Down to Earth Extra December 2023

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

 Iceland Volcano - A Good YouTube Channel

The recent activity in Iceland has resulted in a multitude of stuff on YouTube. THIS CHANNEL is produced by a geology professor from Idaho who actually has done a lot of work on Icelandic volcanism. He produces a daily report which is very informative. Worth watching!

 Down to Earth Extra November 2023

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

 Icelandic Volcanoes

Things seem to be happening fast in Iceland. A town (Grindavik) has been evacuated and an eruption is awaited. Unlike recent volcanic events in Iceland, this time there may be significant danger to infrastructure and lives.

The following video explains what is going on.

Has a New Continent Been Found? 

A correspondent sent me THIS LINK. It tells us about a bit of Australia which moved towards South-East Asia and got split up into fragments on its way. The article includes the following YouTube video. It shows what the authors think happened. All I can say is that it is mighty complicated! (Click the full page symbol to make the video as large as possible. This might make it more comprehensible!)

The amount of evidence collected must be huge. Trying to put it together to make a logical story is beyond my capabilities!

The intriguing thing is that it may explain the Wallace Line - the border between the flora and fauna of South-East Asia and Australia. But the time scales are surely different. The geology talks in terms of hundreds of millions of years, the flora and fauna would be a shorter time scale.

 How Do Moons Have Oceans?

A correspondent emailed to tell me that THIS ARTICLE was interesting and deserved to be in the blog. I concur!

The moons in question are some of those of Jupiter and Saturn. We don't know about those around Uranus and Neptune but stay tuned! 

The obvious one is Enceladus, the ice covered moon of Saturn. It has icy plumes erupting near its south pole. A fly through by the Cassini spacecraft found it to be water containing sodium chloride, quartz and hydrogen.

Read the article to find the moons with oceans, but what interests me and the author is how does liquid water exist in what must be a very cold place. The answer seems to be tidal friction. 

In their orbits the moons are subject to gravitational forces from other moon and their parent planet, and these can vary enormously. Bits of the moons are moving against each other producing enough heat to keep their oceans liquid. The outermost parts are frozen, the interior is liquid.

The presence of liquid water leads to speculation about the presence of life - read about it in the article.

Five images of Saturn’s moon Enceladus, seen in infrared light. Nestled beneath its icy shell is a global ocean — a sea that is erupting into space through fractures in the moon’s south pole, coloured red at bottom right.

 Two Indoor Courses from Nick Chidlaw

Nick Chidlaw is running two courses this Autumn. Details are below.

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I am offering to run two 1-day indoor courses in November, if there is enough interest / availability for the courses to go ahead. These courses are repeats of ones I have run in the past, which pleasingly attracted many students; they are based on locations I where I have run field courses.

One of the courses focuses on the diverse sedimentary legacy deposited  and landforms created during the 'Ice Age' within a part of the west of England. Many of these deposits are only occasionally exposed.  The other course focuses on the concept of geological 'terranes', examining evidence for one along the Highland Border in Scotland.  

For both courses, no prior knowledge of geology or the study locations would be assumed. 

The courses may be attractive particularly to people who are not in a position to visit field locations e.g. insufficient time available because of family / work commitments, health difficulties, or who may be interested in the opportunity to study sediments that are no longer extant. 

Each course would comprise powerpoint-based lectures, together with examination of hand specimens of relevant mineral and rock types, and published geological maps of the field areas. The hand specimens have been collected by the tutor in the field areas described. 

The venue is the Buckingham Room (single storey building by the car park) at The Chantry, 52 Castle Street Thornbury, Glos. BS35 1HB. See website www.thechantry.org.uk 

for further details, including location map. On each course, attendees would bring their own packed lunch and other refreshments, or go into the town for lunch. 

These two courses are independent of one-another - you can choose to do either, or both, according to your interests / availability. The courses are £30.00 each.

Viability will be a minimum of 10 enrolments / fee equivalent for each course. 

If you / anybody else you know would like to attend these courses, do get in touch with me nickchidlaw@gmail.com. 

