Nautilus Video

A correspondent alerted me to this video and it makes nice pleasant viewing. It is even more pleasant if you mute the sound.

All you need to know about Nautilus can be found HERE.

 Down to Earth Extra December 2024

The December 2024 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.

Crystals Hold Secret of When Volcanoes Erupt

I came across THIS ARTICLE in the New Scientist and found it very interesting for several reasons. Its about igneous petrology, Hawaii and volcanoes - what more do you need! It is based on THIS PAPER in Nature.

The researchers used several techniques of studying crystals - mainly olivine - from the 2022 eruption of Maunu Loa to determine the history of the crystals before the eruption. And they found that they had started moving into a higher magma chamber 70 days prior to the eruption. The eruption occurred when this chamber was full.

And seventy days prior to eruption a change in earthquake frequency and ground bulging (inflation) was noticed.

So if a similar change in inflation and earthquake frequency was noticed a warning of imminent eruption could be given.

Studies to see if similar things happened to Mauna Loa and other volcanoes prior to other eruptions are being carried out.

But the Hawaii volcanoes are among the most studied anywhere. Is there sufficient knowledge of other volcanoes to make predictions?

Looking at the Nature paper reminds me that igneous petrology has moved on considerably since I was a student!

A Map of Mauna Loa summit and upper Northeast Rift Zone (Island of Hawai‘i on inset map) with 2022 lava flow field78 (pink), lava flows since CE 184379,80 (dark gray), 1000 ft (~305 m) contours (brown lines), samples (black dots; green for large-volume tephra samples used for mineral chemistry), and monitoring network stations (various symbols; see Fig. S1 for wider view that includes all GPS stations in this study). Basemap generated from a 2005 NOAA digital terrain model81 and a 1983 USGS digital elevation model82. Caldera bounding faults are denoted as black lines with teeth pointing to the downthrown side and 2022 eruptive fissures are denoted with red lines. The 2022 flows crossed the NOAA Observatory access road (dashed black line) and came within ~3 km of Highway 200 (Daniel K. Inouye Highway, “Saddle Road”). B 3-D X-ray computed tomography scan (μCT scan) of an olivine from sample ML22-88 shows the rounded morphology typical of phenocrysts from this eruption and inclusions of melt (yellow), Cr-spinels (red), and fluids (blue). C Phosphorus and D magnesium X-ray element maps of an olivine crystal. Sharp truncations in phosphorus zoning record at least two dissolution events. Patchy zones of truncated high-phosphorus in the phenocryst interior represent older resorption histories, whereas truncation of secondary phosphorus branches by the crystal-melt boundary record the youngest resorption event that is also evident in the rounded morphology of the phenocryst. Diffusion gradients in magnesium show obvious differences along the a- vs. c-axes (shown in lower-hemisphere stereonet inset in C), a result of diffusion anisotropy. Part of the crystal rim in the a-axis direction also shows subtle skeletal rim texture, evidence of late-stage crystal growth.

 Down to Earth Extra November 2024

The November 2024 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.

 Giant Meteorite Strike - the Pluses and Minuses

A correspondent sent me THIS LINK, concerning a giant meteor strike which happened ~3.26 Ga in what is now the Barberton Greenstone Belt of South Africa. I now know that 8 meteorite impacts (identified by small spherules and iridium anomalies) occurred in the greenstone belt. They have been given S numbers and here we are dealing with S2.

The size of the meteor was huge - 40 to 60km across. The Earth it struck was very different from that of today - mostly sea with a few continents. Life was single celled organisms. The meteorite created a 500km crater, a cloud of hot rock dust that circled the globe, ripped up the sea bed and created a huge tsunami. 

But it is not all bad news. Phosphorus and iron were churned up and dispersed. This could be considered as the spreading of fertiliser! It is always good to look on the bright side of life!

The basis of the BBC article is THIS ACADEMIC PAPER. This goes into the minutiae of the investigation and gives much greater detail. 

Rock and thin section images of the Bruce’s Hill and Umbaumba sections. (A–C) Outcrop photos of the Umbaumba section. (A) Overview of the Umbaumba section showing, from base to top, BWBC, S2, fallback layer, and BWBC. (B) S2 spherule bed. (C) Lower part of the fallback layer showing fine laminations. This black chert is composed of silicified carbonaceous matter, siliciclastic debris, and impact-generated dust settling out of the atmosphere. (D and E) Outcrop photos of the Bruce’s Hill section. (D) BWBC below S2. (E) Alternating siliciclastic and siderite-rich chert beds. (F–G) Representative thin section images of carbonaceous matter. (F) Laminated carbonaceous chert below S2 in the Umbaumba section (SI Appendix, Fig. S4). Red arrows indicate fractures filled by chert. (G) Clots of carbonaceous matter and other siliciclastic debris from the fallback later in the Umbaumba section.

