May 15, 2008
Category: academic life
There was an interesting article in Science last week, which argues that a successful career in research requires much the same skills as running a successful business. The author, Peter Fiske, argues that a number of business strategy ideas can be profitably employed in the academic arena, which may be particularly relevant as the competition for research funding becomes ever more intense:
- Product differentiation - developing novel ways of approaching scientific problems, or the techniques that you employ to solve them, so that you stand out as a unique individual within your particular subfield.
- Customer base - specifically, diversifying your sources of funding, so that you are not completely reliant on the fickle attentions of one big 'customer' or funding body
It's an interesting way of thinking about things, and I'd be interested to hear whether people more well-versed in the ins and outs of a successful research "business" see any value in it. However, I was also struck by another interesting point made in this article: that "most businesses are solo ventures led by one person who starts the company and then does all, or almost all, the work." One thing that we academics like to pride ourselves on is that, for the most part, our job is more than something which puts food on the table, it's something we believe in, and find rewarding to do, and will often sacrifice our free time to. Perhaps that's not so different from someone who runs their own little cafe, or t-shirt printing business, or garage. We're not the only ones who make sacrifices for a career we believe in; something that we would do well to remember from time to time, before we start thinking we're too special.
Posted by Chris Rowan at 11:34 AM • 6 Comments
May 14, 2008
Category: geopuzzling
Last week's geopuzzle was really just an excuse to show off more photos of the rather nice sedimentary structures preserved in the Archean rocks I visited the other week. All of the photos show preserved ripple marks. I've always found it difficult to picture how turbulent river and tidal currents always manage to produce these lovely regular structures; it seems that I'm not the only one, as apparently modelling these things is pretty hard. Nonetheless, you can get a lot of environmental information from these bedforms:
- Type of current - constant, unidirectional currents tend to form ripples with a steep side facing in the direction of flow, and a shallow side facing away from the direction of flow. In tidal environments, where you get oscillating back and forth currents generated by waves, the ripples tend to be much more symmetrical in form.
- Current speed - long straight ripple crests tend to indicate slightly slower current speeds than shorter, sinous ones. I assume (but am not certain) that this is something to do with increasing turbulence as the water starts flowing faster.
I thought that the most obvious difference between the first two photos was that the ripple crests in the second photo are much more undulating in form. However, most commentators also picked up on an apparent difference in their symmetry - the first photo appears to have asymmetric ripples formed by a constant current flowing from right to left, whereas the second photo appears to show much more symmetrical ripples consistent with oscillating tidal currents. Looking again, I think y'all might be right.
The final photo, as I said at the time, was tricky. A couple of people noticed that there appear to be two sets of ripples, indicating different current directions, preserved on the same bedding surface:
These interfering sets of ripples are thought to be yet another example of the binding activity of those Archean bacterial mats: the idea is that mat growth stops earlier ripples from being completely reworked by later seasonal currents, which have a different direction. Of course, this implies that these ripples are also formed by the flow of water rather than being aeolian (wind-blown), as a couple of people thought. If this interpretation is correct, then these structures formed in the inter-tidal zone, so we'd expect them to be fairly symmetrical; what do you think?
Posted by Chris Rowan at 12:17 PM • 0 Comments
May 12, 2008
Category: geology
Over the weekend Chris of Goodschist challenged the geoblogosphere to reappropriate Pangaea Day, by taking advantage of Ron Blakey's fantastic palaeogeographic maps to show where the rock beneath our current abode was located on the dinosaur-laden Mesozoic supercontinent. Callam and Brian have both responded, and I'm belatedly weighing in:
In the late Triassic (around 220 million years ago), South Africa was actually pretty much where it is now in terms of latitude, but it was located in the centre of a much larger landmass (often referred to as Gondwana) consisting of Africa, South America, India, Antarctica, and Australia, which had amalgamated several hundred million years earlier, and then collided with Laurentia (North America) and the other ancient continents to form Pangaea towards the end of the Permian. Since then, of course, all of these other landmasses have rifted away, forming the modern oceanic basins which now separate them.
