weekender

UKAFH Weekender – Isle of Wight 2018

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On 14 and 15 April 2018, UKAFH conducted its first weekend event of the year. UKAFH members from across the UK left the mainland behind and sailed across the Solent to the sunny and highly fossiliferous shores of the Isle of Wight.

On Saturday, 14 April, we descended onto Thorness Bay, which is on the north coast of the island. Access to the bay is through Parkdean Thorness Bay Holiday Park, where many of the group were staying in caravans or, the bravest amongst us in tents. The park has excellent facilities, such as toilets, and a bar and restaurant, as well as ample parking and a small supermarket, which made it a very comfortable start to the day.

The weather was glorious and sunny – the first really warm and sunny day of the year, which filled us with hope and anticipation. In fact, we couldn’t have hoped for better or more relaxing weather.

We began in the car park, where Chris Tait and Nicky Parslow displayed some of the fossils that we were likely to find from the Oligocene epoch, such as carapaces from Emys and Trionyx turtles, and scuta from Diplocynodon alligators. We also saw shiny fish bones and vertebrae, and the very rare mammal teeth of Elomeryx – a stout hippopotamus/pig like creature. In addition, we saw echinoids preserved in flint, which can be found derived from the much older Cretaceous sediments.

We walked as a group down the gentle slope from the carpark to the beginning of the bay, where Chris pointed out the Bembridge Insect Beds to the east and where, unfortunately, fossils are few and hard to find. So, we set off to the west, where we could see a gently sloping shingle beach, with some exposures of green/blue clay from the highly fossiliferous Hamstead Beds. Chris explained to us that the best collecting technique is to look carefully and move slowly, and that moving the gravel with a trowel would likely result in uncovering fossils. Chris also painted a picture of what Thorness Bay might have looked like during the Oligocene epoch, about 30 million years ago – a lagoonal area within an estuary, where alligators, turtles and fish would have swum and hunted. Elomeryx porcinus would have been seen grazing on the edge of the lagoon and also swimming out to eat the plants growing in the lagoon. It would have been much warmer during the Oligocene, averaging 20 to 25oC, as the location lay much further south, closer to the equator.

As we headed west, we found that the first part of the bay was less productive than further along, but most people found gastropods, bivalves and fragments of turtle and fish during the early part of the hunt. As we moved along the bay, the first major find was found by UKAFH leader, Elliot Mills, who found a rare E. porcinus tooth and a fish vertebra on the surface of the shingle, within a few centimetres of each other. The group continued to round the first two corners, where more and more fossils were found. Silas Shaul found a beautiful echinoid preserved in flint, high up on the tide line. As pointed out above, this would not have come from the Oligocene epoch, but from the much earlier Cretaceous period. Isabella Rice found part of a Diplocynodon alligator scute and Nicky Parslow found part of an alligator jaw.

As the afternoon drew late, we ambled back to the holiday park and got cleaned up before the evening’s entertainment. At 7pm, we met up in the bar area of Parkdean and, at 7.30pm, Aidan Philpott presented a quiz to four teams. This was quite challenging, but fun at the same time, and there were several prizes, which were distributed for achievements, such as the Best Team Name – “The Not Crocodiles” and the Best Wrong Answer – “Strawberry Daiquiri” in answer to the question “What Beverage is Sir Hans Sloane often credited with having introduced to the UK?” (The answer is actually hot chocolate.) The Yan family won the quiz with a fantastic score of 15 and claimed the golden hammer.

After the success and glorious weather of Saturday’s hunt at Thorness Bay, we met on a drizzly Sunday afternoon at Brook Bay on the west coast of the island.

The cliffs and foreshore at Brook Bay represent part of the Wessex Formation, which is a mixture of mudstone, sandstone and clay. This was deposited during the Barremian age of the Cretaceous period, about 127 million years ago, in what was a large river basin that drained the surrounding hills. At the time, the climate here was warm and intensely seasonal. This intense seasonality is key to understanding the type and abundance of fossils found here. The landscape would have had rivers and tributaries running throughout it, with ponds, lakes and boggy areas – notable in the fossil record by the abundance of fresh water bivalves and fish remains. The water source and warm climate meant the area was, for much of the time, densely vegetated – the abundance of plant fossils here is immediately noticeable in the form of black, shiny lignite that litters the beach.

