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Size-graded layering in the Imilik gabbro, East Greenland

Published online by Cambridge University Press:  01 May 2009

P. E. Brown
Affiliation:
Department of Geology, University of Sheffield, Mappin Street, St George's Square, Sheffield, S1 3JD
D. G. Farmer
Affiliation:
Department of Geology, University of Sheffield, Mappin Street, St George's Square, Sheffield, S1 3JD

Summary

Rhythmic layering in which the layers grade from coarse base to finer top is described in a plagioclase—pyroxene—olivine gabbro. The medium sizes of the various cumulus minerals at each level have significantly different settling velocities. Variation in the proportions of the cumulus minerals accompanies the size grading. It is shown that these characteristics can reasonably be accounted for if hydrodynamic factors exerted the main control, over-riding any chemical effects.

Type
Articles
Copyright
Copyright © Cambridge University Press 1971

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References

Bhattacharji, S. 1967. Mechanics of flow differentiation in ultramafic and mafic sills. J. Geol. 75, 101–12.CrossRefGoogle Scholar
Hess, H. H. 1960. Stillwater igneous complex, Montana. Mem. Geol. Soc. Am. 80.Google Scholar
Irvine, T. N. 1963. Origin of the ultramafic complex at Duke Island, Southeastern Alaska. Miner. Soc. Am. Spec. Pap. 1, 3645.Google Scholar
Irvine, T. N. 1965. Sedimentary structures in igneous intrusions with particular referencetothe Duke Island ultramafic complex. In Middleton, G. V. (Ed.): Primary Sedimentary Structures and their hydrodynamic interpretation. Soc. Econ. Paleo. and Mineral. Spec. Publ. No. 12, 220–32.Google Scholar
Jackson, E. D. 1961. Primary textures and mineral association in the Ultramafic Zone of the Stillwater Complex, Montana. U.S. Geol. Surv. Prof. Pap. 400-B, 1106.Google Scholar
Jeffrey, R. C. & Pearson, J. R. A. 1965. Particle motion in laminar vertical tube flow. J. Fluid Mech. 22, 721–35.CrossRefGoogle Scholar
Krumbein, W. C. 1935. Thin section mechanical analysis of indurated sediments. J. Geol. 43, 482–96.CrossRefGoogle Scholar
Segre, G. & Silberberg, A. 1962. Behaviour of macroscopic rigid spheres in Poiseville flow. J. Fluid Mech. 14, 136–57.CrossRefGoogle Scholar
Shaw, H. R. 1965. Comments on viscosity, crystal settling and convection in granitic magmas. Am. J. Sci. 263, 120–52.CrossRefGoogle Scholar
Starkey, T. V. 1956. The laminar flow of streams of suspended particles. Brit. J. Appl. Phys. 7, 52–5.CrossRefGoogle Scholar
Wager, L. R. 1968. Rhythmic and cryptic layering in mafic and ultramafic plutons. In Hess & Poldervaart (Eds.): Basalts. Wiley, New York, vol. 2, 573622.Google Scholar
Wager, L. R. & Brown, G. M. 1968. Layered igneous rocks. Oliver & Boyd, Edinburgh.Google Scholar