Wednesday, August 20, 2014

Geology Sonnet 2



As mentioned previously, I am writing Geology Sonnets for National Science Week.  These are articles from the high-profile scientific journal Geology, presented in the form of Elizabethan verse. I don’t know how many of these I will get through this week, but here is the second:

The Central Atlantic Magmatic Province
Erupted tholeiitic and potassic.
C O two upset atmospheric balance.
Eco-collapse ended the Triassic.
Green sulfur bacteria’s isotopes
Show photic zone euxinia prevailed.
Stomatal size decreased (show microscopes)
And carbon biomass was soon curtailed.
Compound-specific isotopes will tell
Which phytoplankton thrived in these tough times,
While wax from leaves and calcite from a shell
Record recovery in clastic slimes.
The Triassic ended as it began.
Can those extinctions be surpassed by man?

Caroline M.B. Jaraula, Kliti Grice, Richard J. Twitchett, Michael E. Böttcher, Pierre LeMetayer, Apratim G. Dastidar and L. Felipe Opazo. (2013) Elevated pCO2 leading to Late Triassic extinction, persistent photic zone euxinia, and rising sea levels. Geology 41 955-958.

Abstract

The Late Triassic mass extinction event is the most severe global warming–related crisis to have affected important extant marine groups such as scleractinian corals, and offers potential insights into climate change scenarios. Here we present evidence from Chlorobi-derived biomarkers of episodic and persistent photic zone euxinia. From biomarkers and stable carbon isotopes, we present evidence of rapid mixing of atmospheric and oceanic carbon reservoirs. Global versus regional trends are resolved in kerogen organic matter type, carbonate δ13C, and bulk and pyrite δ34S. This suite of data demonstrates for the first time a comprehensive organic and stable isotope geochemical reconstruction of events leading up to the Late Triassic extinction event and its aftermath. The cascade of events prior to, during, and after the extinction is remarkably similar to those reported for the Late Permian extinction, the largest extinction event of the Phanerozoic. We predict that similar conditions will have occurred during all past episodes of rapid global warming and biotic crisis that are associated with similar rises in pCO2.

See Geology Sonnet 1 here.

Tuesday, August 19, 2014

Geology Sonnets!

Here in Australia, it is National Science Week, and I have been surprised and delighted at the bizarre and creative ways that many people around Canberra have been celebrating science.  It is inspirational, to the point where I might try to join in.  So in this spirit, I give you Geology Sonnets.  These are articles from the high-profile scientific journal Geology, presented in the form of Elizabethan verse. I don’t know how many of these I will get through this week, but here is the first:

Just Sixty-six million short years ago
(Though Deccan volcanism coincides)
The Yucatan was smote a cosmic blow
And the Gulf shelf collapsed in those fell tides
Late Cretaceous sediments were scoured,
Deposited as “boundary cocktail.”
Unsorted forams, lime mudstone, powered
By Chicxulub-induced collapse of shale
The wildcatters call the seismic line
“Middle Cretaceous Unconformity”
Not middle, end; deluvian, malign,
Complete destructive uniformity
The Mesozoic ended with this splat
So Gerta Keller, please hang up your hat

Richard A. Denne, Erik D. Scott, David P. Eickhoff, James S.Kaiser, Ronald J. Hill, and Joan M. Spaw (2013) Massive Cretaceous-Paleogene boundary deposit, deep-water Gulf of Mexico: New evidence for widespread Chicxulub-induced slope failure.
Geology 41, 983-986

Abstract


The single largest-known mass wasting deposit has been identified at the Cretaceous-Paleogene (K-Pg) boundary in the deep-water Gulf of Mexico, in 31 industry-drilled wells and on seismic data, corresponding to the “MCU” (middle Cretaceous unconformity) horizon. The deposit has an average thickness of 10–20 m on the upper slope and 90–200 m on the lower slope and basin floor, and is on an unconformity that represents 9 m.y. to 85 m.y. The deposit contains the distinctive association of lithic fragments, impact-derived material, and reworked microfossils (i.e., the Cretaceous-Tertiary boundary “cocktail”) associated with the Chicxulub impact, and is predominantly composed of graded pelagic carbonates. These new findings substantiate widespread slope failure induced by the Chicxulub impact and provide further evidence of a single impact coincident with the K-Pg mass extinction.

