Tuesday 14 August 2012

Monmouth Beach, Lyme, closed due to danger of landslips.

Monmouth Beach lies to the west of Lyme Harbour, on the Jurassic Coast of Dorset. It is popular with tourists due to its Limestone Pavement, where abundant large Ammonites can be seen, and the ease with which detached fossils can be found on the foreshore. Like many productive fossil-producing sites it is an erosional cliff, prone to rockfalls, which periodically remove sections of the cliff exposing fresh fossils. The fossil beds around Lyme Regis are internationally famous, due to the large Marine Reptile fossils collected their by Mary Anning in the early nineteenth century, and John Fowl's novel The French Lieutenant's Woman, which was set in the area and had a palaeontologist as its male lead.

Tourists inspecting Ammonites on the Limestone Pavement at Monmouth Beach. Discovering Fossils.

This summer has seen exceptional rainfall in Dorset, which can prove hazardous at bedded limestone cliffs such as Monmouth Beach. On 23 June this year 22-year-old Charlotte Blackmam from Nottinghamshire was killed by a rockfall at nearby Burton Bradstock, which is geologically similar to the West Cliffs at Lyme. The problems occur on cliffs made up of alternate layers of limestone and mudstone. In heavy rains water washes the mudstone layers out at the cliff-face, leaving the limestone layers unsupported. Eventually insufficient mudstone remains to support the cliff surface, and the limestone layers collapse, leaving a new cliff-face in which the two layers are more-or-less flush.

The West Cliffs at Lyme Regis, showing the same bedded limestone structure as that which caused a fatal rock-fall at nearby Burton Bradstock in June 2013. Discovering Fossils.

After careful consideration of the condition of the cliffs at Monmouth Beach, which suffered two rockfalls in July and which still appear at risk of further, possibly larger, collapses, Dorset County Council and Natural England (who own the cliffs), have decided to close the beach. It is unclear how long the closure will remain in place, though it will probably last until after English schools reopen in September, when tourism at Lyme Regis drops off abruptly. If the closure lasts longer then it could cause problems for a number of English universities, which tend to run undergraduate field-trips to Lyme early in the academic year.

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