Author: LauraR

This article was originally posted on the EGU Blog network for Geology Jenga.

Happy New Year to you all!

The past few weeks and months have seen some exciting newsworthy stories regarding the Earth’s magnetic field. I thought I’d highlight a few of them for our first post of the New Year.

Magnetic Interactions 2014

For two days in early January, all of us at the Geomag Lab (well, pretty well all of us) travelled to Cambridge University, to attend the UK conference for the geomagnetism community. This year there was also a strong international presence. I would usually write a blog post on the highlights of the research that was being showcased at the conference; however, the meeting organisers beat me to it! Read about the science behind fundamental, applied rock and mineral magnetism, as well as, how an ancient voyage by naturalist Alexander von Humboldt might help us understand the geomagnetic field prior to the 1800s  in this blog post by Dr. Richard Harrison, of Cambridge University.

Logo courtesy of Richard Harrison.

The Aurora that never was.

Credit: Wikimedia Commons, user: United States Air Force, This image or file is a work of a U.S. Air Force Airman or employee, taken or made as part of that person’s official duties. As a work of the U.S. federal government, the image or file is in the public domain.

On 7^th January, there was a large solar flare with an associated fast traveling Coronal Mass Ejection (CME), which was headed straight for the Earth, and was expected to hit our planet by the 9^th of January. Space weather scientists, the media and people across the UK and Europe were glued to the night skies in hopes of seeing aurora borealis at abnormally southerly latitudes. Perhaps the excitement surrounding the potential to observe these mysterious phenomena was fueled, at least in the UK, by the timely airing of the first episode of the new series of Star Gazing Live, in which the team (made up of Prof. Brian Cox and comedian Dara O’Brien) took on the challenge to capture the northern lights.

Space weather has featured heavily in the UK media in the run up to the Christmas, as the UK government pledged a £4.6 million investment in the forecast of space weather. From early this year, the Met Office will forecast, deliver alerts and warnings to key sectors that might be adversely affected by  solar flares and CMEs.

Despite the hype, the skies did not deliver. A great blog post by Dr Gemma Kelly, at the geomagnetism team of the British Geological Survey, explains the reasons behind why the Northern lights didn’t quite happen!

For more information on solar flares, CMEs and why they are important: have a look at my guest blog post for GeoSphere on the Earth’s protective shield and also the information pages of the British Geological Survey.

Last week, Megan and I were away in Oxford taking part in a National Environmental Research Council (NERC) sponsored young entrepreneurs competition. The competition is called, EnvironmentYES! (Think Dragon’s Den!). In the competition, teams of early-career researchers (PhD students and post-dcos) attend a three-day workshop where they are given training and guidance on innovation and how to commercialise research. At the end of the three-day workshop, teams present and pitch their ideas for an imaginary environmental start-up company in competition with each other. The winning teams from each workshop are invited to a final where they compete for a prize of £2500.

Meet the team! Steve, Laura, Megan and Lidong (L-R).

Megan and I are part of a four person team taking part in the competition. One of our fellow PhD students in the school, Steve Hicks, approached us towards the end of the summer, to see if we fancied having a go at the competition. We both agreed to do it as it was an opportunity to learn about the business world, which we knew little about.  Lidong Bie decided to join our team, and so we could get to work! This kick started a few months of preparation for the workshop in Oxford last week.

The first thing we had to do was decide what our product was going to be. We had LOTS of ideas: some quite sensible, whilst others where a little out there. Eventually, we managed to narrow it down to three ideas: using pea straw for the remediation of contaminated land, developing a service to monitor seismicity associated with fracking activities and the monitoring of air quality by measuring magnetic particles on tree leaves. Two of our ideas were based on already published research, which you can read all about here and here.  As it is a business competition, we had to assign ourselves roles within the management of our fictitious company. Steve took on the role of CEO, Lidong became our finance man, Megan is in charge of marketing, whilst I am our research and development officer (i.e, I’m in charge of the science).

Steve approached The University Graduate School, Management School and Technology Transfer Services, all of whom have provided us with lots of help in preparing for the competition. During our first meeting with them, we ‘pitched’ our three ideas (note how I am already slipping into my newly acquired business and commercial vocabulary). When starting a business, as we quickly found out, the idea is important, but not as important as identifying who has a need for the product/service you are offering, i.e. what and who make your market? This was something we thought about a lot when deciding which idea to go with. With the fracking and air quality monitoring ideas we just couldn’t really see who would buy our services/products and so in the end, we settled with remediating contaminated land using pea straw; and so team TERGEO was born.

