Saturday, 23 December 2017

Geo-Ho-Ho: The 12 Days of a BGS Christmas...by Kirstin Lemon

It seems that everyone has been doing advent calendars with a geology theme, so to be a little different we're going for the 12 days of Christmas instead. It's all in the hope that by the time the 12 Days begin we'll all be lying around the house with time on our hands. So grab a cup of tea, a big slice of Christmas cake, relax, and enjoy the 12 Days of a BGS Christmas.

Day 1: Christmas Cards

As part of the BGS Archives we hold a collection of Christmas Cards sent by John Vernon Harrison in the 1920s. JV Harrison was born in 1892 and graduated in Chemistry and Geology from the University of Glasgow in 1914. From 1916 to 1918 he served with the Royal Engineers in Mesopotamia and then in 1918 he joined the geological staff of the Anglo Persian Oil Company. He carried out fieldwork in Persia and Iraq, and also travelled extensively including to Honduras, USA, Mexico, North Borneo, Hong Kong, Japan, Canada, Peru, Jamaica, Venezuela, Trinidad and Colombia. He sent many Christmas cards using photos from his travels all of which are available to view in GeoScenic.
One of the many Christmas cards sent by JV Harrison. This one is from the volcano of Poas in Costa Rica in 1832.

Day 2: Christmas Eve Landslide

We maintain the National Landslide Database that has over 16500 records of landslides from across the country. Much of this information is gathered from surveys and reports by the Landslide Response Team and much of this is from historical evidence. One such historical landslide occurred in Whitby on Christmas Eve in 1787 in the area now known as Henrietta Street. Just under 200 families were left destitute as a result of the catastrophe and together with subsequent landslides in the same area resulted in Henrietta Street being significantly shorter in length.

Day 3: Christmas Day Earthquake (or not)

The UK Seismograph Network
We operate a network of over 100 seismograph stations across the UK meaning that continuous data from nearly all is transmitted directly to our office in Edinburgh. But what about in our historical past? We have carried out research into historical seismicity in the UK pre-1600 and tried to work out whether the information recorded really was from an earthquake or not. One such event was in Stirling on Christmas Day in 1034. This was recorded as an earthquake in the Chronicles of Boece (a 16th Century philosopher and historian) but our research has concluded that it wasn't an earthquake at all but was more likely to be a landslide or a bog-burst!

Day 4: Christmas Lectures

This very British Christmas tradition was begun by Michael Faraday in 1825, and now the Royal Institution Christmas Lectures are delivered annually as a series of lectures on a single topic that are specifically aimed at the general public, especially children. The topics vary widely and have included How to Survive in Space, Crystals & Lasers, and The Message in the Genes to name but a few. Whilst there has not been a lecture series dedicated to specifically to geology (yet!), all of the topics are designed to inspire and engage the next generation of scientists which is something that BGS actively tries to encourage. This year's Christmas Lectures are being delivered by Prof Sophie Scott from University College London who will lead the way on a fascinating journey through one of the fundamentals of human and animal life which is our unstoppable urge to communicate, very appropriate for our Christmas GeoBlogy!

Day 5: North Pole

We all know that Santa lives in the North Pole and to find him, all we need to do is look at our compass and follow it North. But did you know that the magnetic field of the Earth is changing slowly every day and in 2014, for the first time in 350 years, we saw the direction of magnetic north move from being west of grid north to east of grid north. At BGS, our geomagnetism team measures, records, models and interpret variations in the Earth's magnetic field. In the UK, we run three magnetic observatories that constantly monitor the change in the Earth's magnetic field, in Lerwick in Shetland, Eskdalemuir in Dumfries and Galloway, and Hartland in Devon.

Day 6: Reindeer

The Bone Caves at Inchnadamph
Listed in our Secret Geology pages, the Inchnadamph Bone Caves, Assynt in Scotland are where the bones of bears, reindeer and wolves that once roamed this part of the country have been discovered. There are four caves in total that formed thousands of years ago, before the last ice age, as water gradually dissolved the limestone along cracks and fissures. The caves here are only shallow and are the remains of a larger cave system that extended over a wide area. Over thousands of years, the valley has gradually deepened, cutting away part of the cave system, and leaving the caves we see today high and dry on the valley side. Excavations have unearthed the bones of wolves, bears, lynxes and arctic foxes that took refuge in these caves when Scotland’s climate was much colder than it is now. Reindeer bones and antlers have also been found, but reindeer are unlikely to have entered the caves, and so it is unclear how these remains accumulated.

