Eclogite, Pyroxenite and Amphibolite Inclusions in the Sullivan Buttes Latite, Chino Valley, Yavari County, Arizona

  1. F.R. Boyd and
  2. Henry O.A. Meyer
  1. Richard J. Arculus1 and
  2. Douglas J. Smith2

Published Online: 19 MAR 2013

DOI: 10.1029/SP016p0309

The Mantle Sample: Inclusion in Kimberlites and Other Volcanics

The Mantle Sample: Inclusion in Kimberlites and Other Volcanics

How to Cite

Arculus, R. J. and Smith, D. J. (1979) Eclogite, Pyroxenite and Amphibolite Inclusions in the Sullivan Buttes Latite, Chino Valley, Yavari County, Arizona, in The Mantle Sample: Inclusion in Kimberlites and Other Volcanics (eds F.R. Boyd and H. O.A. Meyer), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP016p0309

Author Information

  1. 1

    Research School of Earth Sciences, Australian National University, Canberra, A.C.T. 2600

  2. 2

    Department of Geological Sciences, University of Texas At Austin, Austin, Texas 78712

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1979

ISBN Information

Print ISBN: 9780875902135

Online ISBN: 9781118664858

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Keywords:

  • Amphibolites;
  • Bright green clinopyroxenite;
  • Eclogites;
  • Garnet analyses;
  • Pyroxenit inclusions;
  • Websterites and pyroxenites

Summary

Mafic and ultramafic inclusions are abundant in potassic latite about 25 my in age that crops out on the southwest structural border of the Colorado Plateau. About 60% are eclogite composed of garnet (Py40Alm37Gross23) and clinopyroxene (5–30 mol.% jadeite) with minor amphibole, apatite, rutile, Fe-Ti oxides and rare altered clinozoisite. Phase layering is common and eclogites with contrasting gnt/cpx ratios occur in sharp contact. Layering in general appears to reflect a cumulus origin rather than metamorphic segregation or tectonic or intrusive juxtaposition. Thirty percent of the inclusions are dominated by pargasitic amphibole (up to 90 modal %) with minor diopside, garnet, phlogopite, apatite and oxides.

Websterites and pyroxenites form 2–4% of the inclusions, and some contain strained pyroxene porphyroclasts with exsolved garnet and pyroxene in a mosaic groundmass of orthopyroxene and garnet. Crustal schists, quartzites and granulites constitute the remainder of the inclusion population. All rock types have metamorphic fabrics, and only rare phlogopite- apatite-clinopyroxenite inclusions could represent cumulates from the host latite. Amphibole and phlogopite appear primary in many samples, but secondary growth also occurred. Late stage partial melting in some rocks led to distinctive textures and to formation of plagioclase, corundum and possibly amphibole and rare kyanite.

Distribution coefficients of Fe and Mg between gnt-cpx pairs ((Fe0/Mg0) gnt/(Fe0/Mg0)cpx) range from 3.3 to 7.0 with generally lower values for websterites than for eclogites and amphibolites. Typical orthopyroxene coexisting with garnet contains 1.4 to 2.5 wt.% Al2O3. These data suggest temperatures and pressures of equilibration in the range 700–1000°C, 10–20 kbar. The inclusions may be re-equilibrated samples of an eclogite-rich cumulate sequence formed during Precambrian (1720–1820 my) igneous activity. Highly fractionated rare earth element abundances of the latite suggest that garnet remained in the source material; the latites might have formed by partial melting of part of the cumulate sequence.