Down to Earth Extra September 2023

The September 2023 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.

Geological Sites of the Bristol Region - back in print! 

The revised edition of this book is back in print and is now available from Bristol Museums - £19.50 plus postage. It is described as:-

An accessible introduction to the geology of the region, including the work of many local experts.

The Avon area is highly regarded as one of the more complex geological areas of the country and also contains such iconic sites as the Avon Gorge. The book aims to promote the gathered records that underpin the designation of RIGS. The book is a not a ‘geology book’ per se and doesn’t attempt to be exhaustive, however, it aims to showcase some of the RIGS themselves alongside the people and organisations involved in their conservation. There are several chapters

dedicated to the history of geology and geomorphology in our area and important figures such as William Smith.

The main part of the book is about the sites and modern interpretation of the geological and geomorphological features. Each site’s account includes location and geological maps as well as site descriptions and photographs. There is colour throughout with photographs, graphics and artworks. The book is interspersed with ‘box topics’ of general interest.

ISBN: 9780954523534

Every purchase you make helps to support Bristol Museums, so thanks for shopping with us!

 Mendip Rocks - Read All About It!

Simon Carpenter asked me to publicise Mendip Rocks 2023 and I am only too happy to oblige. 

There is an advert which you can get HERE, or read it below. There is also a booklet which you can get HERE, or read it below. 

First the advert.

And now the booklet.

GEOconservationNEWSletter Summer 2023

GEOconservationNEWSletter Summer 2023 

You can get the latest edition of Geo Conservation Newsletter HERE, or you can read it below.

 Cliff Collapse in Dorset.

A correspondent has sent me links to news about recent cliff collapses in Dorset.

The first is HERE and below.

And the second HERE and below.

Geologic processes in action - spectacular and normal. Best watched from a distance and examined when all activity has stopped.

Many thanks for the links.

 Rain Keeps Earthquakes Away - Sometimes, in Some Places

In the Himalayas, most earthquakes (and there are a lot!) occur in the dry season, a lot less happen during the monsoon. The rain (up to 4 metres) compresses the crust both vertically and horizontally, making it more stable. Climate change may make this phenomenon more pronounced.

The same thinking applies to ice. When glaciers melt the loss of weight leads to decompression melting. At present this is noticed only in Iceland - some volcanoes erupt mostly in Summer.

You can read all about it in THIS ARTICLE.  

 Will "Our" Mammoths be Exported?

I am not the only one to spot THIS ARTICLE in The Guardian. It concerns the recent find of Palaeolithic fossils in a gravel quarry in the Cotswolds. The headline fossils were mammoth bones but much else was found and is suspected to be awaiting discovery. Tools made by Neanderthals were also found.

At first the quarry owners were welcoming and the BBC and David Attenborough made a documentary about the discoveries. But something has changed and the quarry owners want their fossils back!

The suspicion is that the quarriers had a better offer from the UAE who are building a new Natural History Museum in Abu Dhabi and are collecting specimens for it.

Should one oppose this? The British Museum would be a lot emptier if objects could not be exported from where they were found. Indeed many countries want there objects back. 

Does this apply to fossils? If you are a palaeontologist aching to getting your hands on good specimens the answer is obvious - keep the fossils local to me! We can keep cultural objects in Britain but does a British Mammoth have as much culture as a Leonardo Cartoon?

But I would rather see a mammoth in Bristol Museum or even London, rather than flying to Abu Dhabi to see it.

How Old Can an Impact Crater Get? 

Impact craters are assumed to have been formed in the earliest days of planet Earth but few very old craters are known. THIS ARTICLE uses the Vredefort Dome in South Africa as a means of determining what to look for when finding old, deeply eroded, impact craters.

The Dome is very large (300km across) and very old (2 billion years). The researchers drilled across and around the dome to see if they could spot the effects a large astrobleme can be predicted to make. They could - but only just. There is thought to have been about 7 to 10 km of erosion. 10km would remove all evidence. 

The Vredefort Dome is recognised because of its shape - the central peaks, especially - and the results of shock metamorphism. Another kilometre of erosion would remove these also, leaving no trace of the impact.

The basis of the article is THIS ACADEMIC PAPER.

Gravity map of the Kaapvaal Craton. The Vredefort structure does not have a prominent gravity high or low compared to the surrounding craton. Data from the South African Council for Geoscience. Craton boundary from Hasterok et al. (2022).

Cambrian Jellyfish Fossils!!! 

If you write a blog like this you seldom expect to write the words jellyfish and fossils in close proximity. To write "Cambrian Jellyfish Fossils" as a thing would have been an impossible dream. But it is the Burgess Shale so anything is possible. 

I was directed to THIS PAPER by a correspondent. It is based on THIS ACADEMIC ARTICLE published by the Royal Society. As mentioned above the fossils come from the Burgess Shale and from the collection of the Royal Ontario Museum.

Jellyfish are, as the name implies, soft bodied, and are extremely unlikely to be fossilised. But the Burgess Shale is very good at preserving soft bodies the illustration shows the results.

Size variations and general morpho-anatomical details of Burgessomedusa phasmiformis gen. et sp. nov. (a) Holotype ROMIP65781.1 (close-up in figure 2a). (b) ROMIP65782.2–3, with putative gonads (close-up in figure 2b). (c), ROMIP65783.1, with putative gonads. (d) ROMIP65784, with putative stomach cavity. e,f, specimens with putative gonads ROMIP65785 (e), ROMIP65786 (f). (g) ROMIP65787, with a contracted umbrella. (h) ROMIP65788, with putative gonads (close-up in figure 2e). (i) ROMIP65114.1–3. (j) ROMIP65789. (k) ROMIP65790.1–2. Abbreviations: bm, bell margin; go, gonads; man, manubrium; st, stomach cavity; ten, tentacles. Scale = 2 cm.

Morphological details of Burgessomedusa phasmiformis gen. et sp. nov. (a) Close-up of stomach cavity, manubrium, and gonads, ROMIP65781.1. (b) Close-up of tentacles ROMIP65782.2. (c,d) specimen showing disarticulated tentacles (close up in d), ROMIP65791. (e) Close-up of tentacles showing equidistant interspaces, ROMIP65788. (f,g) ROMIP65792, with short tentacles (close up in g) placed under the oral umbrella margin. (h,i), ROMIP65793, with tentacle remnants (close up in i). (j) ROMIP65794, specimen with irregular umbrella margin. (k) ROMIP65795.1, specimen showing tetraradial symmetry. All abbreviations are as in figure 1. Scales = 1 cm.

This discovery has generated a lot of interest and you may have seen it referenced in various newspapers.