Sunday, 1 April 2018

Weeks 78: Scottish Separations

Once upon a time, our unshod feet were life-long allies of the ground. Back then, the Earth would confide all her textural secrets so that, throughout these epidermic conversations, the grass became thick, luscious hair, the mud became a velvetly brown soap and the peatland moss became a bathtub scrub. But now, in the evolution of our bipedalism, our feet are clad, cocooned all day inside leather caves. I wonder if there is a case to be made that Soil Scientists should, for a day or so, tread the earth with naked feet, allowing the silts and the sands and the clays to ooze through the ravines between their toes, to let the brown peaty water to eddy around the ankle like the ripples around an oar. Might this lead to a new, embodied relationship with the soil that our ancestors must have once enjoyed? 

I'm not sure, but until then, it's time to put our shoes back on. Another adventure awaits...


The soles of my shoes kiss farewell with a slab of English stone and then, with unrivaled loyality, join me in the carriage of my train. Nine carriages holding hands are heading for Glasgow. If I were to run a bead over a map of our Kingdom, it wouldn't be any smoother a journey. And it's Spring! The journey showcases a country in renewal. The Sun is climbing the sky, dispensing the frost from the breeze, and in it shines, through the windows of the carriage. Light that has travelled 149.6 million miles, completes its journey on my cheek. Outside, county after county, the calendar is being turned. We pass Lancashire farmsteads, where horses chew on fresh palettes of green. Channels and dykes, are slurping the rain from the land. We sail by solitary cottages, wearing roofs of moss and jackets of ivy, with daffoldils dancing at their ankles. And on and on we ride.

There is yeast in the moorland, here. Like a fresh loaf in the oven, the moors are rising, stretching, reaching out to the candy floss in the sky. The resilient snow caps each like a dusting of flour. With every mile, the trees are losing weight; dense Oaks become Pines, and the woodland floor is a sea of needles. We are edging closer; the notes of a pipe are surfing on the whiff of a broth.

My seat does not face Scotland. I am reversing out of England and up the drive to the city of Glasgow. I watch as the vacuum of the Present sucks farmyards, cottages, trees and streams out of the landscape and into the bag of the past. They disappear from gaze and space becomes dusty again: more farms, more cottages, more trees, more streams, all becoming simultaneously smaller, all falling off the horizon.

I reflect on my recent past; an undocumented past as far as this blog's concerned. Alas, it has become difficult in recent weeks, for one reason or another, to discharge a weekly dose of thoughts. I have been kept away from the pen, mostly, by my duties as the new ECR representative for the British Society of Soil Science. This, however, is not an undocumented undertaking and there is a standalone page dedicated to the work on this blog (click here). My other, and arguably more time-consuming work package, has been an unremitting stretch in the laboratory. The soil samples I collected last Summer have been dried, sieved, crushed, re-bagged, and processed through a melange of different techniques, each of which is intended to provide key information about the conditions of these soils at my study sites. Some samples have been 'ashed' (burnt) to reveal the stocks of Carbon. Some samples have been analysed for Nitrogen. Some samples have been prepared for soil texture analysis (a study into how large the grains are). Some samples are ready to have their acidity measured. These tests, as with so many aspects of a PhD, are ongoing. As such, they do not become smaller, and they do not disappear off the horizon.

The most loyal of this PhDiary's readership will note in acute detail that I have, so far, not discussed the bedrock samples. Since last Summer, these rocks that had once spent thousands of years under the soil, have spent a few thousand hours in a box, under a sink, in one of my lab's dusty alcoves. But I hadn't forgotten them. Instead, I was waiting, patiently, for Week 78 of my PhD - this week - when I would begin a six month process called Cosmogenic Radionuclide Analysis. This is the result of a grant I won from NERC, and you can read more details here:


A seat facing Scotland becomes free, and I take it. Facing forwards, objects on the horizon are now conveyed closer towards me; shadowy figures become trees, a speck of dirt on the window becomes a cottage. The trick is to seize these objects, for we know - as I have just been describing - how quick the Present is swept into the dustpan of the Past. What lies ahead on the horizon for me? Another EGU in Vienna, a trip to Wales, much more laboratory work, the World Congress in Rio... but first, Cosmogenic Radionuclide Analysis.

There is no easy way to explain Cosmogenic Radionuclide Analysis, and I will not even try to explain the entire Science behind it. The ultimate aim, however, is to calculate the concentration of Beryllium atoms in my bedrock samples. (Beryllium is an element, just as Iron, Oxygen and Magnesium are). This Beryllium concentration can then be used in a mathematical equation to work out the rates of Soil Formation. Only one laboratory in the UK is equipped with both the expertise and the equipment to measure Beryllium concentration, and this - as you may now guess- is in Scotland.

