Sedimentary structures

Detail of part of the turbidite sequence of the Crackington Formation (upper Carboniferous) at Millook Haven, north Cornwall, lit by the late afternoon sun. This photo shows alternating sandstone (pale) and shale bands on the inverted limb of one of the recumbent chevron folds. The compass-clinometer is located on the stratigraphic base of one of the sandstone bands, which displays a fining-up sequence (in this case downwards, since it is inverted). Just to the left of the compass-clinometer, the coarser sandstone base has slumped stratigraphically down (in this case appearing up) into the underlying muddy layer (now grey shale). This shows how you can use sedimentary structures to deduce whether the rocks are the right way up, or whether as in this case, they have been subsequently turned upside-down.

The is an unusual detail view of the rocks at Millook Haven, north Cornwall. The striped rocks are turbidites belonging to the Crackington Formation (upper Carboniferous). Way-up structures in the sandstone bands such as fining-up sequences, small-scale slump structures, ripple marks and grooves, etc, demonstrate that these northward dipping rocks (part of the famous chevron fold sequence) have been inverted and are upside-down.

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.

A photo-study of Burton Cliff near Burton Bradstock, Dorset. Having spent the day at Seatown a few miles to the west, and seeing the afternoon light was turning to a beautiful gold, we realised that the yellow Bridport Sands at Burton Cliff would be spectacular in in the light of the setting sun. So we rushed over to see. And so it proved.... These photos were taken in RAW mode using a polarising filter, but no post-processing enhancement other than slight adjustments to the exposure and contrast settings. Burton Cliff is comprised of the Bridport Sands at the top of the Middle Lias in the Lower Jurassic.

A photo-study of Burton Cliff near Burton Bradstock, Dorset. Having spent the day at Seatown a few miles to the west, and seeing the afternoon light was turning to a beautiful gold, we realised that the yellow Bridport Sands at Burton Cliff would be spectacular in in the light of the setting sun. So we rushed over to see. And so it proved.... These photos were taken in RAW mode using a polarising filter, but no post-processing enhancement other than slight adjustments to the exposure and contrast settings. Burton Cliff is comprised of the Bridport Sands at the top of the Middle Lias in the Lower Jurassic.

A photo-study of Burton Cliff near Burton Bradstock, Dorset. Having spent the day at Seatown a few miles to the west, and seeing the afternoon light was turning to a beautiful gold, we realised that the yellow Bridport Sands at Burton Cliff would be spectacular in in the light of the setting sun. So we rushed over to see. And so it proved.... These photos were taken in RAW mode using a polarising filter, but no post-processing enhancement other than slight adjustments to the exposure and contrast settings. Burton Cliff is comprised of the Bridport Sands at the top of the Middle Lias in the Lower Jurassic.

A photo-study of Burton Cliff near Burton Bradstock, Dorset. Having spent the day at Seatown a few miles to the west, and seeing the afternoon light was turning to a beautiful gold, we realised that the yellow Bridport Sands at Burton Cliff would be spectacular in in the light of the setting sun. So we rushed over to see. And so it proved.... These photos were taken in RAW mode using a polarising filter, but no post-processing enhancement other than slight adjustments to the exposure and contrast settings. Burton Cliff is comprised of the Bridport Sands at the top of the Middle Lias in the Lower Jurassic.

A photo-study of Burton Cliff near Burton Bradstock, Dorset. Having spent the day at Seatown a few miles to the west, and seeing the afternoon light was turning to a beautiful gold, we realised that the yellow Bridport Sands at Burton Cliff would be spectacular in in the light of the setting sun. So we rushed over to see. And so it proved.... These photos were taken in RAW mode using a polarising filter, but no post-processing enhancement other than slight adjustments to the exposure and contrast settings. Burton Cliff is comprised of the Bridport Sands at the top of the Middle Lias in the Lower Jurassic.

Originally uploaded as a clue to a GWUK photo. This is a view of Aberystwyth Grits in the cliffs beneath Constitution Hill, Aberystwyth, Sîr Ceredigion. These rocks are of Silurian age (Llandovery) and form a well-developed turbidite sequence of dark silty shales alternating with paler sandstones and gritstones.

Uploaded as a clue to the GWUK photo here.... www.ipernity.com/doc/earthwatcher/39023396

Originanally uploaded for the Guesswhere UK group. A rather old photo taken with an early digital camera, hence rather poor resolution. This is the Skipsea Withow Mere and the location is the Withow Gap on the Holderness coast in East Yorkshire. The rapidly eroding low cliffs have cut a section through the Withow Mere which is a former (post glacial) lake formed in an ice-hollow on the till ('boulder clay') surface. The lake became filled with both drifted and in-situ vegetation which accounts for the peat we see today. The grey pebbly deposit in the foreground is the Skipsea Till, a 'boulder clay' of debris bulldozed by the Devensian ice. Were it not for the glacial till, the area of Holderness would not exist and would be completely under the sea. The Skipsea Withow Mere is a SSSI. More information here: www.york.ac.uk/inst/chumpal/EAU-reps/EAU94-61.pdf

Porth Selau is a safe quiet sandy beach tucked away at the southern end of Whitesands Bay (Porth Mawr). There is no road access - you have to walk. I just liked the textures and lighting on the sands and the miniature braided channels created by this rivulet flowing over the beach.

Porth Selau is a safe quiet sandy beach tucked away at the southern end of Whitesands Bay (Porth Mawr). There is no road access - you have to walk. I just liked the textures and lighting on the sands and the miniature braided channels created by this rivulet flowing over the beach.

I was intrigued by the colours and textures of the cross-bedding in the rock face of this abandoned quarry in the Chatsworth Grit (Namurian) at Hay Wood, above Nether Padley, Derbyshire.

Cross-bedding in Chatsworth Grit (Upper Carboniferous, Namurian) on the free face of Froggatt Edge in the Peak District National Park.

Cross-bedded Crawshaw Sandstone (Coal Measures) on White Edge in the Eastern Edges area of the Peak District National Park. A prominent erosion surface is visible in the centre, where the cross-bedding of the underlying sand unit has been truncated by the overlying sand unit.

This is a view southwards along the low escarpment of White Edge in the Eastern Edges area of the Peak District National Park. Unlike most of the Eastern Edges which are formed of Namurian 'Millstone Grit', White Edge is comprised of Crawshaw Sandstone which is stratigraphically just above the base of the Coal Measures. I love the feeling of wide open spaces in the this area, yet we are only a few miles SW of Sheffield.

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 Hope Valley, Hope cement works, Mam Tor and the Kinderscout plateau are all visible in the background.