Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-03T01:37:30.696Z Has data issue: false hasContentIssue false
  • English
  • Français

Ultramafic Breccias from the Musa Valley, Eastern Papua

Published online by Cambridge University Press:  01 May 2009

D. H. Green
Get access Rights & Permissions [Opens in a new window]

Abstract

In the Musa Valley area rocks of the Papuan Ultramafic Belt outcrop discontinuously over an area of 25 miles by 45 miles. The rocks are part of a folded layered sequence ranging from magnesian dunite and peridotite, chemically and petrographically typical of the alpine ultramafic suite, to olivine gabbro and bytownite gabbro. Agglomerate like breccias consisting of fragments of ultramafic rock in a variable matrix occur as irregular vent-like bodies in the peridotite and dunite and as horizontal sheets in a Pleistocene-Recent sedimentary sequence. The breccias are interpreted as vent and extrusive breccias resulting from the penetration, brecciation and local entrainment (fluidization) of peridotitic country rock by volcanic gases. Olivine alkali basalt was probably the parental magma responsible for the gaseous activity. The breccias show a sequence of stability fields for the assemblages mesh-texture serpentine and bastite (i.e. chrysotile and lizardite mixtures); antigorite; olivine and enstatite; and these are correlated qualitatively with variation in intensity of the brecciation process. Chemically the brecciation process was responsible for the addition of H2O, SiO2, CO2, Al2O3 and O2 and the removal of Fe and Mg from the fragmented rock. Minerals which are of direct crystallization in the matrix fluid environment include chalcedony, fibrous serpentine (chrysotile), magnesite, quartz, andradite, and garnierite. There is no evidence of the presence of an ultramafic, serpentine magma in the genesis of the breccias.

Type
Articles
Information
Geological Magazine , Volume 98 , Issue 1 , February 1961 , pp. 1 - 26
Copyright
Copyright © Cambridge University Press 1961

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baker, G., 1946. Preliminary note on volcanic eruptions in the Goropu Mountains, South Eastern Papua, during the period December, 1943, to August, 1944. Journ. Geol., 54, 19–31.CrossRefGoogle Scholar
Benson, W. N., 1926. The tectonic conditions accompanying the instrusion of basic and ultrabasic igneous rocks. Mem. Nat. Acad. Sci. Washington, 19, No. 1.Google Scholar
Bowen, N. L., 1927. The origin of ultrabasic and allied rocks. Amer. Journ. Sci., 14, 89–108.CrossRefGoogle Scholar
Bowen, N. L. and Tuttle, O. F., 1949. The System MgO-SiO2-H2O. Bull. Geol Soc. Amer., 60, 439–460.CrossRefGoogle Scholar
Flint, D. E., de Albear, J. F. and Guild, P. W., 1948. Geology and chromite deposits of the Camaguey District, Camaguey Province, Cuba. U.S.G.S. Bull., 954–B.Google Scholar
Francis, G. H., 1956. The serpentinite mass in Glen Urquhart, Invernessshire, Scotland. Amer. Journ. Sci., 254, 201–226.CrossRefGoogle Scholar
Francis, E. H., 1959. A volcanic vent in the Bogside Mines, Fife. Geol. Mag., 96, 457–469.CrossRefGoogle Scholar
Gass, I. G., 1958. Ultrabasic pillow lavas from Cyprus. Geol. Mag., 95, 241–251.CrossRefGoogle Scholar
Gonzales, M. L., Peoples, J. W., Fernandez, N. S., and Victorio, V., 1957. The ultramafic and mafic rocks of the Zambales Range, Luzon, Philippines. Bull. Geol. Soc. Amer., 68, 1736.Google Scholar
Hess, H. H., 1938. A primary peridotite magma. Amer. Journ. Sci., 35, 321–344.CrossRefGoogle Scholar
Hess, H. H., 1955. Serpentines, orogeny, and epeirogeny, in “Crust of the Earth”, Special Paper No. 62, Geol. Soc. Amer., 391–408.Google Scholar
Hess, H. H., Smith, R. J., and G., Dengo, 1952. Antigorite from the vicinity of Caracas, Venezuela. Amer. Min., 37, 68–75.Google Scholar
Ingerson, E., 1935. Layered peridotitic laccoliths of the Trout River area, Newfoundland. Amer. Journ. Sci., 29, 422–440.CrossRefGoogle Scholar
Krauskopf, K. B., 1959. The use of equilibrium calculations in finding the composition of a magmatic gas phase: in Researches in Geochemistry (ed. Abelson, P. H.), Wiley and Co., N.Y.Google Scholar
Little, H. W., 1949. The ultrabasic rocks of Middle River Range, British Columbia. Amer. Journ. Sci., 247, 802–822.CrossRefGoogle Scholar
Nagy, B., and Faust, G. J., 1956. Serpentines: natural mixtures of chrysotile and antigorite. Amer. Min., 41, 817–838.Google Scholar
Nockolds, S. R., 1954. Average chemical compositions of some igneous rocks. Bull. Geol. Soc. Amer., 65, 1007–1032.CrossRefGoogle Scholar
Reynolds, D. L., 1954. Fluidization as a Geological Process and its bearing in the problem of intrusive granites. Amer. Journ. Sci., 252, 577–613.CrossRefGoogle Scholar
Ross, C. S., Foster, M. D., and Myers, T. A., 1954. Origin of dunites and of olivine-rich inclusions in basaltic rocks. Amer. Min., 34, 693–737.Google Scholar
Ruckmick, J. C., and Noble, J. A., 1959. Origin of the ultramafic complex at Union Bay, South-eastern Alaska. Bull. Geol. Soc. Amer., 70, 981–1018.CrossRefGoogle Scholar
Shepherd, E. S., 1938. The gases in rocks and some related problems, Amer. Journ. Sci., 35A, 311–351.Google Scholar
Smith, C. H., 1953. Origin of the chromite deposits of the Bay of Islands igenous complex, western Newfoundland, Econ. Geo., 48, 408–415.CrossRefGoogle Scholar
Smith, J. W., and Green, D. H., 1960. The geology of the Musa River area, Papua. Comwlth. Aust. Bur. Min. Res. Geol. Geophys. Report, 52.Google Scholar
Taylor, G. A., 1958. The 1951 eruption of Mount Lamington, Papua. Comwith. Aust. Bur. Min. Res. Geol. Geophys. Bull., 38, 1–100.Google Scholar
Whittaker, E. J. W. and Zussman, J., 1956. The characterization of serpentine minerals by X-ray diffraction. Miner. Mag., 31, 107–126.Google Scholar
Whitten, E. T., 1959. Tuffisite and magnetite tuffisite from Tory Island, Ireland, and related problems of gas action. Amer. Journ. Sci., 257, 113–137.CrossRefGoogle Scholar
Wilkinson, J. F. G., 1953. Some aspects of the Alpine-type serpentinites of Queensland. Geol. Mag., 90, 305–321.CrossRefGoogle Scholar
Wilson, R. A. M, 1959. The geology of the Xeros-Troodos area. Geol. Surv. Cyprus Mem., 1, 1–135.Google Scholar
Worst, B. G., 1958. The differentiation and structure of the Great Dyke of Southern Rhodesia. Trans. Geol. Soc. S. Africa, 61, 284–354.Google Scholar