Ferriters Cove on the Dingle Peninsula

Layers of upstanding Silurian rock on the beach

The mountains look down on the golden crescent of sand at Ferriters Cove. It is isolated and peaceful – where the sound of gently lapping waves is only occasionally broken by raucous calls when flocks of oyster catchers or herring gulls suddenly take flight.

Rock layers here stand up like stacked tombstones with wide knife edges, or stumps of strata with sharp points protrude from the surface like nails on a fakir’s bed. The rocks are fossiliferous marine Silurian sediments, from the Ferriters Cove Formation in the Dunquin Group, dating from between 423 and 395 millions of years ago. They are composed of pale brown, yellow, grey and red siltstones, mudstones, and sandstones. They were deposited in a shallow sea with active volcanoes on its shore and hinterland, which produced volcanic deposits such as lava and tuffs.  The character of the rocks changes as you walk along the beach. Fossils such as brachiopods, corals, and trilobites are found in the mudstones.

Patterns in the Sand at Inch Strand

Natural sand ripple patterns

Inch Strand is a wide beach on a sand spit that reaches out like a peninsula into the sea at right angles to the mainland on the South Coast of the Dingle Peninsula in Ireland. We walked the entire five kilometres of dune-backed shore as the tide was receding. By the time we turned back from the tip of the spit, the ebbing sea had left behind acres and acres of wonderful patterns in the sand, in sculptural forms the like of which I have never seen before. I was totally captivated by these designs, looking as did like elaborate knitting or crochet stitching. Here are just a couple of examples of the patterns in the sand.

Natural sand ripple patterns

Natural sand ripple patterns

Natural sand ripple patterns

Natural sand ripple patterns

Natural sand ripple patterns

Ventry Beach on the Dingle Peninsula

Gallery

This gallery contains 16 photos.

Just a few pictures from my visit to Ventry Beach on the Dingle Peninsula on the west Coast of Ireland yesterday selected from the 480 photographs I took! The weather was amazing for September and I was able to spend … Continue reading

Glimpses of Montreal Biodome

We know there is Nature in the city but in Montreal this can be experienced on a large scale in the Biodôme which is a unique museum of environment. Live collections with more than 4,800 animals from 230 species and 750 plants species in four ecosystems from the Americas, each with a different climate – all under one roof.

To quote from the Lonely Planet guide to Montreal and Quebec City:

you can amble through a rainforest, explore Antarctic islands, view rolling lowlands or wander along the raw Atlantic oceanfront – all without ever leaving the building.

Penguins frolic in the pools…the tropical chamber is a cross-section of Amazonia with mischievous little monkeys teasing alligators in the murky waters below. The Gulf of St Lawrence has an underwater observatory where you can watch cod feeding alongside lobsters and sea urchins in the tidal pools. The appearance of the Laurentian Forest varies widely with the seasons, with special habitats for lynx, otters and around 350 bats.

 [These pictures from the visit to the Biodôme are also shown on my other WordPress site along with more postings of photographs taken in Montreal during my trip to Canada last year].

Rock Patterns & Textures at Tenby – Part 5

Green and red biofilm encrusting cave walls at Tenby

It was exciting to discover all the caves at South Beach in Tenby. The rock layers of the cliffs, which were originally laid down in horizontal layers at the bottom of ancient seas millions of years ago, have been subsequently pushed on-end by earth movements so that they now lie at very steep angles to the vertical. The waves have worked away in weaker areas between the strata and excavated small caves. I couldn’t wait to see inside them. They were variable in size but larger than I expected. Well worth exploring.

The floors were mainly sand, smoothed by the previous high tide. Sometimes pebbles were piled up against the back wall. I was mostly struck by how different they looked from one cave to the next. Some cave walls were almost polished, smooth, pale grey limestone, revealing irregular streaks of white calcite veining, occasionally with fossils. Others were roughly hewn with multiple broken facets.

Most intriguing of all were the mosaics of bright green and deep red organic encrustations coating some walls. I couldn’t work out the rationale for their seemingly ad hoc distribution. I am not sure what they are. Maybe they are cyanobacterial bio-films rather than encrusting algae – because of the location in which they are growing so high on the shore and away from light.

[There are in fact encrusting dark red forms of alga but these seem to be restricted to low shore situations in shallow water. Identification of these kinds of organisms is difficult, because they are not a distinct taxonomic group but are represented by a variety of different genera; and maybe I need to take some samples for examination under the microscope].

The pale grey Hunts Bay Oolite Subgroup limestone of the most western stretch of South Beach, which has most of the caves, eventually gives way to other rocks further east – like the Caswell Bay Mudstones which are more thinly bedded with a variety of colours and textures, and these house perhaps the largest cave – the last one of note before you reach Castle Beach and Castle Hill that act as a divider between South Beach and North Beach in Tenby.

COPYRIGHT JESSICA WINDER 2014

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Rock Patterns & Textures at Tenby – Part 4

This is the fourth part of the series of rock texture pictures from Tenby. All so far have been from South Beach where the Carboniferous strata range from Hunts Bay Oolite, to High Tor Limestone, to Caswell May Mudstones, and Gully Oolite. Many of these close-up images have shown erosion patterns, caused sometimes biologically and sometimes chemically, or a combination of both. The first four photographs in this post show the fine, and approximately-linear ridges and grooves (click the pictures to enlarge them for a better view), that seem to be restricted to the otherwise smoother, un-pitted, darker patches on the surface of the rock. I am thinking that whereas the pits are probably caused by various effects of bio-erosion or bio-erosion plus solution, the almost microscopic grooves here could be the result of chemical erosion which sometimes occurs from contact with acid rain. If so, these micro grooves and ridges are microrills, and like miniature rillenkarren – a feature of karst topography – and they are evidence for relatively recent erosional activity.

The patterns of grooves and fissures in the four images below, could also be a karstic type of solution feature. I am not sure – but they are certainly intriguing and look to my eye rather like the tough wrinkled hides of elephant or rhinoceros.

COPYRIGHT JESSICA WINDER 2014

All Rights Reserved