Posted by Chris Rowan at 10:49 AM • 0 Comments
May 9, 2008
Category: geopuzzling
Spot (and explain, if you can) the differences.
It's not much of a hint to say that the last one is quite difficult - but the last one is quite difficult.
Update: Click through for the answer.
Posted by Chris Rowan at 10:48 AM • 6 Comments
May 8, 2008
Category: basics • geohazards • geology • volcanoes
In the wake of this weeks rather spectacular eruptions of the Chilean volcano Chaitén (which is being well-covered by the Volcanism Blog; more cool photos are available here, and at NASA's Earth Observatory), a commentator has asked for some clarification on "how geologists classify volcanoes as active, dormant or extinct."
The simple answer to this question goes thusly:
- An active volcano is one that is presently erupting (or at least growling a lot, with lots of seismic and thermal activity).
- A dormant volcano is currently inactive, but could feasibly erupt in the future.
- An extinct volcano is one that is both inactive and unlikely to erupt again in the future.
In many ways, I'm not sure that this classification is actually very informative, because these categories turn out to be rather fuzzy and tricky to determine. Even what constitutes a 'presently active' volcano is a little problematic: a cycle of magma chamber recharge and eruption occurs over geological timescales, so it makes little sense to only include volcanoes that have erupted in the past week, month or year (or even the past decade or century). For this reason, places such as the Smithsonian's Global Volcanism Programme put any volcano that has erupted in recorded human history, or in the Holocene (the last 12,000 years or so), onto the active list.
The division into 'dormant' and 'extinct' is also tricky, because what you need is some idea of a volcano's eruptive history; not just the date of its last eruption, but the number and frequency of eruptions over a longer time. For example, lets say that you can date the last eruption of a particular volcano to 20,000 years ago, and dating of older lava flows shows that prior to that time there were eruptions every couple of thousand years or so:
In this case, several eruptive cycles have been and gone since the last eruption, and we might be justified in saying that this volcano is extinct. In contrast, we might find that the eruptions are much more infrequent, say every 15,000 years or so:
In this case, we are still within the timeframe required for one eruptive cycle, and the magma chamber could still be refilling as a prelude to the next explosion. More detailed examination - trying to seismically image the magma chamber, or looking for gas emissions or hot springs, might give us some clues about whether your friendly neighbourhood mountain is dead, or merely dozing.
The problem, of course, is that for many of the world's volcanoes this long-term information is just not available. If we look at Chaitén's eruptive history, there was only one known eruption prior to this week's pyrotechnics, which has been dated to around 10,000 years ago. The eruption has been described as a 'surprise', but in fact we don't know enough to know if we should be surprised or not.
Posted by Chris Rowan at 11:19 AM • 4 Comments
May 7, 2008
Category: fieldwork • geology • geopuzzling
In addition to searching out evidence for Archean microbial mats, my revisitation of the Pongola sandstones gave me the chance to look a bit more closely at their lithology. When I last posted pictures from this sequence, there was a bit of discussion about why the beds appeared to be quite dark - sandstones are generally lighter in colour (being composed mainly of quartz). Is this due to some weird mineralogy? Or just an effect of modern day weathering?
Here's a close-up of one of the dark beds:
It does appear that the dark colour does indeed seem to be a result of minerals actually in the rock, rather than formed by weathering on the surface. However, I'm still not sure what these minerals are; presumably there's just enough squeezed in between this quartzite's cemented quartz grains to change it's optical properties. You'd probably have to make a thin section to know for sure what they are - any guesses?
Read on »
Posted by Chris Rowan at 10:34 AM • 7 Comments
May 6, 2008
Category: fieldwork • fossils • geology • ranting
Last week I ventured into the field in the company of Nora Noffke, of Old Dominion University in Norfolk, Virginia. who is an expert on the fossil record of ancient bacterial mats. It turns out that this record does not simply consist of the well-known stromatolites; in shallow marine environments mat-forming microorganisms can bind and stabilise the sediment surface, leading to the formation of distinctive structures that are not formed by purely physical processes. This is in contrast to the difficulties in distinguishing between those stromatolites that have been formed in association with bacteria, and those that have been precipitated entirely inorganically.
