Are mountain ranges artefacts of expansion?

Discussion about possible earth expansion usually focuses on the ocean regions, and rightly so as that is where most of the newer surface of the earth is said to be located. But continental regions also show signs of having been affected by pull-apart forces, the African rift being the most notable example. And although they are not generally associated with expansion, I think there is evidence that some mountain ranges are products of expansion related tectonics.

To support this assertion I made a short clip of a virtual flyover of a portion of the Rocky Mountains of western Alberta, at roughly 52°N 116°W. The video starts with a view of what looks like a canyon wall, but it’s not really… It does however give some indication of the scale of the activity that might be involved in the formation of mountains.

https://youtu.be/H9Oi50OXH-s

Note the odd looking surface at the ‘top’ of the ‘canyon’ which itself shows signs of earlier tectonic activity.

It seems that the ‘canyon wall’/mountain range in the opening view is one fracture face of an overturned block of crust that, after fracturing, has had the rug pulled out from under it in a rapid, highly energetic event, causing it to topple. However in order to accommodate the depth of the crust fragment (it appears to be deeper than it is wide), some expansion of the underlying substrate would need to occur. Other similarly overturned blocks appear to be present in the vicinity.

It may be that a similar process involving crust fracturing together with stretching of the underlying mantle has been instrumental in creating the major mountain ranges of the continents.

There are plenty of other examples of toppled blocks but this one is easy to visualize because of the banding/layering of the rocks and relatively uncomplicated displacements.

Here are a few stills from the video.

Looking up towards the rim of the canyon.

Ascending to the rim of the ‘canyon’, the faulted, furrowed older surface comes into view.

A closer view showing partially dislodged blocks on the rim.

Rotated overhead view.

Now rotated 180°. The old, faulted surface has become one side of a mountain range.

Now rotated 270°, giving a side view of the old surface and an adjacent block.

Two toppled blocks.

It appears that some major pull apart forces have been operating. I speculate that the apparent large scale crust disturbance is the result of very mobile mantle plume activity that causes doming leading to fracturing and horizontal displacement of the top 20km or so of the crust.