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This is for the intrepid Melburnians who get out of the city, travelling the open spaces, winding up through the north past the more famous Hanging Rock, feeling the sun on their knees and the wind in their hair, exploring Major Mitchell’s old stomping ground, curious about the landscape therein. The wanderers, the dreamers, the scientists and artists. Here forth a note about the geology of the Coliban valley, in the Redesdale area, Victoria, Australia, that I wrote for the Redesdale and District Association:
A 400 Million Year Old Geological Tale
The landforms around Redesdale:
As far back as the expedition of Major Mitchell, the shape of the hills in this area were remarked upon for their flat table-top features, presiding over incised valleys and crumbling slopes pock-marked with giant granite boulders. The shape of the land here is a result of the slow erosion of rock and soil over the past million or so years. However, some of the rocks here are very much older than that.
Beginning at the bottom are the sedimentary rocks (mostly made up of clay and silt and sand, formed on an ancient sea floor, cemented into place some 450 million years ago, hundreds of millions of years before the world would see its first dinosaur) that form the foundation stone of much of Victoria. These are sometimes seen in road cuttings in the area and are typically grey to cream in colour, sometimes displaying their characteristic layered pattern. Pushing up through these like a bubble rising in water are the granites, which arrived around 100 million years later. Eventually they reached the end of their bubble like journey and solidified into the grey-coloured crystalline rocks you see poking up through the paddocks. In geological terms, the granites are ‘igneous rocks’ (as opposed to ‘sedimentary rocks’, like the previously mentioned sandstones).
The final arrival on the scene was the basalts (volcanic rock), which are, by comparison, mere infants, spewing out from nearby volcanic vents within the last few million years. They would have filled ancient valleys and streams carved into the granites and sandstones beneath, valleys which would later be known to geologists as ‘paleochannels’, and created a very flat volcanic plain. However, basalt is not very resistant to the weather. Soon after the volcanoes stopped flowing, Mother Nature would have started to carve new valleys and streams into the volcanic landscape, and much of the basalt would be eroded away. Once the water was through the basalt, it would start to erode away the more ancient rocks beneath, and the different way the different rocks erode can be seen in the different slope angles between the basalt hilltops and the granite slopes beneath. Some little sections of basalt remain, however, and these can be seen in their original flat lying glory, capping many of the hills in the region and creating perhaps the most striking geographical sight in the area.
(WARNING: may contain geological terms!)
Around the paddocks you will see large, grey coloured rocks that are generally rounded in shape. These are members of the rock unit known as the ‘Harcourt Granodiorite’ (‘granodiorite’ is a granitoid rock with more plagioclase feldspar than a typical granite, for the lay people, they’re typically just called ‘granite’). These erode in a characteristic ‘onion skin’ pattern, resulting in rounded boulders and curved sheet like portions that have peeled off the boulders. They also tend to form very coarse sand as they erode, typical of the river sand you see in the Coliban and Campaspe Rivers.
Also around some of the paddocks in the area you will find a paler creamy-pink rock that is in flatter and in more square/rectangular shapes. It has been used extensively in rock walls in the region. It looks a little bit like sandstone, but in actual fact, it too is a granitoid, in this case, a true granite. This is the Metcalfe Granite, and it is part of the same group of rocks to which the Harcourt Granodiorite belongs (and they are of similar age, around 350 million years old). This group of rocks is properly termed the “Harcourt Suite” and includes several regional variations of granite and granodiorite. The interesting thing about the Metcalfe Granite is that it contains many ‘leucocratic dykes’ (leucocratic – pale coloured, as opposed to melanocratic – dark coloured). These are internal zones that have more of the feldspar and quartz minerals and were like internal ‘channels’ when the rock was emplaced. They actually ‘flowed’ through the surrounding rock. As a result, they contain features that look like the layering of a sandstone, and this also explains their more blocky fracture pattern.
