Thursday 25 October 2012

The Marvellous Granites of Seychelles


The Seychelles are the only granitic oceanic islands in the World. Formed millions years ago, the size and shapes of some of these granites are truly mindboggling. TONY MATHIOT tells us about a few of them.

ANSE L’UNION GRANITE BOULDER (at Anse L’Union, La Digue)

Granite. Our glorious granite. Forty islands in the Seychelles archipelago are granitic. The fascination of the Seychelles lies not only in its resplendent greenery or in its pristine beaches or sunshine. The granite is awesome. Majestic. One admires and gasps. Yes, it’s PLUTONIC! But can one go dithyrambic over the granites of Seychelles without venturing into the recondite science of geology stratigraphy or Petrogeny?!

The granites of Seychelles date back to millions of years ago to the Mesozoic era… to the time of Gondwanaland, the time of the first amphibians, the first winged insects, the first dinosaurs.

Granite is an igneous rock that formed by solidification from a molten state (igneous comes from the Latin word ignis: to inflame). It is made up mainly of crystals of quartz, feldspar and mica. And it was formed deep in the earth. And while the magma, that is, the molten matter, was forming, fragments of materials called xenoliths were trapped in the magma before it crystalised – yes, like dust of glitter in a bath of hot treacle!

Since granite was formed deep beneath the earth’s crust, it is because the rocks lying on top of it have been worn away or because it has been pushed upwards by movements of the rocks long ago.

Yes, long ago. And now when one beholds this grandest scenery of granite covering over one acre of land, here on the west coast of La Digue, it is almost stupefying to realize that we are the only oceanic granite islands in the world.



ROS KOSON (at Anse Louis)

On the beautiful west coast of Mahé, one finds this marvelous monstrosity! A veritable natural wonder! Yes, this is Ros Koson (Pig rock) aptly named because it certainly resembles a crouching snarling hog in profile. One can distinctively make out the sunken eyes, the cartilaginous snout over the mouth baring the teeth in a rictus of rage. Definitely one of our most common ungulate mammals!

Of course with so much granite around, it is not uncommon nor unusual to come across boulders or shapes of some recognizable representation.

But upon seeing this particular ‘pig’ up there, one is naturally inclined to wonder just how long has it been perched up there on that giant boulder?

We’ve been told by scientists that once upon a time, meaning so many millions of years ago when all continents were joined that Seychelles, a tiny fragment of the earths crust halfway between Africa and India became isolated during the so-called continental drift… could that rock have landed up there on that boulder during the upheaval and then over the centuries it was shaped into a pig by the ravages of time? Fascinating!

One thing for sure. This is one pet porky that future inhabitants of Anse Louis will certainly inherit and learn to like!.


ROS LESKALYE (ROCK STEPS) (at Port Launay)

The resplendence of Port Launay in North Western Mahé is breathtaking. Here along the boulder-strewn coast the waves of the Indian Ocean come to nudge themselves against the rocks after having spent their rage further away. But amidst this sublime scenery there is a particular feature that certainly can be baffling to the lonely peasant who happens to venture along this part on an afternoon when looking for limpets (bernik).
These steps are mind-boggling. Almost like a gateway to the backwoods used by undersea aliens! Fascinating! Well, geology IS fascinating.
This rather unusual feature is known as a dyke. It is typically the result of igneous intrusion: a long mass of igneous rock that cuts across the structure of adjacent rock. This happens when magma or molten rock move upwards by injecting into cracks at higher levels in the earth’s crust, forcing the sides apart. Magma solidifies in the crack to form a dyke, and in the case here at Port Launay, the dyke do look like a row of steps.

MIRAY DEMON (at Anse Déjeuner)
Miray demon? (the devils wall?) Why on earth would he build a wall here on earth in Paradise?!

Yes, this is certainly a mind-boggling sight. One gets the impression that these different sizes and shapes of granite boulders have been gingerly arranged to rest on top of one another to make a crude wall.

Well, some inhabitant of Anse Déjeuner must have appreciated the extraordinary strength of the devil and gave this bizarre heap of boulders an appropriate appellation!

In fact, once upon a time, a long long time ago, this was one single huge boulder. The ravages of time which spanned thousands of years, created fissures and clefts in it and gradually it was divided into separate pieces of rock which have more less remained in place like interlocking pieces of a gigantic jigsaw puzzle. That’s the mystery of the devil’s wall… For sure, those boulders will never be taken to the crushing plant located a mile away to be turned into aggregate!

Article first appeared on Virtual Seychelles. Original article can be found here: http://www.virtualseychelles.sc/index.php?option=com_content&view=article&id=842:the-marvellous-granites-of-seychelles&catid=51:additions

 

Tuesday 16 October 2012

Scuba Diving in the Seychelles

Perhaps one of the most alluring characteristics of the Seychelles is the clear turquoise waters of the Indian Ocean which surround the islands. The stunning topography of expansive reefs, walls, pinnacles, drop offs, wrecks and canyons make for one of the most diverse marine environments around, teeming with both fish and coral life.

Coral bleaching in the Seychelles in 1998


In 1998, the coral reefs of the Seychelles were affected by the El Nino Southern Oscillation. The exact cause for this event is unknown but it is thought global warming was primarily to blame. The changes in the atmosphere caused an increase in sea temperatures, resulting in significant consequences for the surrounding coral and marine life. The warmer waters caused the coral to repel the bright algae (which gives the coral its vivid colours) from their tissues, thus causing them to take on a pale and white appearance (hence the commonly used term “coral bleaching”). The inner reefs were hit harder than the outer reefs, however the granitic nature of the reefs meant they were not as badly affected as first feared, and 11 years on from the event there has been a remarkable recovery and the diving generally remains excellent.

When to go scuba-diving in the Seychelles


With dive sites ranging in depth from 8m to 30m there are options for both beginners and experienced divers to enjoy. It is possible to dive throughout the year in the Seychelles – however waters are calmest during the months of March, April and May and September, October and November. During these months visibility can reach a staggering 30m and with water temperatures reaching 29oc it makes for a very pleasant and relaxed diving experience. The calmer waters also mean dive boats can reach the more remote sites, where encounters with mega fauna such as sharks and manta rays are common – these sites are particularly good for experienced divers.

During the months June, July and August the south-east monsoon brings stronger winds making access to the more remote dive sites difficult and unreliable. Cooler waters are blown in and temperatures drop to around 25oc. These cooler waters are filled with nutrient rich plankton so visibility can be significantly reduced; however these nutrients encourage the appearance of whale sharks, which can reach an incredible 10m in length. Local dive shops offer specific whale shark programmes during these months, so the chance to snorkel or even dive with these magnificent creatures is very high.

Marine life


Around the inner reefs, marine life you can expect to see among others includes – angelfish, butterflyfish, octopus, lionfish, nudibranchs and mantis shrimp. Slightly further out, napoleon and humphead wrasses, schools of humphead parrotfish, stingrays, reef sharks and green and hawksbill turtles are common.

Sailfish, silvertip, oceanic whitetip and nurse sharks, manta rays and whale sharks are more common around the remoter outer islands – you may even be able to spot the occasional hammerhead shark if you're lucky!

Where to go diving in the Seychelles


When you are a guest with us, we will have all the equipment on board and take you to the best spots. We will of course have the relevant dive masters/instructors available to you as well.

Other local dive schools are also available on the various islands.

Some photos of what to expect

 



 

Many thanks to http://www.expertafrica.com/seychelles/info/diving-in-the-seychelles