Blomidon Sandstone
Blomidon is mainly made of sandstone, a sedimentary rock (meaning the stone is comprised of grains of sand and rock cemented together). The sediment eroded from nearby mountains over 200 million years ago when Nova Scotia was part of supercontinent Pangea and located around the equator. The sediment was carried downstream off the mountains and deposited in lakes and rivers.
As more sediment accumulated on top, the sediment deposited previously was buried. Eventually heat from deep underground and pressure from the weight of sediment above turned the buried sediment into stone. Much of the Annapolis Valley is made of sandstone formed through this process.
Sandstone can be different colours depending on the conditions in which it formed.
In the picture, the red layer on top is oxidized beds of sandstone - the sediment that eroded from the mountains was deposited in oxygen-rich waters and the oxygen caused iron in the sediment to oxidize/rust, making it red.
The darker layer on the bottom formed when the sediment was deposited in waters that were oxygen-deficient. With less oxygen present, minerals in the sand did not rust, leaving them their original colours. That is why the lower level has a mixture of colours in it (brown, grey, green) compared to the top which is more uniformly red. The lower level also likely had more mud in it when it formed, making it a darker, brownish colour. The yellow material is likely something that oxidized long after the stone formed, perhaps after the cliff was exposed to the open air.
The close-up picture makes it look like there are just two main layers but if we take a look at the cliffs from further back, it becomes clearer that there are many alternating layers of different-coloured sandstone that formed as the oxygen level in the waters changed over long periods of time.
The name Blomidon comes from “Blowmedown,” a reference to high winds in the area.