Granites (and granodiorites) are what are known as plutonic igneous rocks. They formed beneath the ground when their rise up from the inner earth ceased upon reaching a natural buoyancy level in the earth’s crust. They then solidified (‘crystallised’) and stayed there. In the local version’s case, this happened around 350 million years ago (for scale, the dinosaurs came onto the scene around 250 million years ago and were gone by 65 million years ago). Locally this meant that the granites rose up into the surrounding sedimentary rocks. Thus these are like blobs within the regionally-more-significant sedimentary rocks (sandstones, siltstones and the like). What this implies is that these granites you see today are seeing their first ever sunshine, having previously languished beneath the earth’s surface for most of their 350 million years of existence.
Atop many of the flat-topped hills of the area you will find crumbling reddish-brown rock with lots of holes in it (properly termed ‘vesicles’). This is basalt, and this is the rock that caps the hills and causes their shape. Basalt is a volcanic rock (think of lava flows in Hawaii). You are looking at the last remnants of huge volcanic eruptions that occurred over the last 4 or 5 million years. Victoria was a very active volcanic place in its recent geological history, and in some areas of south western Victoria, it is even possible that eruptions were still taking place when the first human inhabitants arrived some 40 thousand years ago.
A final, related point; a side note about the colours of rocks. Basalts are dark-grey to black when they are fresh. Granites are normally very pale grey, as are granodiorites (although they can have a range of colours from pinks to greys to blue-ish colours right up to reds and even some greens in places). Most of the pink to red to brown colours you see in these rocks are a result of erosion – “weathering”. The colour comes from the fact that all these rocks contain some minerals that have iron in them (basalt contains a lot of these minerals, granite hardly any). When those minerals weather they produce iron-rich minerals such as limonite and hematite. These are orange-red in colour and spread out and ‘stain’ the surrounding rocks. The effect can be quite pervasive, resulting in the colouration of entire rock pieces. In the case of basalt, the entire rock has had some degree of weathering, and so it is now a dark brown-red colour, having lost nearly all of its original fresh black. In the case of the local granite, the original rock is nearly white, however, the little bit of iron staining that has occurred has given these rocks their slightly pink hue. Indeed, a little bit of iron staining is exactly what gives some of these rocks their spectrum of colour, resulting in the beautiful pinks and creams that you see today.
When I was young I wanted to be a SCIENTIST. I wanted to pour over the literature; I wanted to argue about method. I especially wanted to spend hours traipsing about the wilderness in search of tiny little things that may or may not help my research, and I then particularly wanted to spend back breaking hours in a laboratory dissolving things in solutions and then blasting them with heat and lasers and collecting gasses and measuring them to within inches of their lives.
Naturally, I had visions of spending hours in front of a computer calculating the statistics and determining, within certain bounds, the exact results, resulting in a mystical dream of writing up the research. Of course I would then have it go backward and forward between peers (each with their own particular flavor of review) and finally, after six good productive months of politics and writing, those results would be published in a journal for most of the world not to read.
Of course, none of the above is true. That was not my childhood vision. I mean, I didn’t want to be a fireman or anything like that, sure, but what I’ve just described? No thanks!
No, I had dinosaurs! I grew up in the time where it was discovered that it was an asteroid that hit Earth and killed them! I was a child of the time of ‘Transformers’, and I was especially proud of a T-Rex transformer that I had that none of the other kids did. In hindsight, that just made me a spoilt brat.
I watched the occasional documentary, mostly because my grandmother and mother encouraged it. I remember seeing David Attenborough crack open a rock to reveal a fossil. I guess it was a trilobite, can’t remember, but wow, I was amazed!
I also had politics. My parents always had the ‘adult news’ on at 7pm – the national news, and the current affairs after. If I wanted to spend that time with my mum and dad, I was watching that. I didn’t have half a clue what these people were on about, but clearly it was important. My subsequent high school education ended up being all about science and mathematics, hardly surprising for a son of doctors. Although my best final marks were in English – pretty uncommon for a science and maths nerd.
