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

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

A no-brainer for every earth scientist: time travel!

Because this is a WordPress blog, I receive the weekly WordPress writing challenges, which are all about encouraging and helping aspiring fiction writers, which I am not.

However, this week’s challenge is irresistible – Time Travel! This is the challenge (I took out references to other human beings): we’re giving you a free ticket to the period and place of your choice.. be an invisible observer or an active participant…  let bygones be bygones and just travel in time to the future – don’t forget to come back to tell us how it was (http://dailypost.wordpress.com/2014/03/31/writing-challenge-time-machine/)

Every earth scientist badly desires to go back in time, sometimes to a time period that has been the subject of a research project, sometimes to a time period that just seems fascinating. If I could pick just one period and place, what would be my choice?

My choice is going to depend on the answers to a few other questions that the WordPress challengers didn’t formulate (they didn’t think of earth scientists, alas).

1. How long do I get to stay? Geologic processes take a long time and if I only get a human life span for this trip, then quite a few choices fall by the wayside. A lot of geologic events qualify as extremely boring from a human perspective because they last too long! For example, I would not choose to observe the complete eruption of the Deccan Traps, a 50,000 km2 basalt blob that forms the core of the Indian subcontinent, because that ‘event’ lasted from 68-60 million years ago. You can’t watch only 10-5 of that event (one human life span) to get what you want out of that observation. And while you may think that this was an excruciatingly slow eruption, it was quite sudden and short-lived from the perspective of earth itself. Some scientists think that it exponentially increased the amount of CO2 and GHG in the atmosphere so much that this became a crucial factor in ‘killing the dinosaurs’ (popular speak) at end of the Cretaceous. We have known the end of the Cretaceous as the end of the ‘age of reptiles’ for a long time. Their extinction vacated a niche that subsequently became occupied by a tiny mammal (a sort of vole) and this eventually paved the way for the big mammal take-over including ourselves.                           File:Kille Rajgad from Pabe Ghat.jpg

Field view of the Deccan Traps (Wikimedia)    

 

 Location of the Deccan Traps (www.whoi.edu)

 

2. Do I get to be immune if I choose to visit to a catastrophic geologic event? The great classic being of course the asteroid impact that killed those dinosaurs around 65 million years ago. It would be something to behold, but unless I’d be given supernatural powers (or a very advanced planetary rover maybe?), I wouldn’t survive the observation. I’d love to watch that, though – but from where? I think I’d go sit on the edge of the Cretaceous Edwards Plateau in what is now Austin, TX because I’d like to see the tsunami. I worked in Austin for two years and used to hike the dry river beds north of the city and these amazing deposits on top of the Edwards limestone along the creeks. They looked like regular braided river deposits to me, but at the time the Chixchulub crater had not been located yet (the whole hypothesis of the end-of-Cretaceous asteroid was considered pure speculation by many), so we didn’t think of researching whether they would be something else. But now some of those gravels are considered Chixchulub-impact tsunami deposits (e.g. this article), although that’s still doubted by others. (e.g. here).

Fig 5

Location of Chixculub crater and sites of interpreted tsunami deposits around the Gulf of Mexico. My 1980’s hikes took place just south of the Brazos River site

Having considered all this, I have decided to stay low-risk, I’m going back about 3,500 years and I’m going to my own back yard: Nova Scotia’s Minas Basin, the northeastern extent of the Bay of Fundy.

Minas Basin Glooscap

 

Location of the Bay of Fundy and (insert) hypothetical paleogeography of Minas Basin around 3,500 years ago. W=Wolfville (where I live).

As sea level rose during the rapid warming after the latest ice age, the continental shelf and what is now the Bay of Fundy became quickly inundated. The timing of that inundation has been well documented through countless carefully collected C-14 dates, but there was always an inconsistency between the dates obtained in the Bay of Fundy proper and those in Minas Basin, suggesting that Minas Basin flooded later and that the increase in tide range (Minas Basin has the highest recorded tides in the world) happened quite suddenly. around 3,500 years ago.

A few years ago, a Geological Survey of Canada geoscientist, John Shaw, had a brainwave. What if that was exactly what happened? What if a gravel bar (such as we see everywhere around these previously glaciated coasts) had prevented Minas Basin from marine flooding, ‘holding out’ – if you wish – until some catastrophic event (a storm, likely) breached it after which it the gravel bar never repaired itself again as its remains were constantly attacked by ever-higher tides.

Oddly (or not), the Miqmaq have a legend about their spiritual chief, Glooscap, who wanted to take a bath and asked the beaver to build him a bathtub. Which the beaver did (gravel bar). When he was done with his bath, Glooscap asked beaver to empty the bath, but we know how stubborn beavers are and this beaver was no different, so he refused. Glooscap got mad, threw a couple of rocks at beaver (small islands along the north shore of the basin) and eventually asked the Whale ‘to flip his tail’ and empty the tub. Which the whale did.

Now the former bath tub fills and empties twice every lunar day – and we watch it from our house. John Shaw’s article is referenced below.

I would have loved to sit on top of Cape Blomidon during the event that destroyed this hypothetical gravel bar and watch it happen. The tidal currents are so powerful that no evidence exists of this former gravel bar, so it remains a speculative story, except for those radiocarbon dates.

Would my presence at that time have had any influence on the future evolution of the area? Not my individual presence, not even the presence of a few thousand MiqMaq who lived here at the time. But if this would have happened in the 20th century, society might have intervened, it might have decided that the gravel bar needed protection, locals might have gone about some big engineering construct to ‘keep Minas Basin fresh’ (I can just see the bumper stickers).

And that brings the story back to the human dimension that the WordPress challengers were thinking of.

Reference

Shaw, J., C.L. Amos, D.A. Greenberg, C.T. O’Reilly, D.R. Parrott, E. Patton, 2010, Catastrophic tidal expansion in the Bay of Fundy, Canada. Canadian Journal of Earth Science, v. 47, p. 1079-1091.

