The graphic artist M.C. Escher and his connections with geology

Mobula Rays by Eduardo Lopez Negrete National Geographic    E41-MC-Escher-No-41-Two-Fish-1941

Left: Mobula Rays off Baja California by Eduardo Lopez Negrete / National Geographic. Right: “Two Fish” by M.C. Escher, 1941 from Escher official website

The left-hand photograph circulated on Twitter a few weeks ago and someone commented that “it looks Escheresque”. I found that fascinating: an apparently random natural phenomenon reminded someone of the mathematically composed artwork of the great M.C. Escher.

But of course we know that there is a lot less that is “random” in the natural world than we thought there was roughly half a century ago. M.C. Escher (1898-1972) died before Mandelbrot published his work on fractal mathematics in 1979. Mandelbrot demonstrated that much of the apparent randomness that we observe in nature is the result of relatively simple mathematical relations, controlled by what’s called a ‘strange attractor’. The best treaty on fractal mathematics and chaos theory for non-mathematicians is James Gleick’s ‘Chaos’. I read ‘Chaos’ more than 20 years ago and it completely changed my view on my work, my career and subsequently my life.

For many centuries before Mandelbrot people wondered “only” about symmetry in nature. Everyone observes symmetry and its exceptions, beginning with our own body which appears symmetrical but isn’t: two legs, arms, eyes, ears, lungs, kidneys but one mouth, esophagus, heart, liver, spleen, pancreas, bladder.

The foundations of crystallography and mineralogy are mandatory in every geoscience degree. We learn about molecular lattice structures and resulting crystal form. Depending on molecular lattice structure and resulting crystal structure, some minerals appear perfectly symmetrical, such as a cubic pyrite. At the other extreme is e.g. triclinic plagioclase, which is symmetrical in a more complex way.

pyrite   Albite_-_Crete_(Kriti)_Island,_Greece

Left: cubic pyrite. Right: triclinic plagioclase. (Wikimedia)

Maurits Cornelis (“Mauk”) Escher was fascinated, or maybe obsessed by ‘the systematic compartimentalization of space’ (in Dutch: “regelmatige vlakverdeling” as he wrote in a letter to his nephew Rudolf, a composer).

Mauk’s half brother was Berend Escher (1885-1967), an iconic professor of geology at Leiden University in the Netherlands, whose specialization was crystallography, mineralogy and vulcanology. Berend Escher was also the sole author of the next-to-last Dutch-language introductory geology textbook. The annual MSc-thesis prize, awarded by the Royal Netherlands Geological and Mining Society is named in his honour (full disclosure: I initiated the prize and was chair of its first jury but I didn’t name it).

photo 1

‘Grondslagen der Algemene Geologie’ (Foundations of Introductory geology) by B.G. Escher, 1948 (my copy).

Berend Escher’s textbook doesn’t contain a chapter on crystallography nor one on mineralogy. As an expert in that field, he decided that this subject was too big for just a few chapters in a textbook and in 1950 he published a separate textbook entitled: “Algemene mineralogie en kristallografie” (“Introductory mineralogy and crystallography”). I don’t have a copy of that book nor have I ever seen it.

Did Berend and Mauk exchange thoughts on crystallography and mineral structure? I bet they did. I bet they wrote letters to each other, but if they did, I don’t know about them. We do know that Mauk was a letter writer, because I have a fascinating book with a collection of letters between Mauk and his nephew (Berend’s son) Rudolf Escher, a composer.

Escher 2

Rudolf Escher and M.C. Escher “Beweging en metamorfosen, een briefwisseling” (‘movement and metamorphosis, an exchange of letters). 1985 - my copy

Mauk designed an ‘ex libris’ book stamp for his brother Berend, paying homage to his expertise on vulcanoes.

Escher woodcut volcano for Berend

Mauk Escher explored symmetry in an illusionary manner his whole artistic life. This is not a treatise on that subject, which is too big for one blog post. I include only one illustration here. It is highlighted in “From 2D to 3D: I. Escher drawings crystallography, crystal chemistry and crystal defects” by Peter R. Buseck of Arizona State University, a downloadable 12-page document. Peter Buseck used Escher’s images to teach about symmetry by designing puzzles about them. Here’s one

Escher BrYeBlfishes fishes and lattice lattice 1

Left: M.C. Escher, 1942, Pattern #55 “Fish”. Centre: with lines indicating symmetry (drawn by me). Right: symmetry lines only, immediately showing 3-dimensionality.

I took crystallography and mineralogy at Groningen University in the Netherlands from professor Perdok, who impressed on us (among other things) “that a 2-dimensional space cannot be filled by pentagrams except by M.C. Escher”.

Mauk Escher’s oldest George was an engineer and moved to Canada early in his life. He donated his personal collection of his father’s works to the National Gallery of Canada, giving them one of the largest Escher collections in the world. At that occasion, he talked about his father. His two younger sons became geologists, Arthur in France and Jan in Switzerland.

Why do we continue to be so fascinated by Escher? For one thing, I think that it’s because he shows us something that science alone cannot show us in the same manner: beauty, wonder and unpredictability.

Which is why we always need more Art in Science.

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#Mywritingprocess blog tour: clicking “publish” is exhilarating

thinking of Ellen Gilchrist

This post is not about Earth science, it’s about me. This is part of a relay race: an exploration into how and why people blog about science. Search for #mywritingprocess on Twitter and you find hundreds of bloggers who have tackled this relay.

The idea is to answer a few questions and pass the baton.

I would not have participated in this exploration if I had not been handed a baton, and – in a moment of sheer madness – accepted it. So now I must do my part and pass it on.

Step 1 – who tagged me?

I was tagged by Sarah Boon, who blogs on blogging, nature writing, snow hydrology, mental health and photography. Sarah’s blog is also part of Science Borealis (in fact, Sarah is the genie behind Science Borealis), where this blog humbly also finds a home. I have never met Sarah in person, but we have built up a friendship of sorts in virtuality and I enjoy her writing and admire her frankness.

Step 2 – Answer Four Questions:

a) What do you generally blog about?

