Why is the Ord River Valley near Kununurra, Western Australia, so wide and flat?

posted in: Landscapes, Noah's Ark | 0
Oard River Valley from Kellys Knob
Figure 1. View from Kellys Knob looking across the Ord River valley. Note the wide flat valley and the flat tops of the ranges in the distance.

Figure 1 is a view from Kellys Knob looking south-west across the Ord River valley, which is wide and flat. Some Kununurra streets and houses are visible in the foreground. Further back you can see the Kununurra Airport. And beyond that you can see the ranges on the other side of the valley: the Bandicoot Range to the right, the Deception Range in the middle, and the Carr Boyd Ranges to the left. These ranges all have a similar elevation; you can draw a horizontal line along the tops of them.

It is interesting to explore this valley on Google earth as shown in Figure 2. This figure includes an elevation profile from north-east to south-west along the line marked on the figure. The line begins to the north and east of Kununurra, runs across the Ord River valley, all the way to the Carr Boyd Ranges in the south-west.

Elevation Profile across Oard River Valley south west of Kununurra
Figure 2. Elevation profile across the Ord River Valley south-west of Kununurra, Western Australia. Length of the profile is 40 km. (using Google earth)

The elevation profile in figure 2 illustrates what is visible from the lookout. To the north-east of Kununurra the land reaches an elevation in excess of 150 metres. Across the Ord River the valley is incredibly flat and wide. It has an elevation of 40 to 50 metres. To the south-west the landscape increases in the Carr Boyd Ranges to an elevation of some 300 metres.

This landscape was eroded flat by the waters of Noah’s Flood when they covered the whole area about mid-way through the Flood. The wide Ord River valley was carved a little later after the water level had dropped significantly but while there was still a lot of floodwater, flowing in wide channels to the north into the ocean basins, as the continent was uplifted. The valley is much wider than the size of the present Ord River that now flows through it to the north.

The Carr Boyd Ranges to the south-west are composed of rocks that were deposited early in Noah’s Flood. Geologists have classified them as Precambrian, specifically as Middle Proterozoic. They were folded, metamorphosed, and faulted by subsequent events during the Flood. Lots of sediment was deposited on top of them as the Flood continued, but the receding floodwaters eroded it away, exposing the older rocks as we now see them. To the north-east some of this later sediment was preserved including the Kellys Knob Sandstone.

It is very interesting to explore these landscapes from a biblical Flood perspective. Some remarkable Flood features pop out in an obvious way. Especially in this landscape the wide flat valley formed by the receding floodwaters is something that becomes a compelling indication of the global event that shaped our planet.

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