RE: If Australia a Small Continent or a large Island?
November 9, 2018 at 2:08 am
(This post was last modified: November 9, 2018 at 2:55 am by Anomalocaris.)
(November 8, 2018 at 2:33 pm)Rhondazvous Wrote: I would think the fact that Australia sits on its own tectonic plate classifies it as a continent. Yet, by that definition, India should also be considered a continent, while Europe, with shares the Eurasian tectonic plate with Asia, should not.
It appear then that continental status is based more on politics and culture than empirical science.
That’s not right. Australia does not sit on its own tectonic plate. It shares a much larger plate with New Zealand, Papua New Guinea, Indonesian island of Sulewesi, phillipines, all the sea floor of eastern Indian Ocean, and India. Australia is just a small part of the Indo-Australian tectonic plate.
But that’s not important to whether Australia is a continent or not.
Geologically, a continent is a contiguous block of crust that is primarily granitic in composition,and sits on a deep root of metamorphic gneiss. A geological continent can have a tectonic plate to itself, can share a tectonic plate with other continents, and can be spread over sseveral tectonic plates. Geologically Tasmania and Australia are a single continent because their granitic and gneiss basement rocks are connected under the sea. They share a tectonic plate with India. New Zealand is geologically not part of the Australian continent although it sits on the same tectonic plate. India sits on same tectonic plate as Australia but is part of the single giant euroasia geological continent, which is actually spread over several tectonic plates. Parts of the euroasia continent sits on:
the North American tectonic plate,
the indo-Australian tectonic plate,
the Arabian tectonic plate,
and of course the euroasia tectonic plate.
North American geological continent is split between the North American tectonic plate and pacific tectonic plate. The seam between the two tectonic plates is the San Andreas Fault in California .
Geographically, continent is arbitrarily defined and accepted by convention. By convention Australia and New Zealand are considered a single geographic continent. By convention Europe is regarded as a separate geographic continent even though Europe and Asia are a single geological continent and Europe sits on the same tectonic plate as most of Asia.