The title of my blog pretty much defines its content: Earth, Science and Society. I am a sedimentary geologist, but am more interested in where earth science intersects with societal issues than in the science itself (I was a prof once, but Academia was not for me: I resigned from a tenured position). I find that too much writing on the management of our one and only planet uses humanity as the vantage point instead of the planet itself and that irk has been with me pretty much since grade 8. One of the quotes in my school diary that year (I don’t remember the author) went something like this: “nature scoffs at human suffering and only considers her own greatness”. I suppose it was only logical that a child growing up in an outdoorsy family of avid readers would be interested in earth science and writing. My life long fascination with that quote motivates my writing.

Occasionally I take a side road and write about women in (earth) science or about science and art (stay tuned – my next post will take you there).

b) how does your blog differ from others’ blogs in the same genre?

I really don’t have a good answer to that question. Most earth science bloggers that I follow a bit use their blog in the context of their work, as for example Dave Petley, Matt Hall and Evan Bianco at Agile, or the Deep Sea Discovery teams on the JOIDES Resolution. I suppose each blog is pretty unique, because blogging is more personal than any other form of publishing. I am not going to dare a comparison.

c) why do you write what you do?

My professional career is winding down.  Way back when I was a student, I had dreams of being a science journalist, inspired by the superb weekly science special of my favourite newspaper. Then I became utterly fascinated by my own profession, realized that writing was very very hard and that I didn’t have a natural ability for it. Next I moved to the US and had to learn to write scientific papers in my second language. Simultaneously with all that came the parent phase. But now life is balanced and I have time. If you have learned something, you must share it (thank you, Maya Angelou). I have learned a lot, so I am trying to go back to that dream. There is no excuse – the blogosphere is out there.

d) how does your writing process work? how do you decide what to blog about? What is blogworthy to you?

I aim to write two blog posts per month and that turns out to be a tall order. One monthly post is on whatever hits me, the other one is part of a series of reviews under the header “Canadian Earth Science for @PMHarper”.  The argument for writing this series is here. My aim is to cover the breadth of Canadian Earth Science both in terms of content and authors. It should run for another year or so. Selecting an article is not very spontaneous, I keep a spreadsheet of topics and authors to help me map my progress.

I think a long time about how to tackle an issue and where to start. It takes me forever. Without the structure that I dictated to myself, I think I would quickly give up. Too hard! But I do want to. Clicking “publish” is exhilarating.

I have never taken a writing class, but I have had some very tough editors. I write in my second language. These are two distinct disadvantages. I do hope to enroll in a science writing course some time in the not too distant future. Writing is incredibly hard, but I want that challenge.

Step 3: Tag another writer or 2 to answer the questions the week after you. Give a one-sentence bio of each, and link to their websites

I am tagging Graham Young of Ancient Shore, the other Canadian earth science blogger on Science Borealis. He is curator of geology at the Manitoba Museum.

 

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Canadian Earth Science for @PMHarper 6 – Would CO2 storage in deep saline aquifers carry an environmental risk for shallow aquifers?

The preamble to this series is here. All reviews are stored in the category “Canadian Earth Science for @PMHarper” (see right hand column).

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Lemieux, J.-M., 2011, (Review:) The potential impact of underground geological storage of carbon dioxide in deep saline aquifers on shallow groundwater resources. Hydrogeology Journal, v. 19, p. 757-778. DOI 10.1007/s10040-011-0715-4

The world is warming up and humanity is the cause: we have become a geologic force, and have brought in the age of the Anthropocene. As President Barack Obama stated so eloquently in his commencement address at the University of California at Irvine last week “the question is not whether we need to act; the overwhelming judgement of science, accumulated and reviewed over decades, has put the that to rest. The question is whether we’re willing to act.”

There are numerous possibilities for action, depending on technology and political will.

The carbon dioxide content of our atmosphere now stands above 400 ppm (parts per million) and even if we all had the best intentions and started to intervene tomorrow, we simply can’t stop burning fossil fuels right away, so atmospheric CO2 will continue to rise for a long time to come.

What if we captured some of that carbon dioxide at the source (i.e. industry) and put it back in the ground before it reaches the atmosphere, thus slowing down the rise in atmospheric CO2? This process, known as Carbon Capture and Storage (CCS) - has been tackled by scientists and engineers for only just over 20 years, i.e. ever since the risk of global warming first began to be taken serious by a handful of people. Imagine that everyone had been a climate-change skeptic back then, we wouldn’t have known anything about this subject today! Here is the official (and excellent) Canadian CCS site.

Over the years, I have heard more than one climate-concerned citizen say that we should ‘just put all that CO2 back where it came from’. If only it was that simple, the process would have been routine now, pretty much like taking lead out of gasoline or CFCs out of spray cans.

This article reviews the State of the Art of our knowledge about CCS in deep saline aquifers. That knowledge is impressive but also discouraging. There are still so many unknowns!

So what, exactly, are the challenges?

First: there are only a few possible properly contained subsurface reservoirs for CCS: 1) depleted oil and gas fields, 2) unminable coal beds and 3) deep saline aquifers. This review focuses on this last and preferred option.

Why not the first two options? CCS would be the most efficient and effective if every major (energy) industry (a ‘point source’) could inject CO2 in the subsurface. But not all of Canada’s heavy industry nor its powerplants are located above oil and gas fields or unminable coal seams. Some depleted oil and gas fields are already filled with re-injected CO2 as part of the process of producing the field (a process called ‘well stimulation’). So while those first two options are heavily researched and tested (see for example here and here), it would be better if we could access a rock compartment that is pretty much present everywhere.

Deep saline aquifers are present just about everywhere and are therefore the preferred choice.

Let’s take a look.

CCS

This diagram shows the different possible natural reservoirs for CO2 storage (source of figure). There is no vertical scale indicated, but deep saline aquifers are located at close to 1 km depth, far below the aquifers from which we draw water for human use. 

It is important to note that CO2 occurs naturally in deep saline aquifers (and has been plentiful in such aquifers for millions of years) so that re-injecting it in such an environment mimics a natural process. Naturally occurring chemical reactions (given the right temperature and pressure) in such an environment may turn CO2 into limestone and/or related minerals , but because pressure in these aquifers is very high (because they occur at great depth), CO2 often stays dissolved in the water.

