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Cambrian nepheline syenite complex at Jabal Sawda, Midyan region, Kingdom of Saudi Arabia

Journal of African Earth Sciences

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Abstract

The only nepheline syenite complex presently known in the Arabian Shield is at Jabal Sawda, about 30 km S of Haql in the extreme NW of Saudi Arabia. It is a post-tectonic, composite intrusion with a crudely concentric structure. A core of leuco-nepheline syenite, a partial ring of mela-nepheline syenite, and an almost complete outer ring of alkali-feldspar syenite are the main rock units. Several mega-inclusions of porphyritic nepheline syenite, nepheline monzosyenite, malignite and ijolite are present in the leuco-nepheline syenite. The chemical composition is notable for very high values of Al2O3, Na2O, Ba, La, Nb, Sr and Zr. U{single bond}Pb isotope dating indicates an emplacement age of 553 ?? 4 Ma, one of an increasing number of reliable Cambrian isotope dates in the northern Red Sea region. ?? 1986.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Cambrian nepheline syenite complex at Jabal Sawda, Midyan region, Kingdom of Saudi Arabia
Series title:
Journal of African Earth Sciences
Volume
4
Issue:
C
Year Published:
1986
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of African Earth Sciences
First page:
139
Last page:
150
Number of Pages:
12