Earthwatcher's photos with the keyword: unconformity

Uploaded as a clue to another GWUK photo These cliffs are of 'Old Red Sandstone'. There are two units in the cliff - the upper, coarse, pebbly sandstone is of Upper Devonian age, and rests unconformably on finer-grained sandstone of Lower Devonian age. The Middle Devonian is missing and is represented by the irregular junction (an angular unconformity) between the two units. The Lower Devonian sandstone was deposited first, then uplifted, tilted and eroded during the Middle Devonian, before the upper unit was deposited in the Upper Devonian times. Scanned from Kodachrome 64 transparency film, taken with a Zenit 'E'. See where this picture was taken. [?]

A day on Quinag - photo 23 . On the descent and walk out, we stop to examine the contact of the Cambrian Basal Quartzite resting with angular unconformity on the Torridonian Sandstone (late Precambrian) exposed in the low crags of Druim na h-Uamha Mòire at NC 22673 28186.

A day on Quinag - photo 24 . On the descent and walk out, we stop to examine the contact of the Cambrian Basal Quartzite (the sloping grooved under-surface) resting with angular unconformity on the Torridonian Sandstone (late Precambrian) exposed in the low crags of Druim na h-Uamha Mòire at NC 22673 28186. A fascinating end to a splendid day!

A fine evening looking over the chaotic knock-and-lochan landscape of the Lewisian Gneiss foreland towards Canisp one of the relict Torridonian Sandstone mountains. The red Torridonian Sandstone of Canisp lies unconformably on the Lewisian Gneiss and is itself unconformably overlain by the pale grey Cambrian Basal Quartzite just visible on the summit. A south-easterly view from the Creag Dharaich viewpoint near Lochinver, Sutherland, Scotland.

A fine evening looking over the chaotic knock-and-lochan landscape of the Lewisian Gneiss foreland towards the relict Torridonian Sandstone mountains (L-R: Canisp, Suilven, Cùl Mòr and Cùl Beag). A south-easterly view from the Creag Dharaich viewpoint near Lochinver, Sutherland, Scotland.

View south from Stac Pollaidh to the Beinn Mhòr Coigich group of mountains with Loch Lurgainn in the foreground.

Suilven and the mountains of Assynt beyond, viewed from the Stac Pollaidh ridge. Loch Sionasgaig is in the foreground. Suilven is comprised of Torridonian Sandstone which rests unconformably on the high-grade metamorphic basement rocks of the Lewisian Gneiss which forms the 'knock and lochan' landscape in the middle ground. There is a time gap of about 700 million years separating the two rock units.

A view east from Stac Pollaidh to Cùl Mòr, the next Torridonian Sandstone mountain of the Assynt region.

Originally uploaded for the Guesswhere UK group. This is one of the classic British angular unconformities. Horizontally bedded Carboniferous Limestone unconformably overlying Silurian greywacke siltstones dipping at about 45° This is at Foredale Quarry just south of Horton-in-Ribblesdale, North Yorkshire. Scanned from a Kodachrome transparency.

The little inlet of Pwlldawnau and the headland Penbwchdy, viewed from adjacent to the Pembrokeshire Coastal Path at National grid ref. SM 8808 3692 (a nice place for a sandwich). The prominent pale rock horizon consists of sandstone and conglomerate at the base of the Ordovician age Ogof Hen Formation. This rests unconformably on the underlying shales of the Cambrian age Lingula Flags. The far headland of Penbwchdy is comprised of a microtonalite sill, an igneous intrusion. If you zoom in on the photo you can see near-vertical columnar cooling joints in the sill.

A fine evening looking over the chaotic 'knock and lochan' landscape of the Lewisian Gneiss foreland towards Suilven, one of the relict Torridonian Sandstone mountains. The red Torridonian Sandstone lies unconformably on the Lewisian Gneiss. A south-easterly view from the Creag Dharaich viewpoint near Lochinver, Sutherland, Scotland.

The north faces of Sàil Ghorm (right) and Sàil Ghàrbh (left) , the two northern spurs of Quinag, with Loch a' Chàirn an Bhàin in the foreground, taken from near Kylestrome at grid ref. NC 21161 34782. Quinag is comprised of Torridonian Sandstone resting unconformably on Lewisian Gneiss which forms the rough hummocky ground in the foreground and middle distance. The very summit of Sàil Ghàrbh is comprised of pale grey Cambrian Basal Quartzite, also resting unconformably on the Torridonian Sandstone. So there is a double unconformity in this photo.

A day on Quinag - photo 17 . The magnificent view to the south from summit of Sàil Gharbh (808 m), looking towards Spidean Còinich, the southern spur of Quinag with Lochan Bealach Cornadh at its foot. In the distance are Canisp (middle left), Cùl Mor and Suilven. Loch Assynt, The Minch and the Summer Isles are visible on the right. The upper part of Spidean Còinich consists of the pale grey Cambrian Basal Quartzite (Eriboll Formation) dipping at around 15° east (left) which rests with clear angular unconformity on the nearly horizontally bedded Torridonian Sandstone (Applecross Formation). The same unconformity is also seen on Canisp in the distance.

A day on Quinag - photo 14 . This is the final south-west ridge leading to Sàil Gharbh (808m), the highest summit of Quinag in the NW Highlands of Sutherland. The pink rock is Torridonian Sandstone (Applecross Formation, Precambrian), overlain unconformably by the light grey Basal Cambrian quartzite of the Eriboll Formation.

A day on Quinag - photo 11 . A panoramic view (two landscape-style photos stiched togerther) of Spidean Còinich and Lochan Bealach Cornadh with Suilven in shadow beyond the bealach to the right. A southerly view from part way up the south-east flank of Sàil Gharbh.

A day on Quinag - photo 13 . The Torridonian Sandstone (Applecross Formation) pavement on the approach to the summit of Sàil Gharbh. The abrupt change in colour near the top marks the outcrop of the pale grey Cambrian Basal Quartzite which rests with angular unconformity on the Torridonian Sandstone.

A view northwards from Stac Pollaidh over the 'knock and lochan' landforms of the Lewisian Gneiss foreland. The Torridonian Sandstone mountain Suilven is visible in the distance, with Quinag just peeking out beyond on the left. An extraordinary landscape which never fails to impress me with its stark beauty.

A wide-angle view eastwards from Stac Pollaidh to Cùl Mòr, the next Torridonian Sandstone mountain of the Assynt region. On this day, most of the isolated peaks had their own clouds associated with them and Cùl Mòr was no exception.