Bhavnagar:BAS Aadharit Biometrics Hajari Purva Babat.

Bhavnagar:BAS Aadharit Biometrics Hajari Purva Babat.The Mount Cayley massif has experienced volcanic eruptions sporadically for the last 4,000,000 years, making it one of the most persistent eruptive centres in the Garibaldi Volcanic Belt.[3] Three primary eruptive stages in the history of the massif have been identified.[5] The Mount Cayley and Vulcan's Thumb stages occurred between 4,000,000 and 600,000 years ago with the construction of the stratovolcano and plug domes. A 300,000-year-long period of quiescence followed, during which prolonged erosion destroyed much of the original volcanic structure. This was followed by the third and final Shovelnose stage about 300,000 to 200,000 years ago with the emplacement of parasitic lava domes and flows.[3] Although one of the Shovelnose domes has been potassium-argon dated at 310,000 years old, this date may be in error from excess argon.[4][5] The Shovelnose stage rocks could be much younger, perhaps less than 15,000 years old.[4] Eruptions during the three stages produced volcanic rocks of felsic and intermediate compositions, including andesite, dacite and rhyodacite.[3] The lack of evidence for volcano-ice interactions at the Mount Cayley massif implies that all eruptive stages most likely took place prior to glacial periods. This contrasts with many neighbouring volcanoes, which contain abundant volcanic glass and fine-scale columnar jointing from contact with ice during eruptions.