The Rio Tinto mines

The Rio Tinto ore body is a massive sulfide deposit in the south of the Iberian peninsula. It takes its name from the nearby Rio Tinto, literally “red river,” whose colour is due to oxidation of iron contaminants leached from minerals in the nearby ore body, or from the slag heaps that dot the region. In 1873, a group of investors took over the mine, forming the Rio Tinto Group, which has since become one of the largest mining concerns in the world. However, the exploitation of the region’s mineral wealth started long before the 19th century. rio_tinto

Fig. 1. The Rio Tinto river, showing the deep red colour caused by the high concentration of ferric iron.

Mining activity at Rio Tinto began as early as 3000 B.C.E., when the southern Spain was occupied by the Iberian and Tartessan people. It is probably no coincidence that the Phoenicians, an eastern Mediterranean trading civilization that flourished between 1500-500 B.C.E, established their first Spanish colony at Gadir (Cadiz), which is today just a 3 hour drive from the mines at Rio Tinto. Later, the mines would come under the direct control of Carthage, a Phoenician successor state.

Following the defeat of North African state of Carthage by Rome in the Second Punic War, the entirety of the Iberian peninsula passed into Roman hands, and with it the mines at Rio Tinto. The exploitation of their mineral wealth continued apace under Roman rule, and lead isotope data suggests that Rio Tinto was the primary source of silver for Roman coinage during the early Imperial period (Butcher and Ponting, 2005).

rio_tinto_lead.jpeg

Fig. 2. Fraction of anthropogenic lead in the Greenland ice derived from Rio Tinto and other Roman mines in the Southern Iberian Peninsula. From Rosman et al., 1997.

The smelting process used to extract silver metal from the jarosite ore mined at Rio Tinto resulted in the emission of heavy metal pollutants into the atmosphere, where they were dispersed around the world. The scale of the Roman mining operations in southern Spain may be seen from lead isotope ratios measured in the Greenland ice, where nearly 70% of the anthropogenic (ie. human-derived) lead deposited between 400 B.C.E and 50 C.E. came from the Rio Tinto ore body or its immediate vicinity (Rosman et al., 1997).

While mining activity at Rio Tinto declined in the 2nd century C.E., and again following the fall of the Western Roman Empire in the 5th century, it never completely vanished. In fact, mining continues at Rio Tinto today, with the recent expansion of a copper mine owned by Atalaya PLC, making it the oldest continuously mined formation in the world.

Citations:

Butcher K, Ponting M (2005) The Roman Denarius Under the Julio-Claudian Emperors: Mints, Metallurgy and Technology. Oxford Journal of Archaeology 24:163–197. doi: 10.1111/j.1468-0092.2005.00231.x
Rosman KJR, Chisholm W, Hong S, et al (1997) Lead from Carthaginian and Roman Spanish Mines Isotopically Identified in Greenland Ice Dated from 600 B.C. to 300 A.D. Environ Sci Technol 31:3413–3416. doi: 10.1021/es970038k

Trends in Science

By Tim Jones

The ability to search through colossal amounts of data with a few key strokes is one of the most powerful gifts of the digital age. While vastly improving the standard of common knowledge the world over (with no foreseeable limit to this trend), we have opened up areas of research that would be too arduous for humans, or simply never imagined before the rise of digital data analysis. An awesome example of this is Google’s Ngram Viewer, a corpus of digitised texts containing around 6% of all books ever printed. Linguists use it to track changes in language through time, e.g. the usage of “burnt” vs “burned” or the emergence of phrases such as “it takes two to tango”. I’ve used it to track the occurrence of four words between 1800 and 2000; physics, chemistry, biology, and geology. There are some interesting correlations that can been drawn between trends in word usage and the timing of developments and discoveries in these fields of science. For example, geology begins its greatest period of growth from the year 1829, one year before Charles Lyell began publishing his seminal work, Principles of Geology.