CO2 (or any other gas) will only stay in the aquifer-reservoir that reservoir is properly sealed. The seal is provided by surrounding rock that is impermeable. A typical example of impermeable rock is salt or gypsum. But even such rocks have cracks and/or are broken up by faults. Cracks and faults can lead to leakage from the reservoir rock. This also is a completely natural process, but if we want to store CO2, we want it to stay in the reservoir and not leak back to the atmosphere.

Cheveriepoint Windsor_gypsum2

Gypsum outcrop, riddled with smaller and larger cracks. Yet gypsum is most of the time an excellent reservoir seal.

Another potential risk is that dissolved CO2 can change the acidity of the deep aquifer. A different acidity may cause certain trace elements, such as the toxic elements lead and arsenic, to become mobilized and travel to the shallow aquifer (which is what we use for drinkwater and irrigation). We don’t want that either.

Also, you must be able to take into account that certain effects of CO2 injection will only be noticable far away from the injection site, whereas other effects are realistic near the injection site. The difference is explained by the the architecture of the subsurface. “Architecture” refers to the manner in which the rocks are layered, tilted, folded, faulted and (re)cemented. Each rock formation has a completely unique architecture (this is what keeps geoscientists busy). These effects are called ‘near-field’ and ‘far-field’ effects.

Kentucky outcrop 1 696-9641_IMG

Examples of different archecture in rocks. Left: ‘layer-cake’ beds. Right: complex folding 

If we store CO2 in the deep subsurface, we want it to stay there ‘forever’. How long is forever? Not a single geologic formation stays unchanged forever, but some experience millions of years of utter boredom. Can we predict the rock formation with the most boring future? Keep in mind that the earth cannot things boring forever. Our planet bubbles and burps and sighs and heaves according to the 2nd law of thermodynamics, which dictates that every system always turns to maximum randomness. In the end, any sort of reservoir will come undone.

Long term geologic processes can affect deep groundwater flow significantly, a concern that has affected the research on deep storage of nuclear waste to the point where that has just about become a dead end. And – really weird question, but let’s face it: if we would be able to take significant amounts of CO2 out of the atmosphere, do we want to be able to put it back when the next ice age hits (if humanity is still around)?

It’s these sort of questions and uncertainties that have been the topic of intense research and it’s this research that is reviewed in this article.

How do you research this? Ideally, you should sample and research the reservoir itself, but that’s more or less impossible because it’s so deep. There are two other ways: 1) carry out experiments, in a lab or in super-controlled natural situations and 2) through numerical modeling and simulations (thank goodness for ever more powerful computers). This research is complicated and expensive. The real-world experiments have to run a long time before yielding data that can be understood and extrapolated.

This is what makes this article both discouraging and impressive: such fantastic research and yet so many remaining questions. The author has defined a number of knowledge gaps. He begins by stating that the state of understanding is very immature because quantitative research is no more than 10 years old. Laboratory experiments that study the interaction of minerals and CO2-saturated brines are few and far between. Most numerical models are still very simplistic (that’s mostly determined by not having sufficiently sophisticated computers, we still need better ones, yes we do).

But he ends on a positive note: despite the above, the possible environmental impacts of geologic storage of CO2 in deep saline aquifers on shallow groundwater resources appear to be low. Given proper understanding of the reservoir, leakage of harmful elements or of CO2 itself, can be minimal.

So: while more research is needed, the technology is promising. Let’s hope it will take off.

Currently, CO2 is injected in deep saline aquifers in a number of experimental sites: Sleipner (offshore Norway), Weyburn (Saskatchewan, Canada), Frio (Texas, USA), Midwestern States (USA).

Writing a review article is a big job. The job that led to this article was commissioned by the Geological Survey of Canada. The result is a body of work that serves the interest of all Canadians.

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Canada’s Geoheritage Surge: Geoscience Heritage, Geoparks, Geosites, Geotourism

FIRST POSTED June 4, 2014. Updated June 10, 2014

IMG_2530  Sudbury shatterconesLeft: A fossil tree at the Joggins Fossil Cliffs UNESCO World Heritage Site (NS, Canada). Right: 1.8 billion year old shatter cones (result of an asteroid impact) at Sudbury (ON, Canada – photo Andy Fyon)

Here is a commonly heard complaint: “most citizens don’t know anything about earth science, because it’s not taught in school (and – in extension – therefore citizens don’t know the first thing about earth materials, natural hazards, climate change – fill in the blanks). I don’t buy that. A lot of subjects are not taught in school and most people are not completely ignorant about those (criminal law, orthopedic surgery, etc.).

There is earth science in the secondary school curriculum in Canada, although not a lot. I would love it if there was more, but then other subjects would have to give, and I ask you which ones? Imagine the endless battle that would ensue.  Not worth the energy. An unproductive exercise.

But why makes this a problem? We have the whole planet for a lecture room! Just stick your nose out the door, and there is something to learn about the earth, no matter where you live or travel. Put up a sign, build a trail, an interpretation centre, write a book or develop an app.

And that’s exactly what’s been happening slowly but surely over the last 15 years or so. I call it the Geoheritage surge. I’m not going to write its biography, but I thought it might be useful to list what we have in Canada. And – please! – if you see an omission, tell me and I’ll happily add it!

Also – I don’t really care what we call it. The term “Geoheritage” is popular here in Nova Scotia, because the province is in the process of creating a list of sites, which they call a Geoheritage list (more about it further below). Elsewhere in Canada people prefer the term “Geoscience Heritage” to treat the concept in parallel with built Heritage. “Geosites” is used somewhere else again – simply indicating a place where worthwhile earth science can be observed.  A “Geopark” is an area that meets certain criteria of the Global Geopark Network (more about this also below), etc.

Really, it doesn’t matter. Any initiative that celebrates places that teach citizens about earth history and earth materials, about the history of dealing with the earth and its materials (historic mines for example), it doesn’t matter. Any site that can be a destination for a field trip.

So here goes:

Canadian organizations that do earth science outreach 

The Canadian Geoscience Education Network (CGEN) “is the education arm of the Canadian Federation of Earth Sciences (CFES). CGEN is concerned with all levels of geoscience education in Canada and encourages activities designed to increase public awareness of geoscience”. CGEN is 100% volunteer-run and they are particularly focused on school teachers. CGEN has also developed the “Careers website” and the “Where Challenge” and coordinates EdGeo. EdGeo is responsible for organizing 1-week workshops and field trips for science teachers in the summer across Canada.