Fast-forward about 10 years and I was studying science, specifically geology, at university. If you’re wondering about the time gap, I studied Law for about 3 years at one point, but it WILL NOT appear on my resume since I gracefully withdrew after, shall we say, attendance-related performance issues. I attended enough though to learn a bit about argument, or as they more commonly say, enough to be dangerous. I then worked in real estate for a year, which one might justifiable say that combined with my half-baked and inadequate legal training made me positively lethal.
So any way, after learning the art of snakes and snake oil, I went in to learning about rocks and well, other rocks. This 3-year journey of rocks and their interaction with other rocks and how they all relate to each other was so fascinating that I decided to do an honours project in geology for an extra year. In which I determined the age of some rocks from a costal area in my home state of Victoria (about 50 million years old, in case you’re wondering – I wouldn’t want to leave you hanging).
These rocks were basalts as it happens (like that which erupts from the volcanoes of Hawaii) but what is really important is that this got me out there, cracking open rocks and finding samples. It also involved considerable literature review and statistics and report writing. Remember the start of this essay?
One thing I did do while collecting little bits of rock was stand on a rocky shore platform looking for samples, all alone, in complete disregard of the risks. I am not exaggerating to say that I could have died that day. The water from that freak wave only reached my waist, but any further and I would have found myself in the water, possibly kilometers from land. It does happen. That’s why Universities don’t let people do what I did alone (actually they didn’t then either, I just kinda well, you know…)
Why am I telling you this? Well, it’s because there, there on that platform being hit with a freak wave, I did consider why I was doing it. At the time, I guess I just needed that sample. Badly – my degree depended on it! Plus, what a beautiful place to die! Only kidding.
Nine-odd further years later, I am asking the same questions, but this time, there are no freak waves. Since then, I’ve been staring at rocks and reports and trying to decide where the next big gold or nickel deposits might be found. I’ve worked for a couple of the biggest mining companies in the world, I’ve also slept in a swag in the middle of a frigid desert night between stints supervising dusty, loud drill rigs.
Through all of this, I have continued to have an almost child-like fascination in science and nature. I have read all the famous authors – Gould, Dawkins, Sagan, you name it. I watch the docos. I watch them again. I sometimes write stuff about things on my blog. I follow my little curiosities down the rabbit hole that might begin with a name, lead to a wiki search, and end in several journal articles and a whole new ‘issue de jour’ for the week. I get involved in skeptical arguments and pursue the philosophical reasoning they entail. I pity those around me sometimes; I suspect I am quite, as they politely say, “intense”.
So, I could tell you something about evolution, I could tell you a little about quantum physics (which is only to say, for example, that I could tell you about Schrodinger’s Cat, and also explain that no cats are involved). I could describe the Monty Hall problem and why it demonstrates how flawed our thinking can be.
Why would you listen to me though? I’m a geologist, not a philosopher, or physicist, or even a biologist. In fact, I have never done a single formal course in biology, and that includes school level biology (I did physics and chemistry and geography, there’s only so much room). I did read A Brief History of Time by Stephen Hawking, when I was in high school, but I’m not about to say I’m some sort of cosmologist.
I would ask you to listen only because it is interesting; for no other reason. I would appeal to your sense of intrigue. I am suggesting to you that the real world is far more interesting than anything that you might have seen in the Da Vinci Code or, God forbid, stuff about the megalodon shark in Shark Week.
The real world has every sort of mystery of the sort that Dan Brown wrote his fiction about. But the thing is, it’s not fiction. Even Brown’s fiction contains some real science and real history. And that is the point. Its not just science, it is history and culture too. They all link together to make this great big wonderful story. And anyone can be part of that. Anyone can be that investigator. The scientist at the frontline, and even, with time, the one that the President calls when the aliens land.
For that though you’re going to need skills. Investigative skills, particularly of the sort that can be verified and tested. And this is where you will need some scientific training. Or at least, a good appreciation of rational thought and how something can be known, objectively. You need to have an appreciation of why scientific reasoning has lead to the advances it has. After all, you trust planes not to fall out of the sky, right?
