Age Of Basic Magmatism in Kerala

The Kerala basic dykes that cross-cut the crystalline rocks are quartz or olivinenormative tholeiites. In Trivandrum district. south Kerala, two of these dykes have yielded K-Ar whole-rock dates of 127±2 m.y. and 104±5m.y., whilst the third, 476± 11 m.y. The 104-127 m.y. group age dates the thermal response of the western continental margin distension, and it relates also to the early phase of the Deccan Trap volcanism. The 476 m.y. date is either obtained via crustal contamination or more likely, it represents an older and unrelated thermal event. This event has analog in South Africa, including Madagascar.