This special 2009 issue of the “Geoscience Canada”, the Journal of the Geological Association of Canada, on geoscience outreach pioneer Ward Neal is open access (as are all their issues prior to 2011)

And here is a 2012 report on Canada’s Geoheritage efforts from one of Canada’s geoheritage champions, published in a CFES newsletter (a wonderful publication that seems to have expired).

Museums and interpretive centers: Fifteen museums and natural heritage centres cooperate and communicate efforts in the Alliance of Natural History Museums of Canada. In addition, there is: the Royal Tyrrell Museum in Drumheller (dinosaurs!) – see below.

Globally recognized Canadian sites

The UNESCO World Heritage designation is one of the world’s most prestigious. There are cultural and natural World Heritage sites. Canada has 17 UNESCO World Heritage Sites, of which 9 are natural sites and 8 are cultural sites. Of the natural sites, no fewer than 6 have been designated largely or exclusively because of their Geoheritage. These are:

  1. Canadian Rocky Mountain Park (AB/BC), which includes the late Precambrian Burgess Shale site and the dramatically fast retreating Athabasca glacier complex                                                                                                                     629-2902_IMG  629-2944_IMG Left: Mt Wapta, the site of the Burgess Shale Quarry in the distance. Right: the toe of the Athabasca glacier (in 2005) with a marker indicating its position 13 years earlier.    
  2. Dinosaur Provincial Park, home of the amazing Royal Tyrrell Museum - your best destination for cutting edge knowledge on Cretaceous dinosaurs. Tyrrell Albertosaurus  Tyrrell museum area _  Horseshoe Canyon  badlands Left: Albertosaurus model at the Royall Tyrrell Museum. Right: Horseshoe canyon near the Royal Tyrrell Museum: quick erosion helps to uncover Cretaceous fossils.                    
  3. Gros Morne National Park, which includes the official Cambrian-Ordovician Boundary at Green Point and the Precambrian Woody Point and Table Mountain ophioliteGSSP Green Point
  4. Joggins Fossil Cliffs, “the Coal-Age Galapagos” – a complete early Carboniferous coastal plain ecosystem that includes upright fossilized trees (picture at the top of this blog page).
  5. Miguasha National Park, representing the Devonian “Age of Fishes”.
  6. Kluane/Wrangell-St.Elias/Glacier Bay/Tashenshini-Alsek National Park, an impressive collection of modern glaciers on the Canada-US border.

Global Geopark Network

stonehammer logo           geoparks logo    Left: The logo of Stonehammer Global Geopark, located around Saint John, NB. Right: the logo of the Global Geoparks Network

The Global Geopark Network was initiated under the umbrella of UNESCO but is not a UNESCO Program. It goes too far here to explain the difference. The important thing is that Geoparks are becoming popular venues for attracting tourists to geoheritage sites worldwide but not (yet) in North America where the only recognized Global Geopark is Stonehammer Geopark in the area of Saint John (NB).

Stonehammer Global Geopark was officially recognized in 2010. Efforts to create more Canadian Geoparks (there are a few more underway!) are coordinated through the National Geoparks Committee. The Global Geopark Conference will take place in Saint John in September of this year. Keep your fingers crossed because that’s when the vote will take place for the next Canadian Geopark.

Provincial Geologic Highway maps

NS Geologic Highway Map

Geologic Highway maps are designed especially for the general public. They feature a (simplified) geologic map of the jurisdiction with the main highway system and notable stops with lots of explanation. They are still only in paper (or downloadable) format and badly deserve to be morphed into apps:

Geologic Landscapes highway maps of Northern and Southern British Columbia

What is the Yukon Territory made of? A wonderful publication – free downloadable pdf!

The Geologic Highway Map of Alberta can be ordered here

The Saskatchewan Geologic Higway Map can be ordered here

A geologic highway map for Manitoba is in the making

A geologic highway map for southern Ontario can be downloaded here and the one for northern Ontario is here.

The New Brunswick Geologic Highway map is out of print (I have one, it dates back to 1985 and really really deserves a new edition).

The Nova Scotia Geologic Highway map (pictured above) is a gem and can be ordered from the Atlantic Geoscience Society.

The Traveller’s guide to the Geology of Newfoundland and Labrador can be ordered here.

I could not find a geologic highway map or similar publication for Quebec, the NW Territories, Nunavut or Prince Edward Island. I hope that’s me – tell me!

Individual examples of geoheritage initiatives and communication across the country

British Columbia: Tumbler Ridge Dinosaur trackway and museum

Yukon: The Yukon Beringia Interpretive Centre and The Dawson City / Klondike Gold Rush National Historic Site

Alberta: The Earth Sciences Department of the University of Alberta has an outdoor rock interpretation garden

Ontario:

The Ottawa Gatineau Geoheritage Project promotes greater public knowledge and appreciation of the geology and related landscapes in and around Canada’s National Capital Region.

The Carleton University Department of Earth sciences has an active outreach coordinator: lots of information and events in and around Ottawa. The department’s emeritus professor Allan Donaldson has been active in geoscience outreach for a long time and started Friends of Canadian Geoheritage.

The Ottawa Riverkeeper website pays attention to Geoheritage

The Ontario highlands website has reams of Geoheritage activities, one of which is the iconic Metcalfe geoheritage park

Science North’s Dynamic Earth Centre, home of the iconic ‘Big Nickel’ in Sudbury is an amazing place to explore and learn about the Sudbury area geology and mining.

Greater Sudbury-20111109-00160_elisabeth_kosters_mia_boiridy_Dynamic_North_sudbury_Nov0911          Sudbury Phoenix                                Left: Examining mineral samples under the microscope with Dynamic Earth director Mia Boiridy (photo Andy Fyon). Right: Inside the Phoenix capsule in Dynamic Earth’s own mine! This is the capsule that was used to rescue the 34 miners in Chile in 2010

Book: “Ontario Rocks” is a well-researched treaty on three billion years of geologic history of Ontario, written for the general public.

