The geological history of Carnarvon Gorge, Queensland, Australia

From a biblical Flood perspective

by Tas Walker

Early Flood—the Ascending phase

The oldest rocks in the Carnarvon Gorge area occur at considerable depth and are only known from drilling and geophysical investigations. However, it is likely that the deepest rocks are related to the exposed fold belts of eastern Australia. These were deposited rapidly early during the global Flood (Genesis 6–8), most of them deep under the ocean. In the New England Fold Belt, for example, there was a large volume of a variety of materials deposited including fine silt, poorly sorted sand, beds of chemically deposited silica, and black volcanic lava.

1. Basement rocks:  Geologically, the first event in the Carnarvon Gorge area was the deposition of the basement rocks, an event that affected the whole of eastern Australia. In the Carnarvon area the basement is hidden by overlying sediments, but it is exposed to the north, east and south in the various fold belts.

2. Bowen Basin sediments:  Deposition of the Bowen, Cooper and Galilee Basins, was at the next major event. The Bowen Basin sediments are exposed in the Carnarvon Gorge area. They were deposited quickly while the waters of Noah's Flood were rising.

3. Great Artesian Basin sediments:  As the floodwaters rose to their peak, widespread sediments were deposited in a number of basins over Queensland, New South Wales, South Australia and the Northern Territory. Again, there is lots of evidence for rapid deposition of these formations.

Tectonic movements in the earth’s crust compressed and uplifted these deposits above sea level. Some rocks were folded by the compression while others were severely deformed and disrupted. The basement areas are large and have been given different names depending on where they are exposed (figure 1). The exposed rocks were severely eroded as the water uplifted with the sediment flowed off the continent.

Violent volcanic eruptions took place soon after (or while) the basement rocks were compressed and uplifted (possibly the catastrophic compression heated and melted the sediment locally). Some of the molten rock erupted over the landscape while other molten rock pooled under the earth forming granite plutons. These features are not exposed in the Carnarvon Gorge area.

Because of this rapid uplift the water flowed off the continent depositing sediment and animals in the Galilee, Cooper and Bowen Basins and probably also in the Sydney Basin to the south where the waters likely flowed into the sea. (figure 2). Tectonic movements gently folded these rocks and changed the depositional environment.

Middle Flood—the Zenithic phase

The changed conditions meant that sediment, vegetation and animals were deposited over a much larger series of basins covering a large part of Eastern Australia. These sediments now contain the water reservoir known as the Great Artesian Basin (figure 3).

Eventually the Floodwaters reached their peak and tectonic movements slowly lifted up the continent and lowered the ocean basins. The Floodwaters then started to flow off the continent into the oceans.

Late Flood—the Recessive stage

The receding floodwaters (first in huge sheets and then in wide channels) severely eroded the surface of the continent of what is now Australia and carved the landscape into pretty much the form we see it today. During the sheet-flood phase the flowing water cut the landscape flat and the flat surfaces are visible at various horizons in the area around Carnarvon Gorge

While the Floodwaters were receding volcanic eruptions occurred. These eruptions were driven by earth movements associated with the lowering of the ocean basins and the raising of the continent. These eruptions now form basalt caps along eastern Australia such as the basalt cap in the Carnarvon Gorge area and the well-known plateaus near Brisbane such as Lamington Plateau and Maleny Plateau. Eruptions during this time also formed volcanic plugs such as the Glasshouse Mountains and Mt Warning.

The land around these plateaus and mountains was eroded away by the final stages of the receding floodwaters, leaving them exposed as spectacular landmarks. The receding floodwaters eroded the areas around Carnarvon and the final flow of water eroded the gorge itself. The receding floodwaters also left sediment in some small, local sedimentary basins.

Post-Flood—colonization by plants, animals and people

After the Floodwaters receded the continent was vegetated by seeds and plants left on the surface after the Flood. The oceans and waterways were colonised by marine animals that were left in the waters on and around the continent after the Flood. However, the air-breathing land animals that now live in Eastern Australia migrated from Mt Ararat in the Middle East, probably using landbridges through the Indonesian Islands. Humans have probably been responsible for much of the animal migration.

Landscape erosion, sedimentation and volcanic eruptions have occurred in the 4,300 years since the Flood, but these were minor compared with what happened in the catastrophic year of the Flood itself.

4. Cross section of the sediments comprising the Great Artesian Basin which stretches more than a thousand kilometres across eastern Australia. The wall of Carnarvon Gorge exposes a small part of the bottom section of the sediments in the basin.

5. Comparison of the long-age evolutionary interpretation of Carnarvon Gorge and the biblical Flood model. Read the history from the bottom up—that is, the first events (and the oldest rocks) are at the bottom.  Click for larger image

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