There is nothing trivial about Cosmogenic Radionuclide Analysis. After all, my analysis costs just under £19,000 and it took over a year to successfully bid for analytical support. On this basis, you may expect that such a laboratory is encased within a shell of at least some architectural repute. You may expect many floors of tirelessly working scientists, labouring their minds through challenging intellectual hoops and over perplexing scholarly hurdles. Imagining long hours, you may then expect such a building to be equipped with a series of leisure pods: restaurants, cafes, perhaps a gymnasium? You couldn't be further from the truth if you stood in Penzance. The building is a small, two-tiered complex, with auburn sheets of corrugated metal masking the interior walls. There is no cafe (a van arrives at about 11:30am every morning for those wishing to purchase a snack from the outside world) and inside the coffee room, a perculiar fusion between a doctor's waiting room and a school staffroom, there are no spoons. Instead, the throngs of world leading scientists that bustle in and out each morning to caffeinate their thoughts, must prepare their beverages with no other tool to hand but an over-worked knife. No more than 400m from the building's perimeter is a college where the nation's future hair stylists are perfecting their quiffs and curls and the next generation of daytime carers are practicing feeding baby dolls. No more than 400m away from a world renowned facility and yet, to the innocent visitor, one would be excused from mistaking the college for the facility. In fact, one would be excused from mistaking the facility for just about anything apart from what it actually is.

There is one other thing to mention, before I discuss the work I have been doing this week and that is the elemental Scottishness of the Cosmogenic Radionuclide Analysis facility. Och aye! Most academic institutions these days would, I'm sure, profess to be - and some may even go so far as to celebrate being - culturally diverse. You may, therefore, expect a similarly diverse environment at the Analysis facility. Bit och na, ye coudnae be further fae th' truth! Whin in bonnie scotland, think lik' a scot! It's true. On the final day, my advisor Alan and I were having a debriefing tea. Alan said he was off to an archery match that evening. (There were many Ochs and many Ayes). As I sat there, I saw not a scientist studying the target in a playing field, but an army on horseback clutching their longbows.


The Cosmogenic Radionuclide Analysis is a six month process. To measure Beryllium 10 concentration, pure quartz minerals are required, and most importantly, nothing else. This means that when a sample of bedrock arrives at the laboratory, the first (and arguably most significant) steps are to separate the quartz from all of the other minerals.

I shall now describe the process, as simple as I can:

1) Samples are ground and sieved into four 'fractions' (< 125 micrometers, 125-250 micrometers, 250-500 micrometers and >500 micrometers). A 'nest' or column of sieves, with these gradations, are placed on a sieving shaker machine.

2) The four fractions are placed into separate bags, and the sieves are thoroughly cleaned. I mention this as one of the pertinent pieces of equipment in each room is a hoover!

3) The 250-500 micrometer fraction is then subject to the following analysis. First, the sample is poured into a bottle and a mix of hydrochloric and nitric acids are added, which removes any metals and carbonates. These are shaken overnight.

4) The next morning, the samples are thoroughly rinsed to remove the acids and are then dried in an oven overnight.

5) Another morning comes around. The samples should now be dry and are ready for the next stage of analysis. We still have non-quartz material within the sample. Luckily, some of this is magnetic and the quartz, fundamentally, is non-magnetic. Therefore we can use a Magnetic Separation machine to segregate the non-magnetic quartz from those minerals which are magnetic.

6) We still have a few other minerals to contend with, though, even after magnetic separation. Two of these include feldspars and micas. We can isolate these from the quartz using a useful, but extremely hazardous technique, called Froth Flotation. The procedure is simple. Hydrofluoric acid is added to the sample for an hour; this changes the chemistry of the minerals. Interestingly, the feldspar and mica become hydrophobic (water-hating) and the quartz becomes hydrophillic (water-loving). After an hour, you add a carbonated (gassy) solution to the sample with three drops of eucalyptus oil. The eucalyptus oil holds the bubbles together and a head will form on the surface (like that on the top of a beer). The feldspar and mica - remembering these are hydrophobic - rise and float on the surface; the quartz on the other hand does not float and remains at the bottom of the bowl. The final step, therefore, is to pour off the frothy liquid, together with the feldspar and mica, and thereotically you are left with pure quartz in the bowl.


The destiny of my samples now lie in the hands of the Scots! They will undergo further processing over the next couple of months, before I return again for more chemistry.

And fare-thee-weel, my only luve!
And fare-thee-well, a while!
And I will come again, my luve,
Tho- twere ten thousand mile!

No comments:

Post a Comment