Abstract
The Reporoa Caldera occupies the northern end of the Reporoa Depression, previously described as a tectonic fault-angle depression. Earlier confirmation of the topographic basin as a caldera had been hindered by the lack of an associated young pyroclastic flow deposit of large enough volume to have caused caldera collapse. New exposures on the eastern margin of the Reporoa basin reveal thick lithic lag breccias (>30 m) interbedded within the 0.24 Ma Kaingaroa Ignimbrites. These ignimbrites were previously attributed to the adjacent Okataina Volcanic Centre. Lag breccia thicknesses and maximum clast sizes decrease rapidly outward from the caldera rim, and discrete breccias are absent from ignimbrite sections more than 3 km from the rim. The lithic lag breccias, together with structural and geophysical evidence, confirm Reporoa Caldera as the source of the c. 100 km3 Kaingaroa Ignimbrites, adding another major rhyolitic volcanic centre to the seven previously recognized in the Taupo Volcanic Zone. Other, older, calderas may also be present in the Reporoa Depression.
Similar content being viewed by others
References
Bacon CR (1983) Eruptive history of Mount Mazama and Crater Lake Caldera, Cascade Range U.S.A. J Volcanol Geotherm Res 18:57–115
Bignall G (1990) Hydrology and hydrothermal alteration, Reporoa Well (1), Reporoa, New Zealand. Proc 12th New Zealand Geothermal Workshop. Geothermal Institute, University of Auckland, pp 257–264
Briggs ND (1973) Investigations of New Zealand pyroclastic flow deposits. Unpublished PhD Thesis. Victoria University of Wellington
Browne PRL, Graham IJ, Parker RJ, Wood CP (1992) Subsurface andesite lavas and plutonic rocks in the Rotokawa and Ngatamariki geothermal systems, Taupo Volcanic Zone, New Zealand. J Volcanol Geotherm Res 51:199–215
Calvache V, Williams SN (1992) Lithic-dominated pyroclastic flows at Galeras volcano, Colombia—an unrecognised volcanic hazard. Geology 20:539–542
Druitt TH (1985) Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece. J Geol 93:439–454
Druitt TH, Sparks RSJ (1982) A proximal ignimbrite facies on Santorini, Greece. J Volcanol Geotherm Res 13:147–171
DSIR (1985) Sheet U17—Wairakei. Electrical resistivity map of New Zealand 1:50 000. Nominal Schlumberger array spacing 1000 m. Dept Sci Ind Res, Wellington
Evison FF, Robinson R, Arabasz WJ (1976) Microearthquakes, geothermal activity, and struture, Central North Island, New Zealand. N Z J Geol Geophys 19:625–638
Grindley GW (1959) Sheet N85—Waiotapu. Geological map of New Zealand 1:63 360. Dept Sci Ind Res, Wellington
Grindley GW (1960) Sheet 8—Taupo. Geological map of New Zealand 1:250 000 Dept Sci Ind Res, Wellington
Grindley GW (1961) Sheet N94—Taupo. Geological map of New Zealand 1:63 360. Dept Sci Ind Res, Wellington
Grindley GW (1965) Waiotapu. Geology. In: Thompson BN, Kermode LO, Ewart A (eds) New Zealand Volcanology, Central Volcanic Region. N Z Dept Sci Ind Res Information Ser 50, Wellington, pp 185–186
Healy J (1962) Structure and volcanism in the Taupo Volcanic Zone, New Zealand. In: MacDonald GA, Kuno H (eds) The Crust of the Pacific Basin. Geophys Monogr Ser 6. AGU, Washington, pp 151–157
Healy J, Hochstein MP (1973) Horizontal flow in hydrothermal systems. J Hydrol (N Z) 12:71–82
Healy J, Schofield JC, Thompson BN (1964) Sheet 5—Rotorua. 1st edn. Geological map of New Zealand 1:250 000. N Z Dept Sci Ind Res, Wellington
Hedenquist JW (1983) Waiotapu, New Zealand: the geochemical evolution and mineralization of an active hydrothermal system. Unpublished PhD Thesis, Univ Auckland
Martin RC (1961) Stratigraphy and structural outline of the Taupo Volcanic Zone. N Z J Geol Geophys 4:449–478
Modriniak N, Studt FE (1959) Geological structure and volcanism of the Taupo-Tarawera district. N Z J Geol Geophys 2:654–684
Nairn IA (1973) Geology of the Waimangu Geothermal Mapping Project Area, Central Volcanic Region, New Zealand. Report Open File. Unpublished. N Z Geological Survey, Rotorua
Nairn IA (1981a) Some studies of the geology, volcanic history, and geothermal resources of the Okataina Volcanic Centre, Taupo Volcanic Zone, New Zealand. Unpublished PhD Thesis. Victoria University of Wellington
Nairn IA (1981b) Geothermal resources of the Okataina Volcanic Centre. Geothermal Circ IAN2 Open File. N Z Geological Survey, Rotorua
Nairn IA (1989) Sheet V16AC—Mount Tarawera. Geological map of New Zealand 1:50 000. Map, 1 sheet, and notes. Dept Sci Ind Res, Wellington
Pain CF, Pullar WA (1975) Chronology of ‘paleosurfaces’ and present land surfaces in the Reporoa Basin, North Island, New Zealand. N Z J Sci 18:313–322
Rogan AM (1982) A geophysical study of the Taupo Volcanic Zone, New Zealand. J Geophys Res 87:4073–4088
Studt FE (1963) Geophysics of Waiotapu area. In: Waiotapu Geothermal Field, New Zealand. Dept Sci Ind Res Bull 155:35–41
Walker GPL (1971) Grainsize characteristics of pyroclastic deposits. J Geol 79:696–714
Walker GPL (1983) Ignimbrite types and ignimbrite problems. J Volcanol Geotherm Res 17:65–88
Walker GPL (1985) Origin of coarse lithic breccias near ignimbrite source vents. J Volcanol Geotherm Res 25:157–171
Wilson CJN, Rogan AM, Smith IEM, Northey DJ, Nairn IA, Houghton BF (1984) Caldera volcanoes of the Taupo Volcanic Zone, New Zealand. J Geophys Res 89:8463–8484
Wilson CJN, Houghton BF, Lloyd EF (1986) Volcanic history and evolution of the Maroa-Taupo area, central North Island. Bull Roy Soc N Z 23:194–223
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nairn, I.A., Wood, C.P. & Bailey, R.A. The Reporoa Caldera, Taupo Volcanic Zone: source of the Kaingaroa Ignimbrites. Bull Volcanol 56, 529–537 (1994). https://doi.org/10.1007/BF00302833
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00302833