Collision-driven slab breakoff magmatism in northwestern Anatolia, Turkey

Journal of Geology

Volumn 115, Issue 1, 2007, Pages 63-82

  Altunkaynak, Şafak ^a  

^a ISTANBUL TECHNICAL UNIVERSITY   (Turkey)

Author keywords

[No Author keywords available]

Indexed keywords

GRANITOID; MAGMATISM; PARTIAL MELTING; PLUTON; SLAB; TECTONIC SETTING;

ANATOLIA; EURASIA; TURKEY;

EID: 33846415884     PISSN: 00221376     EISSN: None     Source Type: Journal    
DOI: 10.1086/509268     Document Type: Article

References (107)

1. Aite, M. O., and Gélard, J. P. 1997. Distension néogéne post-collisionnelle sur le transect de Grande Kabylie (Algeria). Bull. Soc. Geol. Fr. 168:423-436.
2. Aldanmaz, E.; Pearce, J.; Thriwall, M. F.; and Mitchell, J. 2000. Petrogenetic evolution of late Cenozoic, post-collision volcanism in western Anatolia, Turkey. J. Volcanol. Geotherm. Res. 102:67-95.
3. Altherr, R., and Siebel, W. 2002. I-type plutonism in a continental back-arc setting: Miocene granitoids and monzonites from the central Aegean Sea, Greece. Contrib. Mineral. Petrol. 143:397-415.
4. Altunkaynak, Ş. 2004. Post-collisional multistage magmatism in northwest Anatolia (Turkey): geochemical and isotopic study of Orhaneli magmatic associations. In Programs and Abstracts of the International Geological Congress (Florence, Italy), p. 1298.
5. Altunkaynak, Ş., and Yilmaz, Y. 1998. The Mount Kozak magmatic complex, western Anatolia. J. Volcanol. Geotherm. Res. 85:211-231.
6. Altunkaynak, Ş., and Yilmaz, Y. 1999. The Kozak pluton and its emplacement. Geol. J. 34:257-274.
7. Arndt, N., and Goldstein, S. L. 1987. Use and abuse of crust-formation ages. Geology 15:893-895.
8. Ataman, G. 1972. L'age radiometrique du massif granodioritique d'Orhaneli. Bull. Geol. Soc. Turk. 15:125-130.
9. Ataman, G. 1973. L'age radiometrique du massif granodioritique de Gürgenyayla. Bull. Geol. Soc. Turk. 16:22-26.
10. Atherton, M. P., and Ghani, A. A. 2002. Slab breakoff: a model for Caledonian, late granite syn-collisional magmatism in the orthotectonic (metamorphic) zone of Scotland and Donegal, Ireland. Lithos 62:65-85.
11. Bingöl, E.; Delaloye, M.; and Ataman, G. 1982. Granitic intrusions in western Anatolia: a contribution of the geodynamic study of this area. Eclogae Geol. Helv. 75: 437-446.
12. Bingöl, E.; Delaloye, M.; and Genç, S. 1994. Magmatism of northwestern Anatolia. International Volcanological Congress, IAVCEI 1994 (Excursion Guide, A3), 56 p.
13. Bird, P. 1979. Continental delamination and the Colorado Plateau. J. Geophys. Res. 84:7561-7571.
14. Black, R., and Liégeois, J. P. 1993. Cratons, mobile belts, alkaline rocks and continental lithosphere mantle: the Pan-African testimony. J. Geol. Soc. Lond. 150:89-98.
15. Bonin, B. 2004. Do coeval mafic and felsic magmas in post-collisional to within-plate regimes necessarily imply two contrasting, mantle and crustal, sources? a review. Lithos 78:1-24.
16. Borsi, S.; Ferrara, G.; Innocenti, F.; and Mazzuoli, R. 1972. Geochronology and petrology of recent volcanics in the eastern Aegean Sea (West Anatolia and Lesbos Island). Bull. Volcanol. 36:473-496.
17. Boynton, W. V. 1984. Geochemistry of the rare-earth elements: meteorite studies. In Henderson, P., ed. Rare earth element geochemistry. Amsterdam, Elsevier, p. 63-114.
18. Bozkurt, E., and Park, R. G. 1997. Microstructures of deformed grains in the augen gneisses of southern Menderes massif and their tectonic significance. Geol. Rundsch. 86:103-119.