Our company Logo

Having chosen our idea we had to formulate it into a viable, appealing and realistic business proposition. I got on with really understanding the science behind the idea and explained to the team how the world of environmental consultancy worked (as I worked as a consultant before I started my PhD). Megan worked hard on identifying who are customers and competition would be. Lidong had the arduous task of getting to grips with endless financial spread sheets and costing up both our site works and overall business running costs. Steve coordinated all the work and researched how we could ‘protect our idea’. Intellectual property and how you can protect ideas, products and know how is fascinating and at the same time, extremely complex.

All our hard work culminated last week, when we attended the workshop in Oxford. The first two days were dedicated to learning more about how to set-up your own business, receiving help and support from a wide range of mentors and hearing from people who have actually gone on to set up their own company (some as a result of participating in the competition). The final day of the workshop saw all the teams go up against each other in front of a panel of ‘investors’. We had to deliver 15 minute business presentations, to compete for the judge’s investment in our company. Our team was put into the first stream (of two), and we competed against five other teams. Some of the ideas pitched by other teams were incredibly interesting: tents with built in solar panels, an app that worked out what the most eco-friendly products available in a supermarket are, a chip that monitors your UV exposure, a  pressure driven turbine that generates power from the main water supply and a solar panel with a kick!  Teams fielded questions from the investors really well and people were so enthusiastic about their idea and business!

The judges verdict was announced at 3pm on Friday afternoon, to a room packed full of expectant participants and mentors. Team TERGEO are super excited to announce that we made it through the regional finals and are now on our way to Grand Final in London on 2^nd December! Watch this space!

Acknowledgements

We couldn’t have got as far as we did in the competition without the help of our mentors. So a big thank you to:

Dr. Dale Heywood, Director of Entrepreneurship studies at the University of Liverpool

Dr. Richard Hinchcliffe, Head of Postgraduate Development at the University of Liverpool.

Dr.Lisa Ahmead, Partnerships and Innovation, Business Gateway, University of Liverpool

Andrew Bowen, ISIS Innovation

Luca Guerzoni, Esperimenta

Becky Herbert, Alan Garmonsway, Emma Faldon, The Pirbright Institute

Bevan McWilliam, RVC Enterprise

The latest in our paper discussions took us away from our usual  territory- and out to Saturn. Cao et al’s paper Saturn’s high degree magnetic moments: Evidence for a unique planetary dynamo looks at modelling the magnetic field of Saturn, which is very different to the field of the Earth. Parts of the magnetic field have been measured by Pioneer 11, and both Voyager missions, and more recently, Saturn has been visited by the Cassini mission, which also recorded magnetic data, and essentially confirmed what was already known. Analysis of the data from Pioneer and Voyager(s) and modelling of low spherical harmonic degrees (g⁰₁, g⁰₂ and g⁰₃) show Saturn’s field to be highly axisymmetric (i.e. symmetrical around the spin axis, with little difference as you move along the equator but poles of opposite sign) and also much weaker than the field of the Earth, being around 30,000nT at the surface, compared to 50,000nT here. The field axis is the same as the rotational axis, to within 0.06^o. There has also been very little change in the field measured between the Voyager missions and Cassini’s arrival. The magnetic moments of the lower spherical harmonic degrees having being well modelled with the available data, in this paper the authors try to model higher degrees, g⁰₄ and g⁰₅ with the new data from Cassini.

Cassini probe approaching Saturn

The results they find agree with what was previously found – that Saturn’s field is highly axisymmetric, with most of the magnetic flux confined to polar regions, and higher degrees of the field are relatively small contributions to the overall measured field – hence not being seen on some more distant orbits of the satellite. They also suggest a similarity to certain types of dynamo models – such as spherical Couette dynamos, where the dynamo is driven by differential rotation between outer and inner layers of a shell. This is a very different type of dynamo to the Earth, with its convection driven dynamo – and indeed may not even be physically possible for Saturn! In this case, the different rotations could be due to a transition in the phase of helium (such as the gaseous atmosphere ‘raining’ liquid helium at pressure), a metallic layer, or the solid core of the planet. This was certainly the part of the paper that provoked most discussion amongst us – and several sci-fi type visualisations of what helium rain might look like!

