Anne Bronte's Rocks

 Anne Bronte's Rocks

A correspondent, in reply to my remark that it was becoming difficult to find things suitable for this blog, sent me THIS LINK to the journal "Bronte Studies". This journal does not usually find its way to the top of my reading list but it takes us back to a time when being educated meant being interested in everything!

If you go to the Bronte Parsonage Museum you will see Anne Bronte's collection of stones.

 Anne Bronte’s collection of stones, as displayed at the Bronte Parsonage Museum. Courtesy of the Bronte Society.

The collection has been studied and found to be largely carnelians - a form of the silica mineral chalcedony. There is also a piece of flowstone and a couple of agates. The stones could not all have come from one site and they seem to have been deliberately chosen.

The article suggests that Scarborough is the most likely place where Anne collected her rocks. Her work as a governess took her to the place. She may have collected them herself or purchased them from a lapidary, of which there were several within the town. Some of the carnelians are of high quality and suggest that Anne knew what she was doing while making her collection. She certainly valued her collection enough to take it back to Haworth.

(You have probably noticed the plethora of links in this post. This is a new feature of Blogger, the app which I use to write this blog. I suspect that I will turn it off in future posts.)

 Air Balloon Geology

Recently a subscriber to this blog asked "I wonder if you know of any geological treatise on the A417 "Missing Link" at the Air Balloon pub site? ..... They plan to keep the strata exposed for all to see when driving past, like has been done on the Cirencester dual carrageway."

Well, the short answer is that I do not know what is happening there. If you do, send me the details HERE and I will pass them on. 

But the request sent me on a mission to discover what the geology is at the Air Balloon Pub. My knowledge of the place is being stuck in a traffic jam, waiting to get on to the M4 at Gloucester. And I discovered the latest addition to the BGS web site - the GeoIndex Beta.

With a little persistence I managed to produce the following map.

The original map can be found HERE.

If you click, on the original map, on a formation you get a pop-up similar to the following:-

The link takes you to THIS PAGE which tells you a lot about the Birdlip Limestone. The parent of this page IS THIS - the Lexicon of named rock units of the BGS.

I used this to name several of the formations on my Air Balloon map.

To search the Lexicon use the Computer Code given in the pop-up, or the Preferred Map Code. (This the code in the last line of the rock names I have put on my Air Balloon map.)

So now I know a great deal more about the Air Balloon Pub area and know how to access a vast amount of Geological Knowledge, but I still cannot answer the question which started this search!

 Dead Sea Models Salt Deposition

A correspondent sent me THIS LINK. The article is based on THIS ACADEMIC PAPER. The Dead Sea is, at the moment, the only water body sufficiently deep enough and salty enough to model the conditions which produced the vast salt deposits which are found in many places and times in the geological record.

The academic paper, in particular, examines, in great detail, all the things which determine the salt deposition. These include temperature, which varies with the seasons, salt concentration which varies with depth, temperature and the season, evaporation which depends on temperature and wind, wind which affects mixing, sizes of the deposited halite crystals and beach deposits.

Reading the reports makes me realise that it is very complicated! And that I am ill equipped to explain it all to you! So read the papers, and hope that you can begin to understand what is going on. 

 Is the Core Separate from the Mantle - Maybe Not

A correspondent sent me THIS LINK which looks at new evidence suggesting that material from the core is getting into the mantle and, eventually, to the Earths surface.

We have long been taught that the lighter mantle floats above the denser metallic core and that there cannot be movement between the two (except for earthquake waves).

But work on helium isotopes casts doubt about the separation. Helium-3 was formed just after the Big Bang and was confined to deep in the Earth, some believed it was confined to the core. Helium-4 is formed from the decay of uranium and thorium and is confined the mantle and the Earths surface. But then Helium-3 was found in volcanic lavas from mid-ocean ridges.

Ruthenium is an element with an affinity for iron and thus is concentrated in the iron-rich core. This applies particularly to Ruthenium-100. Other ruthenium isotopes came to Earth later via meteorites but Ruthenium-100 should be confined to the core. But it is now found at the surface.

So how is the core stuff getting into the mantle? Debate rages with a lot of attention being paid to two huge "blobs" - one under the Pacific and the other under Africa. These are believed to be hot but dense and supplying plumes leading to the surface. Are they "mining" the core or are they a bridge from the core to the surface.

Expect to hear more about this in the future.

 Down to Earth Extra August 2025

The August 2025 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.

 The Grand Canyon - Then and (Almost) Now

My attention has been drawn in the last week to two articles both concerning the Grand Canyon. THIS ARTICLE was sent to me by a correspondent - thank you - and concerns well preserved fossils from the middle Cambrian (Bright Angel Formation) 505 million years old, found in the Grand Canyon, and THIS ARTICLE which suggest that the meteor impact which created Meteor Crater, 100 miles from the Grand Canyon, caused landslides which dammed the canyon. This happened 56,000 years ago - almost yesterday!

The Cambrian fossils found are slightly younger (3 million years only!) than those of the Burgess shale and are mainly priapulid worms with some crustaceans and molluscs. They show that life was innovating new forms. The source paper can be found HERE and has some wonderful pictures of the beautifully preserved (but tiny) fossils.

Crustacean sternal elements from the Bright Angel biota.

Paragnath-bearing triangles are indicated by 1 s, and the successive posterior triangles by 2 s. (A) Posterior end of paragnath-bearing triangle and anterior section of successive triangle. (B) Complete triangle with laterally splayed paragnaths (black arrows). (C) Detail of scaly ornament of median cuticular strip in (B). (D) Detail of anterior setose surface in (B). (E) Complete paragnath-bearing triangle, with articulated anterior section of successive triangle. (F) Detail of boxed area in (E) showing scale-bearing cuticular strip and marginal setal fringes. (G) Articulated paragnath-bearing and partial posterior triangles defining median food groove. (H) Detail of boxed area in (G) showing sphaeromorphic acritarch adpressed onto the food groove cuticle. (I) Subtriangular cuticular lobe, representing possible setulose labrum. (J) Complete paragnath-bearing triangle and articulated, semi-complete posterior triangle. (K) Detail of boxed area in (J) showing spheroidal acritarch adpressed onto the food groove cuticle. Slide numbers and England Finder coordinates listed in data S1. Scale bars, 50 μm except in (C) and (H) (5 μm) and (D), (F), and (K) (25 μm).

The evidence for the damming of the Grand Canyon is not controversial. There are caves 45m above the river which have driftwood logs in them. In the last few years improved dating techniques have been used and they show that the ages of the damming and the meteor impact are about the same. Whether one caused the other is rather more difficult to prove.

Terror Bird Meets it's Doom

A correspondent sent me THIS LINK (I had seen it too!), concerning a dramatic event which happened 13 million years ago in the Middle Miocene.

This was in, what is now, Colombia. The locality is a desert (the Tatacoa Desert), then it was a swamp. A local collector had found the fossil and exhibited it in his own museum. Researchers from a Colombian university were cataloging the collection and discovered two things. The first was that the fossil was a leg bone from the top, land based, predator of the time Phorusrhacinae sp, better known as the Terror Bird. Fossils of this bird are rare, but what was even more exciting was the presence of tooth marks on the bone.

The tooth marks are similar to the teeth of crocodile-like creatures whose fossils can be found in museum collections. The most likely candidate is Purussaurus neivensis which was among the top, water based, predators of the time.

The tooth marks show no sign of healing and suggest that the Terror Bird did not survive, or that it was dead already and the croc scavenged it. (In scientific language being eaten is a trophic event!)

The story gives a fascinating glimpse of life in the past.