ngram_science_edit

Thomas Kuhn, physicist and one of the great philosophers of science, claimed that scientific revolutions involve a paradigm shift, whereby a new discovery is found to be incompatible with an existing understanding of nature, and thus changing the basic assumptions of science to make way for a new paradigm. To highlight the difference between an emerging theory and a dying one, I’ve also made a plot of ‘plate tectonics’ and ‘expanding Earth’. What trends and turning points can you see, and do they relate to real developments in science?

platevsexp

To play with the viewer yourself, follow the link: Google Ngram Viewer


*normalised to number words in the corpus for each year

Radioactive Glass that glows

20160120_114924By Louise Schoneveld.

Currently showing at the  National Gallery of Australia  is the wonderful artwork by Ken + Julia Yonetani entitled – The last temptation. The artwork is make up of beautiful uranium glass chandeliers, with each chandelier size representative of a country’s nuclear output. There are 31 chandeliers in the collection, however only a small selection are shown here in Canberra.

While walking amongst the chandeliers, I began to think; how does the glass glow?

You may have noticed in the images that the normal candles/bulbs of these chandeliers have been replaced with UV lights (black lights). These bulbs emit light mostly in the ultraviolet spectrum which is not visible to our eyes, but you can see some visible violet light that is emitted from these bulbs which causes the bulbs to have 1cm of eerie violet glow that I was unable to catch in photographs.

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This ultraviolet light excites the uranium in the glass causing electrons to jump between shells and emit light in a visible wave length for us to admire. Under white light, uranium glass can be a wide range of colours.

Uranium glass contains very small traces of depleted uranium, a by-product of the uranium enrichment process. Uranium glass has been made for years; since the early 19th century, known as then as Vaseline glass.

https://en.wikipedia.org/wiki/Uranium_glass

But how much uranium is in this glass? is it safe? – I hear you ask.

Yes it is perfectly safe, although the glass is emitting some radiation, it is such a small amount and you will spend such an insignificant amount of time with the objects that it will pose no risk to you. If you slept with a banana in your bed for a year you would probably have a larger dose of radiation than from visiting at these chandeliers*.

20160120_131741So if you have some time in the next few months I highly recommend visiting this wonderful display and contemplating radiation, and how nuclear power could be beautiful instead of scary.

The exhibition is located in the contemporary building of the NGA, between the flags on the Lake Burley Griffin. This display is available to view from Wednesday to Sunday until 3 April 2016.

 

 

 


*as they do not state the amount of uranium in these beads this is only an assumption. One BED (banana evquivalent dose) is often taken as 0.1 µSv

 

Did we just escape an ice age?

By Jess

According to a recent study¹, Earth has narrowly missed entering into a new glacial. And the reason why? COlevels were too high.

But the CO2 that ‘saved’ us from a rather more icy existence is not the product of the mass burning of fossil fuels you are probably thinking of now. The CO2 we are talking about here was already in the atmosphere before the industrial revolution began (~1850).

ice

Did we just escape an ice age? An artist’s impression of Earth’s last glacial maximum²

Pre-industrial revolution greenhouse gas levels are generally used as a baseline from which to measure human contributions to atmospheric concentrations. Pre-industrial COlevels were ~280 parts per million (p.p.m.), we are now at over 400 p.p.m. However, humans have been influencing Earth for a long time before this.

Despite being on a different scale from today’s emissions, over the thousands of years that deforestation and agriculture have been occurring, these activities will have affected CO2 levels. Some studies even suggest that without human activity, pre-industrial CO2 could have been as low as 240 p.p.m.³.

Modelling studies now show that if pre-industrial CO2 concentrations had indeed been at 240 p.p.m., present day Earth would be a much colder place, with large ice sheets already existing and a full glacial to look forward to¹.

So although by no means proven fact, it is possible that early human activity may have prevented Earth from entering an ice age.

However, at the end of this story, global warming is still the bad guy.