Cao, H, Russell, C, Wicht, J, Christensen, U, and Dougherty, M.  Icarus 221, 2012, 388–394: Saturn’s high degree magnetic moments: Evidence for a unique planetary dynamo.

Today’s post was guest written by Kelly Barker. Kelly is a PhD student in the geomagnetism research group at the Department of Earth, Ocean and Ecological Sciences at the Univeristy of Liverpool. Her research project is entitled: Improved application of remote referencing data in aeromagnetic processing: insights and applications from global geomagnetic modelling.

I am afraid this post is a little delayed. The paper we discussed at the end of June was: Alteration and self-reversal in oceanic basalts, Doubrovine & Tarduno, 2006. A companion paper, well worth a look at is: Self-Reversal magentization carried by titanomaghemite in oceanic basalts, Doubrovine & Tarduno (2004).

I chose this paper because of some intriguing results I’ve had working on my Archean aged samples. I was keen to hear what the lab had to say about the paper above, but also about my results and self-reversals in general, as they are pretty controversial due to being quite poorly understood.

It has been suggested, since the late 1950s, that given the right conditions, some oceanic basalts can carry a self-reversed chemical remanent magnetisation (CRM). Research by Verhoogen (1956) suggested that self-reversals could occur in titanomagnetites by ionic reordering during low-temperature oxidation.  Oceanic basalts are good candidates because seafloor weathering is characterised by low-temperature oxidation of titanomagnetites as show by Bleil & Petersen, 1983, amongst others. However, it was not until the research published in Doubrovine & Tarduno, 2004, that a clear example of this process was identified and so, little research into self-reversals was conducted during the 1990s.

In oceanic basalts, oxidation occurs by the removal of iron due to interaction with sea water or sea water bearing fluids. Self-reversals occur at a critical degree of oxidation when it is possible for cation vacancies created at tetrahedral sites (A magnetic sublattice) to migrate into the octahedral sublattice, via diffusion. This process is known as Ionic Reordering . It allows single domain grains (and perhaps also pseudosingle domain grains) that carry a CRM by titanomagnetite to transform into an antipodal CRM. I recommend you take a look at the two papers if you want to understand this process more fully, they’ve got some good formulas which might help!

Verhoogen (1956) reported a large range of titmanomagnetite compositions were this process might be possible (light grey area in theTiO₂-FeO-Fe₂O₃ diagram), but O’Reilly & Banerjee (1966) showed that Verhoogen’s (1956) cation distribution was unrealistic and indicated that self-reversals were only possible in titanomaghemite, (dark grey area in theTiO₂-FeO-Fe₂O₃ diagram). In addition, work by Schult (1968, 1971) shows that ionic reordering should produce N or Q-type thermomagentic behaviour.

The work by Doubrovine & Tarduno (2004,2006) suggests that the compositional field in which true self-reversals can occur, as proposed by O’Reilly & Banerjee (1966) is too broad and that the range is in fact, much more restricted than previously though. The work presented in the paper suggests that the very high oxidation states and high Ti contents are required to produce a true self-reversals negates the possibility of it being a common occurrence in oceanic basalts. The authors suggest that self-reversal is indicative of unusual ocean floor conditions such as extreme fluid flow and iron removal.

Selected References

Bleil, U., and N.Peteresen (1983), Variations in magnetization intensity and low-temperature titanomagnetite oxidation of ocean floor basalts, Nature, 301, 384-388.

O’Reilly, W,. and S.K. Banerjee (1966), Oxidation of titanomagnetites and self-reversal, Nature, 211 (5044), 26-28

Schult, A. (1968), Self-reversal of magnetization and chemical composition of titanomagnetites in basalts, Earth Planet Sci. Lett., 4, 57-63.

Verhoogen,J. (1956), Ionic reordering and self-reversal magnetization in impure magnetities. J.Geophys. Res., 61(2), 201-209

Days two and three of the EGU conference were packed full of interesting talks and poster sessions.  Day two was the big geomagnetism day, with open oral and poster sessions. The highlights of my third day at the conference have to be the Stephen Muller Medal Lecture by Leigh Royden of MIT and the Big Fracking Debate.

