ROCKS IN KNOTS

These Oligocene carbonate sediments exposed on the Ionian Island of Antipaxos are, to put it politely, deformed.

Rock deformation generally requires the immensity of tectonic forces (including pressure and heat) to fold, buckle, stretch and distort rocks into bizarre contortions – if you try picking up a brick, for example, and pushing and shoving it into a fold, and you’ll quickly find out that you lack the power and tenacity of a tectonic plate.

There are, however, conditions in which folds can form on the Earth’s surface relatively easily. And this is what happened at Antipaxos.

These are syn-sedimentary slump folds, meaning, they were formed by the deformation of these strata while they were still, essentially, mud on the bottom of the Oligocene sea. When these layers of muds were deposited on a slope, some small trigger (such as an earthquake) added just enough force for them to detach, and start sliding down slope – sort of a sub aquatic avalanche of slippery sediments. The sediments were in the initial stages of lithification, strong enough to hold together, but mushy enough to fold. In sliding downwards, they deformed, they rotated, they became a true mess, even as in this outcrop, looking as if they’re in knots.

Note: In addition to this amazing slump fold, geologic interests for the traveler to Antipaxos include numerable maritime caves with arched entrances, a vertical rock spire jutting out of the Ionian, excellent beaches for sand analyses, and some very remarkable local wines…

Annie R

Photo by Maki Doukouros, a talented amateur photographer of Greece

http://users.uoa.gr/~vkarak/pdf/34.pdf is an excellent paper on the formation of this slump system by V. Karakitsios, M. Triantaphyllou, and P. Panoussi

The myth: You can’t fold a paper in half more than eight times.* The reality: Given a paper large enough—and enough energy—you can fold it as many times as you want. The problem: If you fold it 103 times, the thickness of your paper will be larger than the observable Universe: 93 billion light-years. Seriously.

How can a 0.0039-inch-thick paper get to be as thick as the Universe?

The answer is simple: Exponential growth. The average paper thickness in 1/10th of a millimeter (0.0039 inches.) If you perfectly fold the paper in half, you will double its thickness.

Lulworth Cove, Dorset, England.

Lulworth Cove is an Alpine fold structure in Lower Cretaceous rocks outcropping on the Dorset Coast in Southern England.

The cove itself whilst being very striking to look at, also shows several geological and palaeontological features important to our understanding of the geological evolution of the area. 

The almost circular shape of the cove is the result of both rock type and folding, and there are “bands” of rock of alternating resistance running parallel to the coast Line. These alternating rock types have been eroded by wind and wave processes to form the cove.

The area is also important economically with petroleum exploration of Oil sands close by. The Oil Sands here form the largest British Oil Field outside of the North Sea, and is the highest quality Oil found anywhere in Europe.


Geoconservation;
The site is a designated UNESCO world heritage site, and is therefore afforded all of the protection that status allows. 
The sea cliffs here are easily eroded, and because of this collectable fossils are not numerous. Please leave hammers at home, and do not prise any fossils out of the cliff face. Collect only loose material at the bottom of the cliffs and leave any well preserved fossils where you find them so that others may enjoy them also.


-LL
Links For more information;
http://www.southampton.ac.uk/~imw/Lulworth-Cove-Introduction.htm
http://www.lulworth.com/education/lulworth_cove_geology.htm

Photograph Ian West

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