You are currently viewing Precambrian mafic dykes in and around the Western Ghats greenstone belt, Western Dharwar Craton

Precambrian mafic dykes in and around the Western Ghats greenstone belt, Western Dharwar Craton

Dykes are igneous intrusive rock bodies. They provide critical sources of information about the composition of the Earth’s mantle. Therefore, geological and geochemical studies of dykes have gained importance recently.

The preliminary field, petrographic and whole-rock geochemical data of the mafic dykes in and around the Western Ghats belt (WGB), Western Dharwar Craton (WDC) is presented in this study. The NNW-SSE trending tholeiitic mafic dykes are basalt to basaltic-andesite in composition. The studied dykes are generally LREE enriched and exhibit negative Nb-Ta and Ti anomalies indicating crustal contamination. Petrological modelling shows that the chemical variability of the dykes is primarily due to crystal fractionation and crustal contamination. Rare earth element (REE) modelling suggests the WGB dykes were likely derived by low-degree partial melting (~3.5%) of a garnet- spinel bearing mantle source. The close similarity in the field, petrography and the geochemical characteristics between the studied dykes and the 2.21 Ga mafic dykes of WDC suggests that the WGB dykes may represent the 2.21 Ga mafic event in the WDC.

King

Geoexplorer and Thinker

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