Day 2 – Tuesday 9^th April – Geomagnetism Day

I spent the majority of my second full day at the conference attending oral and poster presentations related to geomagnetism research. I liked the huge poster halls when they were quiet; with thousands of people presenting each day it can be an overwhelming experience! So, early in the morning I headed down to the poster hall to have a scout at what was on offer. I was most surprised by the variety of research being presented and some of the novel approaches being used. Two posters that really caught my attention were:

1) Is it possible to receive information about the historical geomagnetic field declination from church orientations? (A.Draxler et al.). I liked the idea because most of our information about the recent geomagnetic field comes from observatories, satellites and historical records. The approach presented in this poster is novel and with a larger dataset might provide greater resolution of the already existing models.

2) I’m a big advocate of science outreach and was really pleased to see a poster presenting a geomagnetism outreach project currently taking place in Austria (Bailey et al.). The idea of the project is study regional variations of the geomagnetic field by establishing geomagnetic observatories across three schools. The students have to choose the location for the observatory and set-up the instruments. The data collected will be available to students and researchers via an open project website.

The oral presentations were just as varied as the work being presented during the poster session, with most aspects of geomagnetism being represented. There were talks on the use of paleomagnetism to debate continental breakups during a number of geological eras; outlining the first results from a newly setup geomagnetic observatory in Croatia; using archeomagnetism to establish the deposition temperatures of the pyroclastic flows of the minoan eruption in Santorini; investigations of the Upper Jaramillo reversal from lava sequences in Tenerife; and trying to understand geomagnetic jerks better.

Day 4 – Wednesday 10^th April – Continental Collisions & to frack or not to frack?

I was free to explore what was on offer at EGU today, as there was no sessions which would directly link to my own research. Luckily, there were some really interesting things on! Medal Lectures are great because they are aimed at a wide audience but showcase some of the best research of the past few years. This is true for Leigh Royden’s medal lecture on continental collisions and the role subduction plays in this process. The talk took the audience through some of the examples of where her work (and that of her collaborators) has made major advancements in our understanding of how geometries of subducting plates and process associated with subduction are related to the structure of systems such as the Carpathian Thrust Belt, Apennine region and the Tibetan Plato. What struck me about the lecture, as well as the quality of the research, was what a great speaker Leigh Royden was. Her slides contained only figures and the story she was trying to tell flowed skilfully well. The content of a good presentation is key, but this particular lecture highlighted to me how crucial delivery of that content is on making it a great talk.

To frack or not to frack – the big debate.

This is a hotly debated topic and unsurprisingly the lecture room (one of the largest in the conference centre) was packed. This session took the form of a panel discussion, were four experts set out their views on the subject and then the discussion was open to the floor and the panel would take questions. The panel was diverse: a Professor in hydrogeology (Spain), a member of the Energy and Climate Change Select Committee at the House of Commons (UK), the head of section at the Helmholtz Centre (Potsdam) and a representative of Greenpeace (Austria), which of course lead to heated discussions, amongst the panellist and the audience. I came out of the session a little more informed as to what the pros and cons of fracking are and educated about what the difference stances on the matter are depending on your role within the debate. The event had a designated hashtag on twitter #EGUfrack and you can find more details about the debate in this blog post by Matt Herod, of the EGU blog network.

For more EGU action from other blogs and twitter, take a look at:

GeoLog (http://geolog.egu.eu/) and the EGU Blog Network (http://blogs.egu.eu) will be updated regularly throughout the General Assembly.

Keep up to date via Twitter by following (@EuroGeosciences) with the conference hashtag (#egu2013).

All this week (7^th April -12^th April) I’m attending the European Geosciences Union (EGU) General Assembly 2013, held in Vienna, Austria.  The conference has in the region of 11000 attendees, 13,500 submitted abstracts and more than 600 sessions, workshops and short courses, all related to the geosciences.

In these next few blog posts (not sure how many I’ll get to write yet!), I’ll be giving you an insight into my time at EGU (which is extra exciting for me, as it is my first international conference). I’ll be attending a range of talks, poster sessions, short courses and panel discussions; I hope to give you highlights of my favourite bits. There is so much going on that this will only give the briefest tour of what is on offer here, but there are plenty of sources where you can keep up to date with all the rest of the geosciences action– see the bottom of this post for details on those.

Day 1 – Sunday 7^th April – Ice Breaker

I traveled to Vienna today and met up with other colleagues from Liverpool University. The seismology group have sent a number of delegates, as well as the geomorphology group at the geography department. Not much science happens at the ice breaker (at least not in my case), but we all enjoyed the free wine and food, an excellent way to start the conference :)!

