Bremen Core Repository!

Just before Christmas some fellow students, several lecturers and myself travelled to Bremen Core Repository in Germany to experience what it would be like to log igneous rock cores which were drilled from the ocean floor.

The picture above shows some of the cores which we looked at. These are all igneous rocks which were drilled from the ocean floor by research ships such as the JOIDES Resolution shown below.

But perhaps one of the most interesting cores is the one shown below which captures a slice of time right through the period where dinosaurs went extinct, which is known as the KT boundary.

This core has an iridium rich layer at the top of the green band which scientists believe formed from the asteroid impact which killed off the dinosaurs. Iridium is a rare element on Earth but it is plentiful in asteroids which is strong evidence for a meteorite impact being responsible for the extinction of the dinosaurs.

All of the cores at the repository were divided length ways into two giving a working half and an archive half. The working half could be sampled for scientists to study for research into all sorts of areas (such as palaeomagnetic analysis or microbiology). The archive half is also accessible for study but no samples or altering of this half can be done so that there is always a record kept of the cores in case other people want to study them in the future.

All of the cores were kept in a large room (shown below) which was kept at 4°C, but luckily we didn't spend that long in there and spent most of the days working in a much warmer lab next door!

On our visit we logged the mineralogy and textures, geological structures (such as faults) and metamorphic alteration to the minerals which we could see in the cores. I found this exercise very interesting and it was an exciting thought that once these rocks would have been buried deep beneath the ocean, and modern technologies now mean that we can extract rocks from the Earths interior and from beneath km's of ocean!

Reports for many drilling expeditions can be found on the International Ocean Drilling Programme (IODP) website if you use the search bar at the top. There is also more information about the core repository, events happening there and an interactive map showing where cores have been extracted from:

http://www.marum.de/en/IODP_Bremen_Core_Repository.html

I strongly encourage you to follow the link above and take a look for yourself!

Happy reading!

Diamonds in Antarctica!

Catching up on geology in the news this afternoon and an article called 'New findings hint at diamond deposits in Antarctica' caught me eye.

Research soon to be published in Nature details how diamond bearing rocks called kimberlites have been found in small amounts at Mount Meredith in the northern Prince Charles Mountains, shown on the map below.

Kimberlite rocks are igneous rocks which form at depths of 150 km to 450km depth. They are erupted very rapidly and violently often with the release of carbon dioxide and other volatile gases. The rocks are the source of not just diamonds but also other precious stones such as garnet and spinel.

Although the potential for mining diamonds in Antarctica might exist, there are international laws which currently prevent any exploitation of mineral resources in Antarctica except for scientific purposes. One such act is the 'Protocol on Environmental Protection to the Antarctic Treaty'. So for now we will just have to wait and see, I guess we won't truely know what lies beneath the vast ice sheets of Antarctica until the majority of the ice has melted, and that will be a while...

For further reading try these links below:

http://www.bbc.co.uk/news/science-environment-25417441
http://ossfoundation.us/projects/environment/global-warming/antarctic-ice-melt

Happy Reading!

Geology...in Films!

For those of you that don’t know it, today was the release date for The Hobbit: The Desolation of Smaug which may not be everybody’s cup of tea (it certainly is mine), but no matter what your kind of movie is, I bet that somewhere in it there is geology.

This isn’t the first time this has crossed my mind but I thought seeing as I am doing a blog, now would be a good time to mention it.

Geology is in films. And I don’t meant films about geology like Iain Stewart on TV, I mean films about the hero that goes on a journey and ends up saving the day, or a film where a serial killer is on the loose trying to kill the main character because “he knows too much”.

I couldn’t help but notice the scene in Due Date which is set in the spectacular Grand Canyon in America and you can see the horizontal bedding which has been exposed because of the river cutting a valley don through the geology.

A lot of epic films like Lord of the Rings have scenes which zoom out and show epic scenes of natural beauty. Sometimes people even sort this out when picking a film to watch, which is why review website IMDb has a section specifically for ‘Films Featuring Natural Scenic Beauty’. Looking through the list the first few I recognise are Lord of the Rings, The Sound of Music and Stardust but there are many more which contain scenes of geology. To be honest, most films which have an element of the outdoors or nature in probably have geology in there somewhere.

Sometimes rocks are even important objects in films, for instance Harry Potter and the Philosphers Stone. Granted it’s not quite the same as that rock was created by people not nature but the principle is there.

Or for anyone that watches or has read A Game of Thrones, the blade made out of dragon glass used for killing White Walkers is actually obsidian! Which is basically glass which cools very quickly when erupted from a volcano!

So I implore you to take a look next time you are watching a film, and see if there are any cool looking rock outcrops or props that link to geology.

Happy reading!

The uses of the magnetic field...

We have all used magnets at some point whether its on your fridge door or a mobile phone case, but do you know how they work or why they work or why magnetic fields are so important?

Our Earth has a magnetic field around it which is self-sustaining due to the semi-molten composition of parts of the inner Earth. The axis of the magnet is offset from the Earth's rotation by around 11 degrees which means that the magnetic north and south poles are not in the same positions as the geographical north and south poles. Not only this but the strength of the magnetic field varies across the Earth too.

So knowing this I bet you're wondering what this has to do with geology? Well as you know, some metals are more magnetic than others, so by doing geomagnetic surveying using specialised equipment we can essentially 'map' the sub-surface and locate bodies of ore which could potentially be mined.

Magnetic surveying is also done for oil exploration and in archaeology to detect buried artefacts, grave sites and building remnants, such as the site map of magnetic data shown above. 

We can also use it for dating rocks. In the past, the Earth's magnetic field has flipped, so magnetic north has been at the south and vice versa. Scientists are still not sure why the Earth does this but it can do it quite erratically and either lots or very rarely. This is particularly notable at mid-ocean ridges where plate divergence is occurring and new rocks are being generated which get magnetised to magnetic north as they cool, so the magnetic pattern preserved in the rocks across the ocean floor preserve a record for magnetic field reversals, and because we have dated these rocks (so know how old they are) we can piece together a history for the magnetic field of our Earth.

So there you go. We are all sat inside one giant magnetic field which is useful for geological reasons as well as many others. Of course it does other more essential things, such as protect the Earth from the deadly solar winds which would otherwise make life on Earth impossible, but I thought it was important to mention its geological uses too.

More information can be found at:

http://www.ngdc.noaa.gov/geomag/faqgeom.shtml

Happy reading!