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Bulletin of Volcanology

, 81:29 | Cite as

Lithic-rich and lithic-poor ignimbrites and their basal deposits: Sovana and Sorano formations (Latera caldera, Italy)

  • Greg A. ValentineEmail author
  • Danilo M. Palladino
  • Kailey DiemKaye
  • Claudia Fletcher
Research Article

Abstract

Conceptual models explaining the characteristics of ignimbrites and their basal deposits have mainly focused on variations in particle concentration and speed of the parent pyroclastic currents. Here, we focus on the effects of relative proportions of clasts that are well coupled to the carrier gas phase and those that are poorly coupled, i.e., the proportions of fine and/or low-density clasts compared to coarse and/or dense clasts. We document facies and macroscopic clast populations of two ignimbrite-producing eruptive sequences of similar volume and composition, both erupted from Latera caldera (central Italy). The Sovana ignimbrite has 1–15 vol% dense lithic clasts and locally up to 70 vol% in lithic-rich domains. It preserves evidence of emplacement of multiple overlapping flow units with local internal channeling. The ignimbrite is underlain by two basal deposits: (1) a radially distributed, 20–80-cm-thick vitric tuff referred to as BUS (basal unit Sovana) that thins gradually with distance and shows evidence of emplacement by lateral currents; and (2) a fines-depleted, lenticular, massive lapilli tuff, up to 20 cm thick, with abundant lithic clasts. The Sorano ignimbrite, in contrast, has < 1 vol% dense lithic clasts. It contains multiple reverse coarse-tail graded emplacement units, but we observed no internal channeling. In most places, its basal deposits are 20–100 cm of dominantly planar-parallel, 5–10 cm-thick, reverse coarse-tail graded tuff beds. However, in local depressions near the tops of paleocanyons that were filled by Sorano ignimbrite, the basal deposits are up to 2 m thick and are clearly cross stratified. We interpret the different deposit characteristics in terms of recent modeling and experimental results. The Sovana eruption involved major caldera collapse that introduced abundant dense lithic clasts into the erupting mixtures. BUS may have partly resulted from expulsion of a dilute, fine-grained mixture at the site where the pyroclastic fountain(s) impacted the ground, which then propagated outward as a dilute pyroclastic current ahead of the main ignimbrite-producing currents; the expulsion process is promoted by collapsing mixtures rich in poorly coupled clasts. The fines-depleted layer overlying BUS was deposited by rapid sedimentation of abundant dense clasts from the head of the ash-cloud surge, which accompanied the concentrated underflow that deposited the ignimbrite. Spatial and temporal variations in dense-clast abundance, and likely other parameters, during eruption resulted in multiple flow units. The Sorano eruption lacked poorly coupled clasts and did not produce an expulsion-driven current. Its ash-cloud head deposited ash and small pumice lapilli that were able to move in traction carpets prior to being overridden by a concentrated underflow. The overriding ash-cloud bodies locally deposited cross-stratified horizons in depressions high on the canyon walls, before they were inundated as the concentrated underflows filled the canyons with ignimbrite. To summarize, the differences between the ignimbrites and their basal deposits can be largely attributed to the differences in proportions of poorly coupled relative to well-coupled particles in the collapsing eruptive mixtures; the resulting conceptual model simplifies the previous range of interpretations for basal deposits, and is consistent with recent modeling and experimental results.

Keywords

Ignimbrite Pyroclastic flow Pyroclastic surge Caldera Multiphase flow 

Notes

Acknowledgements

We thank Dr. Andrew Harp for assistance in the field, and La Voltarella for ongoing logistical support. Brittany Brand and Tim Druitt provided very helpful reviews of the manuscript, as did Associate Editor Gert Lube. Computations were conducted at the University at Buffalo’s Center for Computational Research.

Funding information

This research is supported by a grant from the US National Science Foundation to Valentine (EAR-1623793).

Supplementary material

445_2019_1288_MOESM1_ESM.docx (33 kb)
ESM 1 (DOCX 32 kb)
445_2019_1288_MOESM2_ESM.docx (27 kb)
ESM 2 (DOCX 26 kb)