If a 40 p.p.m. increase in CO2 over thousands of years can essentially counteract an ice age, what is the additional 120+ p.p.m. we’ve pumped into our atmosphere capable of doing?


¹ Ganapolski, A., Winkelmann, R. & Schellnhuber, H. J. (2016). Critical insolation-CO2 relation for diagnosing past and future glacial inception. Nature, 529, 200-203.

² wikipedia.org/wiki/Ice_Age (Yes, I know, but it had the prettiest picture)

³ Ruddiman, W. F. (2013). The Anthropocene. Annual Review of Earth and Planetary Sciences, 41, 45-68.

For a professional summary of this research see: Crucifix, M. (2016). Earth’s narrow escape from a big freeze. Nature, 529, 162-163.

Compostable plastic: not as good as you might think

By Eleanor

In an effort to develop a more planet friendly lifestyle, one thing I’ve been doing for the last year or two is buying compostable or degradable bin liners.

I don’t actually compost at home, so the bin liners go straight to landfill, but I thought that at least they’d still break down a bit more quickly and be better for the environment.

I was wrong.

As it turns out, degradable or compostable bags don’t break down any quicker than normal plastic bags in landfill. There may still be a small environmental benefit to buying them, but it isn’t what I thought, so I feel a bit like I’ve fallen into some kind of green marketing scam.

I also know that I’m not the only one to have held this misconception, so today I’m going to explain what the deal is with degradable and compostable plastic bags. In the process of doing this research, I also found out a bit about recycling plastic bags, so I’ll talk about that too.

DEGRADABLE plastic

glad-degradeable

Degradable plastic bags break down into little bits more quickly than normal plastic bags do, when exposed to UV light [1]. As you can imagine, this probably won’t happen in a pile of landfill [2].

It might happen in the ocean though, which is good news for turtles and birds that could otherwise eat or get tangled up in the plastic. But tiny pieces of plastic floating around in the ocean are also pretty bad, as I’ve written about before.

Compostable PLASTIC

compostable-bagCompostable bags break down through the action of bacteria into CO2 and a soil-like substance called ‘humus’, which can be used as a fertiliser. This is good – the plastic is not just breaking up into little bits, it’s actually turning back into something more like soil. But this process requires really specific conditions – temperature, oxygen content, moisture content – which are hard to maintain in your compost heap at home [3, 4]. So these compostable bags will really only turn to compost in a commercial composting facility. I haven’t been able to find any of these in Canberra.

What happens if you send these compostable bags to landfill? Well, if you can’t compost it at home, it’s certainly not going to happen in landfills, which are very anoxic environments. These bags will take just as long to degrade in landfill as any other plastic bag would.

However, there is still one minor benefit of compostable bags to regular ones. Compostable bags are made from plants, not petroleum. When the plants are growing, they take in CO2 from the atmosphere, and so if the bags don’t break down, that carbon is effectively stored in the plastic [2]. I suspect that wouldn’t be a very large amount of carbon in the scheme of things though. And then there’s the ethical question of: should we be using farmland to produce throw-away convenience products like plastic bags, instead of producing food to feed an ever growing population [1]?

Recycling PLASTIC bags

Sometimes you’ll see plastic bags with the recycling logo on them. Does this mean they can be recycled?plastic-bag-recycle

Yes, plastic bags can be recycled, but NOT in the curb-side recycling bin.

In Canberra we have ‘co-mingled’ recycling – cans, jars, paper and cardboard all go in the same bin, and these are sorted at recycling facilities by machinery. But the trick is, if you put plastic bags in with this stuff, they can get tangled up in the machines, and damage them [5, 6].

Instead, you can take soft plastic like shopping bags to dedicated bins at supermarkets (there’s one at Woolworths in Dickson).

Summary

  • ‘Degradable’ bags just break down more quickly into little bits when exposed to UV light. This won’t happen in landfills, and anyway, little bits of plastic are bad.
  • ‘Compostable’ bags can only be composted in a commercial composting facility. This also won’t happen in landfills.
  • Plastic bags can be recycled, but only in dedicated bins, usually located at supermarkets.