19. Chappell, B. W., and White, A. J. R. 1992. I- and S-type granites in the Lachlan fold belt. Trans. R. Soc. Edinb. Earth Sci. 83:1-16.
20. Coulon, C.; Megartsi, M.; Fourcade, S.; Maury, R. C.; Bellon, H.; Hacini, A. L.; Cotten, J.; Coutelle, A.; and Hermitte, D. 2002. Post-collisional transition from calc-alkaline to alkaline volcanism during the Neogene in Oranie (Algeria): magmatic expression of a slab breakoff. Lithos 62:87-110.
21. Cox, K. G., and Hawkesworth, C. J. 1985. Geochemical stratigraphy of the Deccan Traps at Mahabalaeshwar, Western Ghats, India: its implications for open system magmatic processes. J. Petrol. 26:355-377.
22. Davidson, J. P.; Harmon, R. S.; and Worner, G. 1991. The source of central Andean magmas: some considerations. In Harmon, R. S., and Rapela, C. W., eds. Andean magmatism and its tectonic setting. Geol. Soc. Am. Spec. Pap. 265:233-243.
23. Davies, J. H., and von Blanckenburg, F. 1995. Slab breakoff: a model of lithosphere detachment and its test in the magmatism and deformation of collisional orogens. Earth Planet. Sci. Lett. 129:85-102.
24. De Boorder, H.; Spakman, W.; White, S. H.; and Wortel, M. J. R. 1998. Late Cenozoic mineralization, orogenic collapse and slab detachment in the European Alpine Belt. Earth Planet. Sci. Lett. 164:569-575.
25. Delaloye, M., and Bingöl, E. 2000. Granitoids from western and northwestern Anatolia: geochemistry and modeling of geodynamic evolution. Int. Geol. Rev. 42: 241-268.
26. Demirtasli, E.; Turhan, N.; Bilgin, A. Z.; and Selim, M. 1984. Geology of the Bolkar Mountains. In Tekeli, O., and Göncüoglu, M. C., eds. Geology of the Taurus Belt: proceedings of the international symposium. Ankara, Mineral Research and Exploration Institute of Turkey, p. 125-141.
27. Dilek, Y., and Moores, E. M. 1990. Regional tectonics of the eastern Mediterranean ophiolites. In Malpas, J.; Moores, E. M.; Panayiotou, A.;.and Xenophontos, C., eds. Ophiolites, oceanic crustal analogues: proceedings of the symposium "Troodos 1987." Nicosia, Cyprus, Geological Survey Department, p. 295-309.
28. Dilek, Y., and Thy, P. 2006. Age and petrogenesis of plagiogranite intrusions in the Ankara mélange, central Turkey. Isl. Arc 15:44-57.
29. Dilek, Y.; Thy, P.; Hacker, B.; and Grundvig, S. 1999a. Structure and petrology of Tauride ophiolites and mafic dike intrusions (Turkey): implications for the Neo-Tethyan ocean. Bull. Geol. Soc. Am. 111: 1192-1216.
30. Dilek, Y., and Whitney, D. L. 2000. Cenozoic crustal evolution in central Anatolia: extension, magmatism and landscape development. In Proceedings of the Third International Conference on the Geology of the Eastern Mediterranean. Nicosia, Cyprus, Geological Survey Department, p. 183-192.
31. Dilek, Y.; Whitney, D. L.; and Tekeli, O. 1999b. Links between Tectonic processes and landscape morphology in an Alpine collision zone, south-central Turkey. Ann. Geomorphol. 118:147-164.
32. Dupuy, C.; Dostal, J.; and Fratta, M. 1982. Geochemistry of Adamello Masif (northern Italy). Contrib. Mineral. Petrol. 80:41-48.
33. Ercan, T.; Satir, M.; Steinitz, G.; Dora, A.; Sarifakioglu, E.; Adis, C.; Walter, H.-J.; and Yildirim, T. 1995. Biga yari-madasi ile Gokçeada, Bozcaada ve Tavsan adalarindaki (KB Anadolu) Tersiyer volkanizmasinin ozellikleri. Maden Tetkik Arama Dergisi 117:55-86 (in Turkish).