References

  1. Bear AN, Cas RAF, Giordano G (2009) The implications of spatter, pumice and lithic clast rich proximal co-ignimbrite lag breccias on the dynamics of caldera forming eruptions: the 151 ka Sutri eruption, Vico Volcano, Central Italy. J Volcanol Geotherm Res 181:1–24.  https://doi.org/10.1016/j.jvolgeores.2008.11.032 CrossRefGoogle Scholar
  2. Boggs S (2006) Principles of sedimentology and stratigraphy, 4th edn. Pearson Prentice Hall, New JerseyGoogle Scholar
  3. Brand BD, Mackaman-Lofland C, Pollock NM, Bendaña S, Dawson B, Wichgers P (2014) Dynamics of pyroclastic density currents: conditions that promote substrate erosion and self-channelization—Mount St Helens, Washington (USA). J Volcanol Geotherm Res 276:189–214.  https://doi.org/10.1016/j.jvolgeores.2014.01.007 CrossRefGoogle Scholar
  4. Branney MJ, Kokelaar P (2002) Pyroclastic density currents and the sedimentation of ignimbrites. Geol Soc Memoir 27Google Scholar
  5. Breard ECP, Lube G (2017) Inside pyroclastic density currents—uncovering the enigmatic flow structure and transport behavior in large-scale experiments. Earth Planet Sci Lett 458:22–36.  https://doi.org/10.1016/j.epsl.2016.10.016 CrossRefGoogle Scholar
  6. Breard ECP, Lube G, Jones JR, Dufek J, Cronin SJ, Valentine GA, Moebis A (2016) Coupling of turbulent and non-turbulent flow regimes within pyroclastic density currents. Nat Geosci 9:767–774.  https://doi.org/10.1038/NGEO2794 CrossRefGoogle Scholar
  7. Bryan SE, Cas RAF, Martí J (1998) Lithic breccias in intermediate volume phonolitic ignimbrites, Tenerife (Canary Islands): constraints on pyroclastic flow depositional processes. J Volcanol Geotherm Res 81:269–296CrossRefGoogle Scholar
  8. Burgisser A, Bergantz GW (2002) Reconciling pyroclastic flow and surge: the multiphase physics of pyroclastic density currents. Earth Planet Sci Lett 202:405–418CrossRefGoogle Scholar
  9. Cas RAF, Wright HMN, Folkes CB, Lesti C, Porreca M, Giordano G, Viramonte JG (2011) The flow dynamics of an extremely large volume pyroclastic flow, the 2.08-ma Cerro Galán Ignimbrite, NW Argentina, and comparison with other flow types. Bull Volcanol 73:1583–1609.  https://doi.org/10.1007/s00445-011-0564-y CrossRefGoogle Scholar
  10. Cole PD, Guest JE, Duncan AM (1993) The emplacement of intermediate volume ignimbrites: a case study from Roccamonfina Volcano, Southern Italy. Bull Volcanol 55:467–480CrossRefGoogle Scholar
  11. Colucci S, Palladino DM, Mulukutla GK, Proussevitch AA (2013) 3-D reconstruction of ash vesicularity: insights into the origin of ash-rich explosive eruptions. J Volcanol Geotherm Res 255:98–107.  https://doi.org/10.1016/j.jvolgeores/2013.02.002 CrossRefGoogle Scholar
  12. Crowe BM, Linn GW, Heiken G, Bevier ML (1978) Stratigraphy of the Bandelier Tuff in the Pajarito Plateau. Applications to waste management. Los Alamos Scientific Lab Rep LA-7225-MSGoogle Scholar
  13. Druitt TH (1985) Vent evolution and lag breccia formation during the cape Riva eruption of Santorini, Greece. J Geol 93:439–454CrossRefGoogle Scholar
  14. Druitt TH (1998) Pyroclastic density currents. In: Gilbert JS, Sparks RSJ (eds) the physics of explosive volcanic eruptions. Geol Soc, London, Spec Pub 145:145–182CrossRefGoogle Scholar
  15. Druitt TH, Bacon CR (1986) Lithic breccia and ignimbrite erupted during the collapse of Crater Lake Caldera, Oregon. J Volcanol Geotherm Res 29:1–32CrossRefGoogle Scholar
  16. Druitt TH, Sparks RSJ (1982) A proximal ignimbrite breccia facies on Santorini, Greece. J Volcanol Geotherm Res 13:147–171CrossRefGoogle Scholar
  17. Druitt TH, Calder ES, Cole PD, Norton GE, Ritchie LJ, Sparks RSJ, Voight B (2002) Small-volume, highly mobile pyroclastic flows formed by rapid sedimentation from pyroclastic surges at Soufrière Hills Volcano, Montserrat: an important volcanic hazard. Geol Soc Lond Memoir 21:263–281CrossRefGoogle Scholar
