The dynamic nature of Gold Coast’s catchments have been shaped and formed by distinct geological processes that date back 300 million years. Geological studies have found that the Gold Coast region once laid in a deep ocean trench. Though, a chain of volcanic and erosion processes created the mountainous terrain to the coastal flats we relate too.
The geology of the Gold Coast region is referred to as Neranleigh – Fernvale beds, which extend from Ballina to Yeppoon. A timeline is summarised below (for further information please see Rocks and Landscapes of the Gold Coast and Hinterland by Warwick Willmott):
Late Triassic Period (300 MYA) explosive eruptions produced lava and fragmental rocks to form high mountainous ranges.
Jurassic Period (213-144 MYA), erosion of these high rock deposits developed streams with siltstones, shale and sandstone.
Cretaceous Period (146-65 MYA), the stabilisation of volcanic processes slowed down streams to form lakes and finer sediments and coal forming in swampy zones. Further crustal pressures folded and warped these sediments.
Tertiary Period (65-1.6MYA) The explosive Focal Peak Volcano (west of Mt Barney) erupted blanketing ash east of the Hinterland ranges and flows of basalt towards the east. Over a period of millions of years, the fluid flows of basalt formed the landscape we are familiar with today. Such evidence can be viewed from the Hinterland to the coast, even the boulders you may sit on at Burleigh Heads.
Quaternary Period (1.6 MYA to present day)
Pleistocene – 1.6 MYA – 100,00 years ago: last ice age contributed to the rise and fall of the sea many times. Largely contributing to erosion of sediments and the shape of the landscape.
Holocene – modern era: continental movements start to slow down and to present geographic distinctions.