34. Frey, F. A.; Green, D. H.; and Roy, S. D. 1978. Integrated models of basalt petrogenesis: a study of quartz tholeiite to olivine melililites from southeastern Australia utilizing geochemical and experimental data. J. Petrol. 19:463-513.
35. Fytikas, M.; Innocenti, F.; Manetti, P.; Mazzuoli, R.; Peccerillo, A.; and Villari, L. 1984. Tertiary to Quaternary evolution of volcanism in the Aegean region. In Dixon, J. E., and Robertson, A. H. F., eds. The geological evolution of the eastern Mediterranean. Geol. Soc. Lond. Spec. Publ. 17:687-700.
36. Genç, S. C. 1998. Evolution of the Bayramiç magmatic complex, northwestern Anatolia. J. Volcanol. Geotherm. Res. 85:233-249.
37. Genç, S. C., and Yilmaz, Y. 1997. An example of post-collisional magmatism in northwestern Anatolia: the Kizderbent volcanics (Armutlu Peninsula, Turkey). Turk. J. Earth Sci. 6:33-42.
38. Gessner, K.; Collins, A. S.; Ring, U.; and Güngör, T. 2004. Structural and thermal history of poly-orogenic basement: U-Pb geochronology of granitoid rocks in the southern Menderes massif, western Turkey. J. Geol. Soc. Lond. 161:93-101.
39. Gill, J. B. 1981. Orogenic andesites and plate tectonics. Berlin, Springer, 390 p.
40. Güleç, N. 1991. Crust-mantle interaction in western Turkey: implications from Sr and Nd isotope geochemistry of Tertiary and Quaternary volcanics. Geol. Mag. 23:417-435.
41. Gülen, L. 1990. Isotopic characterization of Aegean magmatism and geodynamic evolution of Aegean subduction. In Savascin, M. Y., and Eronat, A. H., eds. Proceedings of the International Earth Science Colloquium on the Aegean region, Izmir, Turkey, p. 143-166.
42. Harris, N. B. W.; Kelley, S.; and Okay, A. I. 1994. Post-collisional magmatism and tectonics in northwest Anatolia. Contrib. Mineral. Petrol. 117:241-252.
43. Harris, N. B. W.; Pearce, J. A.; and Tindle, A. G. 1986. Geochemical characteristics of collision-zone magmatism. In Coward, M. P., and Reis, A. C., eds. Collision tectonics. Geol. Soc. Lond. Spec. Publ. 19:67-81.
44. Hetzel, R., and Reischmann, T. 1996. Intrusion age of Pan-African augen gneisses in the southern Menderes massif and the age of cooling after Alpine ductile extensional deformation. Geol. Mag. 133:565-572.
45. Houseman, G. A.; McKenzie, D. P.; and Molnar, P. 1981. Convective instability of a thickened boundary layer and its relevance for the thermal evolution of continental convergent belts. J. Geophys. Res. 86:6115-6132.
46. Irvine, T. N., and Baragar, W. R. A. 1971. A guide to the chemical classification of common volcanic rocks. Can. J. Earth Sci. 8:523-548.
47. Ishihara, S.; Stephens, W. E.; Harley, S. L.; Arima, M.; and Nakajima, T. 2005. The origin of granites and related rocks. Geol. Soc. Am. Spec. Pap. 389, 390 p.
48. Juteau, T. 1980. Ophiolites of Turkey. Ofioliti 2:199-238.
49. Karacik, Z., and Yilmaz, Y. 1998. Geology of the ignimbrites and the associated volcano-plutonic complex of the Ezine area, northwestern Anatolia. J. Volcanol. Geotherm. Res. 85:251-264.
50. Köprübaşi, N., and Aldanmaz, E. 2004. Geochemical constraints on the petrogenesis of Cenozoic I-type granitoids in northwest Anatolia, Turkey: evidence for magma generation by lithospheric delamination in a post-collisional setting. Int. Geol. Rev. 46:705-729.
51. Köprübaşi, N., and Sen, C. 2000. Fistikli (Armutlu-Yalova) granitoyidinin jeokimyasi. Hacettepe Univ. Yerbilimleri Dergisi 22:33-42 (in Turkish).
52. Marchev, P.; Raicheva, R.; Downes, H.; Vaselli, O.; Chiaradia, M.; and Moritz, R. 2004. Compositional diversity of Eocene-Oligocene basaltic magmatism in the eastern Rhodopes, SE Bulgaria: implications for genesis and tectonic setting. Tectonophysics 393:301-328.
