Bulletin of Volcanology

, 77:97 | Cite as

The ground layer of the Campanian Ignimbrite: an example of deposition from a dilute pyroclastic density current

  • Claudio Scarpati
  • Domenico Sparice
  • Annamaria Perrotta
Research Article
First Online:
Received:
Accepted:

Abstract

A thin, fines-poor, and lithic- and crystal-rich layer locally present, from proximal to distal areas, at the base of the pyroclastic density current deposits of the Campanian Ignimbrite eruption (39 ka), sourced from Campi Flegrei (Italy), is interpreted as a ground layer (GL). It has an average lithic and crystal content of 57 and 25 wt%, respectively. The GL rests on a paleosol or an early fall deposit and is capped by a stratified ash deposit. It is bounded by erosion surfaces and its thickness does not change systematically from the source. The occurrences of GL in places separated from the source by a stretch of sea and the angular to sub-angular shape of the lithic clasts are consistent with deposition from a dilute current. The presence of the GL up to 971 m above sea level and beyond 1400–1500-m-high mountain ridges, allows estimation of the thickness of the PDC as having been at least 1.5 km. To investigate the parameters influencing the transport and emplacement mechanisms that produced the GL, we use field and sedimentological data (grain size and componentry), from samples collected between 30 and 70 km from the source. The progressive decrease in maximum lithic clast and median grain-size with distance from the vent and increasing altitude corresponds to lateral and vertical grading of lithic clasts within the current. The coarser clasts moved toward the basal part of the current, settling in more proximal areas and at low altitude. Farther from the vent (45–50 km), the lower part of the pyroclastic current impacted against the reliefs surrounding the Campanian Plain, causing the emplacement of coarser and more poorly sorted deposits on slopes oriented toward the source.

Keywords

Ground layer Campanian Ignimbrite Italy 
This is a preview of subscription content, log in to check access.

Notes

Acknowledgments

In 1988, one of us (CS) spent one summer with R.V. Fisher to help him to find CI outcrops useful to assess whether large ignimbrites can be emplaced by turbulent and dilute flows. Four localities studied in this paper (Acqua Fidia, Moiano, Mondragone and Triflisco) were found in that occasion. We hope that he would have been happy to look at the ideas presented in this paper. We are very grateful to Melanie Froude for her critical reading of the manuscript. The comments and suggestions of G. Lube, M. Ort, and J.D.L. White to improve the manuscript have been very appreciated.