Either way, rejoice in your fascination for all things interesting. Science is not a specialized territory only inhabited by nerdy, bespectacled introverts who are always portrayed as nerdy, bespectacled introverts. In fact, most scientists are normal. Really, they are.
Most importantly, don’t worry if you don’t want to be a scientist. I was almost a lawyer, and there are plenty of other valid, interesting and important pursuits in life, and no, science is not the only ‘way of knowing’. All that said though, please learn about science and its methods. The modern world demands it.
Reposted from Medium: https://medium.com/architecting-a-life/369f86f61f79
My work and my photography have displaced this site nearly completely. I’ve come back here to caress this blog gently; remind it that it is still wanted. It must feel like an unloved child, bereft of attention.
Work – I am in full swing back in exploration looking for copper-gold and silver-lead-zinc deposits. The work is in outback Queensland, and has involved a range of exploration strategies, from basic geological mapping (what is it and where does it lie in space?) through rock chip sampling (is it worth anything anyway?) up to actual drilling (ok, is there really anything there?). The breadth of science that goes behind exploration is amazing; from physics – the physical properties of the different rock-types give different responses when subjected to different tests, which allow them to, roughly, be distinguished from each other – to chemistry in its central role – it is the minerals that we look for, and only a lab can really tell us how much is there – and then right up to the frontier, where biology has a role to play – the trees themselves suck up elements in the groundwater, and this gets deposited in their leaves, which then fall to the ground. All in all, it is a practical scientist’s playground. The money’s good too.
Play (serious play) – photography. It has become an obsession (like it wasn’t a little bit of one already). What started with a digital SLR a couple of years ago, has morphed into several film cameras, a home developing set up, a film scanner, and various other bits and pieces. All that and it’s only a hobby really. My passion in photography is more for the artistic side. Whilst I am a self-confessed sciencey person, I like my art to be artistic! I’m not a macro-photography kinda guy. That said, I do like macro shots, just don’t do it myself. I prefer to wander about the place, looking for interesting corners and angles, searching for the play of soft light; composing an interesting frame. I think it stems from my love of modernist art and architecture – I am a fan of brutalist architecture for instance (there – go look that up on wiki!!). The actual science behind a photograph is very interesting, but I don’t think about that at all in my photography. I suppose that is part of its appeal?
I finally got around to establishing a photographic portfolio site, and it also will now serve as another outlet – for my ‘artsy side’. Have a look – mkrobinson.com
So long for now, hope to be back a bit sooner next time…
A little embarrassing to share one’s own poetry, but as I am about to move back into minerals exploration, this seemed appropriate. I wrote this the last time I did fly-in, fly-out exploration; something I am unlikely ever to do again.It’s not all that good, I’ll warn you!
Weary site, weary home
Drilling, drilling, drilling on.
Catch a sulphide, cast it out.
See a speck, move about.
Move on now, more to do.
Live the dream, spirits high.
There’s no disappointment; why?
So now to execute the plan.
See the rods go down, turn,
And the metres burn, burn.
A budget tried; the geo lied,
There’s more in the assay,
Well that’s what they say.
And then, while much is had,
Back at home, things are sad,
The other half is away,
And it seems that he’ll stay.
The results come in, a hopeful grin.
Much is forgotten,
As we drill what’s rotten.
Sun setting, a forlorn pit,
As noone thinks to ask,
What will become of it?
Wallowing a weary task.
Mast at angle,
The spoils aren’t in line.
And so the call is come,
The metres are all done.
The Geo rests his head,
Will he lie straight in bed?
Cat flap opens in empty home,
As the wife walks lonely in,
The food bowl empty, quiet moan,
Reward a forgotten sin.
See there, in the freedom bird,
Novel resting in his hand.
His situation is absurd,
He resolves to make a stand.
A stranger to no longer be
In a house of his own.
To only recently see,
So many times lost, groan.
Reconciled, together again,
Weeks lost; catch up required.
