Oceania physical map
Oceania is a region of the world that is not a continent stricto sensu. However, since this region is often assimilated to a continent by geographers, this part of the world can be considered as the smallest of the continents emerging from the Earth. Located in the Pacific Ocean, it covers an area of 8,525,989 km² and encompasses all lands between Asia and America, as well as part of the Malay Archipelago. It is divided into four regions: Australasia, Micronesia, Melanesia and Polynesia.
It covers a macrogeographic region located between Asia and America, with continental Australia as the main landmass of the continent, followed by the much smaller and nearby islands of New Guinea, Tasmania and New Zealand, to which are added some 25,000 small islands scattered in the Pacific Ocean. The desertic or semi-arid region occupies the largest area of the continent with 40% of its territory covered by sand dunes. Oceania is the driest, flattest continent, with the oldest and least fertile lands on earth.
The highest mountain in the continent, Puncak Jaya (4,884 m), on the island of New Guinea, belonging to Indonesia. Mount Kosciuszko, with 2228 m, is the main elevation of continental Oceania.
From a geological point of view, Oceania is not a continent: only Australia, New Caledonia, New Zealand, New Guinea, and Tasmania are of continental origin, having formed on the site of the hypothetical continent of Gondwana. In the past, these islands were a single land, but as a result of rising sea levels, a large part of the surface was under water. The relief of these islands is mountainous and heavily dissected. For example, the highest mountains of Oceania, including Puncak Jaya (4,884 m), are located on the island of New Guinea.
Most of the islands of Oceania are of volcanic origin: some of them are peaks of large submarine volcanoes, some of which still show high volcanic activity (for example, the Hawaiian Islands).
Other islands are of coral origin, being atolls that were formed as a result of the formation of coral structures around volcanoes plunging into the water (for example, Gilbert Island, Tuamotu). A distinctive feature of such islands are large lagoons, which are surrounded by numerous islands, or motu, whose average height does not exceed three meters. In Oceania there is an atoll with the largest lagoon in the world - Kwajalein in the Marshall Islands archipelago. Despite the fact that its land area is only 16.32 km², the lagoon area is 2174 km². The largest atoll by land area is Christmas Island (or Kiritimati) in the Line archipelago - 322 km². However, among the atolls there is also a special type - a raised (or elevated) atoll, which is a limestone plateau up to 50-60 m above sea level. This type of island has no lagoon and no traces of its past existence. Examples of such atolls can serve Nauru, Niue, Banaba.
The relief and geological structure of the Pacific Ocean floor in the Oceania region has a complex structure. From the Alaska Peninsula (part of North America) to New Zealand, there is a large number of marginal seas, deep oceanic troughs (Tonga, Kermadek, Bougainville), which form a geosynclinal belt characterized by active volcanism, seismicity and contrasting relief.