Disappearing Dunwich

Roy Bullard (UK) There are many places around the coastline of the British Isles that are quite simply majestic and, in their own unique ways, full of magic. Dunwich lies between the lovely town of Southwold and the village of Sizewell on the East Coast of England in the county of Suffolk. It is a coastal area that is easy to include in this category and is a place that I love to visit. However, as you sit there on the shore watching the cliffs and the North Sea, it is hard to imagine that so much has been lost since the time when Dunwich was once a large, thriving community. Fig. 1. Sandy cliffs of Dunwich. My aim in this short article is to take a look at the present state of this coastline and compare it with the coast as it once was before huge amounts of coastal erosion had taken place. In addition, I will take a look at the area’s history and mention, in passing, one of its well-worked, mythical tales. A steeply sloping shingle beach now lies in front of the cliffs at Dunwich. These cliffs have changed a lot over time but, over the past few years, erosion has decreased substantially. The cliffs today are overgrown and this indicates a significant slowdown in the rate of erosion. However, with the ongoing threat of climate change and rising sea levels, the local residents and council have joined together to act now to protect the northern … Read More

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Seeing into the ‘Stone Age’: The stone tools of early man

Bob Markham (UK) In the early part of his evolution, man made great use of rock and stone to assist him in his activities. The term ‘Stone Age’ has been given to the period of time during which stone was the main material used for the manufacture of functional tools for daily life. It is generally thought to have commenced about 3.3Ma and was the time when man firmly established his position on earth as a ‘tool-using’ mammal. However, it should be remembered that stone was not the only material used for this purpose. More perishable materials, such as wood, reeds, bone and antler, were also used, but very few of these materials have survived to be found today (but see the box: Non-stone tools). Non-stone toolsA notable exception to the general rule that non-stone tools have not been preserved is the Palaeolithic wooden spear shaft that was recovered in 1911 from a site in Clacton in Essex. At 400,000 years old, the yew-wood spear is the oldest, wooden artefact that is known to have been found in the UK (see http://piclib.nhm.ac.uk/results.asp?image=001066).A number of wooden spears dating from 380,000 to 400,000 years ago were also recovered between 1994 and 1998 from an open-cast coal mine in Germany (see https://en.wikipedia.org/wiki/Schoningen_Spears). Other items are found from time to time from peat-bog conditions, which offer the most favourable medium for the preservation of such material.The stones used to make tools Being a non-perishable material, stone has survived the ravages of time and is … Read More

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Humble flint sea urchins and the stories they tell

Joe Shimmin (UK) Flint is a very hard-wearing rock from the chalk of the Upper Cretaceous. Whole beaches made of flint pebbles can be found many miles away from the chalk strata that the nodules originated in, owing to the rock’s ability to withstand the processes that destroy other rocks quickly. Flint sea urchins are especially hard-wearing, as their rounded shapes require a lot of force to damage, while less-rounded flints tend to break up over time if subjected to high-energy environments, such as beaches and fast-flowing rivers. Because of this robustness, it is possible to find flint urchins, which have undergone some very interesting journeys before being collected, adding to their interest for fossil hunters. Fig. 1. The hardness of flint and the rounded shape of flint urchins make them extremely robust fossils. All flints start off within chalk strata. Where these strata are exposed at the coast or in quarries and cuttings, it is possible to collect flint sea urchins, which, at first, look very much as if they are preserved like every other urchin found in chalk. They have a white calcite-replaced test and all that can be seen of the flint within is a slight blueish tint or maybe a glimpse of the nodule through the anal or oral apertures. Of course, flints can also be found that partially or fully envelop an urchin and, in these cases, highly aesthetic display pieces can sometimes occur. Fig. 2. Two of these pristine fossil urchins, extracted straight from … Read More

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Geology and fossil fauna of the South Ferriby foreshore

John P Green (UK) The large working quarry at South Ferriby, North Lincolnshire (SE991204) is a well known and productive source of Late Jurassic and Cretaceous fossils, exposing beds from the Upper Oxfordian stage, Upper Jurassic (Ampthill clay, Ringsteadia psuedocordata zone) to the Terebratulina lata zone of the Turonian stage (Welton Chalk Formation, Upper Cretaceous). Research on the stratigraphy and palaeontology of the site has been carried out by many authors, and a generalised section detailing the overall stratigraphy and macrofossil occurrences was published by the local amateur geologist, Dr Felix Whitham (1992). However, in recent years, access to the quarry for geologists has been relatively curtailed due to health and safety concerns. In light of this, my research at South Ferriby has shifted to the nearby geological exposures on the easily accessible foreshore, on the southern banks of the Humber Estuary. Fig. 1. South Ferriby foreshore, looking east. In general terms, the beds exposed on the South Ferriby foreshore tilt eastward, exposing the older (Jurassic) rocks to the west and the younger (Cretaceous) rocks to the east. The exposures are largely wave-cut platforms, accessible only at low tide, and are often covered with sand and estuarine sediments, as well as a large variety of erratic rocks and fossils. Especially prominent among the latter are carboniferous corals and limestones, Cretaceous flints, the Jurassic oyster, Gryphaea, and specimens of the Cretaceous (Late Campanian) belemnite, Belemnitella mucronata, most likely derived from chalk of this age that floors the North Sea. The low … Read More

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Encountering desert deposits in Oman

