A visit to the Haslemere Museum

The Haslemere Museum is a hidden wonder for geologists. It has a well established rock and fossil collection for such a modest place, and has a connection to a brilliant Victorian geologist, Sir Archibald Geikie (more on him another day).

The fossils outshone the rocks by far. This was mainly because the rock collection, while not bad, suffered a bit of interior design confusion, as igneous and metamorphics were placed too close together without significant distinction. However, it was nice to see a focus on ancient British rocks!

The meat of the pudding was seeing the trilobites . There were a fair few different types of trilobite on display, as seen below.

Parabolina Spinulosa, a Cambrian trilobite
A Cambrian trilobite, Parabolina Spinulosa, found in North Wales
Another Cambrian trilobite, Paradoxides Bohemicus
Another Cambrian trilobite, Paradoxides Bohemicus
An Ordovician trilobite, Ogygia Buchi, with Mr Whiddington's head for scale
An Ordovician trilobite, Ogygia Buchi, with Mr Whiddington’s head for scale
Calymene Blumenbachii, Silurian
Good ol’ Calymene Blumenbachii to round things off!

That was not all. Every drawer beneath the display cases were able to be opened by visitors, and more examples lay there. The lighting prevented me from taking suitable photos, but all the more to surprise you with should you go visit!

Also particularly enjoyable was the ammonite collection. This was significantly more spread-out than the trilobites, but there was one particular example worthy of a photograph, a massive Titanites (and Titanites are always worth taking a photo of).

Titanites, a massive ammonite from the Upper Jurassic period
The one and only Titanites! With Mr Whiddington and Bob the Frog for scale (a.k.a. attempting to ride the Titan)

There was also a nice wee Harpoceras with a beautiful Aragonite glaze that shimmered like it had only just been cut from the ground:

Harpoceras Exaratum, complete with aragonite shimmer
Harpoceras Exaratum, complete with aragonite shimmer

Mr Whiddington also found some dino friends to play with in the kids’ section, which I am sure he was most pleased about.

Mr Whiddington makes a new friend
Mr Whiddington makes a new friend
Whid makes another friend
Whid makes another friend… and then sits on him

There were some nice looking lagerstätten, including this fossil fish, which was so finely preserved it looked more like something you would find freshly grilled on your dinner plate.

A very well preserved Dapedium Polytum, found at famous fossil haunt Lyme Regis
A very well preserved Dapedium Polytum, found at famous fossil haunt Lyme Regis

The museum shop gave much happiness as they had for sale trilobite fossils! I got one, and it looks real enough, but sadly there was no label as to its species, and the shop assistant did not know. It looks to me like a good old Calymene, but if anyone else has any other ideas, do let me know!

Mystery Trilobite!
Mystery Trilobite!

Another thing that made me very happy was that the shop was selling plastic dinosaurs with feathers! Take a look at this beauty:

Feathery plastic dino!
Feathery plastic dino!

It’s nice to see stuff like this, where toys are reflecting the science, and good on the museum for having such awesome stuff for sale!

There were other nice aspects to the museum, including a lot of stuffed animals, butterfly collection, and a beehive viewer, and some lovely grounds you could take a wee walk in.  And being next to a town centre with lots of lovely shops, I’ll definitely be visiting again.

 

 

 

 

 

 

 

 

The space tech that fell to Earth – GBinSAR!

This is my piece for Accretionary Wedge #60 ‘Momentous Discoveries in Geology’. Enjoy!

GBinSAR? What is this all about?

I am going to talk about a very momentous discovery in geology, the development of a type of radar that helps in monitoring ground movements. It has a long name, you must be warned: ‘Ground-Based Interferometric Synthetic Aperture Radar.’ Or, GBinSAR for short. And it’s a pretty useful bit of kit – it can be used to monitor ground movements of anything from earthquakes and volcanoes, landslides and slope failures, and even glacier movement. So how did this space tech come down to land?

Image of interferometric scattering mapped onto a digital model
An image of the interferometric signal from a GBinSAR setup, mapped onto a digital model for ease of viewing. Reproduced from Leva et al, 2005.

First we need to know about Synthetic Aperture Radar!