There at heart shall his home remain,
What exploration inspired.
Wait! A new way may be found,
Heart and home in one place.
His feet firmly on the ground.
But results come, stealing space.
Cycle, cycle, cycle again,
Flights leave off, and hopes are lost.
Mike Robinson, July 2009
Its been a while, but then science can’t be rushed, and much pondering over certain products made with water must be had first. For around 3 months now we’ve been doing this water exploration program and it’s coming to an end. I wrote about my experiences talking with local farmers and watching them wander around the paddocks with bent pieces of wire here. As I said, there is a certain comfort that this gives the farmers in siting a drill rig to drill a hole for their windmills. It’s not a cheap exercise, so when they commit, they like to feel confident that they’ve given themselves the best possible shot. When you can’t afford a hydrogeologist, and when it’s all you’ve known growing up; it is understandable that you’d see water divining as the way to go.
Scientists, such as myself, do not believe in water divining. Not because we simply reject that which we weren’t taught at school (which is a tempting retort from many who believe in pseudoscience). Rather because there is no evidence for its efficacy. Water divining has been subjected to a number of scientific trials and has failed to produce a significant result. It is, therefore, bunkum in scientific circles. No serious scientist or scientific consultant could use it professionally.
As I said in my previous post, however, there can be some client-liaison and political reasons for not rejecting it out of hand when in the field. It ‘smooths the water’ to let landholders do their thing and feel that they are influencing your scientific process. In fact, through this process, I have learned a lot about the land I’m exploring in and it has revealed numerous insights into otherwise obscured geological features. All this has aided my scientific exploration effort and I think bettered my hit rate. Of the holes planned and sited, the success rate through the program has gone from a predictable 20-30-odd percent to better than 50%. This may not sound too good, but sub-50% success rates in the terrain we’re in are not uncommon. In other terms, you could say that science and keen observation on the ground coupled with a relatively open minded approach to the landholders has enabled me to go from rank amateur in that terrain, to better than a water diviner in less than 3 months. The best water diviners have taken a lifetime to learn the craft and a require a lifetime’s experience.
So, let this be a little message to scientists who find themselves working with real people on real projects out on the ground where pseudoscience is rife. Don’t dismiss the pseudoscience out of hand and thereby fail to gather all the nuanced data that’s available to you. By all means disbelieve, as I do, but remember these are people you’re dealing with. If you get the opportunity to do it, take them through your scientific exploration process. You might be surprised how well they understand what you’re talking about (you shouldn’t be though, unless you’re one of a particular breed of condescending city-scientist), and you may just convert the odd one to the joy of good science well applied!
You may have detected a skeptical vein in me whilst reading. I am skeptical. I am a scientist, it’s my job! Furthermore, I am a geologist who specializes in groundwater. I earn money through the planning and delivery of water (potable or construction water typically) to major projects. Part of that process is the exploration for water. Through a combination of looking at maps, on the ground reconnaissance, and clever things like geophysics, I decide where precisely to drill water wells. It is a scientific process, with a lot of learning along the way. You really do get better with experience, and for me anyway, my background in gold and nickel exploration has helped. I’ve been doing all these various exploration tasks for a several years now (about 6 in fact) and definitely I’ve improved. I know how drill rigs work and I have a decent idea of how (basically) to tease out from the local geology in a given area the better places to look for water (or gold, or nickel or whatever). Again, it relies on the collective knowledge from generations of geological science. Knowledge that I started to learn at university.
Enough about my scientific credentials already! Why I write this is that I am currently working on a project where we are trying to find enough groundwater for the construction of 100km of railway. Railway line construction requires a lot of water (about 800,000L per day every 10-15km of line in this case).
