Ferropicritic dikes of Vestfjella, western Dronning Maud Land: Fe-enriched
Summary Ferropicritic dikes (MgO = 12-18 wt. %, FeO BT B> 14 wt. %) and their differentiates are found cross-cutting Jurassic continental flood basalts of the Karoo large igneous province (LIP) at Vestfjella, western Dronning Maud Land. The dikes show geochemical divergence: (1) Depleted ferropic...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.568.6150 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea066.pdf |
| Summary: | Summary Ferropicritic dikes (MgO = 12-18 wt. %, FeO BT B> 14 wt. %) and their differentiates are found cross-cutting Jurassic continental flood basalts of the Karoo large igneous province (LIP) at Vestfjella, western Dronning Maud Land. The dikes show geochemical divergence: (1) Depleted ferropicritic types (D-FP) have (La/Sm) BN B 1.1-1.3, (Sm/Yb)BN B 3.2-4.5, and they show relative enrichment in Sr, Ti, and V, and depletion in P; (2) Enriched ferropicritic types (E-FP) have (La/Sm) BN B 1.5-1.7, (Sm/Yb) BN B 4.9-5.4, and they show overall enrichment in incompatible trace elements. The Vestfjella ferropicrites are geochemically unique among the Karoo LIP. Primarily high Fe contents of D-FP and E-FP may have been inherited from anomalously Fe-rich eclogite component entrained in a pyroxenitic mantle source. Low-degree melting at high pressures may also have contributed to the high Fe contents. In contrast to other known ferropicrite successions, the Vestfjella ferropicrites represent a quite late stage of plume-related volcanic activity. |
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