Maroa

The Maroa Caldera (Maroa Volcanic Centre) is approximately in size and is located in the north-east corner of the earlier Whakamaru caldera in the Taupō Volcanic Zone in the North Island of New Zealand. Geography Its northern rim is to the south of the Waikato River at Ātiamuri. At Ātiamuri the Ohakuri Caldera which had a paired eruption with the Rotorua Caldera is to its immediate north. The eastern boundary is also defined by the present Waikato River and it extends as far south as probably opposite Orakei Korako on the river. The southern boundary is somewhat ill defined given the subsequent deep deposits from the Taupō Volcano but includes a number of domes of which the highest is Maroanui at . Eruptive history The Maroa Caldera's last major eruption produced of tephra about 230,000 years ago (230 ka). Its earliest eruption was about 300 ka with decreasing frequency and volume to as recently as 16.5ka when an eruption of about occurred from the Puketarata volcanic complex ( to distinguish from another older volcano of this name near Te Kawa). The caldera is now mainly dome lava in filled. In summary going back in time: 16,500 years ago Puketarata tuff ring formed with total volume of in a complex series of eruptions including maar formation 229,000 to 196,000 Pukeahua deposits and dome building 220,000 unclear where Mokai ignimbrite that outcrop in some of Maroa area comes from 229,000 ± 12,000 Ātiamuri deposits from northern Maroa 251,000 ± 17,000 onward two large parallel dome complexes developed 256,000 ± 12,000 Orakonui pyroclastics from a central Maroa source 272,000 ± 10,000 Putauaki pyroclastics from a central Maroa source 275,000 to 240,000 years ago small-scale pyroclastic eruptions 283,000 ± 11,000 Korotai deposits from northern Maroa 305,000 ± 17,000 oldest Maroa dome References