Nova Scotia: The Department of Natural Resources (home of the ‘mineral resources division’ = geological survey) is working on a Nova Scotia Geoheritage list - work in progress.                                                                                                                                         The world famous light house at Peggy’s Cove is built on a unique granite outcrop and there are interpretation panels there. You can order the brochure here                                    The Fundy Geological Museum in Parrsboro celebrates the local geology, but especially focuses on the oldest dinosaur fossil site nearby (Wasson’s Bluff), which also features in PBS’s ‘Your Inner Fish’, the documentary based on the same book by American Paleontologist Neil Shubin (see also my post on Nova Scotia’s Blue Beach).

The Maritimes: Published by the Atlantic Geoscience Society in 2001, “The Last Billion Years” is “a geologic history of the Maritime Provinces of Canada”. This book was a national non-fiction National best-seller that year and hasn’t been out of print since. It serves as a model for  “Four Billion Years and Counting: a Canada’s geological heritage”, which is expected to be available later this year (stay tuned).

512VV5B6TPL._SL500_

A totally unique and separate case: 

The International Appalachian Trail celebrates geoheritage along the entire length of the Appalachian mountain belt – yes, all the way into Europe!

 

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Canadian Earth Science for @PMHarper – 5: refining seismic risk assessment in Canada

The preamble to this series of reviews is here. All reviews can be found under the category “Canadian Earth Science for @PMHarper”

Atkinson, G.M. and K. Goda, 2011, Effects of Seismicity Models and New Ground-Motion Prediction Equations on Seismic Hazard Assessment for Four Canadian Cities. Bulletin Seismological Society of America, v. 101, no. 1, p. 176-189.

If only we could predict earthquakes as well as we can predict the weather for the rest of the week. But we can’t. That is, we know where earthquakes can strike but we don’t know when they will happen. In other words, we can predict them in space, but not in time.

Lots of research goes into attempting to make better earthquake prediction and this is of course necessary because the casualties are enormous: about 800,000 people died in earthquakes worldwide between 2000 and 2012. Many earthquake casualties occur because people are crushed in collapsing buildings and this happens especially in countries that don’t have the right building codes or where building codes were ignored. The latter usually happens due to poverty, lack of good governance and/or corruption (see my older post here).

Two regions in Canada are susceptible to earthquakes. In the west is Coastal British Columbia, which is situated on the large and active Cascadia fault (a good popular book about this feature and its associated risk is ‘Cascadia’s fault‘ by Jerry Thompson).

significant EQ canada 1663_2006 Lamontagne et al 2008 3

Figure 1. From Lamontagne et al., 2008

Eastern Canada does experience earthquakes too, although it will never experience the large earthquakes that are expected for western Canada because it’s geologically very different.

significant EQ canada 1663_2006 Lamontagne et al 2008 2

Figure 2. From Lamontagne et al., 2008

These figures show clearly that no truly large earthquake has ever struck eastern Canada, and we understand geology enough to be sure that that will never happen. However, smaller earthquakes can create all kinds of havoc and damage. As recently as 2010, an earthquake with moment magnitude 5.0 struck near Buckingham (QC) and was felt widely, also in Ottawa.

So earthquake-prone regions require the design and legalisation of building codes But how to quantify this kind of risk? And especially – how to quantify risk for something that happens rarely, such as a – mild – earthquake?

This is the focus of the article by Atkinson and Goda.

The paper is a contribution towards refining the risk of seismic hazard in coastal British Columbia (particularly Vancouver) and eastern Canada (particularly Ottawa, Montreal and Quebec City). The article does not aim to predict earthquakes in time.

The authors ask a question that can be phrased more or less as follows: “given that earthquakes of certain magnitudes occur in these regions, how large is the risk of damaging ground motion (and what implications does that have for building codes)?” To make that question a little easier to understand, you can think of the following question as an analogue: “given that about 2,000 people die in traffic accidents annually in Canada, how large is the risk for a Canadian to die in traffic?” If you wanted to answer that question, you would start collecting data over many years. You wouldn’t only count fatalities, but also age, gender, home province, type of transportation, etc.  and then do the math (Statistics Canada has done that).

It’s more complicated to estimate seismic risk, but there are methods. These methods are based on an in-depth knowledge of the geology of a certain area (which tells us where the zones of weakness in the earth’s crust are). The models also require systematic information on every earthquake that strikes: its depth, its magnitude, over how large an area it was felt, etc. This information is collected constantly. The longer we collect this information, the more precise the models.

Geophysicists have developed models that enable predictions of ground motion on the basis of such data collection. Such models characterize the expected ground motion for a given risk (=probability). They are called “Seismic Hazard Models”

The standard Seismic Hazard Model for Canada was developed by the Geological Survey of Canada  about 20 years ago. This model is the basis for our national building code. Of course, a lot more data have become available in 20 years and – just as important – insights and computer power have improved tremendously. So it’s appropriate to revisit and, if necessary, revise, improve and refine the model.

For example, a better model can improve risk estimates for soil liquefaction, a nasty ‘byproduct’ of some earthquakes: the 1988 magnitude 6 Saguenay earthquake (shown on figure 2) caused liquefaction at 25 km from the epicenter. A good 2011 CBC report discusses the risk of earthquake-induced liquefaction for greater Ottawa.

The biggest earthquake that occurred in Southeastern Canada was the 1663 Charlevoix earthquake (magnitude 7). The authors estimate that this was really a ‘clustered event’, meaning that it consisted of a series of quakes over a period of several hundred years, separated by quiet periods that may last thousands of years. This pattern is related to the geologic make-up of the region, mostly a very old fault that dates back ca. 400 million years. Such seemingly erratic activity can only be properly analyzed and modeled using advanced statistical methods.

After applying their improved methodology and incorporating new data, the authors show that the refined model results in different risk predictions for the four cities. Their model deals better with a number of uncertainties: certain risk windows become narrower. It looks like the seismic hazard for these regions is lower than the original 1995 model predicted. This would be good news (if the model is reconfirmed after additional testing) because it would save money on building codes.

There: expensive data collection and research leads – after decades of work – to improved and even cheaper building codes. Without decades of data collection, such a conclusion would not have been possible.