Day 2 – Monday 8^th April – Super Earths

My day was dominated by science related to Planetary Evolution. How much do we know about the deep interior of rocky planets and what can that tell us about their ability to generate magnetic fields and how size might be related to the onset of plate tectonics.

Tilman Spohn was awarded the Runcorn-Florensky Medal for his contributions to planetary science and gave a lecture on the thermal history of planetary objects. What is the state of matter in the deep interior of planets? In most cases, it seems we have a fair handle on this. So, take the Moon, for example, from seismic data we now know it has a core and solid inner core, but at what point was it able to generate its own magnetic field? He explored the Iron Snow Regime, which provides a mechanism by which, initially no dynamo would have existed, but one could have developed later in the Moon’s history.  The lecture also presented the idea supported by many that Plate Tectonics need to operate for complex life to evolve on a planet, but is the size of a planet related to its ability to have a mobile mantle and therefore moving plates? Can plate tectonics feasibly operate in large planets know as Super-Earths? Some authors believe that there is a planetary mass range that favours the development of plate tectonics and that the probability of plate tectonics occurring may well peak at an Earth sized planet. Is it therefore, just chance that life developed on Earth?

I also went along to John Tarduno’s talk on: Dynamo’s, Planetary Evolution and Life. He presented palaeomagnetic results from the Jack Hills Unit in Australia, that pass a conglomerate test (indicating they are at least the same as the depositional age of the conglomerates) and which record the weakest field intensities recorded so far in the Archaean: 7µT. Tarduno also discussed the implications of these results with relation to the ability of the Earth to retain water and it’s atmosphere at this early stage of its life. Although the evidence suggest there was an active dynamo at this time (Tarduno et al.2010, Biggin et al.,2011, as well as the data reported in the talk), it’s not clear how much protection from solar wind the early geomagnetic field would provide. It is also thought that standoff distances between the Sun and the Earth might have been much reduced and the effects of stellar activities strongly felt on the Earth’s surface. Perhaps there might be some other factors influencing the retention of an atmosphere and water early in the Earth’s history? Was there an initial super ocean on Earth, or a delivery during the Hadean/Archaean, which would allow for water loss, whilst still retaining sufficient to develop the planet into the body we know today?

Tomorrow is the big palaeomagnetism day, with both poster and oral session, watch this space for more highlights!

For more EGU action from other blogs and twitter, take a look at:

GeoLog (http://geolog.egu.eu/) and the EGU Blog Network (http://blogs.egu.eu) will be updated regularly throughout the General Assembly.

Keep up to date via Twitter by following (@EuroGeosciences) with the conference hashtag (#egu2013).

Some selected references:

Tarduno & Cotrrell, (2013) Earth and Planetary Science Letters,367, 123-132,2013.

Biggin et al., (2011), Earth and Planetary Science Letters, 302,314-328.

Tarduno et al. (2007) Nature, 446,657-660.

Tarduno et al. (2010) Science, 327 (5970).

I’m coming to the end of a 5 week visit to The Fort Hoofddijk, the Palaeomagnetism Laboratory at the University of Utrecht, in the Netherlands.  I’ve been carrying out a number of experiments, the results of which I am hoping to present at this year’s European Geosciences Union (EGU) Assembly, in Vienna (7^th – 12^th April).

The Building

The building which houses the lab is pretty impressive, as it is a 19th Century bunker, within the grounds of the botanical gardens at the University. Most of the equipment is found at the back of the building, in what used to be the old gunpowder storage rooms. It lacks any windows, so experiments are conducted without natural light, which reminds me of this comic. Learn more about the building here.

There are strong links and collaborations between the Liverpool Geomagnetism Lab and ‘The Fort’ (as the Utrecht lab is often called). My PhD project is co-supervised by Cor Langereis, who heads up The Fort. In addition, Andy, Mimi and Megan are involved with projects with students at The Fort. I also hear that Andreas and Emma meet Wout Krijgsman (also of The Fort) during their recent sampling trip to New Zealand.

Why the Fort?

The answer is simple, doing experiments at The Fort, saves me a lot of time!