We’re working in a pastoral area, sheep and wheat country. The geology is pretty much granite through and through, and anyone who knows what that’s like will tell you that water is scarce. Surface water is practically non-existent and groundwater is hard to come by. This is nearly a desert. How do I know this specifically in this area? Because I have been talking to the local farmers. These guys have been breaking their backs for generations, eeking out the precious value this land will throw up to those who persevere. The one thing that determines success or otherwise more than anything is water. Stock need it to survive, and having no mains water system, a farmer’s house supply relies on it. Subsequently, the farmers invest a large amount of thought and effort into finding water. The country is pock-marked with drill holes and windmills. With this effort comes a culture of great interest in the techniques deployed to find that precious water.
From my discussions, the number one technique employed to find water here is water divining (“water witching” or “water dowsing”, depends where in the world you are). Before you sigh and stop reading, consider this: a water bore can cost more than $10,000 whether or not you actually find water. A farm would quickly go broke drilling holes if their success rate wasn’t too good. But then, hiring geological consultants such as myself is not cheap either, and materially adds to the cost.
What you need is a method of locating the holes yourself (or even getting a mate to do it for a few beers). Enter divining. You know who they are – they’re the ones with bent pieces of wire or Y-shaped sticks who wander about and find the “stream” and tell you where to drill. There is no scientific evidence for its efficacy whatsoever. Indeed there is scientific evidence that demonstrates that diviners have success rates no better than chance (for a good summary, I do recommend the Wiki page). This scientific ‘disproof’ has been around for at least half a century. Despite claims by practitioners to the contrary, we can probably consign water diving to the quack-bin and declare it bogus. Hocus pocus pseudoscience.
BUT, does it work “in the real world”? Given that so many still use it, even rely on it, what residual value might it poses for the farmers out here?
Well, my unscientific study of the local farmers deploying this unscientific technique suggests that it is valuable indeed. The process of divining has located many successful bores in this district (together with a largely unmentioned number of failed bores!). Any geologist will tell you that drilling completely at random will not give you a good success rate. To this end, drilling on “crossing streams” found by diviners is not random. There is a great deal of local land knowledge that is deployed when divining, thus narrowing the focus of the search. The divining really then just delivers a reason for siting the drill rig in a particular location. With limited resources at-hand, this is perhaps just what is needed – comfort in spending the money.
So how am I to react when confronted with several ‘divined locations’ (I can’t help but make the mistake of pronouncing it ‘divine locations’ here!)? This is difficult country to explore, and even I, the skilled geologist, have limited data. My locations are beset with large error margins. In fact I will plan for a certain failure rate given the known geology.
I decided to let them have the run of it for a while, as the divined spots had some features that made them acceptable exploration targets. One diviner, we’ll call him ‘Bruce’, comes with, it is said, a 100% success rate! (Forgive my skepticism, 100%?) I have spent the last week drilling his targets. So far, we’ve drilled four holes. The first one was an absolute gusher! More water than we hoped for. Even the farmer, lets call him ‘Barry’, said he’d never seen anything like it! Then the second came up with water too. Not as much, but adequate.
At this stage, I’m running through the stats in my head. This is getting like some sort of baseball or cricket statistic. Surely the ‘run’ must end soon. But then comes the third hole, better than the second. So Bruce is 3 from 3. Pretty good. Don’t worry, I’m not about to be ‘converted’.
The fourth hole comes. I press on, drilling deeper than I usually would. Barry is telling me I have to go deeper, Bruce is never wrong! Bare in mind, this is hard, dry granite. No water in that. But then, sure enough, there’s the water! This time though, it’s minimal; not enough for a bore. So how to call this? 3.5 out of 4?
It’s hard to explain this without saying that there was simply a network of water baring fractures in the granite that would have been found anyway. That would be the logical, geologically appropriate explanation. I happen believe this to be the case. We may even have been able to detect the fracture systems with the right geophysics. And then, we might have drilled proper ‘geological holes’. But, like Bruce the diviner might agree (perhaps not) how will I ever know? We can’t drill everywhere, and geophysics for this kind of exploration is costly in both time and money with limited chance of improving the success rate.
