Mayor Island / Tuhua 3.96

Mayor Island is a dormant shield volcano located off the Bay of Plenty coast of New Zealand's North Island. It lies 35km north of Tauranga and covers 13km². The island is quite steep along its coast and rises to 355m above sea level. A saddle about 75m deep separates it from the North Island, while the other side of the volcano rises from the seafloor some 400– beneath the waves. The island is believed to have risen from the sea about 7000 years ago. Hot springs abound, and there are two small crater lakes, Green Lake and Black Lake. These lie within two overlapping calderas formed in explosive eruptions 36,000 and 6,340 years ago. Mayor Island has exhibited a wide range of eruptive styles, including fire fountains, Strombolian explosions, extrusion of lava domes, phreatomagmatic explosions, Plinian falls and ignimbrite. The most recent lava flows have been dated at between 500 and 1,000 years old.The island is considered special by Māori partly because of the presence of black obsidian, a volcanic glass created by the rapid cooling of silica-rich lava, prized as a cutting tool. The obsidian was called Tuhua by Māori who called the island by the same name. Captain James Cook called it Mayor Island when he sighted it on November 3, 1769, in recognition of the Lord Mayor's Day to be held in London a few days later.