53. Marotta, A. M.; Fernandez, M.; and Sabadini, R. 1998. Mantle unrooting in collisional settings. Tectonophysics 296:31-46.
54. Maury, R. C.; Fourcade, S.; Coulon, C.; El Azzouzi, M.; Bellon, H.; Coutelle, A., Ouabadi, A.; et al. 2000. Post-collisional Neogene magmatism of the Mediterranean Maghreb margin: a consequence of slab breakoff. Earth Planet. Sci. 331:159-173.
55. McKenzie, D., and Yilmaz, Y. 1991. Deformation and volcanism in western Turkey and the Aegean. Bull. Tech. Univ. Istanbul 44:345-373.
56. Meulenkamp, J. E.; Wortel, W. J. R.; Van Wamel, W. A.; Spakman, W.; and Hoogerduyn, S. E. 1988. On the Hellenic subduction zone and geodynamic evolution of Crete since the late Middle Miocene. Tectonophysics 146:203-215.
57. Milisenda, C. C.; Liew, T. C.; Hofmann, A. W.; and Kohler, H. 1994. Nd isotopic mapping of the Sri Lanka basement: update and additional constraints from Sr isotopes. Precambrian Res. 66:95-110.
58. Okay, A. I. 1984. Distribution and characteristics of the northwest Turkish blueschists. Geol. Soc. Lond. Spec. Publ. 17:455-466.
59. Okay, A. I.; Harris, N. B. W.; and Kelley, S. P. 1998. Exhumation of blueschists along a Tethyan suture in northwest Turkey. Tectonophysics 285:275-299.
60. Okay, A. I., and Kelley, S. P. 1994. Tectonic setting, petrology and geochronology of jadeite-glaucophane and chloritoid-glaucophane schists from northwest Turkey. J. Metamorph. Geol. 12:455-466.
61. Okay, A. I., and Satir, M. 2000. Coeval plutonism and metamorphism in a latest Oligocene metamorphic core complex in northwest Turkey. Geol. Mag. 137:495-516.
62. Okay, A. I.; Satir, M.; Maluski, H.; Siyako, M.; Monie, P.; Metzger, R.; and Akyüz, S. 1996. Paleo- and Neo-Tethyan events in northwest Turkey: geological and geochronological constraints. In Yin, A., and Harrison, M. T., eds. Tectonics of Asia. Cambridge, Cambridge University Press, p. 420-441.
63. Öngen, S. 1994. Le pluton calco-alcalin d'Evciler (Peninsule de Biga, Turquie-W): age géochimie et signification géodynamique. C. R. Acad. Sci. Paris 319:1033-1039.
64. Pamic, J.; Balen, D.; and Herak, M. 2002. Origin and geodynamic evolution of Late Paleogene magmatic associations along the Periadriatic-Sava-Vardar magmatic belt. Geodin. Acta 15:209-231.
65. Patino Douce, A. E., and McCarthy, T. C. 1998. Melting of crustal rocks during continental collision and sub-duction. In Hacker, B. R., and Liou, J. G., eds. When continents collide: geodynamics and geochemistry of ultrahigh-pressure rocks. Dordrecht, Kluwer, p. 27-55.
66. Pearce, J. A. 1982. Trace element characteristics of lavas from destructive plate boundaries. In Thorpe, R. S., ed. Andesites: orogenic andesites and related rocks. New York, Wiley, p. 525-248.
67. Pearce, J. A.; Bender, J. F.; DeLong, S. E.; Kidd, W. S. F.; Low, P. J.; Güner, Y.; Saroglu, F.; Yilmaz, Y.; Moorbath, S.; and Mitchell, J. J. 1990. Genesis of collision volcanism in eastern Anatolia, Turkey. J. Volcanol. Geotherm. Res. 44:189-229.
68. Pearce, J. A.; Harris, N. B. W.; and Tindle, A. G. 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J. Petrol. 25:956-983.
69. Pearce, J. A., and Peate, D. W. 1995. Tectonic implications of the composition of volcanic arc magmas. Annu. Rev. Earth Planet. Sci. 23:113-134.