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Dr. Gail Atkinson is a seismologist. She is Canada Research Chair in earthquake hazards and ground motion at the University of Western Ontario. A recent article in Time Magazine on concerns about hydraulic fracturing and earthquakes in Ohio quoted Dr. Atkinson. Many areas where hydraulic fracturing takes place do not have proper regulations for this industry in place (industry is always ahead of the law). Dr. Atkinson said: “There’s a very large gap on policy here. We need extensive databases on the wells that induce seismicity and the ones that don’t. I am confident that it is only a matter of time before we figure out how to exercise these technologies in a way that avoids significant quakes.” In other words: correlation doesn’t necessarily mean causality: not every observed earthquake in Ohio has to be caused by hydraulic fracturing and you need a lot of detailed data to do a proper analysis, after which it is possible to write proper regulations.  

Reference

Lamontagne, M., S. Halchuk, J. F. Cassidy, and G. C. Rogers, 2008, Significant Canadian Earthquakes of the Period 1600–2006, Seismological Research Letters Volume. 79, No. 2, p. 211-223. This article is free to download.

Posted in Canadian Earth Science for @PMHarper, General geoscience | Tagged , , , , , , , | Leave a comment

A Tidal power lagoon in Nova Scotia’s Scott’s Bay?

Nova Scotia is where I live – a 700-odd km long NE-SW peninsula that more or less parallels the edge of the continent. What (almost) separates us from that continent is the Bay of Fundy, the Canadian extent of the Gulf of Maine. The ca. 300 km long Bay of Fundy has the world’s highest known tides, rising as much as 16m in upper Cobequid Bay.

 Average tide ranges Bay of Fundy

Figure 1. Left: Gulf of Maine and Bay of Fundy watershed map. Right: Bay of Fundy with tide ranges. In red the different localities discussed in this post. 

Extracting energy from the Fundy tides is an old dream that was first articulated about 100 years ago.

A tidal power station was built at Annapolis Royal in the early 1970s. It is the only barrage-type tidal power station in North America and generates about 20 Mw/day (the world’s oldest barrage-type tidal power station exists at La Rance in Brittany, France and generates about 240 Mw/day). A more recent (1994) barrage-type tidal power station is Sihwa Lake in South Korea, which generates about 254 Mw/day on the incoming tide.

A barrage-type system typically generates power on the basis of gravity, much as in a classic hydro-electric dam. Barrage-type tidal power stations thus require the construction of a solid dam, undoing the estuary. In the early decades after WWII nobody thought twice about undoing estuaries and damming rivers and in the process we lost thousands of free-flowing rivers and estuaries with catastrophic results for global ecosystems. I’m going to assume that my readers are familiar with the controversies.

annapolis river

Figure 2. The Annapolis River at Annapolis Royal (NS). The Tidal power station sits in the middle of the dam that crosses the river. View to the NW. The open estuary is to the lower left. Photo E. Kosters

The Annapolis River tidal power station doesn’t contribute much to our daily energy needs, but it’s an interesting showcase. Even though there was much less public debate about damming rivers and estuaries in the early ’70s than there is now, the debate about the negative impacts of the Annapolis River tidal power station on the regional fish stocks is ongoing.

In the late 1970s, Nova Scotia considered constructing a tidal power barrage-type dam in Cobequid Bay (figure 1). As one local friend tells me “the dump trucks were ready to start piling rip-rap in the bay when word came that the plan was off”. The reason for canceling the plan was that the oceanographers at Bedford Institute of Oceanography had calculated that a dam in Cobequid Bay (where the tide range averages 14m) would reflect the tidal wave in such a way that the average tide range in Boston would rise by at least 30 cm. The amphidromal point (node) of the Bay of Fundy’s tidal wave sits more or less on the George’s bank (in the Gulf of Maine) and the Bay of Fundy is getting close to resonating with the semi-diurnal tidal wave of the Atlantic ocean so the crest of the wave is more or less at the head of Cobequid Bay (at a town called Truro). Canada didn’t want to risk angering its neighbour and having to pay for the damages. The dam was off.

Roaming around this area now (I didn’t live here at the time of this barrage proposal), I find it hard to believe that anyone would have agreed to simply clip out part of this stunning landscape.

620-2028_IMG

Figure 3. Upper Cobequid Bay – these tidal flats would have disappeared behind the tidal power dam that was almost built in the late 1970s. Photo E. Kosters

The interest in tidal power generation subsided until the late 90′s when new technologies and concern about climate change brought the subject back on the global agenda. By this time, we knew that damming estuaries was damning to the environment and thus to ourselves. So this time the focus is on ‘in-stream tidal power’. No damming required. Estuaries stay open to the migration of fish and water and nutrients. A large variety of turbines is designed and tried out all over the world. The engineers are having a ball. Examples are here and here and here and here (random examples).

One of the world’s most powerful currents runs in Minas Passage (Figure 1 above) – current velocities of more than 10 knots (5 m/sec) are not uncommon.

Until a few years ago, Nova Scotia generated close to 60% of its electricity by burning coal. The provincial government decided to aggressively reduce that proportion and invest in green energy schemes. Within a few years, the proportion of coal-powered electricity dropped to just over 40%. The government invested heavily in attracting tidal power companies. There is essentially an open bid system. Also, after much research, Nova Scotia ‘opened’ a government-supported berth in Minas Passage (Figure 1)  in 2009. The research that led into the definition of this berth was thorough: multibeam bathymetric surveys, sediment dynamics studies and all kinds of biological research were carried out or summarized from existing literature. The first pilot turbine was placed on the berth in the Fall of 2009.

84ab9d49ddbd5f0a89047e58f988a48e1-617x328 Tidal turbine without blades by Chronicle Herald photographer Tim Krochak

Figure 4. Left: artist impression of the turbine that was placed in Minas Passage in the Fall of 2009. Right: the Minas Passage turbine after it was retrieved in the Fall of 2010. The turbine had lost all its blades within two weeks of having been placed. 

Not a success right away: the turbine – carefully selected from a number of proposed models, had lost all its blades within 2 weeks of having been placed. To this day, nobody understands how, except that – clearly – the currents are more violent and destructive than anyone had anticipated. A learning experience! Things have slowed down somewhat since then, but nobody is giving up hope. The NS Government, together with a variety of stakeholders has created Force. The FORCE interpretation centre sits where the specially made electricity cable from the Black Rock berth area comes ashore and is open to the public. The next pilot turbine is supposed to be placed later this year. We are still in the experimental stage. We keep our hopes up. A smaller-scale experiment is running further south along the Fundy shore.

