🎰 Omanawa Caldera

The Omanawa Caldera is inferred by an area of magnetic anomaly that exists to the north-west of the Rotorua Caldera. It is located to the north west of the present boundary of the modern Taupō Volcanic Zone and its existence would be compatible with activity in the area of intersection of Taupō Rift and Hauraki Rift before this, about 1.9 million years ago. The area of the caldera is now mainly covered by Mamaku ignimbrite from the Mamaku eruption of 240,000 years ago that formed the Rotorua Caldera, but there are four earlier major ignimbrite eruptions of the Taupō Volcanic Zone that would have also contributed to its infilling.