New Zealand History I – Geology and Environments

These flashcards cover the geological formation of Zealandia and Aotearoa, the impact of plate tectonics and volcanism, and the historical debates regarding the Gondwanan vs. dispersal origins of New Zealand's unique flora and fauna.

Aotearoa

The Māori name for New Zealand, currently considered the exposed portions of the submarine continent Zealandia.

Zealandia

A submarine continent that began to break away from Gondwana approximately $83$,Ma and is mostly too thin to project above sea level.

Gondwana

The southern supercontinent that formed when Pangaea split; Zealandia was originally a part of this landmass.

Plate Tectonics

The geological theory describing the movement of the earth's surface, involving thick continental crust and thin oceanic crust.

Oligocene drowning

A period during the Oligocene epoch ($33.9$ to $23.03$,Ma) when much, and possibly almost all, of current Aotearoa was submerged under the sea.

Alpine Fault

A major geological fault line responsible for the formation of the Southern Alps, primarily within the last $5$ million years.

Taupō Volcanic Zone

A volcanic region active over the previous $1.6$ million years, including volcanoes such as Ruapehu, Ngāuruhoe, and Tongariro.

Caldera

A giant collapsed volcanic crater, such as Lake Taupō, created by repeated and massive eruptions.

ŀruanui eruption

A massive volcanic event occurring $26,500$ years ago with a volume $100 \times$ that of the Taupō $c. 200$,AD eruption.

Pleistocene 'ice ages'

A period over the past million years characterized by repeated changes in sea level caused by water being locked up in glaciers and ice sheets.

Last Glacial Maximum (LGM)

A period approximately $20,000$ years ago when sea levels were more than $100$,m lower than today, reaching the edge of the continental shelf.

Vicariant origin

A biological explanation for species that 'drifted' with a landmass as it separated, specifically referring to a true Gondwanan origin for Aotearoa's biota.

Transoceanic dispersal

The process of species acquiring a new habitat by flying or floating across the ocean after landmasses have already separated.

Nothofagus

A plant genus once thought to be vicariant across the Tasman Sea, but molecular data suggests New Zealand populations are more recent arrivals following earlier extinctions.

Peripatus

Also known as 'Velvet worms,' these animals are considered extant candidates for Gondwanan origin with an estimated age of $85-94$,mya.

Leiopelmatid frogs

A primitive group of amphibians in Aotearoa with an estimated age of $67-130$,mya, suggesting a potential Gondwanan origin.

Tuatara

A reptile lineage with an estimated age of $100-130$,mya, often cited as a prime example of ancient Gondwanan fauna.

Ratites

A group of birds including the Moa and Kiwi; while the group is Gondwanan, New Zealand species are now known to be related to the Tinamous of South America and Elephant Bird of Madagascar respectively.