To prove that you have found this Earth cache you must E-mail me via my profile (click on my name) with the answers to these questions:
1. Describe the shape of the landscape to the North, South and West of Sugarloaf (the Usk glacial valley) can you see any signs that it was formed by a glacier? (glacial erosion tends to leave U shaped valleys, rather than the V shaped ones left by rivers) describe what you see.
2. Find a rock on the top. There are a lot of small loose ones at the Western edge of the summit, describe the texture and visual observations of the composition.
Pictures of the views and trig point would be nice but are not compulsory.
The Sugar Loaf is a 596m tall mountain NW of Abergavenny, and is one of the Black Mountains in the East of the Breacon Beacons National Park.
It is a popular misconception that Sugar Loaf is an extinct volcano; an idea born perhaps from the striking resemblance of its conical outline, particularly when seen from the east, to that of a classic volcano. It is however composed entirely of sedimentary rocks. In common with the rest of the Black Mountains, the hill is formed from Old Red Sandstone which was laid down during the early Devonian period (419.2-358.9 million years ago). Its lower slopes (up to around 1000 ft / 300m) are composed of mudstones and sandstones assigned to the Senni Beds Formation, whilst its upper reaches are composed of the more sandstone-rich sequence known as the Brownstones Formation. The very summit of Sugar Loaf is formed from sandstones of the Quartz Conglomerate Group which are of late Devonian age. There are a number of landslips on its flanks which are believed to date from early post-glacial times. The former Usk Valley glacier (originating in Powys, Mid-Wales and reaching the town of Usk at it's furthest point) divided to north and south of Sugar Loaf as it travelled eastwards, though the mountain itself is largely free from glacial till.
The sandstone that makes up The Sugarloaf:
Sandstone (also known as arenite) is a clastic sedimentary rock made up of sand-sized minerals and/or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone can be any colour, but the three most common colours are red, brown and pink. Since sandstone beds often form highly visible cliffs and other topographic features due to it being easily eroded, specific colours of sandstone can be linked to certain regions. Rock formations that are primarily composed of sandstone usually allow percolation of water and other fluids, they are even porous enough to store large quantities. Fine-grained aquifers, such as sandstones, are more apt to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity.Quartz-bearing sandstone is converted into quartzite through heating and pressure usually related to tectonic compression. The further East you look in wales, the more quartz can be found in the sandstone, this is true for The Sugarloaf as the brownstone summit is rich in quartz conglomerates.
If you are planning to attempt this cache I would strongly recommend that you wear strong shoes/hiking boots and an Ordinance Survey OL13 Explorer map would probably be helpful as well. Below there is a waypoint for free parking on the mountain itself, there is room for a good many cars there and I would recommend starting your walk there if you have children with you since the route is slightly shorter than others and the terrain is more gradual. But if you would prefer to make a day of it different routes can easily be devised.
EarthCache placed with the kind permission of The National Trust Wales.