Day 7: Snowflake Obsidian

The chances of getting a picture postcard Christmas with crisp white snow in the UK are pretty slim. Perhaps the best chance of getting any kind of 'snowflake' is to get your hands on some snowflake obsidian. Obsidian is a type of volcanic glass formed when lava cools down so quickly that crystals don't have time to form. In the case of snowflake obsidian, this usually dark-coloured glassy rock contains white spots that resemble snowflakes that are known as spherulites. Obsidian is relatively unstable (in a geological timescale) and it is rare to find any that is older than around 20 million years. As a result, over time the obsidian undergoes a process called devitrification whereby it loses its glassy texture and crystals form which is what the 'snowflakes' are. Because of this characteristic, obsidian is only found in areas with recent volcanic activity so there are no outcrops in the UK but there are significant deposits in volcanically active countries such as Mexico, Iceland and Indonesia.

Day 8: Puddingstone

Christmas pudding is a much celebrated part of a Christmas dinner in the UK but in geological circles we have a 'pudding' of our own. The Hertfordshire Puddingstone is a type of conglomerate made up of rounded flint pebbles held together by a silcrete matrix and it gets its unusual name as the rounded flint pebbles are thought to resemble the plums in a traditional Christmas pudding. Puddingstone is very hard which led to it having a variety of uses including as supplementary building stone and being used as querns by the Romans.

Day 9: Glitter

What would Christmas and New Year be without a bit of sparkle? Before the modern use of plastic glitter, there were many other ways to 'bling' up your home and body using minerals that are known to both geologists and non-geologists alike. Glitter has been used as decoration from as early as 30,000 years ago when mica flakes were used to give cave paintings a glittering appearance, and Prehistoric humans were also believed to have used hematite to give cosmetics a bit of sparkle too. The ancient Egyptians produced glittering cosmetics using finely ground malachite, and it is now thought Mayan temples were sometimes painted with glitter paint made from mica dust.

Day 10: Coal

Coal miners in a Midlands Colliery, 1944
Coal is often associated with Christmas as you would have been given a lump in your stocking if you were on Santa's naughty list. Coal occurs in the form of layers in sequences in sedimentary rocks with almost all onshore coal resources in the UK being within rocks of Carboniferous age. Coal is made up of the remains of plants from millions of years ago, making it a fossil fuel, and it was mined in the UK from as far back as Roman times. Coal mining in the UK dramatically increased during the Industrial Revolution and reached a peak in 1913 when 287 million tonnes was produced. The use of coal has been steadily decreasing, and it was announced in April 2017 that the UK had gone for its first day without coal generated electricity since the Industrial Revolution.

Day 11: Gold

Gold is synonymous with Christmas but did you know that gold is a mineral that occurs widely in the UK. It has been worked from a few areas, notably in southern and northern Scotland, near Dogellau in Wales, in south-west England and in Co. Tyrone, Northern Ireland. In the 1860s, following the excitement of the Californian gold rush, northern Scotland experienced its very own gold rush, initiated by the discovery of alluvial gold in the Helmsdale River by a miner recently returned from Australia. The excitement was short-lived and the bedrock source was never found. However, scientific advances since then in the understanding of how gold deposits are formed have led to the discovery of new deposits and the revisiting of old ones, all of which use BGS baseline data as a starting point in the exploration process. There are currently gold mines operating in two areas of the UK; one in Cononish, near Tyndrum in the Scottish Highlands and the other in the Sperrin Mountains, in Co. Tyrone, Northern Ireland.

The Sperrin Mountains in Northern Ireland


Day 12: Christmas Trees

Nearly every home in the UK will be lit up with the lights of a Christmas tree this festive season but have you ever stopped to think about where Christmas trees, or specifically, conifers come from. The fossil record shows that they originated in Europe and North America in the Carboniferous period around 310 million years ago. At the BGS we hold more than three million fossils collected over two centuries and one of these collections was assembled by botanist Joseph Hooker (Darwin's best friend) while he was briefly employed at BGS in 1846. These comprise hundreds of beautiful thins sections of fossil wood including some fine examples of fossil conifers, some of which date back to the Jurassic period and beyond.

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