70. Peccerillo, A., and Taylor, S. R. 1976. Geochemistry of Eocene calc-alkaline volcanic rocks in the Kastamonu area, northern Turkey. Contrib. Mineral. Petrol. 58: 63-81.
71. Pe-Piper, G., and Piper, D. J. W. 2002. The igneous rocks of Greece: the anatomy of an orogen. Berlin, Beiträge zur Regionalen Geologie der Erde, Gebrüder Borntraeger, 573 p.
72. Perugini, D.; Poli, G.; and Bonin, B. 2004. Preface: interaction between mafic and felsic magmas in orogenic suites. Lithos 78:ix-xii.
73. Petford, N., and Gallagher, K. 2001. Partial melting of mafic (amphibolitic) lower crust by periodic influx of basaltic magma. Earth Planet. Sci. Lett. 193:483-499.
74. Prat, F. C., and Girbacea, R. 2000. Partial delamination of continental mantle lithosphere, uplift-related crust-mantle decoupling, volcanism and basin formation: a new model for the Pliocene-Quaternary evolution of the southern East-Carpathians, Romania. Tectonophysics 327:83-107.
75. Rapp, R. P. 1995. Amphibole-out phase boundary in partially melted metabasalt, its control over liquid fraction and composition, and source permeability. J. Geophys. Res. 100:891-931.
76. Rapp, R. P., and Watson, E. B. 1995. Dehydration melting of metabasalt at 8-32 kbar: implications for continental growth and crust-mantle recycling. J. Petrol. 36:1-25.
77. Rapp, R. P.; Watson, E. B.; and Miller, C. F. 1991. Partial melting of amphibolite/eclogite and the origin of Archean trondhjemites and tonalites. Precambrian Res. 51:1-25.
78. Ricou, L. E.; Argyriadis, I.; and Marcoux, J. 1975. L'axe calcaire du Taurus, un alignement de fenetres arabo-africaines sous des nappes radiolaritiques, ophiolitiques et métamorphiques. Bull. Soc. Geol. Fr. 16:107-111.
79. Robert, U.; Foden, J.; and Varne, R. 1992. Dodecanese Province, SE Aegean: a model for tectonic control on potassic magmatism. Lithos 28:241-260.
80. Roddick, J. C.; Sullivan, R. W.; and Dudás, F. Ö. 1992. Precise calibration of Nd tracer isotopic composition for Sm-Nd studies. Chem. Geol. 97:1-8.
81. Rushmer, T. 1993. Experimental high-pressure granulites: some applications to natural mafic xenolith suites and Archean granulite terranes. Geology 21:411-414.
82. Seghedi, I.; Downes, H.; Szakács, A.; Mason, P. R. D.; Thirlwall, M. F.; Rosu, E.; Pécskay, Z.; Márton, E.; and Panaiotu, C. 2004. Neogene-Quaternary magmatism and geodynamics in the Carpathian-Pannonian region: a synthesis. Lithos 72:117-146.
83. Şengör, A. M. C.; Görür, N.; and Saroglu, F. 1985. Strike-slip deformation, basin formation and sedimentation: strike-slip faulting and related basin formation in zones of tectonic escape: Turkey as a case study. Soc. Econ. Paleontol. Mineral. Spec. Publ. 37:227-264.
84. Şengör, A. M. C., and Yilmaz, Y. 1981. Tethyan evolution of Turkey: a plate tectonic approach. Tectonophysics 75:181-241.
85. Seyitoǧlu, G.; Anderson, D.; Nowell, G.; and Scott, B. 1997. The evolution from Miocene potassic to Quaternary sodic magmatism in western Turkey: implications for enrichment processes in the lithospheric mantle. J. Volcanol. Geotherm. Res. 76:127-147.
86. Seyitoǧlu, G., and Scott, B. 1992. Late Cenozoic volcanic evolution of the northeastern Aegean region. J. Volcanol. Geotherm. Res. 54:157-176.
87. Seyitoǧlu, G., and Scott, B. 1996. The cause of N-S extensional tectonics in western Turkey: tectonic escape vs. backarc spreading vs. orogenic collapse. J. Geodyn. 22:145-153.
88. 39Ar and Rb-Sr geochronology of high-pressure metamorphism and exhumation history of the Tavsanli zone, NW Turkey. Contrib. Mineral. Petrol. 137:46-58.