Clarissa Wright (UK) Oman is a geologically fascinating country, where the bedrock beautifully exposes a one-billion-year history. I had the opportunity to explore this country in a group expedition, during which we pursued our own scientific studies from January to March 2014. My geological observations during the expedition were opportunistic and involved a variety of sights, having traversed from east to west from Muscat, across the dusty plains of the Empty Quarter (Rub’ Al Khali) desert to the Dhofar Mountains of Qamar. Rub’ Al Khali: The Empty Quarter desert The Empty Quarter desert is the largest sand desert expanse in the world (Peter Vincent, 2008) and is considered to have great oil prosperity under the dunes. The desert may lack bedrock exposure, but it is home to some unexpected sedimentary deposits. We found the light golden sand to be littered with brown bubbly balls – geodes (Fig. 1). When broken open, the insides are glazed with white calcite crystals sparkling in the desert sun. These had formed when rock cavities filled with crystallised calcite. In time, these balls of calcite weathered out from the host rock, before being transported by water and deposited here on the desert plains. Fig. 1. Geode in the Empty Quarter desert. These were not the only interesting deposits found. Strangely shaped pebbles of flint and dark metallic-like forms also lay here (in an area previously documented to have archaeological interest). One can see how these appear to have been hand carved by humans thousands of … Read More

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Erratic rocks in fields and beaches of the Isle of Wight

 Stephen K Donovan (The Netherlands) The Isle of Wight is a marvellous place for the geologist on holiday, but there must be a suspicion that it has all been done before. When I first visited the island in 1999, my late wife Trina said that, of course, I would want to geologise at some point. She was surprised at my immediate and emphatic reply of ‘no’, until I explained that every square inch of the island was already ‘claimed’ by so many geologists and groups of geologists that I could not possibly get involved without starting a priority war. I was there to relax, not fight. Fig. 1. Outline map of the Isle of Wight, showing the positions of the principal settlements and villages mentioned in the text, and Sites 1-3. Key: CP = Chessell Pottery; EC = East Cowes; OH = Osborne House; 1-3 = collecting sites mentioned in the text. Today, I have a different approach. The family Donovan goes to the Isle for their summer holidays most years and I still go to the island to relax, not fight. But I am now working on a range of projects on the Island that are unlikely to impinge on other peoples’ research, while informing my own interests. These have included identifying borings in fossil wood from the Cretaceous greensands that have been misnamed since the nineteenth century (Donovan and Isted, 2014) and exploring closed railway lines using a geological field guide published a hundred years ago (Donovan, 2015). … Read More

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Real ‘Southend Rock’

Bob Williams (UK) Chert and flint are crystalline (perhaps more accurately described as microcrystalline) forms of rock that man has made use of from Stone Age times. The crystals consist of a microcrystalline form of silica, more commonly known as quartz (silicon dioxide). Flint is the better-known form of this substance and is commonly found as very hard concretions in deposits of chalk. It is so hard that, when the chalk is eroded, the flint remains in an almost undamaged state. Fig. 1. The Clactonian culture ‘handaxe’ tool, which was the first tool we found at Southend beach. When fractured, flint and chert nodules disintegrate to produce conchoidal, glass-like breaks, and this creates sharp edges capable of inflicting physical damage. When controlled, this damage can be put to practical use and early species of man (Homo erectus, H habilis, H neanderthalensis and early H sapiens) recognised this fact and put it to good use in their everyday lives. During the Ice Ages, spreading ice sheets eroded many millions of flint nodules from chalk deposits and spread them all over the UK. When the ice melted during warmer interglacial periods, the nodules were deposited wherever they happened to have been transported to. Such flint nodules are referred to as “derived” nodules. Early man came to recognise them and collected them to make use of their physical properties. In this way, the first stone tools appeared and, as skill levels developed in their manufacture, they became more and more sophisticated in form. … Read More

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On the origin of agate: A 300-year-old enigma

Terry Moxon (UK) Quartz has been estimated to occupy around 12% of the earth’s crust and can be found in many forms, ranging from the massive, clear crystals of quartz and amethyst to the microcrystalline quartz that is to be found in jasper, agate, chalcedony, chert and flint. World-wide, the distribution of agate is not equal, but it can be found in every continent and probably exists in every country. However, only three countries extract enough agate for world export: Botswana, Brazil and Mexico. Fig. 1. Empty gas cavities and agate amygdales in a block of Isle of Mull basalt. (Scale bar = 2cm.)Agate is most frequently found in fine-grained, igneous rocks filling gas cavities (Fig. 1), but it can also be found in sedimentary limestone hosts (Fig. 2) and fossil wood (Fig. 3). The most common agates are the wall-lining and horizontally banded types (Figs. 4 and 5 respectively). Rapid identification of agate in the field relies on the natural translucency of a fractured sample, but final confirmation is supplied by examining a thin section under a polarising microscope (Fig.6). Agate and chalcedony show a fibrous structure, whereas the quartz in flint, chert and jasper is generally granular. Granular quartz can demonstrate regular banding, but this is not agate (Fig. 7). Nevertheless, it is the colours and rhythmic banding that makes agate the most recognisable of all gemstones. Fig. 2(a) and (b) show agate in limestone from Tepee Canyon, South Dakota, USA. Note that both agates are surrounded by … Read More

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