This is my fourth visit to The Fort. I’ve visited often because they have equipment which we don’t, yet, have at Liverpool. Whilst at the Fort, I regularly use their2G Enterprises DC-SQUID magnetometer (which happens to be the first ever made) and also, an in house built, robotised AF demagnetiser attached to a 2G Enterprises RF-SQUID magnetometer (the Robot). The Robot

The Robot

is a nifty piece of kit, allowing you to alternating field(AF) demagentise 96 samples without you actually having to do any measuring, which any palaeomagnetist will tell you, is a GREAT advantage! It saves huge amounts of measuring man hours. You prepare the samples by placing them in cubes, which act as sample holders, and load these onto a tray made up of 12 rows, which take 8 samples each. You then produce a file which tells the computer how you want the experiment to run and press GO, and leave it to do its thing. Provided everything works fine, it takes the robot, on average, 48hrs to measure a full batch of 96 samples. The samples I’ve been working with are not standard palaeomagnetism size, (standard being 1 inch). This means I need to use special holders, of which there are only 15 available. A full AF demagentisation of two rows takes less than 12hrs. Whilst here, I’ve also been running some manual AF demagentisation experiments on the AF demagentiser, and a full experiment has taken me 36 man hours to complete.  I could conduct my experiments at Liverpool, and to some extent, I do, but they are considerably more time consuming than doing them here at the Fort!

A Typical Day

The 2G Enterprises DC-SQUID magnetometer (2G, from now on)

2G Enterprises DC-SQUID magnetometer

is usually in high demand, especially after spring and summer, when most of the field work takes place. Students and staff come back from this expeditions loaded with samples, which they are keen to get measuring asap. As a result, a shift system is in place to use the 2G. The first shift runs from 6am-3pm, the second from 3pm to midnight and the graveyard shift runs from midnight to 6am. February isn’t too busy a time, so I’ve been lucky to get the day time shift from 6am onwards.

The squids on the 2G need a little time to stabilise after being turned on, so that is my first task – get everything switched on and ready to go. In the time it takes for the squids to stabilise I can prepare breakfast and get the samples ready to be measured. I usually run two batches of samples concurrently: whilst one batch (of anything between 30 and 45 samples) is heating in the oven, I measure the other on the 2G. The samples I’m working on at the moment don’t respond well to thermal demagnetisation (TH), as I see them altering quite a lot. Therefore, I’ve been carrying out AF demagnetisations too. These only take a couple of minutes to complete, unlike the TH demagnetisations, where the samples have to sit in the oven for an hour.  I perform the AF demagenetisations and measure the samples whilst the TH batch is heating in the oven. In a nine hour shift, I repeat this process four  times, twice for AF batches and twice for TH batches. It’s a pretty repetitive task, so you have to keep yourself entertained, either by watching a film, listening to music, or writing this blog post!

A little thank you

I’d like to take this opportunity to thank everyone at The Fort for all their help during my time here (on this visit, and all my previous ones). I’d especially like to mention Tom Mullender and Maxim Krasnoperov, for all their technical support and teaching me how to use all the equipment. Also, Cor Langereis for his hospitality and valuable discussions!

