Tuesday, October 25, 2016

Bray Strand



This entry is a significant geographic break from the previous ones. After working our way down the Wild Atlantic Way on Ireland's west coast, we're now back on the Irish Sea on Ireland's east coast. This will also be the last post from Ireland --- not because we ran out of beaches, but because we ran out of time.

Bray seems like a classic beach town from an earlier era. A string of old hotels, a small amusement arcade, and an aquarium line the main drag across from the beach.  Bray is on the main railroad line less than an hour south of Dublin, so was an easy weekend escape for the city crowd.


AERIAL VIEW


The beach is gravel - or at least mainly gravel. My cursory internet research hasn't shed much light on the history, but it sounds like gravel was added as nourishment here back around 2000, and maybe again more recently, but I'm not sure. Beaches often have complex backstories and I wish I knew this one.


Longshore transport is generally south to north along this coast. You get a sense of this looking at the jetties at Bray Harbor in the distance. The beach is stacked up against the south jetty. And the narrow beach farther north is backed by eroding bluffs, suggesting a sediment deficit.

A similar situation apparently exists at Greystones (AERIAL VIEW), a few miles south, where structures that cross the foreshore (a marina) have led to beach problems on the downdrift (northern) side.

I added 33 beaches to my collection during our three weeks in Ireland. And this was the 804th post on Gravel Beach. It began back in late 2005 with a beach northwest of Port Townsend, a shot from Cama Beach, and a few pictures from California (Gravel Beach: December 2005).




Monday, October 24, 2016

Derrynane


This white sandy beach seems like a bit of an anomaly on the southwestern coast of the Ring of Kerry. Aerial images don't show much in the way of beaches, even small ones, along this section of rocky coastline, yet this bay has a really nice one. Typically, beaches need both a source of sand and a place for it to accumulate. No sediment, or a coast so steep that sand is lost offshore, prevents beaches from forming.

The sediment here may have been delivered by the stream at the head of the bay. This assumes that the stream valley yields a reasonable amount of sand, perhaps from glacial deposits. Another option, not necessarily exclusive of the first, is that glacial drift was deposited in the lower valley or the bay and waves have redistributed it directly.

AERIAL VIEW

In either case, a broad, relatively shallow bay would have fairly little accommodation space, and a modest amount of sand would accumulate fairly rapidly. And wave action would tend to trap the sand within the bay.

The main feature is a broad spit, backed by dunes, but the beach is strung out along the northern shore behind a series of rocky ledges. And there is a tombolo at the west end linking the beach to Abbey Island.





Friday, October 21, 2016

Waterville



Maybe it was just the nice light at the end of the day (the same day we weren't able to visit Skellig Michael due to the morning's bad weather), but this beach turned out to be a very pleasant surprise. Which meant I took a lot of pictures.


The town faces out across Ballinskelligs Bay toward the open Atlantic and I suspect it can get pretty exciting sometimes. The community is oriented toward the beach, with a nice park, and is protected from those nasty storms by either a high gravel berm or by some very impressive stacks of riprap (much of it red sandstone).


AERIAL VIEW


The beach has the red tone I saw on a lot of these local beaches and that I suspect reflects the oxidized Devonian source for much of this material. There were steep eroding bluffs in both directions, exposing what appeared to be glacial drift (it doesn't look much like the drift we see on Puget Sound).




Northeast of Waterville, beyond the short stretch of bluffs, lies Inny Strand. Unlike Waterville, Inny is a spit with a well-developed set of dunes (and therefore a well-developed golf course). The golf course is protected from the sea by more riprap.



Valentia Island



This post captures several different shorelines, none of them beaches, from around Valentia Island. Valentia lies at the west end of the Iveragh Peninsula and the Ring of Kerry, across a narrow channel from Portmagee - see photo below. The island's southern side consists of green slopes that gently rise to a ridge along the crest of the island. From the south, you don't get much sense of the drama on the other side.

AERIAL VIEW

Bray Head forms the western end of the island. Geokaun Mountain, in the central part, is the highest part of the island. The mountain's north side drops sharply - the Fogher Cliffs - and looks suspiciously like a very large landslide. There's a great view east from the top of Geokaun, looking over bays and islands towards Cahersiveen and beyond that, the higher interior of the peninsula. There's an old, but still active, slate quarry below the northeastern side of Geokaun Mountain. And on the low seacliffs nearby, there are apparently footprints left by Devonian Tetrapods (we didn't visit either the quarry or the trackway).



