You might have noticed that pretty as my komatiite deskcrop is, when I wanted to show the most impressive examples of spinifex textures, such as the variations in crystal size within a lava flow, I had to resort to field photos. In fact, whereas those photos come from a lovely fresh exposure in a stream bed, the hand sample on my desk comes from a nearby field, where the outcrop was rather badly weathered and horrible. This was deliberate: the small exposure in the stream is one of the best examples of spinifex textures found in the entire Barberton Greenstone Belt, and much of its value comes from being able to study the relationships within and between the different lava flows (in fact, we were visiting the locality with 60-odd students in tow for precisely this purpose). Hacking off a chunk simply to beautify my desk would therefore be rather irresponsible.
However, it seems that not everyone in South Africa shares these sensibilities. The people I was visiting Barberton with were rather upset to discover that in the year since their last visit to this locality, the most spectacular example of a spinifex-bearing lava flow had been hacked away from the outcrop, leaving nothing but an ugly scar. Many of the outcrops in the stream bed also bore the scars of a palaeomagnetic drill, which had been inflicted a few years previously. Indeed, ‘palaeomagnetist’ is a bit of a dirty word in South Africa at the moment: as soon as any geologist that I’ve talked with in the last few months has found out that I’m a palaeomagician, I’ve been subjected to a rant about the rather unsightly aftermath of a drilling assault on the komatiite type locality on the Komati River, by somebody who shall remain nameless (for more on the aftermath of this and other recent incidents, read this discussion in the Geological Society of South Africa Bulletin).
Geologists now have access to a wide array of fancy analytical techniques which provide a wealth of information about the formation and subsequent thermal, chemical and tectonic evolution of a rock. Unfortunately, many of these techniques are destructive, requiring that samples be removed to a lab and zapped, cooked or crushed into oblivion. Even more unfortunately, it is also the really rare and special rocks, the formations that formed billions of years ago, or under conditions rarely seen on the Earth’s surface, which are the most tempting targets for our magnetometers and mass spectrometers, because of their potential to offer fundamental insights into the way our planet works.
There are clearly trade-offs involved here: you don’t want to completely shut off valuable avenues of research by preventing any sampling of geologically interesting localities, but you also don’t want to cheat current and future geologists out of seeing these things in their original context, which is still the heart and soul of learning and doing good geology. Many times, these conflicts can be minimised by simply putting in that little bit of extra effort: rather than just hacking away at the outcrop which everyone stops to look at on field trips, take the time to explore around the river bend, or the in the surrounding undergrowth, to see if you can find what you need there. This seems to be the principal complaint in these South African cases: people weren’t willing to go that extra yard to minimise the impact that their research had on everyone else.
There are obviously times when even if the outcrop that you are studying is of incalculable geological value, the potential scientific payoff from sampling a bit of it for laboratory analysis justifies sullying it with the hammer or drill. But it’s a fine line to navigate, and perhaps it shouldn’t be up to any one geologist to make that judgement on behalf of the rest of us – as the South African experience seems to show, the actions of just a few selfish people can play havoc with a country’s geological heritage. But who should decide? And how should it be decided? Perhaps you have some thoughts.