Geology Weekend. Borakalalo. Friday 9th to Sunday 11th June 2023

With the Geology weekend the Bushveld Mosaic 2023 nature course reaches its halfway mark!

We can’t believe the year and course have progressed so far so quickly. After again braving the potholed and challenging road from Brits, all arrived safely at Borakalalo on Friday afternoon. At sunset it was chilly but not too cold. Little did we know what was awaiting us the next day.

Even though we didn’t feel actually feel anything, as the epicentre was somewhere in Boksburg rather than Borakalalo, Bushveld Mosaic was still able to organise a notable earthquake, over the weekend that tectonic plate movement and the resultant earthquakes were on our lecture agenda! , See for details.

The week leading up to Geology at Borakalalo was a tough one for all of us: we had to lodge our first written assignment with Sue, we had to prepare for the mammals test and on top of that we had to read our geology notes in advance for the weekend. It was therefore a huge relief to return to camp after the mammals test with at least one obstacle done. There was a pleasant bit of debriefing around the campfire but most of us retired early.

On a personal note, the settling in at Bora for Friday night saw a bit of “musical beds/tents” action as John and Eleanor discovered their tentpoles stayed at home, rendering their brand new tent useless for the weekend… The solution was a hop-scotch with Debbie giving up her tent to John & Ellie, Lampies giving up his tent to Debbie and Lampies having to sleep in his bakkie! However, no good deed goes unpunished… Lampies woke up on Saturday morning with freshly frozen feet as the frost settled in a decent layer on his sleeping bag where the bottom end protruded out of the back of his bakkie.

Indeed the promise of a cold weekend at Borakalalo did not disappoint. We woke up early Saturday morning after a freezing night and were welcomed by a winter wonderland: a thin blanket of ice covered everything. Everyone was amazed at how low the night-time temperature had dropped on the banks of the Moretele river. At sunrise it had already “warmed up” to minus 1 degree Celsius as André reported, and warm mugs of freshly brewed coffee steamed merrily into the chilly morning air.
Heading for a shower we were solidly thwarted – there was no water! The old Lyster pump proved a real challenge to get going and cranking efforts took quite a few victims amongst the older “manne” before Patrick eventually got it fired up. Many of us had to start the day without a nice hot shower.

Freezing bodies, now wrapped up in the warmest clothes we could lay our hands on, arrived at the lecture room for an early start at 07:30 for what turned out to be arguably the most fascinating lecture so far. There were loads of new terminology and very soon we knew that a rock isn’t just a rock – e.g. many of us also only now understood something of the “acid-test” on limestone, causing the fizzing reaction where the acid breaks down the calcium carbonate.

Patrick Richards, a dynamic MSc graduate from UJ, was our lecturer. It was a father-and-son team, Bevan Richards also being a keen “rock”-er and an Honorary Officer with North West Parks Board. Patrick is absolutely passionate about and has a phenomenal memory regarding rocks – well, at least, he easily remembers stuff up to 5,6 billion years ago! What a privilege it was to have yet another well-prepared, highly knowledgeable lecturer.

Looking at samples

Geology – in a nutshell the study of the origin, evolution, and composition of our planet earth – came alive for us this weekend. In a friendly bantering tone towards the excellent lecturers in all our other fields of study, Patrick made a strong case that “BECAUSE rocks define soil type, soil type defines microbial activity and together in turn, these define vegetation which controls herbivores and herbivores control carnivores… therefore GEOLOGY is the ultimate control on biodiversity” and was there FIRST…

Our two-day rollercoaster ride spanned billions of years (5.56 Ga in the case of planet earth). First we had to grasp the concept of geological time, then we had to get our heads around the formation of earth’s crust in igneous, sedimentary and metamorphic rocks, and then fathom the dynamics of plate tectonics. We all had to reach very far back into our past to dig up long forgotten basic knowledge of elements, minerals and crystals. Two principles  will henceforth forever resonate in our minds regarding geology: (a) the differentiation between Felsic (lighter) rocks and Mafic (darker, denser) rocks,  and (b) the fascinating nature of the never-ending rock cycle, bringing the eternal forming, de-forming and re-formation of igneous, sedimentary and metamorphic rocks into perspective.

In the Field

Lectures continued through the day and in the afternoon it was time to put all of this into practice at the Granite koppies below the wall of the Klipvoor-dam. Here Patrick showed us various examples of granite and feldspar clearly exhibiting the difference between coarse crystals (intrusive igneous rock, slowly cooling off over thousands/millions of years deep within the volcanic body of magma) with clearly visible cleavage of mineral clusters, and the much finer crystalline structure of extrusive igneous rocks such as basalt or rhyolite that formed from lava quickly cooling off and solidifying into rock.

A rock on the ground

Description automatically generatedNext up was an excursion to the old quarry face where we were shown samples of distinct “bedding” layers in sedimentary rock as well as beautiful examples of preserved symmetrical ripple marks in bedrock indicating tidal, or “back-and-forth” water currents historically present in the paleoenvironment of Borakalalo roughly two billion years ago. It took some serious scrambling for those who were adamant to reach the site of the ripple marks with Patrick. Bevan helped everybody down a steep slope, but then had to use some impressive acrobatic moves when he himself took a tumble over a rock. Luckily he was not injured.

Also fascinating was the many well-preserved serpentine figures of  small waterways cut into the now vertical rockface of the quarry.

Before long it was time to go back to camp and we were greeted by an inviting campfire as the temperature suddenly dropped again. As usual, Saturday evening was spent relaxing at the campfire and enjoying braai time.  

The pump apparently worked for a while and Peter advised that we should all shower that evening as water supply for Sunday morning could not be guaranteed. Some took the bait… but were again met with an icy cold welcome in the showers. Sunday morning was the same – our gas installation at Bora being at best somewhat temperamental. Mostof us just resolved to go home without showering for 2 days. A really cold, bushy and rocky experience, lekker!

Waking up Sunday morning it was now a frisky minus 2 degrees Celsius! So – layered in warm clothing and coffee in hand, we filed in for Patrick’s lectures on the nature and formation of Metamorphic rock, that is the changing of existing rock, in solid state, through increase in pressure and temperature, and the fascinating science of plate tectonics. Quite some time was spent by Patrick to show us how to use Google earth for tracking global volcanic activity, studying tectonic plate dynamics and using the detailed geological map layer for South Africa.

In conclusion: the geology weekend really rocked! We were inundated with such a wealth of information that it will take quite some time to fully digest it.

Everyone just hopes that the test on Geology will be reasonable, as the examiners must keep in mind that the work covers events that took place over several billions of years!

In the interest of “good housekeeping” Peter reminded most… and reprimanded some… that we must remain vigilant in keeping our tents, cars and trailers securely closed/locked and the campsite clean of any food and/or rubble lying around, because the baboons and monkeys will grasp every opportunity to take advantage of any slackness to scavenge and make a mess. Peter also reminded us that we need to leave the braai area clean after an evening around the fire as leftover food and dirty packaging can also attract animal visitors with unpleasant results.

The programme ended at about 12:00 and we were all off to our own warm homes and hot showers.

Ed’s Note: Many thanks to the Grasslands team for putting together this very imformative, picture filled report on the Geology weekend.