Monday, December 25, 2006

Swanage



The hard banks of limestone form headlands while softer clays have been eroded into bays. Boat trips offer a fabulous view of the 80 million year old chalk stacks of Old Harry Rocks, the most easterly end of the Jurassic Coast. At Ballard Down the chalk ridge appears and the almost vertical layers of the chalk can only be seen from the sea. At one time, the ridge ran right across to the needles on the Isle of Wight

There is a Heritage Centre at Swanage and boat trips are available to Poole Harbour

Wednesday, December 20, 2006

Monday, December 18, 2006

Friday, December 15, 2006

World Changes during the Triassic, Jurassic and Cretatious Era's


The super-continent of Pangea

During the Triassic era, 240 million years ago, one hemisphere was dominated by a vast ocean while the other hemisphere was dominated by a great super-continent. Pangea. This great landmass included all of what is now known as North America, Europe, North Asia. Africa, South America, India, Australia and Antartica

During Triassic times, Pangea moved gradually northwards. At the end of the permian period, very low sea levels and climate change coincided with a major extinction event. Since then sea levels have risen again allowing a slow recovery of marine life such as corals on land - tropical coal forming forests and swamps diminished as climates got warmer and drier

During the Jurassic era, 170 million years ago, the world was a warmer, less varied place than it is today. There were probably no ice caps at the poles for much of this time. The mild conditions made for much higher sea levels resulting in a smaller area of dry land but extensive shallow continental seas, which teemed with life.

The huge continent of Pangea was splitting up, and familiar modern landmasses such as North America and Eurasia were begginning to appear. Both the North and South Atlantic oceans began to open up. At the same time the ancient tethys ocean began to close

The Cretatious period spanned almost 80 million years from 142 million to 65 million years ago. During this time the world began to take on a familiar look as lands that had once made up the super-continent of Pangea pulled apart. The newly formed Atlantic Ocean extended north and southwards, seperating Africa and Eurasia from the Americas. The continents of Africa, India, Antartica and Australia began to move apart about 120 million years ago as new oceans formed between these constiuents of ancient Gondwana. Asia still had an unfamilliar form, with lands that are now part of its southern edge, such as Indochina and India, still seperate islands.

By about 90 million years ago, the distribution of the contients was looking more familiar. The Atlantic ocean seperated the new world of of the Americas from the old world of Europe, Asia, and Africa. Much of Asia was assembled, except for India. Australia still languished in the deep south, attached to Antartica and India was still attached to Madagascar

Source: The Atlas of the Prehistoric World and Wikipaedia

Monday, December 11, 2006

Budleigh Salterton

Budleigh Salterton has one of the oldest stories of the Jurassic Coast. A story that is also spread out along the length of this coast and beyond

To the west of the sea front lie the famous Budleigh Salterton Pebble Beds. The pebbles are composed of hard quartzite identical to 440 million year old rocks found in Northern France. The pebbles were formed and transported in one of the giant rivers that flowed into the Triassic desert about 240 million years ago

Over the last few thousand years the pebbles have been falling from the cliffs and today form the bulk of the beach at Budleigh Salterton. The larger cobbles and pebbles are very hard and unlike any other rock type found in Southern England. As a result they survive as they are transported along the coast by the waves. They can be seen from Slapton Sands in Devon to Hastings in Sussex

Source: The Official Guide to the Jurassic Coast

Saturday, December 09, 2006

Durdle Door


Thursday, November 30, 2006

Charmouth: The Pebbles



Source: www.bbc.co.uk

Saturday, November 25, 2006

Beer, Devon



Source: Photograph taken by Mark Whitworth and courtesy of the BBC

Thursday, November 23, 2006

The Rock beneath our feet!

