Aspects Of Wicklow No. 1

Cullentragh Mountain: Beginnings.
Irregular as the boundaries of the Garden County are, Wicklow has a definable centre to its very varied half million acres and what better place to start looking at the 'Aspects of Wicklow' than at its geographical heart. This is a location on the eastern slopes of Cullentragh Mountain buried somewhere in the depths of a forestry plantation. You will find no monument here marking the centre of the county but in the vicinity is a standing stone. Access to the forest location is best made from the Military Road about a half mile north from the Shay Elliot Memorial. The presence of the standing stone indicates that man has marked his presence on this barren landscape in a distant past. And it provokes for me a question as to how did this landscape evolve. Part of Wicklow's charm is its varied scenery of high plateau country hewn by water and ice over immense time spans, sculpting out the lovely valleys which radiate west and east of the country. No better place to contemplate origins than walking in the resin scented woods below Cullentragh Mountain where once again raises the question, whence came this place?

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In a time, so remote as to be irrelevant, there was once an ancient sea surrounded by hills and mountains, Then, as now, there were weather patterns of rain, wind, frost and snow, beating endlessly down on the hills, and there was also time, the geological abracadabra factor, the relentless grist to natures mill, and a third very important component the network of rivers and streams to transport the eroding high ground to lower levels. Given sufficient time and exposure the tallest mountains eventually crumbled and ended up on the bed of the ancient sea. Stepping over the rain filled runnels in Cullentragh Wood, I notice these forces, always in process, wafting along clean little streaks of sand always downward.

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At a later geological period other forces which shape Earths crust came into play and volcanic activity fissured the seabed. Thermal vents opened up and carried a cocktail of minerals into the layers of sediments washed from the ancient mountains. These minerals would one-day form the Avoca mineral ground, a rich matrix of Copper, Sulphur, Iron, and lesser metals and mineral salts, waiting to be exploited in a far future. While later tectonic movement squeezed the sea out of existence its once level seabed is all around the Cullentragh area, exposed through the blanket bog as ridges and outcrops. Between the trees of Cullentragh Wood, moss capped green hued boulders appear here and there reminding of another phase in the story of Wicklow's landscape.

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Four hundred million years ago a new active phase of volcanic processes began. From deep underground a huge mass of very hot, almost molten rock was slowly pushed towards the surface. The main components of this rock are the minerals Mica, Quartz and Feldspar. Mixed together they formed Granite. Over eons of time this granite eventually cooled but before it did it bulged the older sedimentary rocks of the ancient seabed pushing them up so as to form once again a range of hills. Even as they formed the relentless assault of weather, running water and time had begun to wear them down. On the edges of the granite uplift, where hot rock met older sediments, deep water circulating as steam, leached out various minerals and metals from the sediments. Near the surface these hot steams condensed back to water again dropping their suspended mineral in a jacketing of white quartz rock. In this way the Lead and Zinc deposits of the Wicklow valleys formed, always within a matrix of white quartz.

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What is now a familiar sight to the hill walker and visitor to the upper reaches of the valleys of Glendalough, Glenmalure, Glendasan, Glenmacnass and other mountain locations, puts one in touch with that which formed millions of years ago. Later geological movements pushed and heaved the sediments out of their horizontal position into contorted bands almost approaching the vertical which can be seen with spectacular effect on the upper lakes of Glendalough.

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But it was, as it is now, always the weather, assisted by the presence of terrestrial plants which perpetually modify the landscape. For immense spans of time, varied weather patterns, sometimes kind and bland and other times manifesting millenniums of polar colds attack the surface rocks, endlessly changing and removing the coverings until the familiar land patterns we now can define as our contemporary Wicklow landscape came into being.

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© PjP xxvii i mmii
Condensed from illustrated lecture text: Glendasan Wicklow Valley by Pat Power.
Text availability or lecture bookings available from :
Pat Power. Ashwood Lower, Arklow Co Wicklow. Tel 0402 - 37386.