A quick-and-dirty geological summary of Cyprus

36390_1516104110722_4901481_nHere’s a summary of the geology of Cyprus. Given that geology is best explained while standing out in the field and looking at outcrops and rocks, this is necessarily limited – but hey, that’s why I call it a summary. As my kickass map shows, Cyprus is split in four general regions: Kyrenia, Troodos, Mamonia and the Mesaoria Basin.

Cyprus lies in a complex collision zone separating the African and Eurasian plates – this is the source of all the earthquakes in the region, as well as of the Kyrenia mountains.

The Kyrenian mountains are mostly made of sedimentary sequences, with some metamorphic and igneous rocks thrown in for good measure. There are three carbonitic formations of Triassic to Cretaceous age (250 – 135), onto which older sequences (Permian-Carboniferous; 350-250) are thrust. This all occurred around the Cretaceous, after which you have regular deposition of marine sediments, which gradually get shallower until the mountains emerged from the sea (no exact date, definitely later than 15 Ma). The mountains are still rising.

Now for the Troodos mountains, which are the spectacular thing to see in Cyprus. In the 60s and 70s, the insights gotten from Troodos revolutionised one aspect of geology, so Cyprus can be proud of having done something in science (Cyprus even hosted 2 international conferences and symposia!). Anyway, Troodos is an ophiolite – a piece of oceanic crust that’s been thrust up, not sediments or whatever. It’s original material. Not only that, it’s an undisturbed ophiolite: as you drive up Troodos, you can literally see what the oceanic crust is made up of and how it’s built up, both in space and time. The only other place in the world where you can see this at this scale and ease is in Oman. Due to the way it formed, the whole thing is inverted: the youngest rocks (chemical sediments and volcanics) are at the bottom, while the oldest rocks (mantle) are at the top – so driving up Troodos is like traveling back in time.

Anyway, it was first formed in the Cretaceous, 90 Ma. At first, you have the mantle – a rock called harzburgite – from which all the other rocks are derived (you have to imagine that it all comes from the same melt, i.e. the same source). After the mantle, you have plutonic rocks (slowly-cooled igneous rocks, derived from the mantle). As a result of the uplift, many cracks appeared in this sequence, which allowed other, more differentiated melts to sneak into them and crystallise – these later become the asbestos, chromite, etc. mines that Cyprus lived off of. In geology terms, this sequence is called the diabase sequence. Afterwards, you get underwater volcanism – you see this as massive and quite beautiful pillow lavas (so called because you can sit on them, very comfortable). Finally, you get chemical sediments in the forms of umbers, which result from all the hydrothermal reactions.

This is the standard sequence for all ophiolites, and it was the Troodos ophiolite that allowed us to figure it out – before, ophiolites were a mystery.

The Mamonia Melange is a mindfuck, and I’ll admit I’ve only been there once and can’t really figure much out about it, and there’s still research to be done there. A melange is basically a mix of randomly related rocks, all jumbled up by tectonics; in this case you have volcanic rocks, marine sediments and metamorphic rocks. The metamorphism is widespread and there’s unique tectonics happening in the region (Paphos is the least stable part of the island). What is known is that they were ‘pushed aside’ by Troodos’s rising in the Cretaceous, but not much else. I found an ammonite there, so that’s cool.

And finally, we have the sediments. Cyprus has continuous, undisturbed marine sedimentation all the way from ~70 Ma to ~2 Ma. You first have deep sea chalks, that gradually get shallower, until 20 Ma, when it’s shallow enough to get the formation of massive coral reefs. They also get gradually shallower (of course, with variations, sometimes deeper, sometimes shallower), until 5 Ma, when you get the Messinian Salinity Crisis. This is when the Straits of Gibraltar closed up and the whole Mediterranean dried up. You see this in Cyprus near Pissouri, where you have walls of gypsum and other salts (formed by the evaporation of sea water) hundreds of meters high. At 4.8 Ma, the Atlantic flooded back in, and you have open marine conditions again.

The area around Nicosia shows this part in time, and it’s where I do my palaeontological work, because this is when you can ask the interesting evolutionary and palaeoecological questions. And the fossils here really are awesomely preserved.

The Nicosia Formation gradually got shallower, until it just wasn’t marine anymore (Athalassa Formation) and until it became completely terrestrial (Fanglomerate, 1.8 Ma). After that, nothing. Only quaternary where there’s arable land and at the various archaeological sites.

If I don’t end up raising the money to get to Japan, I will start a business to provide geological tours. Except I’ve tried to do this for people and they wouldn’t even take even short 2 hour tours for free, so it’s really sort of hopeless.

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  1. Pingback: Friday Fact About: Cyprus Geography and Geology | aphroditerentals8509

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