Rock can be broadly classified into three types. Igneus, metamorphic and sedimentary, with the Jurassic Coast being of the sedimentary type

Igneus, is the rock that originates from magma within the earth's crust, produced by volcanic activity, when it is found on the earths surface
Metamorphic is the rock that is transported into the depths of the earth by geological processes, where it is heated and compressed. This process eventually changes its composition

Sedimentary rock is created by processes that occur on the surface of the earth, by the weathering of existing rock by water, ice and wind. Sedimentary rocks may consist of the organic remains of marine organisms (limestone), land plants (coal) or chemical reactions and evaporation (salt). Sedimentary rocks that constitute the Jurassic Coast are formed largely of the remains of marine animals. Sedimentary rock is often created by the weathering and re-deposition of pre-existing rock, with the parent rock being of igneus, metamorphic or sedimentary type. Rock particles, once created, are generally carried to distant locations by water, wind or ice, before sedimentation occurs

In past times of high sea levels, shallow seas have flooded deep inland and produced vast continent-wide limestone deposits. Chalk is a form of limestone, that developed in the Cretatious era. This rock was formed by millions of tiny plates of single-celled microorganisms called coccoliths. Over a few million years thier calcite plates piled up on the seabed to form a carbonate mud, which is now a form of limestone, up to 300 metres thick. This chalk forms the spectacular white cliffs of Southern England and North Western France

Any fossil content within a sedimentary rock will indicate its age and the type of environment in which it was deposited. Sedimentary rock often contains organic and inorganic materials. For example, early Jurassic black mudstone, found in the cliffs of Lyme Regis, contains organic material in the form of fish teeth and ichthysaurus bones. The mud itself is made of small inorganic rock particles, but its black colour suggests a high carbon content, the result of decomposition of the soft parts of organisms

Most sediment is deposited underwater, and is then buried further before it becomes rock. The exposure of marine sediment above sea level is due either to tectonic plate processes such as earthquakes and volcanic activity or to a general decrease in sea levels such as is associated with glaciation. Once sedimentary rock is exposed, weathering begins, particles are transported, and the cycle begins again

Tuesday, November 21, 2006

Saturday, November 18, 2006

Fossils on the Jurassic Coast

Fossils are the remains of animals and plants that have been preserved in stone and are the raw materials of the science of paleantology. Paleantology looks at the the direct evidence of fossils to study former life on earth and how it has changed over millions of years

The rocks that form the cliffs of Charmouth and Lyme Regis are rich in those animals that swam in the seas during the Jurassic period. As a result of landslides and winter storms, the area is rich in fossils that have been washed onto the beach. These fossils represent one of the richest snapshots of Jurassic life anywhere in the world

Geologists use fossils to help them identify rocks of a similar age, as rocks located hundreds of miles apart can be recognised as being of a similar age, according to the fossils that they contain. Ammonites are especially useful for this purpose as they evolved and changed rapidly (in geological terms), producing different species with distinctive shell forms. The Jurassic period has been dived into a series of Zones according to the appearance and disappearance of different ammonites


Mary Anning: courtesy of Wikipedia

Mary Anning (1797 - 1847) lived all her life in Lyme Regis and has been described as 'the greatest fossilist who ever live'. She collected fossils at a time when scientific enquiry was leading to a change in the way we thought about the evolution of life and our planet, which would culminate with the puplication of Charles Darwin in 'On the Origin of Species'

Mary collected fossils with her brother and father until the death of her father when she was aged 11. Mary took on the family business, becoming one of the most skilled of collectors, with an impressive knowledge of Anatomy. Her record of fossil 'firsts' is remarkable, leading to many eminent geologists of the day visiting the coast to learn from her work


Source: text
S0urce: graphics

Thursday, November 16, 2006

Lulworth Cove and Stair Hole



The coast around Lulworth Cove demonstates all stages in the development of bays and headlands, and how that development is controlled by the underlying geology. Along this section of the coast, the rocks have been tilted into a near vertical position

The oldest rocks, Portland Limestone, provides a barrier to the sea, behind which are progressively softer rocks, Purbeck Limestone, Lower Greensand, Wealdon Clay and Upper Greensand. The youngest rocks are chalk, which although soft are massive in thickness

