Oceania Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! ===Geology=== {{Main|Geography of Fiji|Geology of New Zealand|Geology of Australia|Geography of Samoa}} [[File:Plaque Pacifique.JPG|thumb|The [[Pacific Plate]] comprises most of Oceania, excluding [[Australasia]] and the western portion of [[Melanesia]].|left]] The [[Pacific Plate]], which makes up most of Oceania, is an oceanic [[Plate tectonics|tectonic plate]] that lies beneath the Pacific Ocean. At {{convert|103|e6km2|sqmi}}, it is the largest tectonic plate. The plate contains an interior [[Hotspot (geology)|hot spot]] forming the [[Hawaiian Islands]].<ref name="tecto" /> It is almost entirely [[oceanic crust]].<ref name="platetec2010" /> The oldest member disappearing by way of the [[plate tectonics]] cycle is early-[[Cretaceous]] (145 to 137 million years ago).<ref name="ageof" /> Australia became part of the [[Indo-Australian plate]] 45 to 40 million years ago and this is in the process of separating again with the [[Australian Plate]] being relevant to Oceania.<ref>{{cite journal |last1=Keep |first1=Myra |last2=Schellart |first2=Wouter P. |title=Introduction to the thematic issue on the evolution and dynamics of the Indo-Australian plate |journal=[[Australian Journal of Earth Sciences]] |year=2012 |volume=59, 2012 |issue=6: THEMATIC ISSUE β Evolution and dynamics of the Indo-Australian plate |pages=807β808 |doi=10.1080/08120099.2012.708360 |bibcode=2012AuJES..59..807K |s2cid=128996831 }}</ref> It is the lowest, flattest, and oldest landmass on Earth<ref name="distinct227" /> and it has had a relatively stable geological history. Geological forces such as [[tectonic uplift]] of mountain ranges or clashes between tectonic plates occurred mainly in Australia's early history, when it was still a part of [[Gondwana]]. Australia is situated in the middle of the tectonic plate, has occasional middle-sized earthquakes, and currently has no active volcanism (but some volcanoes in southeast Australia erupted within the last 10,000 years).<ref name="ag" /> The [[geology]] of New Zealand is noted for its [[volcanic]] activity, [[earthquake]]s, and [[Geothermal activity|geothermal]] [[Geothermal areas in New Zealand|areas]] because of its position on the boundary of the [[Australian Plate]] and Pacific Plates. Much of the basement rock of New Zealand was once part of the super-continent of Gondwana, along with South America, Africa, [[Madagascar]], India, Antarctica and Australia. The rocks that now form the continent of [[Zealandia (continent)|Zealandia]] were nestled between Eastern Australia and [[Western Antarctica]].<ref name="tearaz" /> The Australia-New Zealand continental fragment of Gondwana split from the rest of Gondwana in the [[late Cretaceous]] time (95β90 Ma). By 75 Ma, Zealandia was essentially separate from Australia and Antarctica, although only shallow seas might have separated Zealandia and Australia in the north. The [[Tasman Sea]], and part of Zealandia then locked together with Australia to form the [[Australian Plate]] (40 Ma), and a new plate boundary was created between the Australian Plate and Pacific Plate. Most islands in the Pacific are [[high islands]] ([[volcanic]] islands), such as, [[Easter Island]], [[American Samoa]] and [[Fiji]], among others, having peaks up to 1300 m rising abruptly from the shore.<ref name="Factbook-Fiji" /> The [[Northwestern Hawaiian Islands]] were formed {{circa}} 7 to 30 million years ago, as [[shield volcano]]es over the same volcanic [[Hotspot (geology)|hotspot]] that formed the [[Emperor Seamounts]] to the north and the Main Hawaiian Islands to the south.<ref name="geochr" /> Hawaii's tallest mountain [[Mauna Kea]] is {{convert|13796|ft|m|abbr=on|order=flip}} above mean sea level.<ref name="usgsgov" /> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page