Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-05T09:52:24.897Z Has data issue: false hasContentIssue false
  • English
  • Français

Blocks of Plutonic Aspect in a Basaltic Lava from Faial, Azores

Published online by Cambridge University Press:  01 May 2009

M. Jane Baker
M. Jane Baker
Affiliation:
Dept. of Geology and Mineralogy, University Museum, Oxford.
Get access Rights & Permissions [Opens in a new window]

Abstract

A number of coarse-grained blocks, consisting of forsteritic olivine, chrome-diopside, calcic plagioclase, and chromite in varying proportions, were found in an ankaramitic basalt on Faial. With one exception, the blocks show remarkably little alteration. There is no evidence of zoning in any of the minerals. Indications of strain are frequent. Dark scoriaceous material is often present along intercrystal boundaries and fractures. The textures and gradations in composition suggest that these blocks were formed by crystal accumulation.

Type
Articles
Information
Geological Magazine , Volume 103 , Issue 1 , February 1966 , pp. 51 - 60
Copyright
Copyright © Cambridge University Press 1966

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

REFERENCES

Jackson, E. D., 1960. X-ray determinative curve for natural olivine of composition Fo80–90. U.S. geol. Surv. Prof. Pap., 400-B, 432–434.Google Scholar
Lacroix, A., 1893. Les enclaves des roches volcaniques. Paris.Google Scholar
O'Hara, M. J. and Mercy, E. L. P., 1963. Petrology and petrogenesis of some garnetiferous peridotites. Trans. roy. Soc. Edinb., 65, 251–314.CrossRefGoogle Scholar
Ross, C. S., Foster, M. D., and Myers, A. T., 1954. Origin of dunites and olivine rich inclusions in basaltic rocks. Amer. Miner., 43, 862–871.Google Scholar
Tomkieff, S. I., 1939. Zoned olivines and their petrogenetic significance. Miner. Mag., 25, 229–251.Google Scholar
Tsuboi, S., 1923. A dispersion method of determining plagioclases in cleavage flakes. Miner. Mag., 20, 108–122.Google Scholar
Wager, L. R., Brown, G. M., and Wadsworth, W. J., 1960. Types of igneous cumulates. J. Petrol., 1, 73–85.CrossRefGoogle Scholar
Zbyszewski, G., Moitinho d'Almeida, F., da Veiga Ferreira, O., and Torre de Assunção, C., 1958. Noticia explicativa da folha B. S. Miguel (Açores). Carta Geológica de Portugal. Lisbon.Google Scholar