The river that runs into the cove at one time reached the sea, through a cut in the hard Portland Limestone barrier. This allowed the sea to erode the Limestone. Once the sea reached the softer rocks behind, especially the Wealdon Clay, rapid erosion took place. Once the sea reched the chalk, erosion slowed, forming the perfect bay

To the west, the sea has been eroding the Portland Limestone at Stair Hole and the process of bay formation has just begun. Eventually lulworth Cove and Stair Hole will form one larger cove

Source: text

Wednesday, November 15, 2006

The Ammonite Path

Saturday, November 11, 2006

Gateway-Towns - Lyme Regis


The Jurassic Coast by its very nature is 95 miles long, but only a few metres wide. It is served by a handfull of towns, known as gateway towns. They are located very close to the Coast, providing serves for visitors such as hotels, guest-houses, restaurants, shopping facilities, museams and information



The clay cliffs around Lyme Regis are about 200 million years old, marking the start of the Jurassic period, capped by sandstone of about 100 million years in age. After heavy winter rains, huge mudslides flow onto the beach, where they are washed away by rough seas, uncovering the fossils

Lyme Regis is served by a Tourist Information Centre and Museum. You can also take boat trips from here, enabling the viewing of the Jurassic Coast from the sea, possibly the best way to see it

Saturday, November 04, 2006

Old Harry!



Silently Sleeping is the rock formation known as Old Harry's Rocks, located on the extreme South east of the Jurassic Coast

Tuesday, October 31, 2006

Lulworth Stairhole from a Slightly Whacky Angle!

Saturday, October 28, 2006

The Rocks beneath my Feet - Part 1

The Jurassic Coast is a living record of the last 250 million years, which encompasses the Mesozoic Era. The Mesozoic Era includes the Triassic, Jurassic and Creatious periods

The triassic Period of around 200 - 250 million years ago

In Triassic times, the Jurassic Coast was part of a super-continent called Pangaea. This landmass divided to form the continents of the modern world. The Jurassic Coast lay within the arid centre of the super-continent and hot desert conditions prevailed. A huge mountain chain lay to the west. The mountains gradually eroded and thier roots remain in Dartmoor, England and Brittany, France. Rivers flowed north and east, depositing pebbles and sand across southern England. The rivers spilled into the desert, creating vast lakes that were subject to evaporation

The Triassic rocks on the Jurassic Coast are red because deserts contain very little organic material, and, in its absence, iron forms red oxides. In the modern world the Namib Desert in Africa has the sort of conditions that the eastern part of the jurassic Coast would have known during the Triassic period

The Triasic period was a critical period of evolution. The Earth had been decimated by a large mass extinction event at the end of the previous period. The surviving groups of animals evolved and diversified. The first donosaurs evolved and went on to dominate life through the entire Mesozoic era

Most of the groups of four legged animals that we see today had arrived by the end of the Triassic period, including frogs, turtles, crocodiles and mammals

The Jurassic period of around 140 - 200 million years ago

Pangaea started to break apart during the Jurassic era. The Atlantic Ocean opened to the West of Britain and the Americas drifted away from Europe.

The Earth was relatively warm with high sea levels and hardly any polar ice caps. The rocks of the Jurassic Coast recorded the marine conditions during the Jurassic period, conditions that fluctuated from relatively deep seas to coastal swamps

Sea levels rose and fell in a series of cycles, depositing deep water clays, sandstones and finally shallow water limestones. The sea was shallower in the Middle Jurassic, creating an environment of islands surrounded by shallow shoals, similar to the Caribbean of today. Sea levels then deepened and finally shallowed towards the end of the Jurassic, creating the conditions for a forest to flourish in a tropical swamp environment