 


P.S. The term “biodegradable” is a bit ambiguous. In some things I’ve read, it’s used to mean “degradable” and in other things I’ve read it’s used to mean “compostable”.

[1] O’Brine, T. and Thompson, R.C. (2010) Degradation of plastic carrier bags in the marine environment. Marine Pollution Bulletin 60: 2279-2283.

[2] Greene, K.L. and Tonjes, D.J. (2014) Degradeable plastics and their potential for affecting solid waste systems. In: Brebbia, C.A., Passerini, G. and Itoh, H. (eds.), Waste Management and The Environment VII. WIT Transactions on Ecology and The Environment 180: 91-102.

[3] Vaverková M., Adamcová D., Zloch J. How do degradable/biodegradable plastic materials decompose in home composting environment? (2014) Journal of Ecological Engineering, 15 (4), pp. 82-89.

[4] Kale, G. et al. (2007) Compostability of bioplastic packaging materials: an overview. Macromolecular Bioscience 7:255-277

[5] https://www.cleanup.org.au/PDF/au/cua_plastic_recycling_fact_sheet.pdf

[6] http://www.sita.com.au/community-education/site-tours-education/recycling-tips/plastic-bags/

Images from woolworths.com.au, amazon.co.uk and istockphoto.com

 

Five foraminifers that look like celebrities

By K. Holland

Everyone knows the importance of foraminifers transcends science. We’ve searched from the sea floor to the photic zone to bring you these calcifers that have an uncanny resemblance to your favourite Aussie stars. You’ll have to sea them to believe it!

Marvel at this X-traordinary resemblance!

Marvel at this X-traordinary resemblance!

Can't get you out of my head!

Can’t get you out of my head!

Foram? More thike Thoram!

Foram? More thike Thoram!

Be bowled over by Shane Warne's doppelgänger!

Be bowled over by Shane Warne’s doppelgänger!

Striking resemblance!

Striking resemblance!

 

 

RSES social soccer, summer 2015 – a season in retrospect

By Patrick Goodarzi

Popular wisdom cautions against the worship of false idols. This year’s RSES soccer team chose to eschew this by elevating one player, Pat Carr, to near demigod status. The hopes and dreams of an entire School were pinned to Carr before the first ball had been kicked. Even the team’s name – Pat Carr and the Cardiac Arrests, and later Pat Carr and the Carr-pettes – blazoned the strategy. The role of remaining team members was simply auxiliary. Pat Carr was to be our champion. Our light. Our salvation. In Carr we believed.

Such feverish reverence was perfectly rational. The annals of football history do not lie. Any football fan worth their salt will recall the heroics of Carr in the triumphs of last season, when a talismanic performance hauled the team to the lofty heights of division four champions. It was, quite simply, a footballing tour de force. This year, in division three, RSES expected more of the same. It demanded peak Carr. But instead Pat Carr chose to reject his heavenly standing. He down-played his divine influence, and relegated his role to that of an ordinary team player. He refused his destiny, and with it our inexorable rise to glory.

In retrospect, perhaps this was ill-considered. Six defeats over eight matches made for quite an unflattering record. Goals were in short supply. Defensive lapses were not. 0-10 our greatest defeat. The record spared from greater ignominy by an administrative error (a careless swapping of the team names) gifting us a finals place, which, naturally, we went on to lose.

And so here we stand. Abject failures by any conventional metric. Yet to cast a more reflective eye over the season reveals innumerable positives. Most notably, and most encouragingly, was the plight of the new players. New not only to the team, but to the sport. They were unfalteringly magnificent. From their compliance to the conscription policy, to psychological conditioning (the ball is your friend), to voluntary extra training sessions, to extra cheering and support. Under the sage tutelage of a social soccer veteran, the improvement was remarkable. This contingent became the soul of the team. They embodied the virtues of recreational sport, and were the true successes of the season. Where rival sides were guilty of spurning their less experienced players in the pursuit of victory, teamwork and inclusiveness were always paramount to this team’s ethos. Even at our lowest moments the team resisted the temptation to fall back on demigod Carr – always the most potent weapon in the arsenal. To remain resolute with this WMD at our disposal was a testament to this team’s rectitude. It was, as the more pretentious amongst us might say, esprit de corps.

