Abstract
A regional melange zone, 150 km long and 30 km wide, forms the southern boundary and structural capping to a high-pressure blueschist belt in northern New Caledonia. The disrupted country rocks in the melange zone are Mesozoic metagrey-wackes and Eocene chert-limestone sequences which have been penetrated from below by tectonically-injected ophiolite slivers containing metamorphosed serpentinite, gabbro, dolerite, basalt, tuff, chert and shale. An ocean crust origin for these rocks is indicated by chemical, mineralogical and radiometric data from coastal outcrops at Anse Ponandou on the northeast coast. The age (41 m.y.), metamorphic environment (350 ° C at 7 kb), and mineral association (acmitic jadeite-riebeckite-pyropic spessartine-pistacitic epidote-lawsonite-high Si phengite) are significantly different from those of the adjacent regional high-pressure schist belt, indicating a separate structural site for blueschist metamorphism of buried ophiolitic ocean crust during early Tertiary orogenesis.
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Black, P.M.: P2 omphacite intermediate in composition between jadeite and hedenbergite, from metamorphosed acid volcanics, Bouehndep, New Caledonia. Am. Mineralogist 55, 512–514 (1970a)
Black, P.M.: Ferroglaucophane from New Caledonia. Am. Mineralogist 55, 508–511 (1970b)
Black, P.M.: Coexisting glaucophane and riebeckite-arfvedsonite from New Caledonia. Am. Mineralogist 55, 1060–1064 (1970c)
Black, P.M.: Mineralogy of New Caledonian metamorphic rocks I. Garnets from the Ouégoa district. Contrib. Mineral. Petrol. 38, 221–235 (1973a)
Black, P.M.: Mineralogy of New Caledonian metamorphic rocks II. Amphiboles from the Ouégoa district. Contrib. Mineral. Petrol. 39, 55–64 (1973b)
Black, P.M.: Mineralogy of New Caledonian metamorphic rocks III. Pyroxenes, and major element partitioning between coexisting pyroxenes, amphiboles and garnets from the Ouégoa district. Contrib. Mineral. Petrol. 45, 281–288 (1974a)
Black, P.M.: Oxygen isotope study of metamorphic rocks from the Ouégoa district, New Caledonia. Contrib. Mineral. Petrol. 47, 197–206 (1974b)
Black, P.M.: Mineralogy of New Caledonian metamorphic rocks IV. Sheet silicates from the Ouégoa district. Contrib. Mineral. Petrol. 49, 269–284 (1975)
Black, P.M.: Regional high-pressure metamorphism in New Caledonia: phase equilibria in the Ouégoa district. Tectonophysics (1977)
Bocquet, J.: Blue amphiboles of the Western Alps: chemistry and physical characters. Schweiz. Mineral. Petrog. Mitt. 54, 425–448 (1974)
Briggs, R.M., Lillie, A.R., Brothers, R.N.: Structure and metamorphism in the Diahot area, northern New Caledonia (in press)
Brothers, R.N.: Lawsonite-albite schists from northernmost New Caledonia. Contrib. Mineral. Petrol. 25, 185–202 (1970)
Brothers, R.N.: High-pressure schists in northern New Caledonia. Contrib. Mineral. Petrol. 46, 109–127 (1974)
Brothers, R.N., Blake, M.C.: Tertiary plate tectonics and high-pressure metamorphism in New Caledonia. Tectonophysics 17, 337–358 (1973)
Coleman, R.G.: Glaucophane schists from California and New Caledonia. Tectonophysics 4, 479–498 (1967)
Diessel, C.F.K., Brothers, R.N., Black, P.M.: Coalification and graphitization in high-pressure schists in New Caledonia. (in press)
Epstein, S., Taylor, H.P.: Variation of O18/O16 in minerals and rocks. In: Researches in Geochemistry (P.H. Abelson, ed.), Vol. 2, pp. 29–62. New York: Wiley 1967
Ernst, W.G., Seki, Y., Onuki, H., Gilbert, M.C. Comparative study of low-grade metamorphism in the California Coast Ranges and the outer metamorphic belt of Japan. Geol. Soc. Am. Mem. 124, 276 p. (1970)
Eugster, H.P., Wones, D.R.: Stability relations of the ferruginous biotite annite. J. Petrol. 3, 82–125 (1962)
Onuki, H., Ernst, W.G.: Coexisting sodic amphibole and sodic pyroxenes from blueschist facies metamorphic rocks. Mineral. Soc. Am. Spec. Papers 2, 241–249 (1969)
Pearce, J.A.: Basalt geochemistry used to investigate past environments on Cyprus. Tectonophysics 25, 41–67 (1975)
Pearce, J.A., Cann, J.R.: Tectonic setting of basic volcanic rocks determined using trace element analysis. Earth Planet. Sci. Lett. 19, 290–300 (1973)
Popp, R.K., Gilbert, M.C.: Stability of acmite-jadeite pyroxenes at low pressure. Am. Mineralogist 57, 1210–1231 (1972)
Taylor, H.P., Coleman, R.G.: O18/O16 ratios of coexisting minerals in glaucophane-bearing metamorphic rocks. Bull. Geol. Soc. Am. 79, 1727–1756 (1968)
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Black, P.M., Brothers, R.N. Blueschist ophiolites in the melange zone, northern New Caledonia. Contr. Mineral. and Petrol. 65, 69–78 (1977). https://doi.org/10.1007/BF00373572
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DOI: https://doi.org/10.1007/BF00373572