The dense vegetation would have attracted herbivorous dinosaurs, such as huge iguanodonts, sauropods and the heavily armoured Polacanthus, and the presence of herbivores would have attracted carnivores, such as the enigmatic allosaurid, Neovenator salerii (the bones of which can be seen at the Dinosaur Isle museum at Sandown). These dinosaurs left their footprints in the mud surrounding the rivers, ponds and lakes. The dry season then came, rivers ran dry, ponds vanished and lakes became anoxic, with the footprints left in once soft muddy sediment becoming solidified among a parched landscape. Charcoal derived from brush fires found in the Wessex Formation, indicate just how intense the dry seasons would have been. The wet season then followed, which is key to understanding the abundance of fossils here. Intense storms would have caused massive flooding, rapidly depositing sediment in the area, burying plant remains, bivalves and bones, as well as filling the dinosaur footprints with coarse sediment, forming casts of the footprints. Brook bay is famous for its dinosaur foot casts, which, after scouring conditions, can number in the hundreds along the beach.

After a talk about the geology and examples of likely finds by Aidan Philpott, we headed north towards Hanover Point, looking amongst the shingle for ‘rolled’ dinosaur bone. Dinosaur bone is commonly found along this stretch of beach. However, it can be hard to spot amongst the abundance of similarly coloured lignite, but we were an eagle-eyed group and bone was soon being discovered. Dinosaur bone here is often described, as ‘rolled’, as it is most commonly found worn, weathered and rarely articulated – not only from being exposed to beach conditions, but also from the intense storms and flooding it experienced before becoming fossilised. This often makes it hard to identify what bone it is or what animal it came from. However, Silas Shaul made a cracking find of a clearly defined dinosaur toe bone. As well as dinosaur bone, other notable finds included a Sheenstia fish scale found by Emma Philpott and the impression of a pine or cycadean cone found by Elliot Mills.

As the tide fell, the group explored the exposed soft ledges for fossils lodged in the rock pools. Nicky Parslow found some beautiful small in situ footprints on these ledges, which we were able to admire and photograph before they are lost to tidal action.

Later in the afternoon, the drizzle stopped and the sun began shining. As the tide had now retreated, it was a perfect opportunity to show the group a dinosaur trackway exposed far out on the shelf, as well as the impressive Pine Raft. The Pine Raft helps to illustrate just how intense the flooding that occurred here was. Preserved amongst the clay and mudstone are the remains of huge tree trunks, which would have been transported by a flooding event and lodged within the river system, where plant debris continued to build up. It is fascinating to see these huge trees in situ, which really helps us to visualise the area 127 million years ago. The dinosaur trackway also helps to visualise the animals that would have lived here. Exposed far out on the ledge, almost directly opposite Hanover Point, is a series of five footprints from a relatively small herbivorous dinosaur. The strides appear short, so we could imagine perhaps a juvenile Iguanodon casually strolling past. Sadly, along this trackway, one of the footprints is notably absent, because it was recklessly removed some years ago with a rock saw. This gaping square hole served to remind us about the importance of responsible collecting and why we must always observe the fossil code and SSSI restrictions, to preserve specimens for all to enjoy and discover.

We would like to extend our warmest gratitude to everyone who attended the Isle of Wight weekender. It was a pleasure to spend the time with such an enthusiastic and dedicated group of fossil hunters. We hope you all enjoyed, learned and discovered. And congratulations again to the Yan family for winning the coveted Golden Hammer on the UKAFH quiz.

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Left to Right: UKAFH Leaders Chris Tait, Sam Caethoven, Nicky Parslow and Aidan Philpott enjoying a ride on a gribble in Yarmouth!