There is an in-between type of tidal power generation, called ‘tidal lagoon’. Essentially this is a dam, built in an estuary, sometimes connected to the shores, but sometimes isolated by itself, with multiple turbines in the dam. As the tide rises, the lagoon fills with water through the turbines (in some types the turbines generate power both on the incoming and on the outgoing tide) and later empties again.

No tidal lagoon has been built ever. Anywhere. There is a proposal for a tidal lagoon off Swansea (fabulous website) in the Bristol channel where the tides rise as much as 9 m. It’s under investigation.

Recently, Halcyon Tidal power submitted a proposal for an enormous lagoon, to be constructed from shore to shore at Scott’s Bay, NS.

Scotts Bay Halcyon

Figure 5. Halcyon’s proposed lagoon. The dam will be nearly 9 km long and will contain dozens of turbines. Ca. 250 people live in Scott’s Bay. Note location of the official berth at Black Rock on the north shore of Minas Channel (a.k.a. Minas Passage). 

Halcyon is a two-person American company, consisting of an engineer (Dr. Atiya) and a venture capitalist (Craig Verrill). Dr. Atiya holds the patent to a special turbine and he is anxious to deploy it.  Halcyon hosted a community meeting for the people of Scot’s Bay to present and discuss their plan. The meeting is reported here. It was a shameful event for Halcyon: the two gentlemen came with 8 or 10 illegible slides, appeared ignorant on crucial issues of the hostile physical environment and infrastructural requirements. They were also unaware of essential research of the Geological Survey of Canada, were unaware of the electricity need of Nova Scotia (their lagoon would generate far more power than we can use and we have no infrastructure to ‘get rid of it’) and generally displayed a contemptuous and patronizing attitude towards their audience.

Despite their inability to answer simple questions, they had no problem making strong statements. Among others, they stated emphatically that the tidal regime in Scott’s Bay would not change at all (!) due to the construction of this dam; the tidal cycle would only be delayed by 1 hour (exactly….) compared to that of the open bay. Especially this last statement (also present on their website) really puzzled me. Because you need very sophisticated models to make such a statement and they didn’t even know the first thing about some of the basic physical constraints – how could they make this statement?

Several years ago, a different company proposed to build a tidal lagoon in Minas Basin, more or less on the location where the barrage was supposed to be connected to Minas Basin’s northern shore in the 1970s. At the request of the NS Government, scientists of the National Research Council set out to model the potential effects of such lagoons. The modelers recently published their article (Cornett et al., 2013 – see below for full reference). These lagoons would require a dam of about the same length as the one proposed for Scott’s Bay, i.e. they may be thought of as somewhat comparable.

If you have the least bit of interest in tidal power generation, I encourage you to read this article, it’s a beauty. I enclose only one illustration here

lagoons cornett 1

Figure 6 – Cornett et al., 2013

Some of their conclusions (exact quotes):

  1. “a small change in tide range is predicted throughout the entire Gulf of Maine, even for the smallest development scenario”
  2. “the magnitude of the changes in tidal hydrodynamics increase with the scale of lagoon development, with larger lagoons and multiple lagoons inducing greater hydrodynamic changes”
  3. “a single 26.7 km2 coastal lagoon operating in Minas Basin with an RMS power output of 264MW will cause the tide range in Boston to increase by 1.4 cm, while three coastal lagoongs operating in Minas Basin with a combined area of 94.8 km2 and a combined RMS power output of 988MW will lead to a 7.2 cm increase in the Boston tides”
  4. “Interestingly, the tide range at Boston is found to be more sensitive to lagoon development in Chignecto Bay than in Minas Basin, whereas the tide range at Bar Harbor, is more sensitive to lagoon development in Minas Basin. Furthermore, at Saint John the tide range is found to be sensitive to lagoon development in Minas Basin, but insensitive to lagoon development in Chignecto Bay. In summary, lagoon development in Chignecto Bay will increase the tide range at Boston and Bar Harbor, but not at Saint John, whereas lagoon development in Minas Basin will increase the tide range at all three cities”.
  5. “While the scale of these changes represent a small fraction of the tide range at each community, their potential impact on communities and ecosystems warrants careful consideration and further investigation. Without further study it is difficult to comment on whether the potential benefits of tidal power lagoons might outweigh the drawbacks associated with these changes in tidal hydrodynamics”

Nice – when all you need to do is quote. Nothing more needs to be stated, right?

Altogether aside from these geotechnical complications is the issue of Scott’s Bay itself. Should we even consider damming off a part of this breathtakingly beautiful bay? Few people live in Nova Scotia: we are less than 1 million (and greying). One third of us live in greater Halifax, the rest live spread out along our 4000+ km coastline. The climate isn’t great, we are far from markets, our soils are hostile, our seas and bays are overfished. But we have stunning natural beauty and the Bay of Fundy rightfully competed with 20 other locations for ‘one of the seven natural wonders of the world’.

We must reduce our use of fossil fuels and we must explore and deploy green energy, including tidal (and wave!) energy. But we can’t afford to move forward in the same manner that we’ve done for hundreds of years, namely by rash development under the justification of ‘green energy’. We must research and explore tidal power, but I think only true in-stream tidal power – and we don’t need bullies.

cape Split from Baxter Harbor 3

Figure 7. View across Scott’s Bay from above Baxter Harbour. The proposed tidal lagoon dam would cross from here to iconic Cape Split across. Photo E. Kosters

Useful websites

Nova Scotia Department of Energy

Canada Marine Renewables

Reference

Cornett, A., J. Cousineau and I. Nistor, 2013, Assessment of hydrodynamic impacts from tidal power lagoons in the Bay of Fundy. International Journal of Marine Energy, v. 1 p. 33-54.