  18. Druitt TH, Avard G, Bruni G, Lettieri P, Maez F (2007) Gas retention in fine-grained pyroclastic flow materials at high temperatures. Bull Volcanol 69:881–901.  https://doi.org/10.1007/s00445-007-0116-7 CrossRefGoogle Scholar
  19. Dufek J (2015) The fluid mechanics of pyroclastic density currents. J Fluid Mech 48:459–485.  https://doi.org/10.1146/annurev-fluid-122414-034252 CrossRefGoogle Scholar
  20. Fisher RV (1979) Models for pyroclastic surges and pyroclastic flows. J Volcanol Geotherm Res 6:305–318CrossRefGoogle Scholar
  21. Freda C, Gaeta M, Palladino DM, Trigila R (1997) The Villa Senni eruption (Alban Hills, Central Italy): the role of H2O and CO2 on the magma chamber evolution and on the eruptive scenario. J Volcanol Geotherm Res 78:103–120CrossRefGoogle Scholar
  22. Freundt A, Bursik M (1998) Pyroclastic flow transport mechanisms. In: Freundt A, Rosi M (eds) From magma to tephra modelling physical processes of explosive volcanic eruptions. Elsevier, Amsterdam, pp 173–245Google Scholar
  23. Freundt A, Schmincke H-U (1985) Lithic-enriched segregation bodies in pyroclastic flow deposits of Laacher see volcano (East Eiffel, Germany). J Volcanol Geotherm Res 25:193–224CrossRefGoogle Scholar
  24. Funicello R, Giordano G (2010) The Colli Albani volcano: foreword and previous studies. In: Funicello R, Giordano G (eds) The Colli Albani volcano. Geol Soc, London, Sp Pub IAVCEI 3:1–6Google Scholar
  25. Giordano G, De Benedetti AA, Diana A, Diano G, Goudioso F, Marasco F, Miceli M, Mollo S, Cas RAF, Funiciello R (2006) The Colli Albani mafic caldera (Roma, Italy): stratigraphy, structure and petrology. J Volcanol Geotherm Res 155:49–80.  https://doi.org/10.1016/j.jvolgeores.2006.02.009 CrossRefGoogle Scholar
  26. Girolami L, Roche O, Druitt TH, Corpetti T (2010) Particle velocity fields and depositional processes in laboratory ash flows, with implications for the sedimentation of dense pyroclastic flows. Bull Volcanol 72:747–759.  https://doi.org/10.1007/s00445-010-0356-9 CrossRefGoogle Scholar
  27. Knight MD, Walker GPL, Ellwood BB, Diehl JF (1986) Stratigraphy, paleomagnetism, and magnetic fabric of the Toba tuffs: constraints on the sources and eruptive styles. J Geophys Res 91:10355–10382CrossRefGoogle Scholar
  28. LeBerge RD, Giordano G, Cas RAF, Ailleres L (2006) Syn-depositional substrate deformation produced by the shear force of a pyroclastic current: an example from the Pleistocene ignimbrite at Monte Cimino, northern Lazio, Italy. J Volcanol Geotherm Res 158:307–320.  https://doi.org/10.1016/j.jvolgeores.2006.07.003 CrossRefGoogle Scholar
  29. Lipman PW (1976) Caldera-collapse breccias in the western San Juan Mountains, Colorado. Geol Soc Am Bull 87:1397–1410CrossRefGoogle Scholar
  30. Lube G, Breard ECP, Cronin SJ, Jones J (2015) Synthesizing large-scale pyroclastic flows: experimental design, scaling, and first results from PELE. J Geophys Res Sol Earth 120:1487–1502.  https://doi.org/10.1002/2014JB011666 CrossRefGoogle Scholar
  31. Macías JL, Espíndola JM, Bursik M, Sheridan MF (1998) Development of lithic-breccias in the 1982 pyroclastic flow deposits of El Chichón volcano, Mexico. J Volcanol Geotherm Res 83:173–196CrossRefGoogle Scholar
  32. Marble FE (1970) Dynamics of dusty gases. Ann Rev Fluid Mech 2:397–446CrossRefGoogle Scholar
  33. Marra F, Sottili G, Gaeta M, Giaccio B, Jicha B, Masotta M, Palladino DM, Deocampo DM (2014) Major explosive activity in the Monti Sabatini Volcanic District (central Italy) over the 800-390 ka interval: geochronological-geochemical overview and tephrostratigraphic implications. Quat Sci Rev 94:74–101.  https://doi.org/10.1016/j.quascirev.2014.04.010 CrossRefGoogle Scholar
  34. Palladino DM (2017) Simply pyroclastic currents. Bull Volcanol 79:53.  https://doi.org/10.1007/s00445-017-1139-3 CrossRefGoogle Scholar