 

 

 

 

Posted in General geoscience, Nova Scotia | Tagged , , , , , , , , , , , , , | 1 Comment

Canadian Earth Science for @PMHarper 3 – the importance of finding layered oceanic crust

The preamble to this review series is here

Gillis, K.M., J.E. Snow, A. Klaus, N. Abe, A.B. Adriao, N. Akizawa, G. Ceuleneer, M.J. Cheadle, K. Faak, T.J. Falloon, S.A. Friedman, M. Godard, G. Guerin, Y. Harigane, A.J. Horst, T. Hoshide, B. Ildefonse, M.M. Jean, B.E. John, J. Koepke, S. Machi, J. Maeda, N.E. Marks, A.M. McCaig, R. Meyer, A. Morris, T. Nozaka, M. Python, A. Saha, R. Wintsch, 2014, Primitive layered gabbros from fast-spreading lower oceanic crust. Nature, v. 505, p. 204-208

The earth has just two types of crust: continental crust and oceanic crust. Continental crust forms most of the continents. Oceanic crust forms most of the oceans. The earth is like a cracked sphere consisting of a dozen or so pieces of moving oceanic and continental crust. The pieces are called plates and their dynamical interaction is called plate tectonics (from ancient Greek, meaning “pertaining to construction”). We have known about plate tectonics for just 50 years. Plate Tectonics explains everything about the earth’s crust, but while we know this to be the case, it doesn’t mean we have found every explanation for every observation as yet.

Plates move around today and have been doing so for close to 4 billion years (the earth is a little over 5 billion years old). There are only three possible plate movements: plates can move away from each other (spreading), they can collide, and they can slide alongside each other. Plates spread at (mid)ocean ridges where magma wells up and accretes on two sides of a zipper line. This process creates oceanic crust. The best known example of spreading is the Atlantic Ocean that has a beautiful zipper line in the center from where the ocean grows at about 2-3 cm per year (more or less the rate at which your finger nails grow) increasing the distance between the continents. Spreading usually isn’t accompanied by very volatile earthquakes and volcanic eruptions.

Because the earth as a sphere doesn’t get any bigger or smaller, the result of spreading (which increases plate size) is that shrinking must take place elsewhere. Shrinking goes through collision and the most famous collision zones are along the Pacific margin where oceanic crust disappears below continental crust, giving us the ‘ring of fire’ with lots of earthquakes and volcanoes. The most famous area where plates slide alongside each other is along the San Andreas fault in California and along the Great Anatolia fault in Turkey.

But even the Pacific Ocean, which is shrinking as we speak, still has are spreading ridges. Consider the figure below.

Hess Deep 1

Map of the earth’s plates, and their rate of motion in cm/year. The higher the number, the faster the motion. Spreading is shown as opposite facing arrows, collision as arrows pointing to each other and and sliding as half arrows in opposite direction. Note that there is pretty consistent spreading along the length of the Atlantic Ocean and a combination of spreading and collision (subduction) at widely varying rates along and in the Pacific Ocean. The red arrow points to the Hess Deep, the area where the authors collected their samples. Figure 4.1 from Moores and Twiss (1995)

Because these processes have gone on for such a long time, many previously existing plates have disappeared over the eons, they are consumed into more recent plates through collision and sliding processes. How do we know? Because we find pieces of oceanic crust (with a distinct, unique combination of minerals) incorporated in continental rocks. Such pieces of oceanic-crust-now-on-land are called ophiolites and they are studied intensely as they give us a unique window into understanding the history of the earth.

The figure below shows the locations of ophiolites in the world. The most famous one in Canada is right in Gros Morne National Park and this was in fact one of the main reasons for designating the national park as well as getting a UNESCO World Heritage status. The Bay of Islands ophiolite is an important piece of Canadian geoheritage.

ophiolite locations globally

The research project that this article presents was carried out as ‘Legs 345’ of the Integrated Ocean Drilling Program using the drill ship JOIDES Resolution. JOIDES stands for Joint Oceanographic Institutions for Deep Earth Sampling, the largest international cooperative earth science program in the world which has been going on since 1968.

Leg 345 sampled a fast spreading centre in the eastern Pacific, known as the “Hess Deep”. This project was a successor to Leg 147, which sampled the same area in 1993. Bear in mind that the average depth of the ocean here is 4 km.

Hess Deep2

Location of the “Hess Deep” spreading centre in the eastern equatorial Pacific Ocean.

The expedition had two chief scientists: Dr. Jonathan Snow of the University of Houston and Dr. Kathryn Gillis of the University of Victoria. Kathryn Gillis also led the earlier Leg to the same area in 1993.

Jon Snow Kathryn Gillis 2013 IODP

Expedition co-leaders Jonathan Snow (left), Kathryn Gillis (centre) and core curator Chad Broyles (right) aboard the JOIDES Resolution during the expedition. Image source here

Why drill here? To see if they could find the type of oceanic crust that was thought to be typical for fast spreading centres. Why is that important? Because three-quarters of the world’s oceanic crust formed at fast-spreading ridges. Why should we care about that? Because of two reasons:

  1. for the intrinsic value of pure discovery. In this case, discovery that will improve our understanding of the history of the earth.
  2. because many of the earth’s important and valuable minerals occur in rocks that were once part of the oceanic crust. If we can better understand how the oceanic crust formed, we’ll improve our understanding of mineral occurrences.

Bonanza was granted the researchers. The drill ship retrieved oceanic crust with a layered appearance and a unique mineral composition that tells us much about the properties of the molten lower crust, how it differentiates as it solidifies and what this means for interpreting plate movements.

GabbroCoreSection-web

This piece of core is about 5 cm across and about 12 cm long. It shows alternating light and dark layers of gabbroic rock. These rocks – the first of their kind to be recovered – help confirm a long-standing belief that the gabbroic rocks in the lowermost part of the oceanic crust are layered. These layers are defined by the relative abundance of the minerals olivine, clinopyroxene, and plagioclase; differences in the mineral content gives each layer its light and dark appearance. Image courtesy Kathryn Gillis – figure from the article, accessible online (with this figure caption) here

It’s a big achievement to be an IODP (co)-chief scientist. Kathryn Gillis is an outstanding geoscientist and is featured as one of the world’s leading women oceanographers here.