Friday, August 15, 2014

Indian e-commerce

On my recent trip to India, one of the big stories in the newspaper was the rise of consumer good e-commerce.  Flipkart, an Indian company founded by the ex-Amazon Bansal brothers, recently announce that it had raised over one billion dollars of funding for expansion projects.  A day later, Amazon announced that it would be investing two billion dollars in its Indian subsidiaries.  Of course, this is unsurprising.  India is modernizing quickly, and IT is one of the lead drivers of economic growth.  I was in Palo Alto, the northern end of Silicon Valley, a few years back, and waiting for my flight in the Kolkata domestic terminal a few weeks ago, I was struck by the number of IT nerd look-alikes sporting the flat combed hair, short-sleeve shirt, pants and laptop look. I was in stark contrast to the traditional party clothes of Eid, which was two days before.  So the rush into this business is no great surprise.  But what worries me is how the social consequences of this particular business expansion might be.

In Australia, e-commerce has finally cut into traditional retail no a broad scale, with retail growth flat, and employment and tax revenue falling.  This has contributed to social dissatisfaction and hand wringing, but even with the recent cuts to Australia’s economic safety net, the effect on the overall way of lie has been modest. This is because Australia is a wealth y country, and has a relatively intact safety net.  So even with these employment disruptions, everyone has food to eat, safe drinking water, health cover, etc.

However, this is not the case in India, where native startup Flipkart and internet giant Amazon have recently announced more than 3 billion dollars of investment, with the intent of growing their sales by billions of dollars per year.  India has a lot of retailers; with an estimated 40 million of them, they outnumber Australia’s entire population by almost a factor of two.  And unlike the corporate-dominated retail scene in Australia, 95% of the Indian retail sector is owner-operator family style shops.  In general, these are businesses with limited training and financial means.  There isn’t much of a social safety net, as a number of these folks are barely getting enough to eat as is. 

So what will happen when Indian internet shopping comes of age, and customers no longer have to brave the dangerous dirty, difficult streets of their megapolii to buy consumer goods?  In rich countries, people displaced by technological change have retrained using the educational system, fallen back on the social safety net, or managed to simply get by with less.  But never has such a vulnerable segment of the population been targeted by such an efficient set of competitors.

I hope development allows India to grow its way out of this potential pitfall.  But I am not optimistic.  The same paper announcing the new Amazon investment also reported that Indian Overseas Bank was suffering from an unexpected loss in microcredit loan repayments. It would be unfortunate if the geeky rivalry between Bezos and the Bansal brothers resulted in the first iFamine.

Monday, August 11, 2014

Bayesian Geochronology

 Bayesian statistics is a growing field of exploring data-rich, complicated, explanation-poor phenomena. In a nutshell, you start out with an initial assumption, called a “prior” and then modify it with new sets of independent data. The Bayesian approach is one of the hot new techniques to come into Earth Science in the past decade, as it allows us to sensibly integrate disparate sets of data about the same physical process derived from different proxies or fields. Long time geobloggers will know that James is an expert in applying this technique to climate; see his blog and papers for more information.  However, despite the decade-long use in climate science, Bayesian statistics have not often been applied to more interesting areas of geoscience.  E.g. Geochronology.  Until now.

In Geology, Vleeschouwer & Parnell present a new Bayesian method of constructing the geologic timescale.  They point out that the previous timescale, which were just spline fits between selected stratigraphic/geochronological time points, had the perverse effect of yielding smaller error bars in the gaps between data points than near to where there are data. So they try a Bayesian approach instead.

For their Prior, they start off with the rule of superposition- which states that lower stratigraphy is older than higher stratigraphy.  They then apply all the high precision geochronology dates (high-precision CA-TIMS U-Pb in this case), and generate a probability density function for stratigraphy vs time. Their resulting chronology is, sensibly, more erroneous in areas where there is no data, compared to those where data does exist.  But in addition to being more sensible, this approach is far more useful.

Firstly, from the modeled uncertainties in the interpolated regions, one can guestimate the precision (both geochronological and stratigraphic) that is necessary to help constrain the timescale.  So, for example, in some of the more data-poor regions, one can probably usefully constrain the timescale using a less precise microanalytical method such as SHRIMP, if the only available zircons are not suitable for CA-TIMS.  On the other hand, as you approach a high precision date, lower precision techniques become less useful.

In fact, you can tell whether or not a particular age is useful for the timescale simply by looking at how the inclusion of that date alters the PDF.  Previously, the inclusion or rejection of particular ages has been a non-transparent potentially politicized process.  The use of this model allows us to replace the argumentative old men with statistics.

Of course, one needs to be careful in adding data.  A potential flaw would be adding lots of data with a systematic error (for example, of there are still lingering systematic issues with U-Pb vs Ar-Ar dating, or the offsets in some zircon ages dated using laserICP by Gehrels et al. 2008). But one thing this method does allow is the addition of different types of data.