  35. Palladino DM, Simei S (2002) Three types of pyroclastic currents and their deposits: examples from the Vulsini Volcanoes, Italy. J Volcanol Geotherm Res 116:97–118CrossRefGoogle Scholar
  36. Palladino DM, Taddeucci J (1998) The basal ash deposit of the Sovana Eruption (Vulsini Volcanoes, central Italy): the product of a dilute pyroclastic density current. J Volcanol Geotherm Res 87:233–254CrossRefGoogle Scholar
  37. Palladino DM, Valentine GA (1995) Coarse-tail vertical and lateral grading in pyroclastic flow deposits of the Latera Volcanic Complex (Vulsini, central Italy): origin and implications for flow dynamics. J Volcanol Geotherm Res 69:343–364CrossRefGoogle Scholar
  38. Palladino DM, Simei S, Sottili G, Trigila R (2010) Integrated approach for the reconstruction of stratigraphy and geology of quaternary volcanic terrains: an application to the Vulsini Volcanoes (central Italy). In: Groppelli G, Viereck-Goette L (eds) Stratigraphy and Geology of Volcanic Areas. Geol Soc Am Sp Pap 464:63–84, doi: https://doi.org/10.1130/2010.2464(04)
  39. Palladino DM, Gaeta M, Giaccio B, Sottili G (2014) On the anatomy of magma chamber and caldera collapse: the example of tracy-phonolitic explosive eruptions of the Roman Province (central Italy). J Volcanol Geotherm Res 281:12–26.  https://doi.org/10.1016/j.jvolgeores.2014.05.020 CrossRefGoogle Scholar
  40. Perrotta A, Scarpati C (1994) The dynamics of the Brecca Museo eruption (Campi Flegrei, Italy) and the significance of spatter clasts associated with lithic breccias. J Volcanol Geotherm Res 59:335–355CrossRefGoogle Scholar
  41. Pittari A, Cas RAF, Edgar CJ, Nichols HJ, Wolff JA, Marti J (2006) The influence of palaeotopography on facies architecture and pyroclastic flow processes of a lithic-rich ignimbrite in a high gradient setting: the Abrigo Ignimbrite, Tenerife, Canary Islands. J Volcanol Geotherm Res 152:273–315.  https://doi.org/10.1016/j.jvolgeores.2005.10.007 CrossRefGoogle Scholar
  42. Roche O (2012) Depositional processes and gas pore pressure in pyroclastic flows: an experimental perspective. Bull Volcanol 74:1807–1820.  https://doi.org/10.1007/s00445-012-0639-4 CrossRefGoogle Scholar
  43. Roche O, Gilbertson MA, Phillips JC, Sparks RSJ (2004) Experimental study of gas-fluidized granular flows with implications for pyroclastic flow emplacement. J Geophys Res 109:B10301.  https://doi.org/10.1029/2003JB002916 CrossRefGoogle Scholar
  44. Roche O, Montserrat S, Niño Y, Tamburrino A (2008) Experimental observations of water-like behavior of initially fluidized, dam break granular flows and their relevance for the propagation of ash-rich pyroclastic flows. J Geophys Res 113:B12203.  https://doi.org/10.1029/2008/JB005664 CrossRefGoogle Scholar
  45. Roche O, Niño Y, Mangeney A, Brand B, Pollock N, Valentine GA (2013) Dynamic pore pressure variations induce substrate erosion by pyroclastic flows. Geology 41:1107–1110.  https://doi.org/10.1130/G34668.1 CrossRefGoogle Scholar
  46. Roche O, Buesch DC, Valentine GA (2016) Slow-moving, far-travelled dense pyroclastic flows during the Peach Spring super-eruption. Nature Comm 7:10890.  https://doi.org/10.1038/NCOMMS10890 CrossRefGoogle Scholar
  47. Rosi M, Vezzoli L, Aleotti P, De Censi M (1996) Interaction between caldera collapse and eruptive dynamics during the Campanian Ignimbrite eruption, Phlegraean Fields, Italy. Bull Volcanol 57:541–554CrossRefGoogle Scholar
  48. Sohn YK (1997) On traction-carpet sedimentation. J Sed Res 67:502–509Google Scholar
  49. Sparice D (2015) Definizione delle litofacies e ricostruzione dell'architettura dell'Ignimbrite Campana. PhD Thesis, Dept Earth Env Resource Sci, Università di Napoli-Federico II, Napoli, ItalyGoogle Scholar