The viability deadline for both courses is Saturday 4th November. If either or both courses become viable on that date, enrolments will be able to continue until 1 week before the dates the courses are to run. 

If viability is not reached for either or both courses, fee received will be returned soon after to those who have sent them in. 

Any queries, do get in touch. I look forward to hearing from you soon.

Dr Nick Chidlaw

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Saturday 25th November

'The Ice Age in the Severn Vale and Cotswolds'.  10.00 am - 5.00 pm 

The Quaternary period corresponds to the geological period we are currently living in; it includes what is popularly known as 'The Ice Age', together with the much milder climatic episode that began when the last glaciers in the British Isles disappeared, and which continues to the present day.  The Quaternary period began about 2.6 million years ago, and is divided into two major parts: the Pleistocene epoch (Corresponding to The Ice Age), and the post-glacial Holocene epoch, divided at c. 12,000 years ago. A new epoch, the Anthropocene, during which humans have begun to radically influence geological processes, is being considered. Detailed studies have shown that The Ice Age was in fact composed of cold or glacial conditions alternating with interglacial climates as warm, or warmer, than today, each of these alternations lasting tens of thousands of years. In Britain, as elsewhere, this climatic 'restlessness'  has had dramatic consequences: as ice sheets have grown and retreated, they have changed sea levels, caused extensive erosion of the earth's crust, movement and deposition of the resulting sediments, caused the crust itself to sink and rise, river systems to drastically change their courses as well as downcutting or infilling their valleys, and forced animal and plant life to migrate, leading in some cases to extinction. 

Erosion in the British Isles have been very extensive during the Quaternary, so that deposits laid down since the beginning of the period older than about 600,000 years are very fragmentary. In the uplands such as in Scotland and Wales, repeated glacial action has successively modified landforms and removed older Quaternary sediments, resulting in a limited legacy from which to deduce events. In the lower lands of eastern and southern England, where glaciers reached their maximum extents, the landforms and sediments are better-preserved, and the oldest and most diverse record can be found. The Severn Vale and Cotswolds, lying within this tract, has a great variety of Quaternary landforms and deposits, developed over a wide range of time. 

On this course you will be introduced to these landforms, including anomalous river drainage patterns, dry valleys, river terraces, estuarine platforms and landslides; and deposits laid down by rivers, glaciers, freeze-thaw action, springs, and the Severn Estuary. These deposits are mostly nor normally exposed, but some become temporarily so by human activity e.g for sand and gravel extraction, and ground engineering projects. The tutor has examined a number of these, and their details will be described. Course highlights include the Cotswold scarp being one of the most extensive areas of landsliding in British Isles, and evidence for the Severn Vale not existing prior to the Quaternary. 

A handout outlining the day's programme, and a list of optional suggested reading, would be provided on the course.     

     Glacial till overlain by outwash gravels. Anglian Glaciation. Gravel pit exposure (now infilled) near Moreton-in-Marsh, Glos.    

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Sunday 26th November

'Highland Border Geology, Scotland; evidence for a terrane boundary' 10.00 am - 5.00 pm 

Many tectonic plate collision zones around the world contain ‘terranes’: regions of crust with well-defined boundaries, that differ significantly in their geological development from neighbouring regions. Ancient long-since stabilised collision zones globally are often composed of a set of interlocking (often fault-bounded) terranes, each of which originated in different places and had different tectonic histories, but which were progressively amalgamated into the  arrangement seen today. The crust of the British Isles is composed of a number of such terranes, brought together by plate collisions that culminated in the ‘Caledonian Orogeny’ (mountain-building episode, Early Silurian – Mid Devonian times). On this course, we trace one of these terrane boundaries along the Highland Border of Scotland between the Isle of Bute (near Glasgow) in the west, to Stonehaven (near Aberdeen) on the east coast. We will look at the character of the two terranes involved, the nature of the boundary between them, evidence for when the terranes were separated, and for when they finally became joined.

A handout outlining the day's programme, and a list of optional suggested reading, would be provided on the course.    

Contrasting landscape along the Highland Border, Scotland: low-lying cultivated land of the Midland Valley in the foreground; the rugged Grampian Mountains in the distance. 

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