Thursday, October 20, 2016

Kerry Cliffs


Beaches are actually the anomaly along most of the Kerry coastline -- rocky shores are far more common. But not all rocky shores are equal. Some sea cliffs are simply higher and more spectacular than others. Here, west of Portmagee, the land rises steeply, then just plunges hundreds of feet into the Atlantic.





AERIAL VIEW

I believe most of the Iveragh Peninsula is composed of Devonian Old Red Sandstone, even if it isn't all red and doesn't all consist of sandstone. But it was all deposited in rivers and desert conditions a very long time ago.


We could see Skellig Michael offshore. We had booked a trip out a day or two before, but gale force winds jinxed those plans. The 700' high rocky spire was the site of a small monastic community between 700 and 1200AD and their stone huts can still be visited, perched high on the rock. This year, tourism to this site (already a UNESCO World Heritage site), went through the roof, since it was featured in the last two minutes of last year's Star Wars: The Force Awakens (it's where Rey finds Luke).



St. Finian's Bay


This was a wonderful little pocket beach nestled among an exceptionally ragged rocky coastline. You can see from both the photos and the aerial view that the sedimentary rocks here have a distinct grain that runs out to sea. Of course, if you think about it, both the Dingle and the Iveragh Peninsulas (that's this one) are just large-scale manifestations of the same thing. Thus the role of structural geology in shaping coastlines at multiple levels.

AERIAL VIEW


We passed it several times and each time, conditions were different.

St. Finians Bay lies below an area of west Kerry called the Glen. It offers great views towards Skellig Michael, 6 miles out in the Atlantic.

Two notable aspects of this beach:


1. The strand line was marked by an enormous amount of plastic - something I simply hadn't noticed to this extent on other beaches. Besides the plastic in the wrack, piles of plastic debris had been collected and piled up at the parking lot. I have no idea whether I just wasn't paying attention at other beaches, whether other beaches get cleaned more regularly, or whether this particular beach is simply a plastic magnet. Plastic, like other flotsam, is highly subject to currents and wind and seems to accumulate in places where subtle aspects of the configuration of the shoreline conspire to trap material.

2. There is a small chocolate factory five minutes away, which makes this remote beach almost as good as one with its own coffee roaster or its own brewpub.


Ballinskelligs West


In the previous post, I noted that there were really two beaches at Ballinskelligs. The first, described in that post, is the larger and better developed. The second is a thin strip to the west, separated from the main beach by the stream that drains the wetlands and peat bogs upslope. This beach extends from the Ballinskelligs Priory west to the McCarthy Mor Castle (a fairly simple, but much deteriorated, square stone tower), which is built on rocky ledges offshore of the main beach.

The AERIAL VIEW really helps on this one.

This beach is a spit - actually a tombolo. Whereas the main beach to the east appears to have an ample sediment supply and a fairly simple relationship to waves wrapping into the bay from the south, this western beach is confused by a lack of sediment and a more complicated, albeit less energetic, wave regime. The small barrier beach itself consists of a shingle ridge and a mixed beach of sand and scattered pebble.


Not to second guess the monks who retreated from Skellig Michael to build this abbey 800 years ago, but they seem to have picked a poor building site (at least in the long term). Bedrock ledges and a rocky lag on the foreshore probably help to protect this promontory a little bit, but it looks like that without the big concrete wall (which I'm sure was built much more recently), most of this site would be long gone.

I've got a lot more photos of Ballinskelligs - the beach, the McCarthy Mor Castle, and the Priory - over on the other blog



Wednesday, October 19, 2016

Ballinskelligs



Ballinskelligs is located on the northern shore of a bay with the same name, near the western end of the Iveragh Peninsula and the Ring of Kerry. We spent three days here, so these photos come from several different walks - thus different lighting, different weather, different tides.


AERIAL VIEW
The main beach is a sandy crescent-shaped strand a couple of kilometers long. There are grassy dunes at the west end, but much of the rest of the beach is backed by a low bluff. There is a smaller, very different beach, just off the western end of the main beach, which we'll come back to in a subsequent post. But for reference, it is the one with the castle on it.


At  first blush it's a sandy beach, but the sand may be just a veneer in most areas. A gravel storm berm is visible at the base of the bluff. In addition, several small streams cross the beach, exposing the coarse gravel that extends beneath the beach.

The beaches I like best are the ones with a lot of interesting details.