Okay, so synthetic aperture radar uses microwaves to get a backscattered image of the environment – this basically means that microwaves bounce off whatever surfaces the instrument is aimed at, and returns a signal which is picked up by the same device. The resolution of a SAR instrument is very high, so it is easy to pick up tiny fluctuations that may suggest something has changed.

Now we can take it down to land! 

So normally SAR instruments operate from satellites in space, but they’re quite wide-range, and sometimes for a particular slope, volcano or glacier you need an even higher, more precise resolution. So we do something very simple – we bring the SAR instrument down to the ground, and set up a couple of stations around the target area, and the radar image can then be made by combining the signal from both instruments. This is exactly what Ground-Based Synthetic Aperture Radar does.

So we have GB SAR, what about the ‘in’?

When you combine two different signals, you’re calculating the interference between them to form the image. This is what’s known as interferometry, and it explains the ‘in’ part of GBinSAR. Interferometry is mega-cool; it was first used on Venus and the Moon! It’s a beautiful example of how space tech has ended up being useful for geohazard mitigation on Earth, so all opposers of blue sky science, take note!

All right, but who invented this stuff?

The original SAR was first conceived back in 1938, by Sir Watson-Watt, and was called the ‘Bedspring Antenna’. SAR technology did not actually come into proper use until 1978 when the SEASAT satellite was first put up.

The movement from space satellites to ground-based inSAR did not happen officially until 1999, when the EU’s Joint Research Centre did some dam experiments and published the first paper on the subject. Since then companies such as Ellegi-LiSA labs in Italy have worked towards creating saleable models. The LiSA model from this lab is currently the most widely used.

Okay, so tell me more about where it’s been used. I want some examples!

GBinSAR is used all over the world to monitor any geological surface that might be likely to start making a run for it. For instance, in Japan it is used to monitor landslides in unstable areas easily affected by typhoon rains, such as the Tottori prefecture, and this has led to some very successful evacuations recently.

On the island volcano of Stromboli, GBinSAR is used to constantly monitor minor changes on the main volcanic debris slope, so that landslide-tsunamis can be mitigated. It’s possibly the best tech to use here, as erecting monitoring equipment on an active debris slope is nigh on impossible, so having this multiple-receiver setup placed around the sides of the slope allows high-resolution data to be captured without causing too much damage to the hardware.

This technology is also used in civil engineering. It’s been used to monitor deformation of dams in Poland, and even structural deformation of bridges!

So this is an awesome piece of tech, and it’s really changed the world of hazard mitigation. I’d definitely say that the idea of converting space-based Synthetic Aperture Radar to a ground-based model is one of the greatest geological revelations ever, because it has helped save lives and provide early warning systems for disasters. Although it’s something that goes by unnoticed most of the time, let’s give some applause to the humble GBinSAR device and its space-age predecessor.


References:

1.) Guido Luzi, ‘Ground Based SAR Interferometry: a Novel Tool for Geoscience’, Geoscience and Remote Sensing New Achievements 2010

2.) Kazuo Ouchi, ‘Recent Trend and Advance of Synthetic Aperture Radar with Selected Topics’, Remote Sensing 5, 2013, pp. 716 – 807

3.) D. Tarchi, H. Rudolf, G. Luzi, L. Chiarantini, P. Coppo, A. J. Sieber, ‘SAR interferometry for structural changes detection: a demonstration on a dam,’ Proceedings of IGARSS’99 Hamburg pp 1522 – 1524

4.) D. Leva, C. Rivolta, I. Binda Rosetti, S, Kuzuoka, T. Mizuno, ‘Using a ground based interferometric synthetic aperture radar (GBinSAR) sensor to monitor a landslide in Japan’, Geoscience and Remote Sensing Symposium, 2005, Volume 6, 2005

5.) Teresa Nolesini, Federico Di Traglia, Chiara Del Ventisette, Sandro Moretti, Nicola Casagli, ‘Deformations and slope instability on Stromboli volcano: Integration of GBinSAR data and analog modelling’, Geomorphology 180 – 181, 2013, pp. 242 – 254

6.) Rafal Kocierz, Przemyslaw Kuras, Tomasz Owerko and Lukasz Ortyl, ‘Assessment of Usefulness of Radar Interferometer for Mesuring Displacements and Deformations of Dams’, Joint International Symposium on Deformation Monitoring, 2011

7.) Stefan Pradelok, P. Kuras, T.Owerko, L. Ortyl, R. Kocierz, O. Sukta, ‘Advantages of radar interferometry for assessment of dynamic deformation of bridge,’ Proceedings of Bridge Maintenance, Safety, Management, Resilience and Sustainability, Sixth International IAMBAS Conference, 2012

“I would like Richard Herring to jump into a volcano.”

