Paragenesis of a cordierite-garnet granulile from Assam, India
By: Sastri, G.G.K
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Material type: 
ArticleDescription: 331-336pp ; Illustration.Subject(s): Cordierite garnet - Assam - India | Metamorphic rock - Assam - India
In:
Geological magazine : Vol. 100 Iss. 1-6 Year. 1963Summary: Abstract
A cordierite-garnet granulite from Assam, India, carries optically positive cordierite, garnet, spinel, biotite, and sillimanite. The optics of the cordierite are: α = 1·534, β = 1·540, γ = 1·548, 2V = + 81°, while the composition of the garnet inferred from the writer's charts, in terms of the end-members, is Al73Py20Sp2An3Gr2. The development of an iron-rich garnet in association with a magnesium-rich cordierite is discussed, and data are presented to show that such garnets have a restricted compositional range. It is doubtful if the FeO/MgO ratio in a cordierite-garnet assemblage can be used for interpretation of the physical conditions governing the formation of the host rock.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
|---|---|---|---|---|---|---|
Article
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Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002548_45 | ||
Serials/Scientific Journal
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Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002548 |
Abstract
A cordierite-garnet granulite from Assam, India, carries optically positive cordierite, garnet, spinel, biotite, and sillimanite. The optics of the cordierite are: α = 1·534, β = 1·540, γ = 1·548, 2V = + 81°, while the composition of the garnet inferred from the writer's charts, in terms of the end-members, is Al73Py20Sp2An3Gr2. The development of an iron-rich garnet in association with a magnesium-rich cordierite is discussed, and data are presented to show that such garnets have a restricted compositional range. It is doubtful if the FeO/MgO ratio in a cordierite-garnet assemblage can be used for interpretation of the physical conditions governing the formation of the host rock.
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