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The IODP is an astonishingly productive program, initiated in 1968 by the United States only five years after the theory of plate tectonics was formulated. The only individual countries that are full members are the United States, Japan, Korea, Australia/New Zealand, and China. The European Union is a full member too. Canada was a full member, but withdrew some years ago. Canada now operates under the auspices of the European Union membership (see www.iodp.ca for more details). This is embarrassing because Canada, the world’s second largest country bordering three oceans, has as much voice in IODP as any small European member country. Which is not a full voice, that’s for the full members. Despite the remarkable achievements of Canadian scientists, we don’t really count in this international arena.

JOIDES Resolution The JOIDES Resolution drill ship

 

Reference

Moores, E.M. and R.J. Twiss, 1995, Tectonics. W.H. Freeman and Co., New York, 415 p.

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

Blue Beach is not for sale

(Originally posted in March 2014. Updated a few times, last in May 2017)

Blue Beach location1 Blue Beach 5

Left: Google Earth image showing location of Blue Beach – Avonport Station coastline. Right: aerial photo of the cliff (in the shade) and beach at low tide. 

One of the world’s prime fossil locations, Nova Scotia’s iconic Blue Beach, hit the press recently (here and here) although readers outside Nova Scotia or readers not familiar with paleontology may not have noticed. As a result, confusion arose among the public and even among some of my followers, so here is a bit of background (NOTE: This post was originally published on March 17, 2014. On May 11, 2014, Blue Beach hit the press again in the Chronicla Herald (here) in relation to the research visit by world-renowned paleontologist Dr. Jenny Clack, who visited the site; on May 13, the Chronicle Herald published another piece here).

“Blue Beach” is informally named.

The cliffs along Blue Beach are exposed in rocks of the Tournaisian Horton Group which here represent shallow fluvio-lacustrine deposits forming the edge of the early Carboniferous Maritimes Basin which was located at a tropical latitude at the time. The Tournaisian lasted from 359-345 million years ago. It was a very interesting time interval in earth history, because this is when the first 4-footed vertebrate animals (i.e. with a spine just like us) set foot on land. A 4-footed vertebrate is generically known as a ‘tetrapod’ (‘tetra’ is Ancient Greek for ‘4’, ‘pod’ means ‘foot’). If you don’t find the whole animal, but just its footprints, then you usually can’t tell whether the animal is an amphibian or a reptile (or a mammal, for that matter, but mammals didn’t exist yet in the Carboniferous) so you call it a tetrapod. If you find a whole series of footprints of what obviously was a 4-footer wandering through life, you call it a ‘trackway’, as in ‘tetrapod trackway’.

Eochelysipus horni trackway Mossman and Grantham 2008

Tetrapod trackway from Blue Beach. Figure from Mossman and Grantham, 2008

This short 15 million year time interval is also known as ‘Romer’s Gap’. It’s named after the scientist (Alfred Romer) who identified the interval as a crucial period in earth history: few 4-footed vertebrates existed earlier than 360 million years ago and many of them went extinct at the end of the Devonian, the period during which fishes were especially abundant (the UNESCO World Heritage site at Miguasha in Quebec is testimony to that ‘age of fishes’). The first true reptiles are found in sedimentary rocks younger than 345 million years. In fact, the world’s oldest reptile (fossil) is also from Nova Scotia – it was found at Joggins Fossil Cliffs, now a UNESCO World Heritage Site (www.jogginsfossilcliffs.net). It’s called Hylonimus Lyelli and is Nova Scotia’s provincial fossil. The oldest sedimentary rocks at Joggins are ca. 345 million years old. So big evolutionary changes happened in a relatively short period of time. Fishes went on land, amphibians evolved, reptiles evolved, all in the blink of an eye – that’s putting it a bit too simplistic, but you get the idea. Unfortunately, the world doesn’t have a lot of exposed sedimentary rocks from that period, so our understanding suffers from a gap. Hence “Romer’s Gap” (the Wikipedia entry is really good).

The rocks exposed between Blue Beach and Avonport Station are one of the few locations on earth that represent exactly that time interval. The paleo-environment was ideal for preserving remnants of life at the time: it was a shoreline at the mouth of probably multiple river systems. The body of water in which these rivers emptied may have been fully saline, it may have been brackish to fresh. In other words, a fertile environment. Lush vegetation grew on land, much of which wasn’t eaten, as there were no large land animals and no birds. As the vegetation died (and much of the dead vegetation that became buried eventually became coal), it supplied the soils with organic detritus and thus with plenty of nutrients, so the area teemed with life. Rapid sedimentation in a subsiding basin (the Maritimes Carboniferous Basin) ensured that dead bodies (plant or animal) were quickly buried: an ideal condition for preservation. In addition, the area was subsiding as it was part of a rapidly opening and deepening sedimentary basin, so the thick sediment packages became quickly buried, out of reach of other destructive forces.

So the rocks at Blue Beach – Avonport Station are the showcase for an entire ecosystem. Amazing!

Fast forward 360 million years to today: the rocks are exposed along the Minas Basin, a side arm of the Bay of Fundy, which experiences the world’s highest tides. Along this stretch, the average tide range is about 12 m. This makes for a perfect 3D exposure along km-wide low-tide rocky and muddy beaches and in the cliff, which is up to 20 m high in places. The tides erode these soft shales rapidly – new discoveries are constant.

IMG_1682

Blue Beach – excellent 3D outcrop! There is minor faulting and deformation in the shales, but virtually no diagenetic alteration. 

