Contributions to Mineralogy and Petrology

, Volume 91, Issue 1, pp 93–104 | Cite as

Petrology and geochemistry of Cambrian boninites and low-Ti andesites from Heathcote, Victoria

  • Anthony J. Crawford
  • W. E. Cameron


In the Heathcote Greenstone Belt of central Victoria, a sequence of boninites and low-Ti andesites is overlain and intruded by tholeiitic basalts with affinities to backarc basin basalts. Two suites of boninites have been identified: one (Type A) with Ti/Zr ratios of 63±4, (La/Yb)N of 2–3 and HREE 5 times chondritic levels. The other suite (Type B) overlies Type A boninites and has Ti/Zr ratios of 23±3 and lower TiO2 and HREE contents (2–3 × chondrite), but shows significantly greater LREE enrichment, with (La/Yb)N greater than 5. Fractionation within both suites was largely controlled by the low-Ca pyroxenes protoenstatite and enstatite. Plagioclase-phyric low-Ti, high-Mg andesites occur in fault contact with the boninites, and have Ti/Zr and (La/Yb)N ratios very close to those of Type B boninites, but at higher absolute abundances of TiO2 and HREE. They are not related to either boninite suite by any realistic fractionation scheme, but originated from the same source as Type B boninites by approximately half the degree of partial melting that generated the boninites.

Type A boninites could have been generated when LILE-enriched hydrous fluids derived from a subducted slab invaded depleted, clinopyroxene-poor lherzolite at depths less than 30 km, and initiated H2O-undersaturated partial melting. In a later partial melting event at similar depths, continued influx of metasomatic fluids into by now highly-depleted peridotite could have generated Type B boninites and low-Ti andesites. The presence of boninites and low-Ti andesites in the Cambrian Heathcote and Mount Wellington Greenstone Belts in southeastern Australia suggests that the early history of the Lachlan Foldbelt took place in a subduction-related, intraoceanic setting.


