Earthwatcher's photos with the keyword: Crackington Haven

Rocks, sand, sea and a lone photographer illuminated by the last sliver of the setting sun at Crackington Haven, Cornwall. I was hoping to see the Green Flash, having seen it once a few years ago from north Cornwall, but it didn't appear on this occasion. I think there was too much dust/water droplets in the atmosphere.

Little Barton Strand is a rocky inlet just north of Pencannow Cliff and Crackington Haven, notth Cornwall. The stripy rocks are interbedded grey shales and turbidite sandstones of the Crackinton Formation (upper Carboniferous), which are mostly inverted - turned upside down - by the Variscan earth movements at the end of the Carboniferous. This locality is also where the truncated Cleave valley terminates abruptly. Its waterfall can be seen on the far right plunging over a near vertical lip on to the rocky beach.

A zoomed-in view of the base of the cliff on the north side of Crackington Haven, north Cornwall. Grey shales and thin turbidite sandstones, (pale grey-brown) of the Crackington Formation (upper Carboniferous) have been strongly deformed into isoclinal recumbent folds by the Variscan earth movements at the end of the Carboniferous. For an interpretation and further details, see this photo:

Beautiful evening sky at Crackington Haven, north Cornwall, viewed from near Hallagather about 18 minutes after sunset.

The 80 metre high cliff of Pencannow Point towers over the northern side of Crackington Haven, north Cornwall. A figure in the lower right corner helps give a sense of scale (see note). Grey shales and thin turbidite sandstones, (pale grey-brown) of the Crackington Formation (upper Carboniferous) have been strongly deformed into isoclinal recumbent folds by the Variscan earth movements at the end of the Carboniferous. A zoomed-in view of the lower part with a geological interpretation is here:

The 80 metre high cliff of Pencannow Point towers above the northern side of Crackington Haven, north Cornwall. Photo taken from near Hallagather.

By special request: an interpretation of the zoomed-in view of the base of the cliff on the north side of Crackington Haven, north Cornwall. Original photo here: Grey shales and thin turbidite sandstones, (pale grey-brown) of the Crackington Formation (upper Carboniferous) have been strongly deformed into isoclinal recumbent folds by the Variscan earth movements at the end of the Carboniferous. This is an attempt to interpret the main geological structures, as seen on the more-or-less 2-D vertical cliff face: Yellow lines are arbitrary bedding traces Blue dashed lines are synclinal axes Red dashed lines are anticlinal axes Sedimentary features (ripples, sole structures, etc) in the sandstones enable us to determine the 'way-up' of the beds and hence classify the folds into anticlines and synclines. In this photo, the general 'younging' direction is to the south east (right). The folds were probably initially upright as the Variscan compression developed but continuing deformation and complex thrusting rotated the whole stack of folds in a clockwise sense so that the fold axes became approximately horizontal. The deformation is more intense here compared with Millook Haven 3.5 miles to the NE: This probably reflects (a) more shales (weaker rocks which deform more readily) in the Crackington Haven section and (b) the more southerly location is slightly closer to the 'source' of the deformation. As a general rule, in Cornwall the most intensely deformed rocks are towards the south.

A delightful place in a lovely part of Cornwall.

These elongated ridges are seen on the inverted bedding surface of a turbidite sandstone bed (Crackington Formation, upper Carboniferous) on the south side of Crackington Haven, north Cornwall. The scale can be deduced from the limpets - the largest is about 4 cm across. The ridges are casts of sandstone infill into what was originally a hollow groove in the underlying sediment. The grooves were formed at the time of sediment deposition by fast-flowing water making small erosion scours around irregularities on the Carboniferous sea bed. Sometimes the current flow was sufficiently powerful to drag along pebbles and small boulders, which created long linear grooves. Here, the rocks have been turned almost completely upside-down by intense folding at the end of the Carboniferous, so the grooves now appear as ridges. These sedimentary structures are generally known as 'sole structures' and are valuable as 'way-up' indicators - we can tell whether the rocks are the right way up or have been inverted, as is the case here. Also in this example, the scours are asymmetrical - deeper at the upstream end (lower right) and shallowing off at the downstream end (upper left), so they also provide evidence for the water current direction at the time of deposition. So in this case, the water flowed from lower right to upper left. But the rocks have been inverted by folding, so..... Here, the rocks are dipping (sloping) to the north (right) at about 30°, having been completely overturned by the folding. To restore this slab into its pre-folding position we need to imagine it 'flipped over', by rotating it through approx. 150° in a clockwise sense, like closing the left-hand side of an open book. Once we do this, the sole structure ridges on the upper surface of the slab become protrusions on the underside of the slab, with the asymmetric deeper upstream side to the left (south) and the shallower downstream side to the right (north). Therefore, the original current direction which transported the sediment of the Crackington Formation was from south to north: the source of the sediment lay to the south, and was transported northwards by the water currents. NB: The information board by the public toilets at Crackington Haven is excellent, except for where it states that the Crackington Formation sediment derivation was from the north. Sorry, but they've got that bit wrong! The evidence is there on the beach for all to see.

Another view of the sole structures on the inverted (upside-down) base of a turbidite sandstone slab in the Crackington Formation on the south side of the beach at its type locality, Crackington Haven, north Cornwall. The palaeo-current direction in this photo was from lower left to upper right. The scale can be deduced from the limpets - the largest is about 4 cm across. A full explanation of the structures and what they can tell us can be found here: www.ipernity.com/doc/earthwatcher/39023846

A view of the south side of Crackington Haven and neighbouring bay of Tremoutha, with the headland of Cambeak in the distance; viewed from the coast path on the north side of Crackintgon Haven The sole structures in the previous two photos are on the rocks in the foreground.

Little Barton Strand is a rocky inlet just north of Pencannow Cliff and Crackington Haven, notth Cornwall. The stripy rocks are interbedded grey shales and turbidite sandstones of the Crackinton Formation (upper Carboniferous), which are mostly inverted - turned upside down - by the Variscan earth movements at the end of the Carboniferous. The upper surface of slab in the middle foreground displays superb sole structures on what would have originally been its base, but has subsequently been inverted. This locality is also where the truncated Cleave valley terminates abruptly. Its waterfall can be seen on the right plunging over a near vertical lip on to the rocky beach.

Here the truncated Cleave valley terminates abruptly. Its waterfall is just out of sight in the shadowed gully on the right plunging over a near vertical lip on to the rocky beach of Little Barton Strand. Castle Point is just out of shot to the left.

Just inland from its truncated termination at Little Barton Strand, the Cleave valley heads inland, but running nearly parallel to the coast for a short distance just east of Castle Point.

Castle Point near Crackington Haven, north Cornwall, is comprised of interbedded grey shales and turbidite sandstones of the Crackington Formation (upper Carboniferous) rather complexly deformed here into recumbent chevron folds which themselves have been cut by northward-directed and dipping thrusts. The rocky inlet in the foreground is Orchard Strand.

Heading out of the Cleave valley towards Castle Point on the South West Coast Path, amid a spectacular carpet of furze and heather.

Spectacular sole structures - scours, ripples, grooves, etc. - on the inverted (upside-down) base of a turbidite sandstone slab in the Crackington Formation at Little Barton Strand, near Crackington Haven, north Cornwall. The palaeo-current direction in this photo was from bottom to top, which on restoration of the slab to its original non-inverted state, corresponds to a palaeo-current and a sediment derivation from the south. A full explanation of the structures and what they can tell us can be found here: www.ipernity.com/doc/earthwatcher/39023846