Protecting our geoheritage
Nova Scotia has an amazing geodiversity, covering about 1 billion years of earth history. Not all of this Geoheritage (see Nova Scotia Geoheritage Map here) contains evidence of evolution of life (fossils), but a lot of it does. The province has been the hunting ground of professional paleontologists for nearly 200 years! Realizing that much of our unique fossil heritage could be carted away easily, the province created a law in 1974 called the ‘Special Places Protection Act’. Without going in to too much detail, this law basically declares every fossil the ownership of the people of Nova Scotia, i.e. the province. No fossil can be private property. Now, there are lots of fossils that the province is not interested in, such as gazillions of raindrop imprints or mud-cracks or fish scales. But it’s worded in an extreme way so that you can’t take off with any fossil (raindrop or tetrapod trackway) and claim that you didn’t know about that being an illegal act. I live approximately 4 km from Blue Beach, so have wandered there frequently and found 1 special fossil, the tail piece of a trilobite. I handed it over to the Nova Scotia Museum of Natural History, where it is catalogued and where anyone can come to study and admire it.

trilobite tailpiece question mark. Horton Bluff section

A trilobite pygidium (tailpiece) that I found at Blue Beach – it is now at the Nova Scotia Museum of Natural History

Such a law is difficult to police, of course, especially in a thinly populated place with wild coastlines. I remember visiting Arizona’s Petrified Forest and every visitor is essentially guarded by an interpreter / park warden to make sure that nobody picks up anything. Excellent. But we can’t do that here, it is logistically and financially impossible. (there was a sentence here that stated that Neil Shubin et al, who found the most important early dinosaur bones at Nova Scotia’s Parrsboro shore in the early 1980s, collected these bones and took them to Chicago without further ado, but I was notified by Neil Shubin himself that I was wrong, so that sentence is no longer here. Do read the comments below and do read Neil Shubin’s ‘Your Inner Fish’).

So the law is good, but its operationalization is weak.

Only a few people have properties on top of the cliff above Blue Beach. If you own property on the coast in Nova Scotia, you own it to the high tide line. So even if your property borders a site such as Blue Beach, those fossils aren’t even close to being yours (the law aside) because the highest high tide comes halfway up the cliff.

Sonja Wood and Chris Mansky own a property on top of the cliff at the entrance to Blue Beach. Chris Mansky is a well-known amateur fossil hunter and I don’t mean amateur in a negative way. He is one of those rare individuals without formal training and with an extremely keen eye. Two other equally famous amateur fossil collectors in Nova Scotia are Don Reid and Eldon George. Over the decades, Chris Mansky has rescued an amazing array of unique fossils from being destroyed by the tides. He and Sonja have stored these fossils in a Quonsett hut on their property and have shared their findings generously with anyone who wished to see them – a lot of those were school kids but Chris was also made co-author on a number of scientific articles by professional paleontologists who researched Blue Beach (professionals are allowed to collect for research purposes if they apply for a heritage collections permit from the NS Department of Communities, Culture and Heritage; anything they find is than catalogued by the NS Museum). Chris and Sonja only asked for donations. The fossils are not theirs, as they make very clear on their website (http://www.bluebeachfossilmuseum.com). They can’t be sold.

Sonja and Chris have made various attempts at creating a visitor and interpretation centre on their land, including getting money promised by the county. An architect created a design for a museum. But the money didn’t come through so I can only assume that none of these plans is considered viable any longer, so they have put their property up for sale. That’s too bad. (In 2017 the property is no longer for sale and they still live there; there is no movement on the interpretive centre).

The question is, of course, what will eventually happen to “their” collection, which legally belongs to the province and could – theoretically – be moved to the provincial storage facility at Stellarton, a good 3 hours driving away. That would be really sad, because while the province (Nova Scotia Department of Communities, Culture and Heritage through the Nova Scotia Museum of Natural History) would of course (as they are mandated by law to do) provide access to the collection to scientists, it would be inaccessible to the general public, unless the Museum organizes a specific exhibit. Our small and thinly populated province doesn’t have money for remote interpretation centres. Such initiatives require separate funding.

Sites such as Blue Beach are important for public education and for furthering the collective understanding of our the history and evolution of life on earth and they are part of our Geoheritage. While the Blue Beach-to-Avonport stretch of coastline is unaffected by all this uproar, it would be a really good idea if there was an interpretation centre that conserves and showcases the fossil collection in the area itself rather than somewhere further away where visitors can’t relate to the environment. The museums and interpretation centres at Joggins and at Parrsboro are testimony to that principle. They each get tens of thousands of visitors each year and are not only visitor sites, but also research facilities. The beach at Joggins is now more protected from illegal fossil hunting than before because paid interpreters are on the beach during the warmer part of the year, guiding visitors and poring over their finds. This is a positive development.

So I do hope the collection made possible by Sonja and Chris’s efforts can be made available for public viewing in a centre somewhere as close as possible to Blue Beach itself. Since Sonja and Chris do not own the collection, it’s clear that the location of an interpretation centre doesn’t have to be on their property, because the collection isn’t theirs. Also, the cliffs and beach are not endangered by the intended sale of their property.

References

Calder, J.H., 1998, The Carboniferous evolution of Nova Scotia. In: Blundell, D.J. And A.C. Scott (eds.),  Lyell, the past is the key to the present. Geological Society, London, Special Publications , v.143, p. 261-302

Clack, J. A., 2002, An early tetrapod from “Romer’s Gap”. Nature, v. 418, 4 July 2002, p. 72-76.

Gibling, M.R., N. Culshaw, M.C. Rygel and V. Pascucci, 2008, The Maritimes Basin of Atlantic Canada: basin creation and destruction in the collisional zone of Pangea. In: Sedimentary Basins of the World, V. 5, p. 211-244 (Elsevier).

Hunt, A.P., S.G. Lucas, J.H. Calder, H.E.K. Van Allen, E. George, M.R. Gibling, B.L. Herbert, C. Mansky and D. Reid, 2004. Tetrapod footprints from Nova Scotia: the Rosetta Stone for Carboniferous tetrapod ichnology. Geological Society of America, Abstracts with Programs, v. 36, no. 5, p. 66

Martel, A.Th. and M.R. Gibling, 1992, Wave dominated lacustrine facies and tectonically controlled cyclicity in the lower Carboniferous Horton Bluff Formation, Nova Scotia, Canada. In: Anadon, P., L.L. Cabrera, K. Kelts, Lacustrine Facies Analysis, Int’l Assoc. of Sedimentologists special publication no. 13, p. 223-240.