TiO2 Cambrian Partial Melting Enstatite Greenstone Belt 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Arculus RJ, Wills KJA (1980) The petrology of igneous blocks and inclusions from the Lesser Antilles island arc. J Petrol 21:143–199Google Scholar
  2. Bougault H, Maury RC, Elazzouzi M, Joron JL, Treuil M (1981) Tholeiites, basaltic andesites and andesites from Leg 60 sites; geochemistry, mineralogy and low partition coefficient elements. Init Rept DSDP 60:657–677Google Scholar
  3. Cameron WE, Nisbet EG, Dietrich VJ (1979) Boninites, komatiites and ophiolitic basalts. Nature 280:550–553Google Scholar
  4. Cameron WE, McCulloch MT, Walker DA (1983) Boninite petrogenesis: chemical and Nd-Sr isotopic constraints. Earth Planet Sci Lett 65:75–89Google Scholar
  5. Cawthorn RG, Davies G (1983) Experimental data at 3 kbars pressure on parental magma to the Bushveld complex. Contrib Mineral Petrol 83:128–135Google Scholar
  6. Coish RA (1977) Ocean floor metamorphism in the Betts Cove ophioite, Newfoundland. Contrib Mineral Petrol 60:255–270Google Scholar
  7. Crawford AJ (1980) A clinoenstatite-bearing cumulate olivine pyroxenite from Howqua, Victoria. Contrib Mineral Petrol 75:353–367Google Scholar
  8. Crawford AJ, Keays RR (1978) Cambrian greenstone belts in Victoria: marginal sea crust slices in the Lachlan Foldbelt of south-eastern Australia. Earth Planet Sci Lett 41:197–208Google Scholar
  9. Crawford AJ, Beccaluva L, Serri G (1981) Tectono-magmatic evolution of the West Philippine-Mariana region and the origin of boninites. Earth Planet Sci Lett 54:346–356Google Scholar
  10. Crawford AJ, Cameron WE, Keays RR (1984) The association boninite-low Ti andesite-tholeiite in the Heathcote Greenstone Belt, Aust J Earth Sci 31:161–175Google Scholar
  11. Crawford AJ (1985) The geology and petrogenesis of a low-Ti, high-Mg andesite suite from Mount Dryden, Victoria (in prep.)Google Scholar
  12. Dietrich VJ, Emmerman R, Oberhansli R, Puchelt H (1978) Geochemistry of basaltic and gabbroic rocks from the West Mariana Basin and the Mariana trench. Earth Planet Sci Lett 39:127–144Google Scholar
  13. Dietrich VJ, Gansser A, Sommerauer J, Cameron WE (1981) Palaeogene komatiites from Gorgona island, east Pacific — a primary magma for ocean floor basalts. Geochem J 15:141–161Google Scholar
  14. Dick HJB, Bullen TE (1984) Chromian spinel as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas. Contrib Mineral Petrol 86:54–76Google Scholar
  15. Gamble RP, Taylor LA (1980) Crystal/liquid partitioning in augite; effects of cooling rate. Earth Planet Sci Lett 47:21–33Google Scholar
  16. Green DH (1984) Genesis of MORB, ophiolitic basalts and boninites. (Abstr) Workshop on Expt Petrol, Monash UnivGoogle Scholar
  17. Grove TL, Bence AE (1977) Experimental study of pyroxene-liquid interaction in quartz-normative basalt 15997. Proc 8th Lunar Sci Conf: 1549–1580Google Scholar
  18. Hellman PL, Smith RE, Henderson P (1979) The mobility of the rare earth elements: evidence and implications from selected terrains affected by burial metamorphism. Contrib Mineral Petrol 71:23–44Google Scholar
  19. Hickey RL, Frey FA (1981) Rare earth element geochemistry of Mariana forearc volcanics, DSDP Hole 458 and Hole 459B. Init Rept DSDP 60:735–742Google Scholar
  20. Humphris SE, Thompson G (1978) Hydrothermal alteration of oceanic basalts by seawater. Geochim Cosmochim Acta 42:107–125Google Scholar
  21. Humphris SE, Morrison MA, Thompson RN (1978) Influence of rock crystallization history on subsequent lanthanide mobility during hydrothermal alteration of basalts. Chem Geol 23:125–138Google Scholar
  22. Jenner GA (1981) Geochemistry of high-Mg andesites from Cape Vogel, Papua New Guinea. Chem Geol 33:307–332Google Scholar
  23. Lofgren GE (1977) Dynamic crystallization experiments bearing on the origin of textures in impact-generated liquid. Proc. 8th Lunar Sci Conf: 2079–2095Google Scholar
  24. Marsh BD (1976) Some Aleutian andesites — their nature and source. J Geol 84:27–45Google Scholar
  25. Natland JH (1981) Crystal morphologies and pyroxene compositions in boninites and tholeiitic basalts from DSDP Holes 458 and 459B in the Mariana forearc region. Init Rept DSDP 60:681–707Google Scholar
  26. Nelson DR, Crawford AJ, McCulloch MT (1984) Nd-Sr systematics in Cambrian boninites and tholeiites from Victoria, Australia. Contrib Mineral Petrol 88:169–177Google Scholar
  27. Nesbitt RW, Sun SS (1976) Geochemistry of Archaean spinifextextured peridotites and magnesian and low-magnesian basalts. Earth Planet Sci Lett 31:433–450Google Scholar
  28. Pearce JA (1975) Basalt geochemistry used to investigate past tectonic environments on Cyprus. Tectonophys 26:41–67Google Scholar
  29. Pearce JA (1978) Petrogenetic studies of metabasalts using immobile trace element ratios. J Geol Soc Lond 135:192–215Google Scholar
  30. Pearce JA, Cann JR (1973) Tectonic setting of basic volcanic rocks determined using trace element analysis. Earth Planet Sci Lett 19:290–305Google Scholar
  31. Reid DL (1979) Petrogenesis of calc-alkaline metalavas in the mid-Proterozoic Haib volcanic subgroup, Lower Orange River region. Trans Geol Soc S Afr 82:109–131Google Scholar
  32. Rhodes JM, Dungan MA (1979) The evolution of ocean floor basaltic magmas. In Deep Drilling Results in the Atlantic Ocean (Eds) Talwani M, Harrison GC, Hayes DE; Amer Geophys Union M Ewing Series 2:262–272Google Scholar
  33. Roeder PL, Campbell IH, Jamieson HE (1979) A re-evaluation of the olivine — chromite geothermometer. Contrib Mineral Petrol 68:325–334Google Scholar
  34. Saunders AD, Tarney J, Marsh NG, Wood DA (1980) Ophiolites as ocean crust or marginal basin crust: a geochemical approach. Proc Int Ophiolite Symp, Cyprus, 193–204Google Scholar
  35. Sharaskin AY, Dobretsov NL, Sobolev NV (1980) Marianites; the clinoenstatite-bearing pillow lavas associated with the ophiolite assemblage of the Mariana Trench. Proc Int Ophiolite Symp, Cyprus, 473–479Google Scholar
  36. Sun SS, Nesbitt RW (1977) Chemical heterogeneity of the Archaen mantle: composition of the earth and mantle evolution. Earth Planet Sci Lett 35:429–448Google Scholar
  37. Sun SS, Nesbitt RW (1978) Chemical regularities and genetic significance of ophiolitic basalts. Geology 6:689–693Google Scholar
  38. Sun SS, Nesbitt RW, Sharaskin AY (1979) Geochemical characteristics of mid-ocean ridge basalts. Earth Planet Sci Lett 44:119–138Google Scholar
  39. Tatsumi Y, Ishizaka K (1982) Origin of high-Mg andesites in the Setouchi volcanic belt, southwest Japan; II. Melting phase relations at high pressures. Earth Planet Sci Lett 60:293–304Google Scholar
  40. Varne R, Brown AV (1978) The geology and petrology of the Adamsfield Ultramafic Complex, Tasmania. Contrib Mineral Petrol 67:195–207Google Scholar
  41. Walker DA, Cameron WE (1983) Boninite primary magmas: evidence from the Cape Vogel peninsula, PNG. Contrib Mineral Petrol 83:150–158Google Scholar
  42. Wood DA, Gibson I, Thompson RN (1976) Element mobility during zeolite facies metamorphism of the Tertiary basalts of eastern Iceland. Contrib Mineral Petrol 55:241–254Google Scholar
  43. Wood DA, Marsh NG, Tarney J, Joron JL, Fryer P, Treuil M (1981) Geochemistry of igneous rocks recovered from a transect across the Mariana Trough, arc, forarc and trench, Sites 453-461, DSDF Leg 60. Init Rept DSDP 60:611–645Google Scholar

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • Anthony J. Crawford
    • 1
  • W. E. Cameron
    • 2
  1. 1.Department of GeologyUniversity of TasmaniaHobartAustralia
  2. 2.Department of GeologyAustralian National UniversityCanberraAustralia

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