The season offered scant highlights on the pitch, save for a few notable moments: The eruption of gallic passion following a refereeing injustice. The subsequent dismissal. The almost-booty-goal. The brave goal-keeping. The nonchalant goal chipped from outside the area. The barbarous slide tackling. The suspect sportsmanship of opposition players. These are the moments that will remain on the lips of fans for the next twelve months.

What remains to be expressed is gratitude to all those who devoted their time to the season’s cause. Special mention to Hannah, for organising. Your valiance has laid strong foundations for the next generation of low level recreational soccer heroes. Bravo.

rses_summer_soccer_team

RSES Summer Soccer Team 2015. They did not disgrace themselves

COP21: The Outcomes

Last week the leaders of almost 200 nations came together in Paris for the 21st UNFCCC Conference of Parties. On Saturday, 12 December 2015 these leaders reached an agreement that will signal the end of the use of fossil fuels, with the aim of rapidly replacing coal, oil and gas with clean energy sources worldwide.

A Strong, Universal Agreement

All nations are apart of the agreement and the majority have contributed positively to the agreement

The governing leaders of the world have acknowledged that climate change is a global problem which is happening faster and at a greater, more devastating impact than first thought. To have all the world’s nations, regardless of their size or economy, be apart of the agreement is a huge achievement.

cop-21-negotiators

A few of the 50 000 negotiators that attend the 12 day conference in Paris. Credit: UNFCCC

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COP21: Australia’s Position

Climate change is a global problem that requires all nations to come together to be a part of the solution. Australia equates to 5.15% of the world’s landmasses and 1.3% of greenhouse gas emissions, the 13th largest emitter in the world per capita out of 195 nations.

Countries by carbon dioxide emissions in thousands of tonnes per annum, via the burning of fossil fuels.

Countries by carbon dioxide emissions in thousands of tonnes per annum, via the burning of fossil fuels.

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Organizing the Central Australia Student Field Trip

By Jen

Central Australia 20140920 - 215

Last year myself and fellow PhD Jessica Lowczak organized a geological field trip for 19 students through Central Australia. This was one of the most rewarding things I’ve done, and despite there being many a stuff-up along the way, I am quite proud of the experience as a whole. It is nearly 2016, and therefore time for the new cohort of students to start thinking about where they want to go on the next trip, and how they are going to organize it.

The student field trip traditionally occurs every two years and is a great way for the PhD cohort to bond while learning the regional geology of an area decided by the students, including subject matters outside their own areas of expertise. The students who attended the trip in 2014 spent two weeks together knocking knees in the back of troop-carriers, and snoring loudly next to one another in tents. All in the 35 degree heat of the Australian desert. They each had to research one area of the region we were travelling to and write a short report that was turned into a field guide -special thanks to Morgan Williams for putting this together.

Challenge: Deciding where to go. We decided on Central Australia for three reasons, the first being that Jess had been there on a geological field trip during her undergrad, and secondly the region showcases many different types of Earth Science, including igneous, metamorphic, and sedimentary processes, palaeontology, economic and structural geology, meteorite impact zones, tectonics, and climate change. The third reason is that Central Australia is a beautiful part of the country that most of us had never seen.

Central Australia 20140921 - 274

The night sky of Central Australia*

Challenge: Transport. How to economically carry 19 people and their luggage through the desert which sometimes does not have roads? We decided that troop carriers would have the lowest cost per person, while providing us with the option to go off road if needed. We had a large trailer attached to the back of each, one carried the luggage, and one was stocked with two weeks-worth of food.