References

  1. Allen SR, Cas RAF (1998) Lateral variation within coarse co-ignimbrite lithic breccias of the Kos Plateau Tuff, Greece. Bull Volcanol 59:356–377CrossRefGoogle Scholar
  2. Bailey RA, Carr G (1994) Physical geology and eruptive history of the Matahina ignimbrite, Taupo volcanic zone, North Island, New Zealand. N Z J Geol Geophys 37(3):319–344CrossRefGoogle Scholar
  3. Barberi F, Innocenti F, Lirer L, Munno R, Pescatore T, Santacroce R (1978) The campanian ignimbrite: a major prehistoric eruption in the Neapolitan area (Italy). Bull Volcanol 41(1):10–31CrossRefGoogle Scholar
  4. Branney MJ, Kokelaar BP (2002) Pyroclastic density currents and the sedimentation of ignimbrites. Geol Soc London Memoirs 27Google Scholar
  5. Buesch DC (1992) Incorporation and redistribution of locally derived lithic fragments within a pyroclastic flow. Geol Soc Am Bull 104(9):1193–1207CrossRefGoogle Scholar
  6. Buesch D (2012) Flow direction indicators in lithic-rich, basal ground layers in western exposures of the Miocene Peach Spring Tuff, California. Am Geophys Union, Fall Meeting 2012, abstract #V41B-2780Google Scholar
  7. Druitt TH (1985) Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece. J Geol 93(4):439–454CrossRefGoogle Scholar
  8. Fedele L, Scarpati C, Lamphere M, Melluso L, Morra V, Perrotta A, Ricci G (2008) The Breccia Museo formation, Campi Flegrei, southern Italy: geochronology, chemostratigraphy and relationship with the Campanian Ignimbrite eruption. Bull Volcanol 70(10):1189–1219CrossRefGoogle Scholar
  9. Fisher RV (1990) Transport and deposition of a pyroclastic surge across an area of high relief: the 18 May 1980 eruption of Mount St. Helens, Washington. Geol Soc Am Bull 102:1038–1054CrossRefGoogle Scholar
  10. Fisher RV, Orsi G, Ort M, Heiken G (1993) Mobility of a large volume pyroclastic flow-emplacement of the Campanian Ignimbrite, Italy. J Volcanol Geotherm Res 56:205–220CrossRefGoogle Scholar
  11. Folk RL, Ward WC (1957) Brazos River bar [Texas]; a study in the significance of grain size parameters. J Sediment Res 27:3–26CrossRefGoogle Scholar
  12. Freundt A, Schmincke HU (1985) Lithic-enriched segregation bodies in pyroclastic flow deposits of Laacher See Volcano (East Eifel, Germany). J Volcanol Geotherm Res 25(3):193–224CrossRefGoogle Scholar
  13. Orsi G, De Vita S, di Vito M (1996) The restless, resurgent Campi Flegrei nested caldera (Italy): constraints on its evolution and configuration. J Volcanol Geotherm Res 74:179–214CrossRefGoogle Scholar
  14. Ort M, Orsi G, Pappalardo L, Fisher RV (2003) Anisotropy of magnetic susceptibility studies of depositional processes in the Campanian Ignimbrite, Italy. Bull Volcanol 65(1):55–72Google Scholar
  15. 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(3):343–364CrossRefGoogle Scholar
  16. Perrotta A, Scarpati C (1994) The dynamics of Breccia Museo eruption (Campi Flegrei, Italy) and the significance of spatter clasts associated with lithic breccias. J Volcanol Geotherm Res 59:335–355CrossRefGoogle Scholar
  17. Perrotta A, Scarpati C (2003) Volume partition between the plinian and co-ignimbrite air fall deposits of the Campanian Ignimbrite eruption. Mineral Petrol 79:67–78CrossRefGoogle Scholar
  18. Perrotta A, Scarpati C, Luongo G, Morra V (2006) Chapter 5 The Campi Flegrei caldera boundary in the city of Naples. Developments in Volcanology, 9 (C), pp 85–96. doi: 10.1016/S1871-644X(06)80019-7
  19. Rosi M, Sbrana A (1987) Phlegraean Fields. CNR Quaderni de ‘la Ricerca Scientifica’ 114(9):1–175Google Scholar
  20. Rosi M, Vezzoli L, Castelmenzano A, Grieco G (1999) Plinian pumice fall deposit of the Campanian Ignimbrite eruption (Phlegraean Fields, Italy). J Volcanol Geotherm Res 9:179–198CrossRefGoogle Scholar
  21. Scarpati C, Perrotta A (2012) Erosional characteristics and behaviour of large pyroclastic density currents. Geology 40:1035–1038CrossRefGoogle Scholar
  22. Scarpati C, Perrotta A (2015) Stratigraphy and physical parameters of the Plinian phase of the Campanian Ignimbrite eruption. Geol Soc Am BullGoogle Scholar
  23. Scarpati C, Sparice D, Perrotta A (2014) A crystal concentration method for calculating ignimbrite volume from distal ash-fall deposits and a reappraisal of the magnitude of the Campanian Ignimbrite. J Volcanol Geotherm Res 280:67–75CrossRefGoogle Scholar
  24. Scarpati C, Sparice D, Perrotta A (2015) Facies variation in the Campanian Ignimbrite. Rend Online Soc Geol Ital 33:83–87Google Scholar
  25. Schumacher R, Mues-Schumacher U (1996) The Kizilkaya ignimbrite—an unusual low-aspect-ratio ignimbrite from Cappadocia, central Turkey. J Volcanol Geotherm Res 70:107–121CrossRefGoogle Scholar
  26. Self S, Rampino MR, Newton MS, Wolff JA (1984) Volcanological study of the great Tambora eruption of 1815. Geology 12(11):659–663CrossRefGoogle Scholar
  27. Sohn YK, Chough SK (1989) Depositional processes of the Suwolbong tuff ring, Cheju Island (Korea). Sedimentology 36(5):837–855CrossRefGoogle Scholar
  28. Sparice D (2015) Definizione delle litofacies e ricostruzione dell’architettura dell’Ignimbrite Campana. PhD thesis, University of Naples Federico II, pp. 242 (in Italian)Google Scholar
  29. Sparks RSJ (1975) Stratigraphy and geology of the ignimbrites of Vulsini volcano, Central Italy. Geol Rundsch 64:497–523CrossRefGoogle Scholar
  30. Sparks RSJ, Self S, Walker GPL (1973) Products of ignimbrite eruptions. Geology 1:115–118CrossRefGoogle Scholar
  31. Suzuki-Kamata K (1988) The ground layer of Ata pyroclastic flow deposit, south-western Japan—evidence for the capture of lithic fragments. Bull Volcanol 50(2):119–129CrossRefGoogle Scholar
  32. Suzuki-Kamata K, Kamata H (1990) The proximal facies of the Tosu pyroclastic-flow deposit erupted from Aso caldera, Japan. Bull Volcanol 52(5):325–333CrossRefGoogle Scholar
  33. Valentine GA (1987) Stratified flow in pyroclastic surges. Bull Volcanol 49(4):616–630CrossRefGoogle Scholar
  34. Valentine GA, Buesch DC, Fisher RV (1989) Basal layered deposits of the Peach Spring Tuff, northwestern Arizona, USA. Bull Volcanol 51:395–414CrossRefGoogle Scholar
  35. Walker GPL (1985) Origin of coarse lithic breccias near ignimbrite source vent. J Volcanol Geotherm Res 25:57–171Google Scholar
  36. Walker GPL (1972) Crystal concentration in ignimbrites. Contrib Mineral Petrol 36:135–146CrossRefGoogle Scholar
  37. Walker GPL, Heming RF, Wilson CJN (1980) Low-aspect ratio ignimbrites. Nature 283:286–287CrossRefGoogle Scholar
  38. Walker GPL, Self S, Frogatt 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
  39. Williams R (2010) Emplacement of radial pyroclastic density currents over irregular topography: the chemically-zoned, low aspect-ratio Green Tuff Ignimbrite, Pantelleria, Italy. PhD thesis, University of Leicester, p. 232Google Scholar
  40. Wilson CJN, Walker GPL (1982) Ignimbrite depositional facies: the anatomy of a pyroclastic flow. J Geol Soc 139:581–592CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Claudio Scarpati
    • 1
  • Domenico Sparice
    • 1
  • Annamaria Perrotta
    • 1
  1. 1.Dipartimento di Scienze della Terra, dell’Ambiente e delle RisorseUniversità di Napoli Federico IINaplesItaly

Personalised recommendations