Martel, A.Th. and M.R. Gibling, 1996, Stratigraphy and tectonic history of the upper Devonian to lower Carboniferous Horton Bluff Formation, Nova Scotia. Atlantic Geology, v. 32, p. 13-38

Mossman, D.J. and R.G. Grantham, 2008, Eochelysipus horni, a new vertebrate trace fossil from the Tournaisian Horton Bluff Formation, Nova Scotia. Atlantic Geology, v. 44, p. 69-77

Tibert, N. E. And D.B. Scott, 1999, Ostracodes and agglutinated foraminifera as indicators of paleoenvironmental change in an early Carboniferous brackish bay, Atlantic Canada. Palaios, v. 14, p. 246-260.

Posted in General geoscience, Geoheritage, Nova Scotia | Tagged , , , , , , , , , , | 4 Comments

The Eemian and the #Anthropocene

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Figure 1. River Eem at town of Eemdijk (to the right), Netherlands. The view is to the North. Eem floodplain (ca. 1 m below MSL) to the left. Location of photo: 52o15’17.65″N, 5019’38.42″E

The Eemian interglacial warm period is known as the Sangamonian in North America and as Isotope stage 5e in paleoceanographic and climatic circles. It followed the Saale/ Illinoian glacial period.

The Eemian lasted from ca. 130,000 – 115,000 years ago and was followed by the most recent glacial period (Weichselian/Wisconsinan), which lasted until about 11,000 years ago when the current warm period, the Holocene began.

Marije Vlaar figure 3

Figure 2. ‘Maximum ice cover’ is the maximum ice cover of the Saale/Illinoian glacial period. The ‘Glacial Depressions’ shown on this figure are Saalian in age and were inundated by the subsequent Eemian Sea (see figure 3). The Weichsel/Wisonsinan ice cap didn’t reach as far South as those of the Saale glacial. ‘Ice-pushed ridges’ are moraines. The ‘faults’ are part of the tectonic fabric of the failed rift system of the Rhine/North Sea. Figure from Vlaar, 2007

Marije Vlaar figure 4.jpg

Figure 3. Maximum extent of the Eemian sea. Figure from Vlaar, 2007

The Eemian interglacial was on average about 2degC warmer than the Holocene has been so far. There have been other periods in Earth history that have been lots warmer, but the Eemian is so young that it is therefore especially relevant to study. Why? Because continental configurations were the same as today, so that it becomes possible to model and understand the oceanographic and atmospheric conditions of this period. A better understanding of the Eemian is essential for enabling better models for future global warming. Lots of scientists research aspects of the Eemian interglacial. Here I only mention the NEEM project here (www.neem.dk). NEEM stands for North Greenland Eemian Ice Drilling, an international ice core research project aimed at retrieving an ice core from North-West Greenland (camp position 77.45°N 51.06°W) reaching back through the previous interglacial, the Eemian.

Few people know that the Eemian is named after the River Eem in the Netherlands. Full disclosure: I grew up in a town on the River Eem (not the one in the picture) and spent my high school years rowing skiffs, doubles and 4-s on the river. My first job was a paper route which required bicycling many long hours along the river, delivering the local rag to the dispersed farms. The graphic artist M.C. Escher lived in that area too. One of his better known images is ‘Day and Night’ which might very well have been inspired by the landscape along the Eem river

EscherDayandNightLR

M.C. Escher: ‘Day and Night’ – possibly inspired by the Eem River valley landscape

It’s barely a river with its total length of 18 km and 10 km wide surrounding floodplain. But this little valley bears superb testimony to our fluctuating climate and to the creativity of humankind to deal with adverse conditions.

veluwe met eem

Figure 4. Digital elevation model of the central Netherlands, showing the terminal moraine of the Saalian/Illinoian ice cap and the River Eem, draining the interior moraine valley to the North. Source: www.ahl.nl. The western portion of the Saalian terminal moraine is known as the ‘Heuvelrug’, its eastern portion as the ‘Veluwe’. Even though the moraine was breached by melt water near at its southern tip, its inner valley drains mostly northwards through the River Eem and the ‘Lunterense Beek’,  a somewhat longer river that is largely rerouted as a canal (not indicated on figure).

The Eemian/Sangamonian lasted only about 20,000 years, a relatively short time for an interglacial warm period. Eemian global mean sea level (MSL) stood ca. 4-6 m higher than present-day (Holocene) Mean sea level and global mean temperature was about 2degC higher than at present (the ‘present’ is changing rapidly of course). Of course, climate is warming and sea levels are rising rapidly since the last 200 years but it’s still safe to state that Eemian MSL stood about 2m above Holocene MSL.

When sea level rose during the Eemian interglacial, the North Sea flooded these lowlands and the bowl-shaped inner valley of the moraine became a shallow marine embayment, a natural receptacle for sediments washing in from the surrounding the inner slopes of the moraine (Figure 3.)

The moraine consists of gravel-loaded sands, loams and clays and was thus very susceptible to erosion prior to during early deglacation when the climate was still Arctic (tundra) and without much vegetation. Washed down slope sediments interfinger with marine sediments deposited in the Eem floodplain. This package of sediments tells us the story of the changing environmental conditions over time so well that it became the designated type locality for the Eemian interglacial.

After its short journey, the Eem empties in the former “Zuiderzee” tidal basin, renamed the “IJsselmeer” after it was isolated from the tidal sea by a 31 km barrier in 1932. The Dutch subsequently reclaimed a large portion of the IJsselmeer. The southern edges of these reclaimed land areas are visible in Figure 4.

Early people started settling here a little more than 1000 years ago. The town of Amersfoort (literally meaning ‘ford across the Eem/Amer, where ‘Eem/Amer’ means ‘water’) became a logical site for a trading post with the river Eem as its commercial access route as well as for beer brewing, thanks to reliable access to clear water. The river continued to have a commercial function until well into the 1960’s: when we rowed on the river in those years, we learned to manoeuver our skiffs in the wake of the barges that barreled empty and high upriver and full and low downriver. By that time, the river was very polluted: our parents warned us never to go swimming.