The expansion of shallow seas encouraged an explosion of life in the Jurassic period, with many species evolving rapidly in order to take advantage of the new habitats. Dinosaurs walked the earth and the dominant carnivores in the seas included plesiosaurs and crocodiles. This information is drawn from the evidence of fossils found on the Jurassic Coast, along with the numerous fossilised ammonites (related to the modern-day squid) that lived during this period

The Cretatious period of around 65 - 140 million years ago

During the Cretatious period, America continied to drift away from Europe and the Atlantic developed into a recogniseable ocean. In the early part of the Cretatious era the Jurassic Coast would have been similar to the modern day Gulf of Arabia with lagoons covered by salt flats. Conditions would have become more hospitable, with lush swamps inhabited by dinosaurs. Mid-way through the period, movement of the earth deep under the South-West of England tilted the rocks to the East. As the Atlantic Ocean and Mediterranean expanded, a vast sea developed over the area. Within the clear warm waters billions of microscopic algae bloomed, their skeletons sank to the sea floor to form the pure white chalk that is seen in this area

The cretatious period was when some of the largest and most feared dinosaurs walked the earth. It is also the time when the first flowering plants are thought to have appeared. The end of this period in time is critical to the shape that the modern world would take. A mass extinction took place which heralded the end of the reign of the reptiles as the dominant life on earth. Dinosaurs, marine reptiles and ammonites were among those species that became extinct at this time. The modern world that followed would be dominated by mammals, flowering plants and grasses

Chalk: the youngest of the Cretatious rocks found across the Jurassic Coast

Source: The Official Guide to the Jurassic Coast

Friday, October 27, 2006

Fossils

I have wanted an ammonite for many a long day now, and as you can see from this picture, I am now the proud owner of one. However, all is not as it seems ... I bought this one for a few pounds in Lyme Regis. It is a Promicroceras Planicosta and was found at Lower Lias, Lyme Regis ... it is approximately 190 million years old!



Ammonites are an extinct member of the molusc family, possessing an external shell, coiled in a flat spiral and divided into chambers. They appear in the Carboniferous period and mysteriously died at the end of the cretatious era

Geologists are able to use fossils to help them identify rocks of similar age. Rocks which are hundred of miles apart can be recognised as being of the same age due to the fossils that they contain. Ammonites are especially good for the purpose as many evolved and changed rapidly (in geological terms), producing different species with distinctive shell forms. The Jurassic has been divided into a series of zones based on the appearance and disappearance of different ammonites

Source: The Official Guide to the Jurassic Coast

Monday, October 23, 2006

Taking another trip to the Jurrassic Coast today, watch this space!

Friday, October 13, 2006

Brownsea Castle



Brownsea Castle is a mid 16th century square blockhouse protected by a moat which was built on Brownsea Island in Poole Harbour. It was renovated during the 19th century as a stunning residence, sadly though, it was badly damaged by fire in 1895. It has however, been rebuilt and is now used exclusively by the John Lewis Partnership

The island is owned by the National Trust and is open during the months of April - September. Many boat trips of Poole harbour leave from Poole quayside. A boat trip is possibly the best way to see Brownsea Island.

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Wednesday, October 04, 2006

Lyme Regis



Lyme Regis is notorious for the fossils that are found there. The rocks here are of the Jurassic era, making them in the region of 140 - 200 million years old

Mary Anning (1799 - 18470) lived for her entire life on Lyme Regis and has been described as 'the greatest fossilist who ever lived'. She collected fossils at a time when scientific enquiry was leading to a change in the way people thought about the evolution of life and our planet. A story that would culminate with Charles Darwin's 'On the Origin of Species', published in 1959

Source: The Official Guide to the Jurassic Coast

Saturday, September 30, 2006

Brownsea Island from the water!





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Thursday, September 28, 2006

Chessil Beach



Unbelievable as it may seem this picture was taken while standing in the carpark! As you rightly guessed it was a wet day, and I am stood in the carpark located next to the Heritage Centre! Not a lot of visitors to Chessil that day

In the distance you can see the mound of pebbles which is Chessil beach!

