Deccan Traps

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The Deccan Traps is a large igneous province located in west-central India and is one of the largest volcanic features on Earth. It consists of multiple layers of solidified flood basalt that together are more than 2,000 m thick and cover an area of 500,000 km². The term 'traps' is derived from the Swedish word for stairs, referring to the step-like hills forming the landscape of the region.

The Deccan Traps formed between 60 and 68 million years ago,[The Deccan beyond the plume hypothesis][Geochronological Study of the Deccan Volcanism] at the end of the Cretaceous period. The gases released in the process may have played a role in the extinction of the dinosaurs. Before it was reduced to its current size by erosion and continental drift, it is estimated that the original area covered by the lava flows was as large as 1.5 million km². The volume of basalt is estimated to have been 512,000 km³.

It is postulated that the Deccan Traps eruption was associated with a deep mantle plume. The area of long-term eruption (the hotspot), known as the Réunion hotspot, is suspected of causing both the Deccan Traps eruption and opening the rift that once separated the Seychelles plateau from India. Seafloor spreading at the boundary between the Indian and African Plates subsequently pushed India north over the plume, which now lies under Réunion island in the Indian Ocean, southwest of India. The mantle plume model has, however, been challenged.

A large impact crater has been recently reported in the sea floor off the west coast of India. Called the Shiva crater, it has also been dated at 65 million years, right at the Cretaceous-Tertiary (K/T) boundary. The researchers suggest that the impact may have been the triggering event for the Deccan Traps as well as contributing to the acceleration of the Indian plate in the early Tertiary.[2003 GSA] However, opinion in the geologic community is not unanimous that this feature is actually an impact crater.[Space daily Deep Impact] Also, the reported age is in the middle of the ages given for the Deccan rocks.

The planet Venus is also thought to undergo vast basaltic flood eruptions, but on an even greater scale than those at Deccan Traps. It is not known whether the mechanisms are similar; Venus appears to lack Earth's plate tectonics and its internal structure may differ in other ways as well.

See also

• Deccan Plateau
• Siberian Traps
• Geology of Venus
• Geology of India

References