3/24/2023 0 Comments Isle of jura beaches![]() ![]() ![]() The relative rebound is greater in those areas where the ice sheet was thickest and this is why the uplift is more pronounced towards the north-west of Jura The land rebounded slower than the sea level rose, therefore the sea level was initially much higher locally than it is today and beaches and shore platforms were gradually lifted out of the sea as the land continued to rise. At the same time, the landmass initially sank under the weight of the ice cap then gradually rose again as the ice retreated in a process geologists describe as ‘glacio-isostatic uplift’. During glacial periods, sea levels dropped as fresh waters were held captive by the advancing ice sheets and rose again when the glaciers melted. These geological phenomena reflect changes in relative sea level associated with the advance and retreat of ice sheets during the Quaternary Ice Age. Jura is internationally renowned for its raised shore platforms and immense raised beaches, which abound on the west coast along with numerous caves, rock stacks and rock arches. Today, these dikes are most apparent on the west coast where erosion of the less-resistant rock into which they are intruded has left them exposed as natural walls. They were formed during a period of intense volcanic activity in the Lower Tertiary period, some 56 million years ago, when upwelling magma filled cracks in the Earth’s crust radiating out from centres of eruption on Arran and Mull. The predomination of quartzite is most apparent amid the Paps and the ridges in the island’s north-west.Ī series of linear basalt dikes cut into the quartzite rock on a south-east–north-west orientation throughout the island, although they are more numerous in the south. Excepting the low-lying areas of the east coast, which mainly consist of Scarba conglomerate and Port Ellen phyllites, the isle of Jura is largely formed of Jura quartzite, a metamorphic rock which has its origins in the late Pre-Cambrian or Dalradian age.
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