-foreword: Richard Herring has a fab show out at the moment called We’re All Going To Die! This is a reply to his article in the Metro last week, enjoy –

 

Dear Richard Herring,

I must admit I read your article in the Metro last week with great interest, for I am a geologist and as such I feel I am adequately qualified to assist you in your volcano-jumping quest.

I am very much in accord with your desire to become a perfect fossil, a symbol to the future for our times. But there is one very important thing you must understand first: in order to become a perfect fossil, you must choose the method with the greatest – dun dun duuuun! – PRESERVATION POTENTIAL!

For example, you could choose to walk into the lava lake of the fabulous Nyiragongo. But the surface temperature of the lava here is more than 1000°C. Your body matter would quite simply burn away and leave no trace in the fossil record. Darnit! It would have looked lovely and dramatic too!

Nyiragongo in full blazing lava-lake glory!

Okay, so no jumping into actual lava. What now? Well, you could try jumping into the centre of a dormant volcano, like the island of Vulcano in Italy. There’s no lava, but there are enough poisonous gases to put an end to things within minutes. These gases are so heavy they cannot rise through the lighter air, so stay sunken in the crater waiting for an unsuspecting potential-fossil.

Image of Vulcano's craterBut this option has its downsides too. The dormant volcano may become active again in future, and a massive explosion may blast you out of the crater along with the volcanic plug that’s blocked it up for all that time. Your preservation potential would be – literally – shattered. So maybe this option’s no good..

We could try one of Vulcano’s cousins, Stromboli. If you are lucky enough to get close to Stromboli while it’s erupting, you might stand a chance of being hit in the head by a boiling lava bomb (like my old teacher did – don’t worry, he survived – it was not his time to become a fossil!).

Stromboli generally being badass

Provided enough lava bombs by chance hit you, you could become buried in rapidly cooling rubble, which has a little more preservation potential than the previous options.

But we’re going for perfection here. Let’s skip across to Vesuvius. Everyone knows AD79, the eruption that decimated Herculaneum and Pompeii, right? Okay, most people in that debacle died in the massive pyroclastic flow (a mess of fluidised ash, air and hot stuff from the earth’s belly) that engulfed the region. Pyroclastic flows can move as fast as a car on the motorway, and it would be a pretty quick way to go! Maybe this would be a good option, then? You would be fossilised in ash, provided that nobody disturbed your remains. For what would happen if you were disturbed?

Some bodies from Pompeii, lacking detail in their features.

Volcanic ash is not the strongest of materials, even when it forms a concrete-ish mass called an ignimbrite. It’s still quite easy to disturb, and in a volcanic area, earthquakes and future eruptions seriously lower your chances of perfect preservation. There’s also the fact that the intense heat from the pyroclastic blast will strip away the finer features of yourself, the minutiae that would render you a perfect fossil.

So what is the ultimate solution? There has to be one, right?

Oh, and there is:

Your best bet really is just to wait until a massive volcanic eruption or meteor strike occurs, and while the ensuing particles to taint the atmosphere and the oceans with poison, wait in a shallow muddy sea until the water becomes completely devoid of oxygen (ensuring all the fishy things in the sea won’t nibble at your body), then wait until the toxic atmosphere really takes hold.

Et voilà! A couple of million years from now and your body will be perfectly, wonderfully preserved! (Provided plate tectonics doesn’t get in the way in the meantime!) You would have successfully become a Lagerstätte, which is the word we geologists use for the most amazingly preserved fossils in the world!

Amazingly preserved ichtyosaur agerstatte

Yours most sincerely,

Cambriangirl 😀

 

Walking with Dinosaurs!

Last week was the Birmingham premiere of the best show currently touring the UK right now – Walking With Dinosaurs!

In a word, it was AWESOME!