Because of its economic importance, it became essential that the river had a consistent water level and thus it became enclosed in artificial levees (‘dykes’) from the early Middle Ages onwards. The floodplain, now isolated from sediment-laden seasonal flooding, was pumped dry using windmills (first) and power-driven pumping stations (later). Its sediments compacted and its elevation sank to below sea level. It always remained relatively wet, however, and thus was and is used predominantly for grazing dairy cattle and for producing hay.

Times change – these days, the river is purely a recreational ribbon in the landscape. Also, dairy farming no longer has the economic significance it used to have. A significant part of the Netherlands is man-made; the country has an extremely high population density, so there is little room for nature. Changing economic conditions such as along the Eem are opportunities for re-instating a bit of nature: these days the floodplain of the Eem is allowed to regain some wetland characteristics, attracting large flocks of different species of geese, wild swans, herons and many other birds.

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Small-scale water management in the Eem floodplain using wind and solar power. New wetland showing as water patches in the distance. Large-scale wind turbines on the horizon.

Growing up here, I never knew anything but a man-made landscape. I lived in the Anthropocene before that term was invented. The Dutch were and are hailed as the prime example of a people who have conquered nature. They must continue to do so if they want to keep their feet dry (2/3 of the Dutch population, ca. 10 million souls, live below sea level). Where possible, they now try to work with nature rather than against it because they have learned that the land otherwise becomes sterile. And they have become innovative in enabling the return of once considered worthless wetlands. They try to make room for rivers, some wildlife AND for green energy projects. It’s optimistic, it’s hopeful.

As I see it, the Anthropocene started here more than 1000 years ago. People continued to adapt to hostile circumstances and their adaptations have been novel and innovative and they have been able to improve them over time (the Eem floodplain was definitely not a bird sanctuary in the 1960’s). People are tenacious and creative, and this makes me hopeful about the future. Areas such as this can be an inspiration for well-designed interventions that will be needed to survive in the Anthropocene that now confronts everyone.

References:

http://en.wikipedia.org/wiki/Eem   http://members.upc.nl/t.meijer64/paginas/ae-pub-eem_BCM.htm

Bosch, J.H.A., P. Cleveringa and R. Meijer, 2000, the Eemian stage in the Netherlands: history, character and new research. Netherlands Journal of Geosciences, v. 79 no. 2/3, p. 135-145. This article can be accessed at: http://members.upc.nl/t.meijer64/paginas/ae-pub-eem_BCM.htm

NEEM Community members, 2013, Eemian interglacial reconstructed from a Greenland folded ice core. Nature, 493, pp 489-494. http://www.nature.com/nature/journal/v493/n7433/full/nature11789.html

Vlaar, M., 2007, Reconstruction of the Palaeo-ecology of the Eem Polder by means of dendrochronology, pollen and macrofossil analysis. Unpublished MSc thesis, Utrecht University. http://vkc.library.uu.nl/vkc/archaeology/SiteCollectionDocuments/Scripties/2007/Marije%20Vlaar/MA%20Thesis%20Marije%20Vlaar%202007.pdf

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Canadian Earth Science for @PMHarper – 2: The Canadian contribution to the International Polar Year

The preamble to this review series is here

 —

Melling, H., R. Francois, P.G. Myers, W. Perri, A. Rochon, R.L. Taylor, 2012, The Arctic Ocean – a Canadian perspective from IPY. Climate Change, DOI 10.1007/s10584-012-0576-4. Published online at http://link.springer.com/article/10.1007%2Fs10584-012-0576-4/fulltext.html

The fourth International Polar Year, coordinated by the International Council for Science and the World Meteorological Organization, lasted from March 2007 to March 2009. It was a global scientific effort in which thousands of scientists from more than 60 countries collected data for more than 150 research projects, an enormous accomplishment.

Poles and oceans play a critical role in controlling climate, a globally relevant issue of which the details are still only partially understood. Big questions such as what parameters exactly control climate, how stable climate systems are and how quickly they can destabilize can only be answered through reams of minutely executed projects, defined on the basis of carefully articulated research questions. Eventually, the combined results of these effforts will lead to universally valid answers.

The Canadian contribution to this IPY was typically Canadian! Canadian scientists “wanted to contribute in a constructive manner to the larger international effort”. The Canadian IPY activities “were linked with those of other countries in order to advance Arctic marine science and move it closer to societal relevance, public policy and applications” and were focused exclusively on the Arctic.

It’s important to be aware of how completely different the earth’s polar regions are. The North polar region is an ocean surrounded by continent masses, whereas the South polar region is a continent surrounded by ocean. You can’t think of more opposing conditions. Water absorbs heat in a much different way than land, so the Arctic’s role in governing climate is bound to be much different from that of Antarctica. In addition, the Arctic Ocean is unusual compared to other oceans because a relatively large portion of it is occupied by shallow (less than 500 m deep) continental shelf (light blue in the figure below). A continental shelf is the portion of a continent that is permanently flooded by the ocean. Shallow waters warm more easily than deep waters, so the shelves of the Arctic Ocean are like hot water bottles along its sides.

polar regions

This article summarizes seven research projects that were carried out along a 13,000 km ship trajectory from Victoria to Halifax, traversing the three oceans that Canada borders (aptly named C3O). The ships from which the data were collected were Canadian coast guard vessels that were on their scheduled Arctic patrols. Talk about a win-win opportunity. Research is expensive, doing research in the Arctic is hideously expensive, so if you can reduce that expense by making use of paid-for ship time, you’re a genius in my book. By designing the research along this trajectory, the scientists established a baseline for future studies.

Quick primer to oceanography. If you have never thought about why and how ocean currents flow, there are two things you must remember:

  1. There are surface currents and deep currents. Surface currents are largely driven by wind (weather!), additionally pushed around by the rotation of our planet. Surface currents occupy the top 50-200 m of the oceans and their temperature is mostly controlled by the sun. Deep currents occupy the rest and since the world’s oceans have an average depth of 4000 m, that’s a lot of water that’s difficult to observe.
  2. The movement of the deep ocean water is driven by differences in density between water masses, again heavily influenced by the rotation of our planet. What causes density differences? Only two parameters to remember for the purpose of this blog post: salinity and temperature. Mean global ocean salinity is 35 parts per million (ppm). What makes for variability in salinity? Climate: in lower latitudes, average air temperature is relatively high, the water evaporates and the remaining water body becomes more salty. Salty water has a higher density than fresh water, so if the two come in contact, the salty water will sink below the fresh water. Warm water absorbs more gases from the atmosphere than cold water, hence warm water is less dense than cold water and thus cold water will sink below warmer water.

