Walking back from Spaniard Rocks now, I took a route closer to the dunes where the character of the shore is quite different from the wet sand and strandlines between high and low tide levels. Here there are pebbles. Rhossili’s pebbles intrigue me. I love scrambling over the banks of stones at the very top of the beach. The colours are lovely pastel shades with pinks and blues and overall reminding me of sugared almonds. A total delight. Many rock types are represented. Some have interesting patterns.
I like the way that the numbers of beach stones seem to increase or decrease depending on how they are pushed around the shore between one visit and the next, and how the sand changes its level and distribution throughout the year and the transition from season to season. This time the wooden ribs and keel of the shipwrecked ketch Anne were only just visible above the sand and pebbles. I like the way that pebbles are arranged partly buried in the damp sand that quickly dries to a different hue and texture. The pebbles underlie the tall sand dunes of the Llangennith Burrows. The dunes have been scooped out by stormy seas and footsteps in many places to demonstrate that even wind-blown sand is stratified; and marram grass roots exposed to air show how deep they penetrate the soft fine sediments to bind them together and stabilise the dunes.
These images show how a combination of high tide and strong wind action in October 2012 caused waves to erode away the deposits at the foot of the solifluction terrace which is attached to the seaward side of Rhossili Down at the end of the Gower Peninsula.
Roots of the Marram Grass, about a metre long, have been exposed along extensive tracts as the sand which it had been consolidating has been washed away. A wider belt of pebbles is also revealed where the former gradual slope of accumulated sediments has been cut back to form a near vertical low face about 0.5 of a metre high.
This erosion process is a continuation of one that has been taking place at this location over thousands of years. The solifluction platform or terrace, when it was first formed, extended as a vast apron of sediments far out into the bay. Now the terrace is reduced to a relatively narrow platform at the base of Rhossili Down on its seaward side.
Marram Grass on Llangennith sand dunes in Gower, almost flattened at times by the driving winds in February, is digitally transformed in these images to colourful abstractions highlighting the natural striped patterns created by the bent stalks.
An empty Skate egg case, or Mermaid’s Purse, caught up in marram grass on frosted sand dunes at Broughton Bay, Gower, West Glamorgan, New Year’s Day 2010. Looking a bit like a fat beetle clinging to the vegetation, the egg case was frozen into position where the wind had blown it from the water’s edge. Minute ice crystals glistened on the dune in the early morning sun. The blades of marram grass and the lower ‘horns’ of the egg case seemed to have been arranged in ready-made holes where the sand grains had frozen together instead of drifting snuggly up to them.
Marram Grass, Ammophila arenaria (L.), is the single most significant plant species for the establishment and stabilisation of sand dunes. The sharp, spikey ends on the leaves can force their way upwards through the build up of dry, wind-blown sand. The rootlets and rhizomes can grow in all directions through the loose sediment – forming an inter-meshing network that binds the small particles together.
This extremely drought-resistant perennial plant grows upto 1.2 metres high. It has specially adapted leaves that can roll inwards to prevent water loss in dry conditions. The flower spikes appear between May and August; they are 25cm long and covered with smaller spikelets.