The T-rex below, for example, actually had me a bit scared! The sound, man… Way more intense than watching Jurassic Park in 3D.

ahmagadtrex

Not only were the dinosaurs incredibly textured and well-done that they really did look alive, but they were huge, and it was only at points where I noticed the paleontologist running around beneath them ‘for scale’ that I really became aware of the size of them. The brachiosaur was astonishing.

2013-04-10-19-31-19-humanforscale

First off all they brought out a ‘baby’ brachiosaur, and I thought initially that this was their way of managing to avoid making a huge adult-size brachiosaur puppet, but only five minutes later, after the allosaur had given the baby a bit of grief, the paleontologist turned around to a loud booming behind the curtain.

‘What could that be? Looks like the baby’s mother is coming out to defend it…’

And a head emerged from behind the curtain. The brachiosaur had to bend to get out, and when it extended its neck fully it near reached the highest lights in the stadium.

2013-04-10-19-35-brachiosaur-adult

The rocks on the stage moved around and became smoking volcanoes to symbolise the Deccan Traps as the paleontologist explained the role of flood basalts in the extinction of the dinosaurs.

2013-04-10-20-07-volcanoes

Flowers popped up from the ground as the paleontologist explained that flowering plants developed much later than dinosaurs evolved.

2013-04-10-20-16-flowers

There was a lot of meaty info, which was great for the kids in the audience, and makes me one very happy geologist. So seriously, if you have kids, or if you’re just overly enthusiastic about dinosaurs this is well worth a watch, and a great way to spend the evening!

(In fact, @thegeologyshop and I were so thrilled we got dino balloons afterwards… as you do…)

2013-04-10-20-48-happygeologists

Volcanism, Impacts and Mass Extinctions Conference: the livetweets!

Last week was the Volcanism, Impacts and Mass Extinctions conference at the Natural History Museum, London. The first event under this name, it lasted three days, each packed with dozens of lectures and plenty of discussion, and brought together nearly all the main players in the field of mass extinction research. It was exciting as this field of research is often fraught with disagreements over boundary distinctions and predominant causes of extinction – you just have to go back to the whole Alvarez thing to see how difficult it first was to acknowledge that impacts could even cause an extinction, and more recently to Courtillot to see how difficult it has been to accept the role of flood basalts. Discussions are bound to get exciting, and in this aspect the conference really didn’t let me down. I am hoping to see this conference return in two years’ time.

GEO-HEROES

Before I lay out what the haps were (because that section is long and requires much scrolling) I will briefly announce that I met many of my geo-heroes at this conference.

I met Gerta Keller (the event organiser) and Tony Hallam, saw Mike Benton but sadly didn’t have the chance to chat, and ran into Paul Wignall again. I also met so many cool people who answered loads of questions I had about my final year dissertation. Ace!

THE HAPS

@DaisysGeology and I were there (along with a few other tweeps) and we livetweeted the entire event. Below follows the Storify of our report, which should provide some interesting insight into the field of mass extinction research. (NOTE: if you don’t want to scroll endlessly like it’s a tumblr blog, click on the Storify icon. Otherwise, proceed.)

[View the story “VIME13 Livetweets” on Storify]

volcano speaks

I made a hasty attempt at this wee Friday writing challence – of course with the theme being volcanoes I have added a tiny geological twist. It is heavily influenced by my first memories of being in a volcanic landscape (Vulcano, Sicily).

Here’s the original article:  http://my.telegraph.co.uk/theshortstoryclub/louiseatmyt/645/friday-challenge-the-volcano/

volcano speaks.

There’s a stratocone up ahead, swaddled in ash. There’s streets of puffed cumulus above. It’s hot but that’s offset by the fierce sporadic wind. You would imagine you’d be thinking ‘Isn’t my life strange?’ or ‘How amazing is it that I’m here?’ – but you’re not.

Emptiness of this kind doesn’t bring self-reflection, and you know this all too late, because it’s pulsing with another energy, an energy that at first seems alien but after a while its vivid colours start to seep into your own and you realise it is in fact a very, very ancient part of yourself.

