by Mark Nicholson
Hornblende Gneiss
If I had painted the above, I think it would be a considerable improvement on a Mondriaan, but I didn’t. It is a photomicrograph of a thin section of a piece of ordinary rock under polarized light. Cut any rock into thin sections of 30 micrometers (30 millionths of a meter), prepare a slide, move it around under polarized light and you will have more fun than a child with a kaleidoscope ever did. That rock is a piece of gabbro about which I will elaborate later. So let me start with a geology refresher of one paragraph.
All rocks comprise mixtures of minerals such as iron compounds, calcium, feldspar or quartz (silica). They might form from deposits of sand, coral or mud that sink in seas and lakes. Over thousands of years, they become sedimentary rocks such as sandstone, limestone or shale. Alternatively, rocks can form deep in the earth’s crust. These are intrusive igneous rocks e.g. granite (rich in quartz) or gabbro (low in quartz). When volcanoes spew molten rocks out, they solidify as extrusive rocks such as lava, pumice, obsidian or fine-grained basalt. Finally, if you heat and/or squash any of these rocks for long enough…and we are often talking about millions of years, they change character into a metamorphic rock such as gneiss and schist. Sedimentary rock such as chalk will metamorphose into flint, while limestone turns into marble. The latter may feel hard but wash it with vinegar or lemon juice in your kitchen and it will gradually dissolve.
On a field trip to northern Scotland in the mid-seventies, our geology professor picked up a chunk of Lewisian gneiss that he told us was approximately 3000 million years old. He then asked us to reflect on the duration of mankind’s (the neologism ‘humankind’ had not yet come into being) recorded history, say 5000 years. On the same scale, he continued, that 5000 years is equivalent to one hour out of the life of a 70-year-old person. He advised us not to think too highly of humanity’s time span on earth. Ever since I have come to realize that most humans can only handle a limited spectrum of dimensions. Too large or too small a number tends to be unimaginable.
In July 1976, the Israelis had just humiliated Ugandan dictator Idi Amin at Entebbe airport by rescuing Israeli and non-Israeli Jewish hostages in one of the most daring raids of the century. Early the same year, Idi Amin provoked Kenya by saying that much of western Kenya belonged to Uganda. This resulted in increasing tension and the upgrading of Kenya’s fighter jets from the US. After the Israeli raid, Amin again threatened Kenya, blaming the latter for allowing the Israelis a refuelling stop in Nairobi, without which the raid could not have taken place. He also took vengeance on Kenyans living in Uganda, slaughtering 245.
That month I was between universities and hunting for some holiday work. A South African geologist friend based in Kenya hired me as a blasting supervisor. I drove to Nakuru, collected a quarry master, fuses, a ton of dynamite, bundles of cordite and off we headed west. I didn’t know a stick of dynamite from a stick of Edinburgh rock but thankfully my Gikuyu companion did. I felt hugely important driving a short-wheel base Landrover with two red flags, which meant that the police could not stop us. I was a sub-contractor and while, no doubt, the contractor took 90 percent of my wages, I was young, and I knew a bit about rocks as I had just won the geology prize, the only university award I ever received.
We based ourselves in Trans Nzoia, a district adjacent to Uganda under the shadow of a huge extinct volcano known as Mt. Elgon. During the colonial period, that was as far west as white ‘settlers’ went. Our work was to be in West Pokot, on the border of Uganda, then as now, the stunningly beautiful and mountainous Wild West of Kenya. ‘Here be dragons’ might sum up West Pokot: it is still little known and rarely visited.* The tribe are the Pokot, distant cousins of one of the larger ethnic groups of Kenya, the Kalenjin. The Pokot’s reputation is that of a bunch of belligerent cattle-thieving pastoralists. Twenty-three years later, I was working there again and little had changed. It was common to see lowland Pokot, stark naked but clutching a Kalashnikov, appearing out of the bush on the empty track to Alale on the Uganda border; and they would use it. Coming back from Lake Turkana in the north in 1999, I made the mistake of hooting impatiently at a goat, which refused to budge off the road. The next thing I knew the herder fired his AK-47, a single, extremely loud shot straight over my head. I took the hint and wasn’t seen for dust. Even today, the Pokot are usually at war with other pastoralists: the Karamojong to the west, the Turkana in the north or the Samburu to the east.