89. Stampfli, G. M., and Borel, G. D. 2004. The TRANSMED transects in space and time: constraints on the Paleotectonic evolution of the Mediterranean domain. In Cavazza, W.; Roure, F.; Spakman, W.; Stampfli, G. M.; and Ziegler, P. A., eds. The TRANSMED atlas: the Mediterranean region from crust to mantle. Berlin, Springer, p. 53-80.
90. Sun, S. S., and McDonough, W. F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Saunders, A. D., and Norry, M. J., eds. Magmatism in the ocean basins. Geol. Soc. Lond. Spec. Publ. 42:313-345.
91. Sylvester, P. J. 1989. Post-collisional alkaline granites. J. Geol. 97:261-280.
92. Tankut, A.; Dilck, Y.; and Önen, P. 1998. Petrology and geochemistry of the Neo-Tethyan volcanism as revealed in the Ankara melange, Turkey. J. Volcanol. Geotherm. Res. 85:265-284.
93. Taylor, S. R., and McLennan, S. M. 1985. The continental crust: its composition and evolution. Oxford, Blackwell Science, 312 p.
94. Tekeli, O. 1981. Subduction complex of pre-Jurassic age, northern Anatolia, Turkey. Geology 9:68-72.
95. Thorpe, R. S.; Francis, P. W.; Hammill, M.; and Baker, M. C. W. 1982. The Andes. In Thorpe, R. S., ed. Andesites: orogenic andesites and related rocks. New York, Wiley, p. 187-205.
96. von Blanckenburg, F., and Davies, J. H. 1995. Slab breakoff: a model for syncollisional. magmatism and tectonics in the Alps. Tectonics 14:120-131.
97. von Blanckenburg, E; Früh-Green, G.; Diethelm, K.; and Stille, P. 1992. Nd-, Sr-, and O-isotopic and chemical evidence for a two-stage contamination history of mantle magma in the central-Alpine Bergell intrusion. Contrib. Mineral. Petrol. 110:33-45.
98. Walker, J. A.; Moulds, T. N.; Zentilli, M.; and Feigeson, M. D. 1991. Spatial and temporal variations in volcanics of Andean central volcanic zone (26 to 28). In Harmon, R. S., and Rapela, C. W., eds. Andean magmatism and its tectonic setting. Geol. Soc. Am. Bull. Spec. Pap. 265:139-155.
99. White, A. J. R., and Chappell, B. W. 1977. Ultrametamorphism and granitoid genesis. Tectonophysics 43: 7-22.
100. Wilson, M. 1989. Igneous petrogenesis: a global tectonic approach. London, Harper Collins, 466 p.
101. Wortel, M. J. R., and Spakman, W. 2000. Subduction and slab detachment in the Mediterranean-Carpathian region. Science 290:1910-1917.
102. Yilmaz, Y. 1981. Tectonic evolution of the southern margin of the Sakarya continent, NW Turkey. Yerbilimleri 11:33-52 (in Turkish).
103. Yilmaz, Y. 1989. An approach to the origin of young volcanic rocks of western Turkey. In Şengör, A. M. C., ed. Tectonic evolution of the Tethyan region. The Hague, Kluwer Academic, p. 159-189.
104. Yilmaz, Y. 1990. Comparison of young volcanic associations of western and eastern Anatolia under compressional regime: a review. J. Volcanol. Geotherm. Res. 44:69-87.
105. Yilmaz, Y.; Genç, S. C.; Gürer, O. F.; Bozcu, M.; Yilmaz, K.; Karacik, Z.; Altunkaynak, Ş.; and Elmas, A. 2000. When did the western Anatolian grabens begin to develop? In Bozkurt, E.; Winchester, J. A.; and Piper, J. A. D., eds. Tectonics and magmatism in Turkey and the surrounding area. Geol. Soc. Lond. Spec. Publ. 173: 353-384.
106. Yilmaz, Y.; Genç, S. C.; Karacik, Z.; and Altunkaynak, Ş. 2001. Two contrasting magmatic associations of NW Anatolia and their tectonic significance. J. Geodyn. 31:243-271.
107. Yilmaz, Y., and Polat, A. 1998. Geology and evolution of the Thrace volcanism, Turkey. Acta Vulcanol. 10:293-303.