Sedimentary structures

The southern end of Stanage Edge, the longest of the Eastern Edges, in the Peak District National Park, Derbyshire. Stanage Edge is comprised of Rivelin Grit (aka Chatsworth Grit), Namurian age, Upper Carboniferous. The coarse-grained gritstone was deposited in a series of delta distributary channels. The gritstone is normally strongly cross-bedded, and intraformational erosion surfaces are common. The Edge has been worked for millstones in several places and examples such as these can be found in many places, lying where they were abandoned when the demand for imported French stones rose in the latter part of the 19th century.

The southern end of Stanage Edge, the longest of the Eastern Edges, in the Peak District National Park, Derbyshire. Stanage Edge is comprised of Rivelin Grit (aka Chatsworth Grit), Namurian age, Upper Carboniferous. The coarse-grained gritstone was deposited in a series of delta distributary channels. The gritstone is normally strongly cross-bedded, and intraformational erosion surfaces (as in this photo) are common.

The southern end of Stanage Edge, the longest of the Eastern Edges, in the Peak District National Park, Derbyshire. Stanage Edge is comprised of Rivelin Grit (aka Chatsworth Grit), Namurian age, Upper Carboniferous. The coarse-grained gritstone was deposited in a series of delta distributary channels. The gritstone is normally strongly cross-bedded, and intraformational erosion surfaces are common.

An image from a photostudy of the Mother Cap Stone, an extraordinarily photogenic natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. In this photo it is caught in the golden light of the setting sun.

An image from a photostudy of the Mother Cap Stone, an extraordinarily photogenic natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. In this photo it is caught in the golden light of the setting sun. This is an uncropped version of the next photo. I like both; which do you prefer?

An image from a photostudy of the Mother Cap Stone, an extraordinarily photogenic natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. In this photo it is caught in the golden light of the setting sun.

An image from a photostudy of the Mother Cap Stone, an extraordinarily photogenic natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. In this photo I tried to capture another aspect of its profile, this time silhouetted against the dark clouds and golden light of the setting sun.

An image from a photostudy of the Mother Cap Stone, an extraordinarily photogenic natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. In this photo it is still illuminated by the bright western light a few minutes after sunset.

An image from a photostudy of the Mother Cap Stone, a natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. This was a rather cloudy and gloomy autumn day, but the late afternoon sun provided some low-angle brightness which emphasised the textures of the outcrop.

An image from a photostudy of the Mother Cap Stone, a natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. This was a rather cloudy and gloomy autumn day, but the late afternoon sun provided some low-angle brightness which emphasised the textures of the outcrop.

An image from a photostudy of the Mother Cap Stone, a natural rock tor of cross-bedded Chatsworth Grit (Namurian) high on the South Yorkshire Eastern Edges in the Peak District National Park. This was a rather cloudy and gloomy autumn day, but the late afternoon sun provided some low-angle brightness which emphasised the textures of the outcrop.

This is probably the best exposure of the Red Chalk in the UK. The top-to-bottom sequence is: Cenomanian (White) Chalk -- disconformity -- (~ 2 million year time gap) Hunstanton Formation ('Red Chalk') Carstone Formation ('Lower Greensand' - brown!)

Seaford Chalk with solution pipes, infilled with Palaeogene sands and gravels. Hope Gap, Seaford, Sussex. Taken with an early Kodak 1-megapixel digital camera.

Hope Gap looking eastwards across Cuckmere Haven towards the Seven Sisters. Brown Palaeogene sands and gravels infill the solution hollow in the Chalk at the top of the cliff on the left. Taken with an early Kodak 1-megapixel digital camera.

Some of the slabs of Chatworth/Rivelin Grit near the road at Upper Burbage Bridge are covered with plant fossils - stems, straps, small trunks, all roughly aligned at right-angles to the current flow direction. A sort of upper Carboniferous log jam, I suppose.

Pleistocene river gravels of the proto-Thames form low cliffs on the south coast of Mersea Island, Essex. This is a site of regional geological importance and is a SSSI. Active erosion is taking place, with the cliffs receding northwards. Rising sea-levels associated with global warming will exascerbate this effect.

Pleistocene river gravels of the proto-Thames form low cliffs on the south coast of Mersea Island, Essex. This is a site of regional geological importance and is a SSSI. Active erosion is taking place, with the cliffs receding northwards. Rising sea-levels associated with global warming will exascerbate this effect.

Originally posted for the Guesswhere UK group. This distinctive piece of coastline is at Trwyn Maen Melyn, near Aberdaron at the western end the Lleyn Peninsula, NW Wales. In geological circles, these blobby rocks are famous here. They are part of the Gwna Mélange, a chaotic mass of diverse rock fragments, boulders and rafts, some of them 100s of metres across, all set in a fine-grained schist matrix. The age is now thought to be Cambrian and the mélange is an example of an olistostrome , a rock assemblage thought to represent a huge submarine debris flow (or several debris flows) into a deep ocean trench which existed here at that time. The Gwna Mélange crops out on much of NW Lleyn, Bardsey Island and over considerable parts of N and W Anglesey.