A lava bomb riddled with holes – there’s a scientific word for that. The red, soft, rusted earth – there’s a scientific word for that, too. But at that moment the specifics fail you and you do nothing but sink into the picture. You’re not really aware of it and you won’t even realise it afterwards, forever describing it to people as an experience of otherness. What really happens is you become a part of it, and at the precise moment the earth opens out to you what you are really thinking is ‘How can there be so much to all this?’

The photo comes out bland; you wonder how you will convince people how alive this emptiness is.

 

Shelf Stacking and Twitterstorm Surges

Every so often things prove that us geologists are like the very processes we study – stack the weight of too many things atop the proverbial continental shelf and you might just generate a landslide and corresponding surge of the ocean lashing back against the shore.

In this case, we geologists are the water in that ocean, and Tory politican Iain Duncan-Smith is the man on the shore, adding the final load to the shelf in the form of some ill-advised and acerbic comments on one geology graduate’s real shelf-stacking activities.

Of Cait Reilly’s workfare experience in Poundland, he said;

“Who is more important – the geologist, or the person who stacked the shelves?”

It’s obvious he’s just saying this in an attempt to garner as much support as he can for his controversial welfare overhaul plans. And regardless of how much he knows about geology, he’s betting on those who receive his rhetoric not knowing very much at all.

So he said his piece, and the geological community saw the opportunity to reach a mainstream audience, and proceeded to hit IDS with a barrage of information about what it is that geologists do. We raised the tide with this one, inundating a shore filled with a lot more than just one paltry politician: all the non-geologists that through no fault of their own never usually give geology a second thought, all the people IDS is trying to play off with divisive word games.

I think this is a very positive thing indeed, because if we don’t define ourselves, who will? And what I really liked was the fact that we formed lively and animated responses, demonstrating that geoscience is anything but dull, and geologists are more than able to shout and have fun and show emotion like the rest of those on social networks. We’re a passionate and spirited bunch, and what better an advert for such a great science?

Everybody do the Tangaroan!

It’s new, it’s exciting, and while it kind of sounds like a dance move, the Tangaroan style is in fact the newly classified third type of eruption style. We’ve got eruptive and effusive and now this.

Where?

It was classified by a team of researchers from the National Oceanography Centre (Southampton, UK) and Victoria University (Wellington, New Zealand) who studied Macauley volcano in the south west Pacific.

When?

The news appeared in this month’s edition of Nature Geoscience. The paper is called ‘Highly vesicular pumice generated by buoyant detachment of magma in subaqueous volcanism‘.

So what’s the deal?

Well, the Tangaroan style is specifically an underwater eruptive style. If it had happened subaerially it would be intermediate – somewhere between effusive and eruptive. And the main defining feature of this style is its foaminess. See, lots of vesicles form in the magma, and as it bubbles up it turns into a kind of foam, which detaches as packets of pumice and rises. Because of the effects of decreasing water pressure, the bubbles continue expanding so you end up with various sized bubbles by the end of it.

Pumice (which is usually a sign of explosive activity in subaerial volcanoes) is quite common in underwater volcanoes, and this new research means that underwater volcanoes currently marked as having explosive eruptions in the past may be reassessed under this new category. Exciting stuff!

Quite interesting:

The style is called Tangaroan after the Maori god of the sea, but it also acts as a homage to the ship used to collect samples, which shares the name. Fun fact: Tangaroa is also part of the Cook Islands’ mythos and has yellow hair, so when Europeans first visited, they were considered the children of Tangaroa.

Pumice rafts off New Zealand

In August of this year, a vast pumice raft was spotted off the coast of New Zealand. This is a rather interesting phenomenon – rocks floating in the ocean! – and it arises from the fact that pumice is lighter than water.

See, pumice has tons of vesicles in it – namely, air holes, gaps in the rock. It is made from very viscous, ‘bubbly’ magma. In other words, it is the froth on the latte of a volcanic eruption.

First noticed by a New Zealand marine aircraft, and reported by science writer Rebecca Priestly, who happened to be sailing close by, this particular pumice rafting event was not caused by what we would think of as a ‘normal’ volcano. No – it was underwater. It was apparently caused by Havre seamount in the Kermadec Islands, the volcanic byproducts of an underwater subduction zone just north of New Zealand.