  50. Sparks RSJ (1975) Stratigraphy and geology of the ignimbrites of Vulsini Volcano, Italy. Geol Rundsch 64:497–523CrossRefGoogle Scholar
  51. Sparks RSJ (1976) Grain size variations in ignimbrites and implications for the transport of pyroclastic flows. Sedimentology 23:148–188CrossRefGoogle Scholar
  52. Sparks RSJ, Walker GPL (1977) The significance of vitric-enriched air-fall ashes associated with crystal-enriched ignimbrites. J Volcanol Geotherm Res 2:329–341CrossRefGoogle Scholar
  53. Sparks RSJ, Self S, Walker GPL (1973) Products of ignimbrite eruptions. Geology 1:115–118CrossRefGoogle Scholar
  54. Sulpizio R, Dellino P, Doronzo DM, Sarocchi D (2014) Pyroclastic density currents: state of the art and perspectives. J Volcanol Geotherm Res 283:36–65.  https://doi.org/10.1016/j.volgeores.2014.06.014 CrossRefGoogle Scholar
  55. Suzuki-Kamata K (1988) The ground layer of Ata pyroclastic flow deposit, southwestern Japan—evidence for the capture of lithic fragments. Bull Volcanol 50:119–129CrossRefGoogle Scholar
  56. Suzuki-Kamata K, Kamata H (1990) The proximal facies of the Tosu pyroclastic-flow deposit erupted from Aso caldera, Japan. Bull Volcanol 52:325–333CrossRefGoogle Scholar
  57. Sweeney MR, Valentine GA (2017) Impact zone dynamics of dilute mono-and polydisperse jets and their implications for initial conditions of pyroclastic density currents. Phys Fluids 29:093304.  https://doi.org/10.1063/1/5004197 CrossRefGoogle Scholar
  58. Valentine GA (1987) Stratified flow in pyroclastic surges. Bull Volcanol 49:616–630CrossRefGoogle Scholar
  59. Valentine GA, Fisher RV (1986) Origin of layer 1 deposits in ignimbrites. Geology 14:146–148CrossRefGoogle Scholar
  60. Valentine GA, Sweeney MR (2018) Compressible flow phenomena at inception of lateral density currents fed by collapsing gas-particle mixtures. J Geophys Res Sol Earth 123:1286–1302.  https://doi.org/10.1002/2017JB015129 CrossRefGoogle Scholar
  61. Valentine GA, Wohletz KH (1989) Numerical models of Plinian eruption columns and pyroclastic flows. J Geophys Res 94:1867–1887CrossRefGoogle Scholar
  62. Valentine GA, Buesch DC, Fisher RV (1989) Basal layered deposits of the Peach Springs Tuff, northwestern Arizona, U.S.A. Bull Volcanol 51:396–414CrossRefGoogle Scholar
  63. Vezzoli L, Conticelli S, Innocenti F, Landi P, Manetti P, Palladino DM, Trigila R (1987) Stratigraphy of the Latera Volcanic Complex: proposals for a new nomenclature. Period Mineral 56:89–110Google Scholar
  64. Walker GPL (1983) Ignimbrite types and ignimbrite problems. J Volcanol Geotherm Res 17:65–88CrossRefGoogle Scholar
  65. Walker GPL (1985) Origin of coarse lithic breccias near ignimbrite source vents. J Volcanol Geotherm Res 25:157–171CrossRefGoogle Scholar
  66. Walker GPL, Self S, Froggatt PC (1981) The ground layer of the Taupo ignimbrite: a striking example of sedimentation from a pyroclastic flow. J Volcanol Geotherm Res 10:1–11CrossRefGoogle Scholar
  67. White JDL, Houghton BF (2006) Primary volcaniclastic rocks. Geology 34:677–680.  https://doi.org/10.1130/G22346.1 CrossRefGoogle Scholar
  68. Wilson CJN, Walker GPL (1982) Ignimbrite depositional facies: the anatomy of a pyroclastic flow. J Geol Soc Lond 139:581–592CrossRefGoogle Scholar
  69. Yasuda Y, Suzuki-Kamata K (2018) The origin of a coarse lithic breccia in the 34 ka caldera-forming Sounkyo eruption, Taisetsu volcano group, central Hokkaido, Japan. J Volcanol Geotherm Res 357:287–305.  https://doi.org/10.1016/j.jvolgeores.2018.04.017 CrossRefGoogle Scholar

Copyright information

© International Association of Volcanology & Chemistry of the Earth's Interior 2019

Authors and Affiliations

  1. 1.Department of GeologyUniversity at BuffaloBuffaloUSA
  2. 2.Dipartimento di Scienze della TerraSapienza-Università di RomaRomeItaly

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