So, what is the upshot of this? Well, I have spent a week drilling holes and conversing with Barry. We get on well and he has been helpful above and beyond the call. It has been a pleasure. What about the divining? Well, Barry wouldn’t let me drill anywhere that didn’t come approved by Bruce anyway. So, the upshot is that we have a happy landholder, and a happy geologist drilling good water bores (the task for which I am paid). Everyone’s a winner, except, perhaps, science. I come out of this a little miffed that I couldn’t show Barry a better way. But then I’m not from round here. It seems that local knowledge has beaten science in this round. Next time, I will have better data, and a better story. I hope.
I still don’t believe that we wouldn’t have found the water without Bruce though!!
Many people might not associate Saudi Arabia with volcanoes and earthquakes. A more common image might be miles upon miles of sandy desert. However, the Arabian region is home to some large fields of volcanoes that have erupted in the last thousand years or so. In May 2009, 40,000 people were evacuated from the Harrat Lunayyir province in northwest Saudi Arabia in response to a series of earthquakes, some over magnitude 5, in case larger, more damaging quakes were to come. In response to this, the Saudi Geological Survey invited the US Geological Survey to help investigate not only whether more, larger quakes could occur, but also if this could signal volcanic eruptions in the region. A recent paper in Nature Geoscience documents the scientific investigations that followed (Pallister, et al., 2010).
It was a Sunday, but not just any old Sunday. This was the first one, ever. Today, we would call it the 23rd of October 4004 BC, but of course Christ had not even been born yet. This famous Sunday was the first day on Earth, the first 24 hours after God created the Earth and everything around it. It was to be a busy week ahead, culminating in the first humans, Adam and Eve, in a heavenly garden. The Following Sunday was to be a day of rest, even God needed his beauty sleep after all that.
I speak, of course, of the date that was calculated by Archbishop James Ussher (1581–1656) for God’s creation by a strict literal reading of the Bible, and especially the Book of Genesis (which you may well know has agonizingly long genealogies). Dates such as Ussher’s have been used to support creationist’s conception of the age of the Earth.
We now know, of course, that Ussher’s dates are fiction. The Earth has been dated at 4.54 Billion years, based on radiometric dating of meteorites, as well as dates on lunar and terrestrial material; quite a departure from Ussher’s calculation. The advancement of dating techniques is a marvel, and perhaps geology’s enduring contribution to science. More remarkable is how varied geochronological techniques so readily agree with each other, in another triumph of modern science.
So, in honour of the wonderful contribution of geochronology to our understanding of this fine planet, the only one we have, I would like to dedicate the 23rd of October as Geochronology Day. It is perhaps a fitting way to put all creation myths to bed, recognizing that they are only works of literature. Earth has a long and fascinating history, one worth celebrating, and it is made all the more wonderful through a deeper scientific understanding.
Viva la Science!!
A rough version of a talk I’m doing at uni. Thought I’d try out recording it. Thoughts?
The journey continues. After reading “What is this thing called science” by A. F. Chalmers, I got a rush of blood to the head and decided to take the plunge. It is fascinating stuff, and what is particularly interesting to me is that, as a geologist, I was born just after probably the most significant revolution in geology of all time – the plate tectonics revolution. It is an amazing story of the progress of science, one that should be told and analysed more (and if I have the time, I will!)
So now, the history and philosophy of science is firmly on my agenda. Here’s the recent additions:
The astute reader will note the lack of Lakatos here. My mistake, let me get through these three first…
Also, this may take me a while – lacking a formal education in philosophy, some of these folks can be quite obtruse… but you get there in the end…
You sit on the beach and grasp a handful of sand. Peering closely, you focus on one tiny grain. It is small, white and smooth. Bringing it closer to the eye, you notice tiny worn ridges and grooves, with even smaller silty grains in between. It’s quite unremarkable, this miniscule grain with its infinitesimal debris. There must be a million million just like it that you have ignored. Yet you examine more closely. Soon you see the variations in colour, remnants of its glorious sovereign existence before being lost in the morass. You inspect the variation in form, the undulations in its structure. Fraction by fraction, this cubic millimetre of Earth reveals itself to you, and begins to tell you a story.