The weirdest thing for me when studying geology was finding out that pumice rafts can appear as a result of underwater volcanic activity. Undersea volcanoes are usually typified by mafic magmas, whereas pumice is more commonly associated with felsic or andesitic activity – stratovolcanoes such as Mount St Helens, or Vesuvius.  It’s got the same chemical formula as obsidian, which is often associated with a type of felsic magma called rhyolite.

And, to further these associations, when Vesuvius erupted in 72AD the resultant Plinian style eruption column rained out a crap-ton of pumice over the sea in the Bay of Naples.  This made sense to me when I first heard it – Vesuvius is andesitic. So in my mind, pumice equals felsic, andesitic, big Vesuvius-type stuff.

What was new to me was realising that pumice can quite often be mafic, and that underwater volcanic eruptions involving mafic material and pumice are actually quite common. Just take a look at this image from a study published in PLOS earlier this year[1].

[1]The study is actually open access, so you will be able to download and read at your leisure.

So what kind of conditions would lead to an undersea volcano producing pumice rafts? Well, they are very common around subduction zones, where you will find more violent forms of eruptive activity that are more likely to cause the viscous bubbliness necessary for pumice to form. Not that it doesn’t happen in spreading ridge settings, it’s just less common. The major pumice rafts in the news recently have been from the Tonga – Kermadec region.

This particular raft grew to over 20,000 square kilometres. A venerable floating island indeed. It is made all the more interesting by the fact that pumice in recent years has been shown to be a decent substrate for distribution of marine life around the oceans. Take a look at this snapshot of a piece of pumice colonized by various life forms. How cool is that?

 

Great Scot! A Primer On James Hutton

Saltire composed of ammonites

It’s St Andrews Day today. Hooray! An excuse to drink whisky and generally be loud and simultaneously insanely proud of my identity and depressingly horrified by it.

There is just one thing stopping me from doing this, and I must sort it before the fun can begin.

David Cameron and Alex Salmond today have published some very spirited and motivational speeches on Scottish culture and achievement. Unfortunately, they both failed to mention geology, and being a geologist I know that a lot of major geological advances (such as the theory of Uniformitarianism, which underpins all geological study today) were achieved by Scottish geologists.

Why so many Scottish geologists? Well, we’re not better at geology than anyone else, we just happen to be surrounded by some of the most interesting and complex rocks in the UK. The Moine Thrust, the Tay Nappe, the Lewisian Complex… there’s an awful lot to keep us busy.

I’m going to focus on Hutton. James Hutton. A very cool bloke. For a start, he was a plutonist, someone who believed that all rocks on the planet originally came from an internal volcanic source. The plutonist is the natural enemy of the neptunist, someone who believed that all rocks originated via crystallisation in the oceans, and they warred for years over who was correct. Now we know that the plutonists had the right idea, although some sedimentary rock can form in a kind of neptunist way (coral reefs).

So this Uniformitarianism stuff. What does it mean?

Well, in 1788 Hutton went to the now-famous Siccar Point, and after studying its curious rocks overlying each other, he decided that an unimaginably long time must have passed between them being deposited, a large span of time in which the original rocks were tilted practically vertical. He threw out the window the concept that the Earth was only 6000 years old. These rocks were the evidence, the starting point for a geological revolution.

He published his Theory of the Earth[1] in 1795, and the reception of this new idea was varied – he was simultaneously applauded and accused of being an atheist (a pretty serious accusation in the 18th Century!).

A century later, Charles Lyell decided to develop his work even further, eventually publishing the famous Principles of Geology. The new viewpoint – that of slow-moving forces over long periods of time – became known as Uniformitarianism, and the old viewpoint of gods causing sudden, violent events became known as Catastrophism.

Some people today still hold to Catastrophism, in spite of the evidence against. And by this I mean they hold to the idea that all change on Earth’s surface comes from short-term, high-impact events. It’s a world apart from what we call Neo-catastrophism today, a more integrated idea which holds that long-term processes are occasionally supplemented by short-term events.

But thanks to this intrepid Scot, whose revelation about the Earth was almost as monumental as Galileo’s, an even greater number of us today are able to use his ideas, build on them, and discover more about this restless, ever-moving planet. Nae limits, eh no?

[1] You may be interested to know that both volumes of Theory of the Earth are available on Project Gutenberg:

Theory of the Earth, Volume 1

Theory of the Earth, Volume 2