Editing Kalkajaka National Park (section)

==Natural history==
The national park’s distinctive hard black boulders (often termed [[granite]]) and range are composed of the igneous felsic intrusive Trevethan [[Granodiorite]] which is predominantly a white to grey, medium-grained, porphyritic [[biotite]] [[monzogranite]] to granodiorite. The age of the intrusive is Late [[Permian]] and has been dated from 259.1 to 251.9 million years old. The Trevethan Granodiorite was originally magma that slowly solidified under the earths crust.<ref>{{Cite web|url=https://macrostrat.org/map/loc/145.2302/-15.6719#z=12.7 |title=Macrostrat|website=macrostrat.org}}</ref><ref name="nch"/>

The softer land surfaces above the solidified magma eroded away over time, leaving the magma's fractured top to be exposed as a mountain of grey granite boulders blackened by a film of microscopic blue-green algae growing on the exposed surfaces.  Colder rains falling on the dark, heated granite boulders causes the boulders to progressively fracture, break, and slowly disintegrate, sometimes explosively.<ref name="nch"/>