Do surface and deep water never mix? They sure do. To keep with the main topic of this paper, I will mention only the situation in the North Atlantic. There, the warm, salty waters of the Gulf Stream (named for the warm and thus salty Gulf of Mexico where it originates) meet cold polar waters. The salty water cools, becomes more dense, and sinks below cold (less salty) surface waters, then flows back South as deep water, supplementing the deep ocean with oxygen along the way. The linked system of surface and deep ocean currents is called the ‘global conveyor belt’, a term coined by the iconic oceanographer Wallace Broecker (Lamont Doherty Geological Observatory, NY).

Now, let’s look at the 13,000 km study area discussed in this paper. This figure shows the trajectory and sampling stations of the Canadian IPY trajectories.

Picture1

The Yellow Line is the ship track, officially called the C3O section. Other sampling stations (not discussed in this blog post) are represented by circles etc. Surface currents are represented by arrows: pink for warm, white for cold.

The Arctic Ocean is in contact with the Pacific ocean via the Bering Strait and with the Atlantic Ocean via the Davis Strait (between Baffin Bay and the Labrador Sea). It also receives a lot of (seasonally changing) fresh water from the surrounding continents, most of it from large rivers. On our side of the Arctic, these are the Mackenzie and the Yukon.

Because of a couple of unique conditions in the Northeastern Pacific, the water flowing into the Bering Strait is relatively fresh (lower salinity) compared to that of the Arctic Ocean. It’s also full of nutrients that support the food chain there. In addition, its elevation is about 40 cm above that in the Beaufort sea. As a result, the flow of ocean water from the Bering Strait to the Davis Strait is like a giant river flowing down an extremely gentle gradient. This “river in the ocean” receives additional fresh water from northern rivers, so it stays relatively fresh thus less dense along the way. In the past, it would gradually become more saline because of the formation of pack ice: when ice forms, fresh water is taken out of the ocean water body, thus increasing the salinity of the remaining sea water (and also reducing the temperature at which it freezes). But in the last decade, the surface waters remain relatively fresh and this expedition contributed to understanding why that happens

Here are the results:

/static-content/images/316/art%253A10.1007%252Fs10584-012-0576-4/MediaObjects/10584_2012_576_Fig2_HTML.gif

The C3O section of seawater temperature (top) and salinity (bottom), measured in July 2008.

These diagrams are 2 dimensional (distance/depth) cross sections of the ship trajectory showing the variability of the two most crucial oceanographic parameters temperature and salinity. The vertical scale on these diagrams is pressure, which you can pretty much translate to depth 1:1.

Take a good look: the upper cross section shows the temperature variation along the trajectory. Clearly, the North Pacific is relatively warm (red). Once these waters enter the Arctic Ocean through the Bering Strait they remain recognizably warm until somewhere between the Amundsen and Coronation Gulf, nearly 8,000 km further. At that point, the surface waters become significantly colder as they become mixed with the relatively fresh, cold waters of the “Beaufort gyre”, a surface current that rotates in a clock-wise direction in the Beaufort Sea. Until a few years ago, the Beaufort gyre was permanentaly capped by sea ice.

The relatively fresh and recently ice-poor Beaufort gyre also influences the salinity along the same part of the transect, as shown in the lower diagram: from the Beaufort Sea to Coronation Gulf, salinities are only about 2/3 of mean ocean salinity.

These observations were supported by measurements on other tracers, such as the element Barium. Barium is a tracer of river water and its concentration was very low during the IPY observation years, which supported the conclusion that the observed freshening of the water along the transect was caused by influx from the changing position and behaviour of the Beaufort gyre.

Lots of other significant discoveries were made along this IPY transect. I can’t dwell on them more, or this post becomes as long as the article itself. Therefore only a short summary of the conclusions:

  1. the Canadian Arctic climate shows asymmetric cyclic variability in the last 10,000 years. During warmer intervals, there is less ice in the western Arctic and this coincides with more ice in the east and vice versa.
  2. Wind is a crucial influence on water movements
  3. When ice is far from shore, winds, waves and storm surges create hazardous conditions for coastal communities. Decreasing summer ice thus increases vulnerability of these settlements.
  4. Changes in the outflow from the Arctic to the Atlantic Ocean influence the global water cycle.
  5. There is more fresh water in the Canada basin during the last decade than before and this causes a decrease in nutrient supply, which affects the very base of the food chain.

Canada is one of only a handful of nations bordering the Arctic Ocean. Global climate is changing rapidly and Arctic research is more important than ever. It is therefore more than a little embarrassing that Canada still hasn’t moved on the replacement of its aging ice breakers, as reported here

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Tantalum, your smart phone and the world economy

I listen to BBC World Service a lot. Today I caught the program “More or Less” (http://www.bbc.co.uk/programmes/b006qshd), presented by Tim Harford.

“More or Less” is about “the numbers and statistics used in political debate, the news and everyday life”. 

Today’s first part of the program discussed important numbers of 2013. The first guest was Dr. Pippa Malmgren, a highly respected American policy maker and recognized Global leader (http://en.wikipedia.org/wiki/Pippa_Malmgren).

Dr. Malmgren’s favourite number for 2013 was 73, the periodic table number for the element Tantalum, “one of the rare earths” and these elements are very important, because they are essential components of mobile phones and computers and thus critical for the modern economy. Dr. Malmgren went on to explain that critical minerals are minerals with a limited supply. The issue with being able to produce them is whether there is enough investment to “pull these minerals out of the ground”. She explained that it takes about 15 years before a Tantalum or a Phosphate mine (she mentioned phosphate because it is a fertilizer) sees a return on capital and this is generally way too long for investors, so it’s difficult to raise the money to develop such projects. She then jumped from critical minerals to the shortage of talent “to dig these things out of the ground”. As a result of this global talent shortage, new graduates from the Colorado School of Mines, “America’s best engineering school”, are expected to make higher starting salaries than those of the Harvard business school for the first time ever this coming year. This, she thought, was important, because it might motivate “those with a talent for math” towards engineering degrees (essential for the “real economy”) instead of towards finance and business degrees where everybody was drawn to in the past “because that’s where you made the most money”.

