Abstract
Liquid plus vapour inclusions of CO2 are widespread in plagioclase microphenocrysts in small tholeiitic intrusions and tephra of the Moeraki and adjacent areas of northeast Otago, New Zealand. They imply the presence of immiscible CO2 droplets in the magma at depths of about 7–14 km. Their presence within 5 μm of the edges of microphenocrysts as little as 35 μm thick and 118 μm long indicates minimal feldspar crystal growth during the final ascent and quenching of the magma. Delicate branching clusters of lath-like microphenocrysts escaped disruption during this ascent. Such CO2 inclusions are a potential source of ‘excess argon’ perturbing K−Ar age determinations.
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References
Allen CC (1980) Icelandic subglacial volcanism: thermal and physical studies. J Geol 88:108–117
Beard JS, Lofgren GE (1992) An experiment-based model for the petrogenesis of high-alumina basalts. Science 258:112–115
Belkin HE, De Vivo B, Roedder E, Cortini M (1985) Fluid inclusion geobarometry from ejected Mt. Somma-Vesuvius nodules. Am Mineral 70:288–303
Benson WN (1943) The basic igneous rocks of eastern Otago and their tectonic environment. Part IV. The mid-Tertiary basalts, tholeiites and dolerites of north-eastern Otago. Section A: Distribution and geological occurrence. Trans R Soc NZ 73:116–138
Benson WN (1944) The basic igneous rocks of eastern Otago and their tectonic environment. Part IV. The mid-Tertiary basalts, tholeiites and dolerites of north-eastern Otago. Section B: Petrology, with special reference to the crystallisation of pyroxene. Trans R Soc NZ 74:71–123
Bergman SC, Dubessy J (1984) CO2−CO fluid inclusions in a composite peridotite xenolith: implications for upper mantle oxygen fugacity. Contrib Mineral Petrol 85:1–13
Cas RAF, Landis CA, Fordyce RE (1989) A monogenetic, Surtla-type, Surtseyan volcano from the Eocene-Oligocene Waiareka-Deborah volcanics, Otago, New Zealand: a model. Bull Volcanol 51:281–298
Coombs DS, Cas RA, Kawachi Y, Landis CA, McDonough WF, Reay A (1986) Cenozoic volcanism in north, east, and central Otago. In: Smith IEM (ed) Late Cenozoic volcanism in New Zealand. R Soc N Z Bull 23:278–312
De Vivo B, Maiorani A, Trigila R (1987) On the origin of cordierite-bearing rhyolites from Mt. S. Angelo (Lipari, Italy): Fluid inclusions and petrological studies. Periodico di Mineralogia 56:71–84 (Published 1988)
Gerlach TM (1986) Exsolution of H2O, CO2, and S during eruptive episodes at Kilauea Volcano, Hawaii. J Geophys Res 91:12177–12185
Glazner AF (1984) Activities of olivine and plagioclase components in silicate melts and their application to geothermometry. Contrib Mineral Petrol 88:260–268
Greenland LP, Rose WI, Stokes JB (1985) An estimate of gas emissions and magmatic gas content from Kilauea volcano. Geochim Cosmochim Acta 49:125–129
Harris DM (1981) The concentration of CO2 in submarine tholeiitic basalts. J Geol 89:689–701
Helz RT, Thornber CR (1987) Geothermometry of Kilauea Iki lava lake, Hawaii. Bull Volcanol 49:651–668
Jambon A, Zimmermann JL (1987) Major volatiles from a North Altantic MORB glass and calibration to He: A size fraction analysis. Chem Geol 62:177–189
Kerrick DM, Jacobs GK (1981) A modified Redlich-Kwong equation for H2O, CO2, and H2O−CO2 mixtures at elevated pressures and temperatures. Am J Sci 281:735–767
Kirby SH, Green HW II (1980) Dunite xenoliths from Hualalai volcano: evidence for mantle diapiric flow beneath the island of Hawaii. Am J Sci 280A:550–575
Kjartansson G (1966) A comparison of table mountains in Iceland and the volcanic island of Surtsey off the south coast of Iceland. Náttúrufrædingurinn 36:1–34
McInnes B (1990) Relation of alkaline magmatic rocks to gold, Simberi Island, Papua New Guinea (abstract). Geol Ass Canada Program with Abstracts 15:A87
Moore JG, Batchelder JN, Cunningham CG (1977) CO2-filled vesicles in mid-ocean basalt. J Volcanol Geotherm Res 2:309–327
Murck BW, Burruss RC, Hollister LS (1978) Phase equilibria in fluid inclusions in ultramafic xenoliths. Am Mineral 63:40–46
Nakamura Y, Coombs DS (1973) Clinopyroxenes in the Tawhiroko tholeiitic dolerite at Moeraki, north-eastern Otago, New Zealand. Contrib Mineral Petrol 42:213–228
Nelson ST, Montana A (1992) Sieve-textured plagioclase in volcanic rocks produced by rapid decompression. Am Mineral 77:1242–1249
Roedder E (1965) Liquid CO2 inclusions in olivine-bearing nodules and phenocrysts from basalts. Am Mineral 50:1746–1782
Roedder E (1983) Geobarometry of ultramafic xenoliths from Loihi Seamount, Hawaii, on the basis of CO2 inclusions in olivine. Earth Planet Sci Lett 66:369–379
Roedder E, Coombs DS (1987) Inclusions indicating crystallization at depth of plagioclase microphenocrysts in a New Zealand dolerite. American Current Research on Fluid Inclusions (ACROFI) Symposium, Socorro, New Mexico, Program and Abstracts (unpaginated)
Solovova IP, Naumov VB, Kovalenko VI, Guzhova AV, Kononkova NN (1990) Investigation of magmatic inclusions in minerals of Pantelleria volcanic rocks (Italy) (abstract). PACROFI III Program and Abstracts 82
Wang B, Zhang Y, Yang C (1990) Study of melt inclusions in minerals of volcanic rocks from the Great Wall Station area of China, King George Island, Antarctica (abstract). International Mineralogical Association 15th General Meeting, 12–17 July, Beijing, Abstracts 573–574
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Coombs, D.S., Roedder, E. On the significance of CO2 inclusions in plagioclase microphenocrysts in tholeiite from Moeraki, New Zealand. Bull Volcanol 56, 23–28 (1994). https://doi.org/10.1007/BF00279726
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DOI: https://doi.org/10.1007/BF00279726