 Etheldred Benett Memorialised

Etheldred Benett unveiling 

All Saints Church, Norton Bavant 24th September 2024

A chance reference to Etheldred Benett crossed my desk some years ago and I was immediately hooked. To discover that this remarkable woman was born and lived in Wiltshire, just a few miles from my own home village, was a revelation. It turned out that she also explored the surroundings of my own village, Dinton, looking for fossils. She found at least one, an unidentified ammonite. I subsequently found that she was but one, albeit the most fascinating, of geology’s early pioneers, and the only woman, among those who were very active in Wiltshire, Wiltshire can rightly claim to have made a unique contribution to the development of our science in the 18th and 19th centuries. (See Sarum Chronicle issue 2022 ISBN 978-1-9161359-5-6)

A few years before its unveiling in 2022 in Lyme Regis, a young local girl had asked her mother why there was no statue to such a famous fossil collector as Mary Anning, a contemporary of Etheldred Benett. By May of that year, over £100k had ben raised and the statue was unveiled by such luminaries as Prof Alice Roberts and Prof Hugh Torrens. I spoke to Prof Torrens on the day and outlined plans for a more modest memorial for our local hero, EB. As the person who rediscovered her collection at the Philadelphia Academy of Natural Science in the US he was delighted. Alas, now, due to health reasons,  he cannot receive emails so probably does not know that EB’s memorial has been installed.

I visited All Saints Church in the village of Norton Bavant near Warminster to see the Benett family mausoleum and the family chapel. The Benetts were huge landowners which included the manor house in Norton Bavant where EB lived for 43 years. To my surprise there was not a single reference to EB in the church for her geological work. That just had to change!

My approaches and suggestions to the Parochial Church Council (PCC) were positively received so then the task of raising funds to pay for a memorial board kept me busy. The PCC had the daunting task of applying for a faculty, the permission to make changes to the church given by the local diocesan authorities, nearly always a tortuous event.

All my enquiries for a grant received a positive response. I am truly grateful for the financial support that made the memorial possible. The sponsors were:

• Wiltshire Council which gave the largest sum as allocated by the Area Board for the Warminster area.
  
  
• HOGG gave a contribution and gave advice on the wording used on the memorial board.
  
  
• The Curry Fund of the GA gave funds. Dennis Curry, who was a gifted geologist, was the oldest son of the founder of Curry’s the electrical retailer. He took over the firm on the death of his father. His generous gift of shares to the GA provided the capital for the establishment of the Curry Fund which makes grants to support geological projects throughout the country. This is not the first time that the Wiltshire Geology Group has used grants from the Curry Fund. Some years ago when Curry’s, the business, was involved in restructuring an individual involved bought Pyt House, the birthplace of EB. That property is now on the market again at £18 million – small world!
  
  
• Lovell Stone now own Chicksgrove Quarry near Tisbury, the location for EB’s first ever measured and labelled geological section in 1815, described as ‘an indefatigable feat’. Simon Hart, the CEO also made a donation.
  
  
• Professor Renee Clarey of Mississippi State University also secured a donation from the Geological Association of America. 

Following an item in a geological email I received indicating that Prof Clarey was preparing a data base of locations important in the historical development of geology, I wrote enquiring if Chicksgrove Quarry was on her list. It was not but Prof Clarey and I exchanged a number of emails and on a conference visit to the UK we met and I took her to Chicksgrove Quarry. We were also generously invited to lunch with Sir Henry Rumbold and his wife who live at Hatch House, once part of John Benett’s vast estate. Sir Henry is a descendant of one of EB’s brothers (EB never married) and has displayed at his home a portrait of EB as a young woman as shown on the memorial board.

The unveiling took place on 24th September in All Saints churchyard. Twenty people were in attendance, including Sir Henry Rumbold, a representative from Wiltshire Council, members of the PCC, WGG members, the current owner of EB’s old home next to the church and a journalist from the Warminster Journal. Kindly provided by the PCC, we enjoyed tea and refreshments in the church, following the formalities.

After nearly 200 years, EB now has a modest memorial in her home churchyard which captures a little of her huge contribution to the early development of the science of geology.

Etheldred Benett – RIP.

Steve Hannath

Chair of Wiltshire Geology Group

 Hurricane Helene - an Interesting Video

A correspondent brought THIS VIDEO to my attention. I concerns the devastation brought about by Hurricane Helene. He comments:- 

This is a fascinating piece, because in the second section of the destroyed road, it looks to me that the road has been built on an ancient river course that has been reactivated for the first time in centuries.