Vol­canic va­ri­ety

There are sev­eral ways vol­ca­noes have been formed in the Newer Vol­canics Prov­ince, but many sites dis­play el­e­ments of more than one type.

Australian Geographic - - Wild Australia -

1 Ash cone Sim­i­lar to a maar but with steeper sides and a crater sit­ting above ground level. The only ones in the NVP are a clus­ter of five at Mt Burr, north-west of Mt Gam­bier Range.

2 Sco­ria cone Th­ese erup­tions were vi­o­lent, shoot­ing out very hot, bub­bly lava, which cooled on de­scent into small stones called sco­ria. They would heap around the erup­tion point to form a cone. A breached cone is where lava breaks through the crater wall, e.g. Mt Ele­phant.

3 Lava shield The lava that comes up through a ground vent is quite runny and streams away to form low hills with gen­tly slop­ing sides. They’re the most com­mon vol­cano in the NVP and a good ex­am­ple is Mt Pier­re­point near Hamil­ton.

4 Maar crater Ris­ing hot magma en­coun­ters ground­wa­ter, cre­at­ing high-pres­sure steam to shat­ter the magma and rocks into ash, which falls to form a shal­low crater. The best ex­am­ple is Lake Pur­rum­bete.

5 Com­plex vol­cano Has char­ac­ter­is­tics of more than one erup­tion type, such as Tower Hill, which has sco­ria cones nested in a maar lake.

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