articles/s41561-019-0338-2 Yours, Paul H.

Below is an interesting paper that I came across. Iurino, D.A., Bellucci, L., Schreve, D. and Sardella, R., 2014. Exceptional soft tissue fossilization of a Pleistocene vulture (Gyps fulvus): new evidence for emplacement temperatures of pyroclastic flow deposits. Quaternary Science Reviews, 96, pp. 180-187. https://www.sciencedirect.com/science/article/pii/S0277379114001553 The abstract states: “Here we report an exceptional case of soft tissue fossilization of a Late Pleistocene Eurasian griffon vulture (Gyps fulvus) in the pyroclastic sequence of the Alban Hills volcanic region (SE Rome, Italy).” CT scans of the natural cast revealed extraordinary detail in the natural cast of the head, including everted tongue, beak, feather insertions and the nictitating membrane of the eye. The PDF file of this paper can be found at: https://www.researchgate.net/publication/262431624_Exceptional_soft_tissue_fossilization_of_a_Pleistocene_vulture_Gyps_fulvus_New_evidence_for_emplacement_temperatures_of_pyroclastic_flow_deposits https://www.researchgate.net/publication/266734626_EXCEPTIONAL_SOFT_TISSUE_FOSSILIZATION_OF_A_LATE_PLEISTOCENE_VULTURE_GYPS_FULVUS_FROM_ALBAN_HILLS_VOLCANIC_REGION_ITALY https://www.researchgate.net/profile/Dawid_Iurino https://www.researchgate.net/profile/Luca_Bellucci3 Yours, Paul H.