Rockin’ on – The Kimberley Story
Think of Australian travel and it’s all sandy beaches with blue ocean waves rolling in. It’s sun-drenched coastlines, wild fish on wilder reefs and waterfalls through tropical rain forests.
But our country has so much more to offer, and one of it’s jewels is the Kimberley region of Western Australia. The vast scale of the region is breathtaking, and the stories that it’s old stones can tell through the science of geology, is eye-opening.
To understand the present-day geology of the Kimberley Coast, step back approximately two billion years in time, to a period of topographical upheaval. Continental collisions formed ranges that were eroded by water, creating sedimentary deposits. Volcanic activity pushed lava and magma into cracks in the deposits of sandstone, forming crystallised quartz. As a result of all this activity, the Kimberley region boasts an array of unique geology. (2)
What’s it made of?
The 423,500 square kilometres (roughly) of territory called The Kimberley is made up of flat lying sedimentary rocks. These rocks were deposited around 1800 million (yes that’s right MILLION) years ago by river systems that existed across the area way back then. There are even basalt lava flows in the rocks (particularly near Mitchell Falls) which show that there has been geological eruptions and movement in the past.
The Drowned Coast.
Geological movements have caused the uplift of these sedimentary rocks (sandstone and quartzites) creating valleys and rivers around 250 million years ago. As sea levels rose from approximately 120 metres below current levels following the end of the last glacial maxima 18 000 years ago, the Kimberley coast line became drowned with the sea, filling what were once river valleys, resulting in the jagged irregular outline of the Kimberley coastline we see today. (1)
(1) The Kimberley Society: http://www.kimberleysociety.org/kimberley_region/geography__geomorphology_and_geology.phtml