It is a very long story. It is an account no campfire could contain. Where it begins is only part of the tale; a part shrouded in the error bars of science, clumsily approximated by crude machines. To start at the finish is the only option on hand. How did it arrive at you feet? You look at the sea, the surf lapping at your feet; the sand in constant flux; insight creeps in, the dawn of new understanding. There are many grains twirling around. Some of those scratches and striations are now explained – it has been a rough ride for this crystal of quartz, knocked around by a thousand waves.
Looking further afield, you notice the froth of a longshore current, battered by the surf, interrupted by rips. There is movement there, and it comes along the beach. You and your grain of sand walk against the flow, constantly aware of the opposing flow only meters offshore. Suspended sand swirls in the breaking waves and the turbulent water heaves. As the surf gets choppier, you find yourself at an entrance where muddy water surges out into the deep. It is a river, and it is flowing. The water is not clear, clays and silts cloud the current and obscure the ripples of sand beneath. You look upstream; it stretches out into a vast estuary, the hills and the headwaters in the distance. You cannot follow this grain’s prior journey any further; already you are far from your car, far from the comfort of civilization. Whence did this miniature grain originate?
Having walked the length of the coast to the river, you have reversed perhaps the most recent decades of the grain’s history. The span of time reaches back far, far further than that. You have merely glimpsed a small episode on a diminutive stage. Were you to travel upstream, you would begin to grasp the forces at work. Look again at that grain. It is translucent in the light, a shimmering signal of its illustrious past. Underneath the craggy exterior lies a former glory.
Travelling upstream, you would find larger grains with the telltale reflectance of partially worn crystal faces. These are your grain’s younger cousins. Quartz is very tough; a great deal of abuse is required to wear down a noble crystal face. There would be other grains too, of different parentage. Feldspars, birefringent, coloured with earthen hues; flakes of mica, sparkling in the sunlight, flittering away in the flow. You have travelled back in time, seeing your grain in younger days, perhaps a thousand years ago.
Climbing the shores, boarding an all-terrain vehicle, you traverse the steep slopes of an increasingly incised valley. Returning to the bank, you see not sand, but pebbles, and boulders, huge, lumbering hunks of rock. Immovable for man, toys to the forces of nature. Focusing closely at a rounded stone, you are struck with the diversity. All the cast is there, but in varying states of disrepair. The feldspars are softening, the micas peeling off. But there, there like glass, is your quartz. Steadfast in adversity. Rubbing your finger over the specimen, crystals of quartz fall into your hand, splendid crystal faces twinkle in the rays. You are close to the source. Ten thousand years.
Gazing further up, you can see the granite dressed hills of the headwaters. You are drawn inexorably towards the majestic vista. Hiking boots on, you tramp up the slopes. Here, in the furthest reaches of this guiding stream, you find a large rock face. It shows its age, the skin peeling like an old onion. The crumbling face reveals beautiful perfection beneath. A batholith, older than the very hills it supports. Drilling in, you retrieve a core of sparkling granite. There, there in that smooth exposed surface, you see the players in their heyday, ready to act out the next scene, anticipating an audience. Yet there has been a pause. Time frozen in the act of crystallization. The quartz crystals are perfect, the feldspars lustrous pink, dark mafic minerals teasing for identification. You are at the chrono-crossroads, where time has stood still. This rock has been like this for six hundred million years, waiting unwearyingly for the next act. Pushed and heaved through the Earth, your grain’s distant cousins have remained firm, with only the slow decay of atoms for company.
Before even that ancient crystallizing moment, those grains had another story to tell. Granite to migmatite, migmatite to metamorphosis; metamorphosis to diagenesis, and then on to sedimentation before one day, on a beach, near a river … it is a story for another day. We have reached back some half a billion years, and yet there is another four billion to go. Cycle upon cycle, these minerals have seen it all. They will see it again. How privileged we are to comprehend the journey for but an imperceptible stretch of time.