The light-brown sandstone was deposited rapidly in the first part of Noah’s Flood, about 4,500 years ago as the waters were rising. Shortly afterwards, the sediments were uplifted and folded, and the rising waters of the catastrophic Flood continued to deposit kilometres of other sediments in deepening, continent-wide basins on top.
In the second half of the Flood as the land was then rising, the floodwaters receded in wide, fast-flowing sheets from the continent into the ocean, eroding the overlying sediment from the area—a depth of kilometres—depositing it on the continental shelves.
As the receding floodwaters waned, a huge shield volcano erupted about 40 km to the south-west, spewing thick flows of basaltic lava around the region. The black basalt contrasts with the tan sandstone. The shield volcano was partly eroded as the remaining floodwaters continued to recede, leaving the prominent central core, known as Mount Warning. The beach sand around the rocks is a post-Flood deposit and quite recent.
For an overview of the biblical geological history of the area and how it compares with the conventional geological explanation see: Geological history of Brisbane, Australia.