Fieldwork photos

Here are a few snaps from my sampling trip. I didn’t take many, because the light wasn’t great for photography, and also because my camera was also being a little bit badly behaved.

WhiteMfolozi.jpg

A view of the river I was working in, from the camp I was staying in.

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Categories: fieldwork, geology, outcrops, photos

Carnival of the post-docs

The 4th Carnival of the Post-docs is up at Minor Revisions, whose author has really excelled herself with an voluminous collection of links – just what I needed to get through a brain-fried post-fieldwork afternoon.
Whilst you’re over there, the host blog itself is well worth a read – and I was intrigued to discover that my link in this post (included in the carnival) directed some (well-deserved) traffic its way. It didn’t occur to me that I had that much power…

Categories: academic life, links

The highs and lows of fieldwork

Four trying days into my latest field expedition, I seriously considered packing it all in and coming home, as I was clearly channelling the spirit of Murphy.
Firstly, my vehicle broke down on the drive out. As it happened, this was not the car I was supposed to be driving, which had been trapped in its garage by some idiot’s car (I’m currently plotting some signage warning people not to mess with people who walk about with hammers and diamond tipped drills). Fortunately, the gearbox decided to stop working as I was coming into a reasonably sizeable town rather than in the middle of nowhere, but I lost a day waiting for it to be repaired.
The next couple of days would be amply covered by the phrase ‘teething troubles’. There was lots of sweaty lugging of drills and assorted paraphernalia a couple of km each way along a rocky river valley, in temperatures which were a lot higher than the low autumnal sun suggested to my high northern latitude sensibilities. It took some time to get used to drilling again; and, because Archean basalts are a little harder than the Neogene sediments I was used to, I kept drilling cores which were too short. I also found that the kit I had been given contained no specialised core extractor; I puzzled for quite a while over getting the damned things out of the rock before working out how to bodge it with a non-magnetic screwdriver (which, it turns out, is the approved method here – or, it has been up to now…). Then, just as I was sorting out all these problems, in a moment of wincing clumsiness I broke the water pump used to cool the drill.
At this point, I was not in a particularly good mood, since my efforts to that point had yielded precisely one core. Hence the temptation to march back to Jo’burg in a huff. Fortunately, however, my habit of stubbornly and masochistically clinging to lost causes actually worked in my favour for once. I took the unexpected half day of non-drilling to get a better feel for the geology of the area I was sampling, which led to the useful discovery that the map which I put up before I left was not entirely accurate, missing out at least one major fault which duplicates some of the stratigraphy (as well as a moderately sizeable intrusive sill, but I already knew about that).
The next day, a trip to a hardware store and some magic with silly putty and a drinking straw got the pump working again, and I finally started making progress. I even persevered through a windy Sunday which turned the river valley I was working in into a giant sand blaster. And Monday – the last day – was great. Nice weather, everything working smoothly, I was feeling on top of the geology, and I got everything done which I set out to do. I had 100+ cores, and I was feeling pretty good about having stuck it out. I was even sketching out a blog entry about one of the possible reasons why it’s so easy to forget the hard fieldwork days and remember the good ones: the bad ones generally occur at the beginning of a trip, as a sometimes necessary precursor to the good ones, which generally occur at the end.
Then, yesterday morning, I awoke to discover that the car had a flat tyre. So much for that theory, then.

Categories: fieldwork, geology, ranting

Nuclear Seismology

From ye olde blog, November 2006: A barely remembered anecdote, the buzz about the North Korean “nuclear” test, and a Web of Knowledge search combined to bring this paper up on my screen:

    Seismic tomographic inversion of Russian PNE data along profile Kraton [1]

The acronym ‘PNE’ is made more explicit in the next result:

    Origin of upper-mantle seismic scattering – evidence from Russian peaceful nuclear explosion data [2]

That’s right – PNE stands for ‘peaceful nuclear explosion’, a phrase from a simpler time when people seriously advocated using nuclear explosives to dam rivers, create new anchorages, and release gas from underground reservoirs (which, shockingly, turned out to be radioactive). Both the USA and USSR engaged in this interesting pastime, but the Soviets detonated 239 PNEs against the Americans’ 28, a disparity that is probably due more to the relative power of each country’s citizenry (I suspect even in those days. if given the choice very few people would fancy a close-up view of mushroom clouds) than a difference in official enthusiasm.
Anyway, it seems some Russian geologists had the bright idea of using PNEs to undertake controlled source, wide-angle seismology on a scale not achieved before or since.

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Categories: geology, geophysics, paper reviews

Algae and earthquake precursors

From ye olde blog, May 2006: an interesting report from the BBC:

Concentrations of the natural pigment chlorophyll in coastal waters have been shown to rise prior to earthquakes.

These chlorophyll increases are due to blooms of plankton, which use the pigment to convert solar energy to chemical energy via photosynthesis.

This is based on an article by Singh et al. [doi] in Advances in Space Research, part of a special issue devoted to the use of satellite remote sensing for studying and predicting natural hazards such as earthquakes. The authors claim that you can detect a rise in sea surface temperature just before large coastal earthquakes. The blooms observed in this study are, they say, result from an increased flow of heat energy from the ocean to the atmosphere, enhancing the upwelling of cold, nutrient rich water and fuelling a boom in the growth of photosynthetic algae.
This is all very interesting, but what is unclear in the paper is the reason so much heat energy is being released prior to the earthquake, which is itself releasing accumulated strain energy. And, looking at the paper, I’m not really sure the relationship is quite as clear-cut as is claimed.

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Categories: earthquakes, geohazards, geology, paper reviews