Well, that’s a lot! Let’s peel the onion on this one.

About Tantalum

First of all, Tantalum is not a a rare earth element. The rare earths are the Lanthanoids (nos. 57 through 70) plus Scandium (21) an Yttrium (39). Rare earth elements aren’t rare, by the way, they are plentiful in the earth’s crust, but they tend to occur very diluted in deposits together with lots of other elements. While Tantalum is not a Rare Earth element, it does also occur very diluted: its crustal abundance is 0.7 g/ton  (http://minerals.usgs.gov/minerals/pubs/commodity/niobium/myb1-2011-niobi.pdf). So you truly have to dig large volumes of rock to get a reasonable amount of one particular element. And if there is no or limited use for the other elements in the deposit, then you end up with a lot of useless waste. Hence there is a lot of R&D going on that focuses on finding uses for some of the other elements in such deposits. A Tantalum-Niobium International Study Centre with nearly 100 organizational members exists since 1974 with headquarters in Belgium (http://tanb.org).

According to the United States Geological Survey’s commodity database “Tantalum is ductile, easily fabricated, highly resistant to corrosion by acids, and a good conductor of heat and electricity and has a high melting point”.  (http://minerals.usgs.gov/minerals/pubs/commodity/niobium/). Easy to see that it’s useful for fine manufactured products such as mobile phones, computers and automobile electronics. Tantalum is not the only unusual element in your smart phone, there is a host of others, but I’m not getting into those in this post.

Tantalum is typically found in pegmatite veins. Pegmatite veins look spectacular in outcrop, because they tend to have very large crystals, due to the fact that they originate by dewatering of metamorphic rocks (these are rocks that are altered from their original state due to being exposed by very high temperatures and/or pressures) or by hot alteration of certain magmas (magmas are rocks that result as the lithification of original crustal melts). The picture shows an example of such a pegmatite vein: the man is putting his hand on a single crystal of K-feldspar (a very common mineral) at the Ruggles pegmatite mine near Grafton (NH, USA). http://www.newark.osu.edu/facultystaff/personal/jstjohn/Documents/Rocks-and-Fossils-in-the-Field/Ruggles-Pegmatite.htm

Finding such veins in the subsurface requires the skills of specialized geologists. And that is where Dr. Malmgren erred: because no matter how good the engineers that graduate from the Colorado School of Mines (an excellent school indeed), engineers don’t “find stuff” – geologists do. The School of Mines produces geologists as well, as do hundreds or other schools in the US and another three dozen or so in Canada.

Tantalum hasn’t been produced in the US since more than 50 years, so it imports it mostly from Australia, Brazil, and Canada, but a lot of the Tantalum that the US imports is actually produced from recycled foreign and domestic scrap (http://minerals.usgs.gov/minerals/pubs/commodity/niobium/mcs-2013-tanta.pdf).

Tantalum mining in Canada

I have found three Tantalum prospects/mines in Canada:

1. Tanco Mine near Bernice Lake (Manitoba). This is an old mine (the deposit was discovered in the 1920s) and it’s nearing depletion, the quality of the resource is decreasing. Early last year, 40% of its workforce was laid off (http://www.winnipegsun.com/2013/03/13/tanco-mine-near-lac-du-bonnet-laying-off-40-of-staff).

2. War Eagle mine in Northwest Territories (http://www.wareaglemining.com/s/MACTantalum.asp). Here is an excellent photo of typical pegmatite veins at the War Eagle deposit (http://www.wareaglemining.com/s/Image.asp?i=photos/mac/6meterClimbingWall.jpg&id=78627.)

Click on a percentage in the above legend to enlarge or reduce this picture

3. The Lilipad Lakes mine of Avalon Rare Metals in Northern Ontario (http://avalonraremetals.com/projects/lilypad_lakes/) another pegmatite. Here is an excellent illustration of the size and concentration of the resource:

https://i2.wp.com/avalonraremetals.com/_resources/projects/lilypad3.jpg

Tantalum mining in/and the rest of the world

Unfortunately, about 50% of the world’s Tantalum is mined artisanally in countries with troublesome human rights records, notably the Democratic Republic of Congo. The excellent website http://www.mining.com contains a superb video by a German non-profit (Edeos) on “the real price of a smart phone”: http://www.mining.com/video-from-production-to-disposal-whats-the-life-of-a-smart-phone-actually-like-38873/. Full disclosure: yes, I have a smart phone, and a tablet and a pc. I know.

Dr. Malmgren gave the impression that finding and producing these resources is simply a matter of making sure that there are enough talented engineers (and geoscientists) to find the stuff and enough investors to pay for pulling it out of the ground. I’m sure that this impression on my part is caused by the fact that her contribution was only a few minutes of radio time. Because I’m equally sure that a woman of her stature realizes that future critical resources aren’t simply produced by more people and more money.

Personally, I believe that no matter the talent and no matter the money, there will be increasing conflict and dragging of heels over earth resources in the near and more distant future: indigenous peoples are increasingly standing up for their human rights, their land rights and their labour rights. All people are standing up for environmental protection. Countries and corporations won’t be able to just bulldoze (literally) over people because of profits. The mining industry knows this and works hard at improving its practices. The Prospectors and Developers Association of Canada has the E3 Plus program (http://www.pdac.ca/programs/e3-plus), to help exploration companies improve social, environmental and health&safety practices. But the dialogue and protests over the Keystone and Northern Gateway pipelines, over hydraulic fracturing of shale gas, over blood diamonds and blood Tantalon are, I believe, only the first steps in forging completely new ways of managing our earth’s resources.

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