Monday, September 25, 2006

Back to Lulworth Stairhole!




Another picture of the Lulworth Stairhole ... also known as the Lulworth Crumple! What you see is another cove being created next to Lulworth Cove. The breach has been made by collapsinig caves and arches. This has revealed the famous Lulworth Crumple, a complex fold formed by major earth movements that occurred in the same period that the Alps were formed.

[Courtesy of The Official Guide to the Jurassic Coast]

The rocks in this area are from the jurassic and Cretatious era, which are from 65 million to a little over 140 million years ago

Tuesday, September 19, 2006

Old Harry's Rock

I visited this rock formation way back in the summer, viewing it from the sea!



The rocks are caused by the erosion of waves, which attack the weak joints in the rock, forming arches and caves. Eventually they collapse leaving isolated stacks like 'Old harry'.

The rocks in this area are chalk from the Cretatious era of around 65 million years ago

Tuesday, September 12, 2006

The Cliffs between Durdle Door and Lulworth Cove

Sunday, September 10, 2006

Durdle Door



The picture above is of a pathway I descended from a car park, just off the road that leads to Lulworth Cove, which is a mile or so from Durdle Door. At the edge of one the chalkstone cliffs at the end of the windy path I could see more chalkstone cliffs to the right and left



Looking out to sea and below the cliff edge I was stood on, at the foot of the long windy path is Durdle Door. It is a perfect coastal arch, carved out, by the erosive action of the sea

The rocks in this area are of chalk, from the Cretatious Period of approximately 65 million years ago

Tuesday, September 05, 2006

Gateway Towns - Portland

Although the Jurassic coast is approximately 95 miles long, it is but a few yards wide, reaching up to the edges of the beachs, coastline and cliffs, therefore just a few yards wide in some locations. Bearing that in mind, there are a number of other features lying just beyond the boundary of the Jurassic coast. For example there are a number of what are named gateway towns lying just behind the boundary ... there are also castles and other buildings of historical importance. One such building is Portland castle, as shown below ...



Portland castle was built by Henry VIII in 1540. Forming part of his coastal defense system against invasion by the French. Positioned so close to the enemy across the narrow channel, he took no chances and built the castle walls fourteen feet thick

Saturday, September 02, 2006

Brownsea Island



I saw Brownsea Island in the summer from a boat trip. The trip started from Poole Harbour in Dorset to Swanage, via Old Harry Rocks. It was a beautifull sunny day and just the time to see some of the Jurassic Coast at its best.

Brownsea Island is the largest Island within Poole Harbour. It is a former hill above river valleys from when sea levels were lower than they are today. It seperated to become an island during flooding from the Flandrian Trangression after the Pleistocene Ice Age ... and Poole Harbour was formed

The Pleistocene is the most well known of the Earth's Ice Ages. The ice sheets once covered all of Antartica, along with large areas of Europe, North and South America, and smaller areas of Asia. The glaciation of the Pleistocene consisted of several glacial advances followed by interglacial phases when the ice retreated and a relatively mild climate prevailed. Carbon-14 dating of fossils indicates that the last glacial period ended around 11,000 years ago

Thursday, August 24, 2006

Chesil Beach!




This is a beach that I visited in the summer, I did initially have great difficulty finding it, but once I did, I was were amazed. It is awesome, and appears to stretch for miles, which of course it doesnt, it actually stretches for 17 miles. This picture was taken from a hill overlooking the beach! The amazing thing about Chessil is that to get to the water you need to ascend a mound of pebbles and shingle, only to then descend the mound to get to the waters edge



The above picture is probably the more familiar scene, with the rock which is Portland clearly visible from the beach. Chessil is one of the largest barrier beaches in the world, consisting of pebbles and shingle that have withstood the fullforce of the Atlantic Ocean for thousands of years, The beach protects 'the fleet', which is the largest tidal lagoon in Britain