The only down side to that was we had to get six students to be 4WD trained, so they did an intensive two day course and gallantly drove the whole 1500km from Adelaide to Alice Springs.

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The trusty steeds

Win: No animal Deaths. Not one kangaroo was mown down while we were at the wheel, although ironically the hire company destroyed the vehicle that did not have a bull-bar, just hours after collecting the vehicle from us. They made the mistake of driving back at night and hit a fully-grown, red kangaroo.

Win: Competent mechanics. How many geologists does it take to change a tyre? One. Special mention to Phil Brandl who went full survival mode and conducted a flawless mid-desert tyre change near Lake Eyre.

Win: Famous! We got to be on TV for a 4WD show that was being filmed at Arakroola Wilderness Sanctuary while we were there. Special mention to Patrick Goodarzi for being on TV while wearing an improvised orange-bag fly-guard.

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Improvised orange-bag fly guard

  • Fun fact: petrol costs an astounding $2.50/L in the desert, but more disconcertingly a Magnum ice-cream costs $6.

Challenge: Food. We were faced with the daunting prospect of having to feed 19 people on a budget, using nothing more than a fire or camp-site barbecue. We decided to divide people into groups and each group would prepare three meals. They had to provide us with a list of ingredients that we would pre-buy, for a main meal and a dessert.

Win: Campfire Chinese food. Special mention to Mimi Chen and Fang Fang who provided us with the unexpected delight of campfire Chinese noodles and fried rice with shrimp! A further special mention to Kate Holland who ensured that the Cake Friday tradition was kept alive and well in the desert.

  • Fun fact: we fed everyone for approximately $7 each per day! Apologies for all the Corn Flakes and sandwiches you were forced to consume..

Challenge: Actually finding pieces of relevant geology. Although we knew which areas displayed which geologic features, it was sometimes difficult to pinpoint a precise location or a precise rock that everyone could physically see so that we could talk about it. There was one point where we had everyone searching for an Ediacaran fossil for a good hour or two. We found it in the end (Thanks Jess Amies).

There was another point where we wanted to find some shatter cones associated with the Gosses Bluff meteorite impact crater. It turned out the area was on sacred Aboriginal land and we were forbidden to enter, so we performed one of the many U-turns of the trip and left disappointed.

Win: Uluru is quite hard to miss. Thank God. Some of the other cool features we did find included glacial tillites, fossils, structural slicken lines, S-C fabrics, carbonatites, apatites, and lots of garnets.

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Uluru at sunset

Challenge: Safety. Jess and I had to take a one day remote first aid course so that we could be on hand if anyone hurt themselves. This involved learning how to treat snake and spider bites, how to do CPR, and how to make improvised splints and stretchers.

In the end Jess and I were probably the two who suffered the most on the trip, but those issues were solved by chugging litres of Hydralite and Metamucil.

Challenge: Preventing a Lord of the Flies Scenario. We severely underestimated the number of hours we would all spend cooped up in those vehicles; needless to say tensions began to arise within the group. Those in the front car (named Full Frontal – the best car) were pitted against those in the back car (suitably named Rear End) when an incident involving a stolen Toblerone sent shock waves through the group.

There is no happy ending to this story. War broke out, the chocolate was never recovered, and the relationship between the groups remains tense to this day.

  • Fun fact: In the desert, chocolate is a serious matter. Stealing someone’s chocolate is an intolerable act of war.

Win: Desert aerobics: Special thanks to Jo Stephenson, Laura Crisp, and Liane Loiselle for running road-side aerobics classes to prevent us from all getting DVT, going mental, and killing each other.

Win: Everyone made it back alive.

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Except perhaps Chris Renggli?

Thanks to the 19 people who came on the 2014 trip, you made it one of my most treasured experiences that I will never forget. With all that in mind, have fun organizing the next trip!

*Images courtesy of Philipp Brandl and Christian Renggli