Our task back in 1976 was to collect rock samples for ‘sub-grade’ (the base and strongest part of any road) for the construction of a tarmac road from Kitale north to Lodwar on the west side of Lake Turkana, known also as the Jade sea. The road was to be the first tarred road connecting Kenya to what was then Sudan (today South Sudan). The Norwegian consultants had hired a chief engineer with the memorable name of Peter Squelch, to whom I was answerable. The road we were working on was a rough, narrow, rock-strewn and often extremely steep track heading north, falling gradually through deep ravines down to the lowlands of Turkana. To the east were the Cheranganis (see below), a massif nearly 4000m high comprising old gneisses and other rocks, totally unlike the basaltic mountains of central Kenya. The scenery was, and still is, stunning.
We would stop at some suitable area of bare rock or near massive boulders, drill into the rock, fill the holes with explosive, lay the fuses, run for cover and blow it. The first problem was that the diameter of the drill bit was just a bit smaller than the sticks of dynamite. We had to unpack the dynamite, split it lengthwise with a knife and repack it, but we rapidly found out that handling nitroglycerine with bare hands gives one a violent headache so we had to resort to rubber gloves. The second problem was that it was very difficult to know how much dynamite to use on different types of rock. One of two things tended to happen. Either there was a massive explosion totally obliterating the rock with shrapnel flying in all directions and bombarding us behind our cover. Alternatively, there would be a deep thud and the boulder would remain intact. It took us several days to work out the right amount of dynamite for the different rocks. The dark gabbro boulders were the most beautiful but also the most difficult to drill into.
By August we had reached the Marich pass, where prospectors have long panned for gold in the river. On one Sunday, we found a massive boulder of gabbro. After two hours of drilling, we blew the rock. A massive explosion ensued but there was little to show for it. We drilled again and plugged the holes with even more dynamite. The resultant explosion in a narrow defile shook the surrounding hills and the echoes seemed to reverberate for minutes. It was decades before mobile phones but people in the nearby village of Sigor obviously panicked and alerted the police and army, fearing the opening salvos of a Ugandan invasion. Within an hour, army helicopters were hovering overhead, police trucks arrived and later a contingent of heavily-armed GSU soldiers arrived from barracks in faraway Eldoret. We were taken in for questioning but were released once we had explained our perfectly legal operation.
Unlike the rest of Kenya, August in the area is a season of heavy downpours, which still make rivers extremely dangerous to cross. Many lives are lost. Twenty years earlier, the father of a Polish friend of mine was in the same area after checking on leopard-hunting prospects. In his fascinating autobiography, he tells the following delightful story:
“It was just after heavy rain had fallen and all the mountain streams were swollen. On the opposite side of one of these rivers now tearing over our road, stood a little girl apparently terrified at the thought of crossing such a dangerous river where the rushing water would come up to her waist. Just then, a Pokot arrived at the torrent and we could see that she was asking him to help her cross, but there was a certain difficulty. In one hand, he held a bundle of something, plus his wooden stool or headrest. In the other, at the end of a string plaited from some cut-up bag-shorts, he was leading a large white goat. After a certain moment, the two apparently reached an agreement. The Pokot pushed out his underbelly, the girl got hold of whatever he was offering, and both walked calmly through the fast-running water. After their crossing, the little girl waved goodbye and both proceeded on their respective ways. One has to be resourceful in life! “
Credit: Sophie Walbeoffe-Kasiunia
*The other ‘no-go’ area of Kenya was then north towards Somali, and known as the Northern Frontier District (NFD). Parts of it still are dangerous today and under the control of Al Shabaab.