Essexite occurrence in the Deccan volcanic province of Saurashtra,western India |
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| Institution: | 1. Saint Mary''s University, Department of Geology, 923 Robie Street, Halifax, NS, B3H 3C3, Canada;2. National Taiwan Normal University, Department of Earth Sciences, 88 Tingzhou Road Section 4, Taipei 11677, Taiwan;3. B.N. Church Geological Services, 600 Parkridge, Victoria, BC V8Z 6N7, Canada;1. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China;2. University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | The occurrence of essexite in the Deccan volcanic province of Saurashtra, India, is reported here for the first time. The essexite body occurs as a large stock-like intrusion in horizontal flow basalts. Petrographically it is characterized by the presence of titanaugite, labradorite, olivine, iron oxides and accessory amounts of alkali feldspar, analcite, biotite and apatite. Chemically it is characterized by enrichment in LILE, HFSE and REE as compared to the other tholeiitic and alkaline basalts of the area. It is therefore concluded that the essexite magma has not formed by differentiation out of the tholeiitic magma predominantly encountered in the Deccan volcanic province, but possibly represents a separate melt derived as a 5 to 10% partial melt at shallower depth (15 kb pressure) within the upper mantle. |
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