It turns out that the Pongola Supergroup - the Archean rocks that I am currently trying to extract a magnetic signal from - is a good place to look for these 'microbially induced sedimentary structures'. As we've already seen, ripple marks, dessication cracks and other sedimentary features are extremely well preserved in the sandstones which make up the upper part of the sequence, despite their venerable age of 2.9 billion or so. Furthermore, the tidally-influenced shallow marine environment is which these rocks seem to have been deposited is prime mat-forming territory. Nora was kind enough to point out some of the outcrops that featured in her recent paper in Geobiology, which describes a section through the Pongola sandstones and makes the case that many of the preserved sedimentary features are consistent with the presence of a thriving bacterial mat ecosystem. I am not confident that I would have really noticed any of these myself: this is one of those times when knowing what you're looking for - through a good grounding in the sort of features formed by modern mat growth in similar environments - is essential if you're going to distinguish the real deal from modern weathering patterns on the bedding planes. Two examples are found beneath the fold.
Read on »
Posted by Chris Rowan at 11:25 AM • 5 Comments
May 5, 2008
Category:
Brian's had the cool idea of summarising some of his pending scientific papers using tag clouds, and I'm joining Lab Lemming, ReBecca and Maria in jumping on the bandwagon. The following two clouds, which may or may not provide some insight into what I'm all about scientifically, are generated from the text of a couple of my papers, sans references and figure captions, using tagcrowd on its default settings (hence the appearance of 'et', 'al', and 'figure/fig'). I thought it also might be fun to compare the clouds to the list of keywords that you actually have to provide yourself. The first one is for my recent JGR publication about New Zealand tectonics (yes, the one I promised to write some posts about; something I will get around to once I've completed a couple of neccesary background posts).
My keywords: remagnetization, greigite, vertical axis rotation, New Zealand, Hikurangi margin.
Number two was submitted to Earth and Planetary Science Letters just before I went away, and is based on work I did between finishing my PhD and leaving Southampton, and focuses on diagenetic changes to the magnetic mineral assemblage within marine sediments, and their effects on the paleomagnetic signal they carry.
My keywords: sediment diagenesis, sulfate reduction, magnetite dissolution, greigite, superparamagnetism, hysteresis.
I'm apparently not too gratuitously self-citing, but it does seem that, since my PhD supervisor's name appears on both lists, I'm a bit of a suck-up. That'll surprise him - although since both papers concern the effects of evil greigite, and he's been heavily involved in its ascent up the heirarchy of Important Magnetic Minerals in recent years, I could hardly help citing him lots. Given that certain recent reviews have suggested that I seem to be rather good at upsetting people I'm rather surprised that more researcher names don't appear (the only other one on the JGR paper is retired).
There is also a reasonable degree of overlap between my chosen keywords and the ones that appear in the tag cloud. It's no surprise that they're not completely identical (as the most important concepts or themes in a paper are not neccesarily related to how frequently you mention them), but it does seem that you can potentially get a reasonable sense of what a paper might actually be discussing from this sort of thing. The question is whether it actually has any utility in finding papers and/or assessing whether you want to read them.
Posted by Chris Rowan at 7:33 AM • 7 Comments
April 25, 2008
Category: bloggery
I'm off into the field again for a week. Since the geoblogging around here has been fairly light of late, you might not even miss me. Hopefully, a bit of fieldwork is just what I need to get me out of the slight creative hole that I've found myself in of late.
Also, since I'm going to be in the same area, I'm hopefully going to get a look at this outcrop again.
Posted by Chris Rowan at 11:17 AM • 0 Comments
Chris Rowan is a geologist specialising in the dark arts of paleomagnetism, and getting people to pay him to travel to exotic destinations for fieldwork. Having drilled up New Zealand during his PhD, he is now a post-doc at the University of Johannesburg. 
