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The three groups of islands of Tonga are volcanic or coral reefs within oceanic crust of the Pacific tectonic plate. The archipelago comprises two parallel chains of islands with differing geologies.
The western Islands sit on the edge of the Indo-Australian plate just west of the Tonga Trench. They form the volcanic Tongan Volcanic Arc created in a fore-arc setting during subduction of the westwards moving Pacific tectonic plate under the Indo-Australian plate at the Tonga Trench.
The volcanoes developed as the descending Pacific plate melted. They have only fringing coral reefs. In 2014 a new island was created through this continued volcanic activity.
The eastern islands comprise mostly limestones and sit above the subsea Tonga ridge of oceanic crust that runs parallel and just east of the volcanic Arc and Tongan Trench.
These islands consist of low-lying coral limestones surrounded by fringing reefs with only one (Eua) having Eocene oceanic crust rising above sea level.
Globalshift considers that both sets of islands have no oil and gas potential, onshore or offshore.
The volcanic and coral islands of Tonga have no history of drilling and production. No exploration wells have ever been drilled in any the islands of the country or in their surrounding waters.
Globalshift does not forecast any future production of oil or gas from the country.
For recent events see News
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