Nova Scotia Government tidal energy video on YouTube

Posted in (Geo)science and politics, Energy, General geoscience, Nova Scotia | Tagged , , , , , , , , , , , , | Leave a comment

Canadian Earth Science for @PMHarper 4 – Ice ages and Klondike gold

The pre-amble to this series of reviews is here

Froese, E.G., Zazula, G.D., Westgate, J.A., Preece, S.J., Sanborn, P.T., Reyes, A.V., Pearce, N.J.G., 2009, The Klondike goldfields and Pleistocene environments of Beringia. GSA Today, v. 19, no. 8, p. 4-10.

We live in a time that is characterized by the coming and going of Ice Ages. Many people think of the Ice Ages as something of the past, but our current Holocene period (roughly the last 10,000 years) is just the latest warm interval in 2 million year period of glacials and interglacials (whether humanity is warming the planet to the extent that we won’t be able to return to an ice age at some point, is not the subject of this blog post).

For this post, I am only concerned with northern hemisphere ice ages. During such periods, Arctic ice caps swelled, crawled southward and at some point began to retreat again. When ice caps reached their southernmost extent, we talk about a ‘glacial maximum’. The most recent glacial maximum, called the ‘last glacial maximum’ (LGM), lasted roughly from about 26,000 to 20,000 years ago.

While ice caps can overrun all kinds of topography and generally cover a continental area indiscriminantly, it’s not unusual for certain pockets to remain free of ice, usually because it’s too dry, as in today’s Dry Valleys in Antarctica. During the LGM, and probably during earlier glacial maxima as well, parts of Yukon and Alaska were ice-free, as shown in these illustrations.

Beringia LGM

Alaska and Yukon during the Last Glacial Maximum (26,000-20,000 years ago). Global Sea Level stood ca. 120 m lower than today. The green colours show regions that are currently under water but were land during the LGM, thus forming a continuous land area between NW North America and NE Asia (the ‘Bering Land Bridge’). The pinkish area is now and was then land and it was largely unglaciated, except for local uplands. Figure 1 from the discussed paper. Original image from Ehlers and Gibbard, 2004.

Beringia today and LGM

The entire area is known as Beringia, a 3,000 km wide region. Figure from Yukon Gov’t website

This ice-free region was a freeway, an interstate, a favourite hiking trail for every living being that couldn’t fly or swim and had the urge to travel east to North America, or West to Siberia. Included in this crowd were the ancestors of indigenous Americans (they likely also paddled, but that’s a different story).

Beringia was likely also largely ice free during the waxing and waning of earlier continental ice sheets, maybe as far back as 2 million years ago. So each time the continental ice caps covered the region, this area remained ice-free, a perfectly delineated refuge for plant and animal species traveling, living and dying through the cold spell. And the absolute most special thing of all is that it is possible to acquire precise dates for when various ecosystems existed thanks to the presence of a number of active volcanoes in the Aleutians. Volcanoes blanket large areas with ash. The ash of each volcano has fairly unique composition so that we can distinguish between different ash layers. Also, volcanic ash contains unstable isotopes that enable dating them precisely using radiometric dating methods.

What does this have to do with gold mining?

Miners dig. They create holes in the ground, sometimes very large holes and in this way they expose underlying rock and/or sediment. Ever since the first Klondike Gold Rush in the late 1990′s, the area has been a treasure trove of Quaternary-age fossils, exposed by the work of gold miners, followed on their heels by paleontologists from all over the world. Much of the gold is sourced in a mountain called the King Solomon’s Dome, so many of the gold mines are located in the banks of creeks running off the dome where the gold that eroded off the mountain became part of the sediment deposited around it. The climate had a big control in how much sediment was produced from mountain erosion. During ice ages, the sediment became frozen solid and much of it remains frozen today, sometimes mixed in with wind-blown dust from those times and also mixed in with volcanic ash. This lovely mixture (gravel, ice, silt, and ash) is known as ‘muck’. This muck is “Beringia’s Ice Age Freezer”. To this day, the best muck sites are on north and east-facing slopes or in narrow valleys, i.e. areas that receive the least sun and are thus also covered by insulating soils and vegetation.

solomon_s dome

Yukon’s King Solomon’s Dome, showing radial drainage patterns. Many of the Klondike gold mines exist along these creeks and rivers. 

Interestingly, these valley sides and bottoms were better drained during glacial times thanks to the presence of burrowing ground squirrels which no longer live there. They aerated the soil, so that it could support grasses and herbs, the favourite food for large herbivores such as mammoths, horses and bison (also found as stomach remains in these fossils). Today’s interglacial (warm period) vegetation would not support those grazers!

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 What a fascinating story, made possible by blending the knowledge and experience of so many different experts: a diversity of paleontologists, soil scientists, (paleo)-ecologists, geologists, miners and historians (and forgive me if I forget someone). This is one of those role-model-stories that goes to show that our different scientific fields are not isolated from each other, that innovation takes place by bringing gaps between well-established fields.

For knowledge to truly develop and progress, it must be able to both deepen and widen. Deepening through specialization (how do you tell one volcanic ash layer apart from another, for example) and widening through connecting specialized findings with each other (e.g. ground squirrel burrows and fossilized stomach content). Most of these knowledge cooperations aren’t planned at the onset, i.e. decades ago when earlier generation scientists established the original knowledge base in their field.

This kind of dynamic is always difficult to explain to the general public (including politicians). Many people continue to think that scientists just dally along, meandering happily along their hobby paths without feeling an ounce of accountability towards the tax payer (usually their sponsor). Such people would like to see more innovation, more direct results. Problem is, that’s very hard to enforce and efforts to control and direct have a serious risk of impoverishing of the knowledge base.

While this story may seem to be just another lovely hobby story (what is really the societal relevance of extinct mammoths, right?), this research does improve our understanding of the intricate smaller-scale details of climate change and that in turn may help improve predictions about what’s awaiting us in the near future.

In addition, this story forms part of the rich cultural heritage of Beringia-Klondike and it may some day become formally recognized internationally.

External links

The popular version of this journal article is a downloadable pdf on the website of the Government of Yukon

Yukon Beringia Intepretive Centre

US National Park Service Klondike Goldrush website

Wikipedia Beringia page

Wikipedia Klondike Gold Rush page

Travel Yukon page on Klondike Gold Rush

Canadian Encyclopedia entry on Klondike Gold Rush

Wikipedia entry on Dawson City

Official Dawson City visitors website

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