Vleeschouwer and Parnell (2014) demonstrate this in the second half of their paper, using astrochronology.  This is the appearance in the sedimentary record of depositional changes that are related to Milankovic cycles- the changes in the Earth’s orbit that govern, for example, the extent of ice sheets in the modern Earth.  Astrochronology cycles do not add additional tie points to the geochron/stratigraphy tie curve, as they are relative dates with no fixed reference.  However, what they can do is constrain the slope of the line.  So changes in stratigraphic distance between periodic eccentricity cycles tells us how the stratigraphic progression changes with time, often on a much shorter timescale than what we can access using traditional U-Pb geochronology.  The Bayesian approach allows us to integrate the strengths of both methods, giving a more accurate and reliable timescale.  

Tuesday, August 05, 2014

OCO

 A month out, and already the carbon tax is ancient history.  And while no household bills have yet appeared to demonstrate the savings (or lack thereof) to the common battler, there is no doubt as to the identity of the big winners.
I do not have any specific inside information on this topic, so this is only my best guess as to what Gina Rinehart has been joyfully singing as she dances through the empty corridors of her palace (cue Disney winter wonderland music)...

OCO
Let it go,
There’s no carbon tax any more.
OCO
Let it go,
Put more oil rigs off shore.

The snow fell late on the mountains this year.
Carbon footprint, or a dream?
A country in isolation
Burning coal, and making steam.

The wind is howling and the swirling turbines glide.
Couldn’t keep them out, Murdoch knows I tried.

Don’t let them in. Don’t let them see
Transmission lines are too costly.
Conceal the real
Cost of the pole.
Their bills will grow...

OCO
Let it go
There’s no carbon tax any more
OCO
Let it go,
Let’s just heat the earth some more
I don’t care
If it’s hot today
OCO
Let it go,
The coal never bothered me anyway.

It’s funny how some distance makes Europe seem so small.
Their carbon trading system can’t get to us at all.
Out here in the smoky air
No asthmatics can breathe,
To give them a reprieve.

OCO
Let it go
There’s no carbon tax any more
OCO
Let it go,
Let’s just heat the earth some more
I don’t care
If it’s hot today
OCO
Let it go,
The coal never bothered me anyway.

Standing
Smoking
By the donors chosen
You won’t
Fine me
The tax is so behind me
Carbon, free to go.

Let it go
OCO
We won’t tax that anymore
Let it go
Let it go,
Let’s just heat the earth some more
I don’t care
If it’s hot today
Let the seas rise on...

The coal never bothered me anyway!



Sunday, August 03, 2014

Volcanoes in the mist

Flying home from Singapore on a rare daytime flight, I was fortunate enough to pass over easternmost Java in a window seat.  Unfortunately, although I was looking for volcanoes, one effect of volcanoes (or any large mountain) in the tropics is that they tend to generate rainfall, so most of them were mostly obscured by cloud.  Despite this, I did get some glimpses here or there through the clouds.  And the coastlines and reefs of Java, Bali, and Lombok were fantastic in any case.

The first picture, taken over eastern Java, shows Balarang in the upper left. Ijen and Raung are covered in cloud, as is most of the western Bali hills beyond.

In the second picture, mount Angung on Bali is barely peeking out of the clouds on the far left, while Mt. Rijani on Lombok can be seen protruding from the clouds in the center


Monday, July 28, 2014

Urban Butterflies

I have mentioned before that Changi Airport in Singapore is a step above your average travel hub, to the point of seeming almost magical to the sleep-deprived, Jetlagged traveller.. But this is the first time I have been here in the daytime.  So I made sure to stop in to see the butterfly garden. A step above EWR. So here are some phone pictures:



Saturday, July 26, 2014

Science isn’t always linear

 These days mostly I build scientific instrumentation- I don’t do a lot of science.  But last year I did get a small grant to look at some novel stuff.  I don’t want to go into it right now; but the process was interesting enough to share.  Figure one shows how we thought the project would progress; that is what we proposed to the funding body.
 Figure 1: We’ll do this- what could possibly go wrong?

Figure two is how it all actually went down. Obviously, there were a few complications, dead-ends, and in the end we discovered some cool stuff, which was actually not too far from where we were aiming to go.  The point is that science, especially natural science, does not always flow in a linear, predictable, orderly manner.  But if you’re lucky, it does eventually go somewhere.


Figure 2: This is how it actually went down.