Every year, the UK magnetism community gets together at a conference to showcase the most recent advances in the field, establish collaborations and discuss (sometimes heatedly) new projects and findings.
This year, Magnetic Interactions, was hosted by the Lancaster Environment Center. They certainly did a great job! An interesting program of talks was put together, alongside a good poster session and an excellent curry for dinner!
All of us at Liverpool Geomagnetism attended the conference, with much of our recent work on display (more on that later). Labs from other Universities were represented too, including Oxford, Imperial, Plymouth, Leeds and Cambridge. Talk and poster topics ranged from discussion on geomagnetic excursions and jerks, through nanopalaeomagnetism and magnetic tracing of particulate pollutants.
Work from other labs
For the most part, the attendees are based at UK Labs, but this year, the invited speaker was none other than Ted Evans (University of Alberta, Canada) who gave a very interesting talk on what he has called the cryptonchron enigma. So what is a cryptonchron? It is described as a tiny wiggle seen in the Geomagnetic Polarity Time Scale (GPTM) which is smaller than the major chrons, a small feature of dimensions on the scale of:40-80nT, 10-20Km. Their underlying cause is currently unexplained, although recent studies suggest they might be attributed to short reversal periods or intensity fluctuations of the geomagnetic field (Boulingand et al. 2006). But the enigma remains: what are cryptochrons? With his collaborator G.Hoye, Ted has developed a computer model which calculates the magnetic anomaly over a section of oceanic crust. The output of this model suggests that cyptochrons could be considered subchrons which could indicate that the field might be reversing more regularly than was previously thought.
A pick of other interesting talks and posters included: Sarah Dodd (Imperial) & Conall Mac Niocaill, (Oxford), who propose that magentostratigraphic data can help in understanding the eruption rate and exact chronology of Large Igneous Provinces (LIPs), which a particular focus on the Etendeka Flood Basalts of Namibia. Richard Harrison, from Cambridge, presented his new approach to palaeomagnetic measurements, where the source of uncertainty introduced during bulk rock measurements, is removed by performing paleomagnetic measurements at sub micron length scales, in what is being called: nanopalaeomagnetism. One of the hosts, Barbara Maher talked about how magnetic particles found in particulate pollutants which accumulate on tree leaves allows monitoring of pollution in urban areas.
What the Geomag Lab has been up to
As I mentioned earlier, the Liverpool Geomagnetism Lab had a strong presence at the conference:
• Andy gave a talk in which he discussed the findings of his recently published article in Nature Geoscience were he and his collaborators link long term variations of the geomagnetic field to whole-mantle convection processes.
• I also presented the latest findings of my research on Archean age rocks of the Barberton Greenstone Belt. Combined with data previously published by Andy (Biggin et al. 2011), I’ve been able to constrain the age of the magnetic signal recorded in the rocks of the Hooggenoeg Formation, to 3.2Gyr.
• Emma Hodgson has been researching non-ideal behaviour in interacting single and multi-domain grains, using synthetic magnetic samples. She presented a poster with experimental results from her recent work which indicates that there is violation of Néel’s Laws of thermoremanent behaviour in interacting single domain samples.
• Wilbor Poletti (a visiting student from the University of Sao Paulo, Brazil) has compared classical Thellier-Thellier(TT), Triaxe (TR) and Microwave (MW) methods for determining palaeointensities using Brazilian baked clays. In his work, he has improved the experimental protocol for the MW method. He also shows that the MW method is significantly affected by the “cooling-rate effect” and a pseudo-single domain bias, but these are easily accounted for, performing an experimental correction, which means all three methods for determining palaeointensities are now comparable.
• Keeping with the paleointensity theme; Megan (who also contributes to the blog) has been working on determining the past geomagnetic field intensity using Turkish pottery fragments has found that, as is well known, experiment success rate is very variable. Putting aside methodology issues, she discussed other potential issues e.g. dating uncertainty, pottery compositional variability and kiln design.
• Andy also presented the PINT database (which has been recently updated with 227 new records taken from 14 references) with the aim to reach a consensus on what the properties of the most reliable paleointensity measurements are.
• In his work, Andreas Nilsson, has used data from the Pint database, using archaeological artefacts/lavas and lake/marine sediments, has constructed a new continuous spherical harmonic model for the geomagnetic filed over the past 9000 years.
• Finally, Neil has been questioning if how we calculate pole positions (from Fisher distribution statistics) is actually the best way to go about things? He proposes a new method which defines the virtual geomagnetic pole (VGP) from the expectation of angle between VGP and spin-axis of the Earth, adopting a spherical exponential distribution. This method consistently gives confidence limits that are smaller than those derived from Fisher, yet more likely to contain the true pole position.
The conference was a huge success. The conference organisers did a brilliant job, and it provides a great platform for us all to showcase the best of our work. Already looking forward to the next one – Cambridge here we come!

Often, as an undergraduate geology student, my lecturers referred to the past as the key to the future. This was never an easy concept to grasp. However, a recent article in New Scientist magazine (13th September 2011 ) really puts the research, we are doing, at the Palaeomagnetism Laboratory in Liverpool into perspective.  Understanding how a large solar storm would affect satellites is important, and even more important is learning what we can do in order to minimise the disruption and damage caused by one. The Earth’s magnetic field protects us from the effects of solar storms and acts as a shield against the charged particles referred to in the New Scientist article. Understanding how the Earth’s magnetic field has behaved in the past is a useful tool in trying to understand how it might behave in the future. This ties in with Andy’s post back in June 2011: “Why should the taxpayer fund palaeomagnetic research?” This is a true example of how our work can contribute to modern society and highlights why the past is the key to the future!