croixdusud.info Nouvelle-Calédonie

Gondwana super-continent

During Carboniferous, 350 million years ago (350 My), continental masses of the earth had merged in a unique continent that geologists name Pangea. Towards the end of Triassic (200 My), Pangea split in two continents, Laurasia in the Northern hemisphere and Gondwana extending mostly in the southern hemisphere. Gondwana then included Africa, Madagascar, Arabia, Australia, Antarctica, South America, India, New Guinea, New Zealand. Gondwana was a continent of the Jurassic and Cretaceous times.

At the end of Jurassic (135 My), Gondwana started to break apart. The oldest grounds of current New Caledonia were then located on the eastern margin of this continent as part of the Australian block. Towards the end of Cretaceous, about 85 million years ago, this old New Caledonia broke away and so did New Zealand.

New-Caledonia was then isolated.

It drifted away carrying a Gondwana flora and fauna (including non flying birds such as the Cagou). This explains why New Caledonian flora and some elements of its fauna, have strong relationship with Australia, New Zealand, New Guinea and, to a lesser extent, South America and Southern Africa. Isolation and plants adaptation to toxic soils on ultrabasic rocks which were obducted 30 MY ago, ensured their protection until today. In Australia many species disapeared because of the increasing dryness of its climate. As a result, New Caledonia is now a kind of "Jurassic Park" particularly with regards to its vegetation which is highly endemic and which has kept archaic characteristics.

gondwana
Gondwana before breaking apart.
AMS : South America, AFR : Africa, PA : Arabic peninsula, MD : Madagascar, IND : India, ANT : Antarctica, AUS : Australia, New Zealand, New Guinea, New Caledonia. P.Sud : South pole.