Australia Through Time - iPad App

On the weekend 11-13 July 2014 various Australian government institutions had invited to join GovHack 2014.

Governments collect and publish enormous amounts of data, but have limited resources to get it into the hands of their citizens in engaging ways. GovHack is an event to draw together people from government, industry, academia and of course, the general public to mashup, reuse, and remix government data. GovHack is about finding new ways to do great things and encouraging open government and open data.

Most projects targeted the obvious data, like census data or the national archives. Science data are not that attractive because the sources are normally not accessible through simple API and often domain knowledge is needed to understand the data. Not all entries have to be applications in the sense of an app, also interactive infographics are welcome. One entry this year made use of data from Geoscience Australia to make an interactive infographic of the development of the Australian continent through time.

The Australia Through Time iPad App is an interactive app that runs on iPad or in the browser, showing the geological, mineral and biological history of Australia from the Cambrian to the present. It is based on the Australia Through Time poster by Geoscience Australia.This app presents the data in a visually appealing format, condensing it into smaller, readable screens and includes an animated sea-level bar and continental-drift visualization which makes changes in the data more apparent. It uses an intuitive drag gesture to slide through the timeline and display varying content.

Who Shot the Sheriff?

Mass extinctions are among the most intriguing events in earth history and their cause a matter of heated and passionate debate. An article in EOS by Keller et al. reports on a recent workshop at the Natural History Museum in London.

Since the seminal paper by Alvarez et al. on the nature of the K-T boundary it had always been the argument mainly between the proponents of the impact hypothesis vs. the flood volcanism hypothesis. And both sides had good arguments to support their cause. At this recent workshop 150 scientists from different disciplines got together to discuss the cause of Phaenerozoic mass-extinctions in a multi-disciplinary approach.

It will be interesting to read the proceedings from this workshop. In preparation, Keller et al. have published an extensive summary of their view on the subject in Geoscientist.

We are still looking for the smoking gun.

iGeology - BGS iPhone App

The British Geological Survey (BGS) has published a nice new application for iPhone: a geolgical map of Britain called iGeology. It is for free and with the GPS on board the phone you can find out what rock is below your feet.

• Enter a place name or postcode, or locate yourself with your phone's in-built GPS.
• Pinch open to zoom in.
• Tap on the geological map
• What are you standing on? Deposits from an ice age?
• What is the bedrock beneath the superficial deposits?
• Need a more detailed description? Follow the links to the BGS rock name database (Lexicon) and learn about the different rock formations where you are.

The geological data are served though the BGS Web Map Service (WMS)

Identification of Tsunami Deposits in the Geologic Record

Sediments deposited by tsunamis have been studied in the past as records of catastrophic events. The earthquake and tsunami that struck the Indian Ocean region on Boxing Day 2004 and claimed around 200,000 lives highlighted the need to study the sedimentary record of past tsunamis to help with planning disaster mitigation measures in coastal areas threatened by tsunamis. To help with the description and assessment of paleo-tsunami records the USGS has published an Open-File Report

Peters, Robert, and Jaffe, Bruce E. (2010): Identification of tsunami deposits in the geologic record; developing criteria using recent tsunami deposits. U.S. Geological Survey Open-File Report 2010-1239, 39 p. http://pubs.usgs.gov/of/2010/1239/.

This reminds me that I have not heard for a while about the "Mother of all Tsunamis" triggered by the Chicxulub impact. The field seems to have quieted down after 2008.

Stratigraphic concepts and agetagging

Stratigraphic 'homonyms' are quite common, a result of ambiguous placenames which have been used to name stratigraphic units. The stratigraphic terms used in Jens' post on Table Mountain stratigraphy nicely illustrate this:
He wrote about the South African 'Peninsula Formation' which is a synonym for the 'Peninsula Sandstone'. Unfortunately, this 'Peninsula Formation' is homonym to the 'Peninsula Formation' from British Columbia. The latter is of Cretaceous age, whereas the South African was formed during the Ordovician!

Geoscientists using stratigraphic terms surely have a clear concept of what they mean. However, whereas for human readers it may be easy to determine such a concept by lithological descriptions or the broader geological or tectonic context, this is much harder for computer algorithms and thus, agetagging.
Fortunately, the regional context can easily be discovered by geotagging technologies, therefore the geographic concept of a stratigraphic term is most important. Stratigraphic homonyms may exist at much lower regional level, e.g. from different provinces or states and most likely there are also significant conceptual differences between scientists. etc etc. However, such regional concepts are sufficient for the approximation for our agetagging purposes. The concept of a South African 'Peninsula Formation' is surely completey different from the Canadian.

.. a lot of complications with 'strato-semantic' text analyis.. stratigraphic analysis of geoscientific texts requires a combined approach, good agetagging is not possible without geotagging.

Table Mountain stratigraphy update

During my recent holiday in the Cape I visited my alma mater, the University of Cape Town and its Department of Geosciences. At his visit John Rogers of the geology department told me about his recent work on Table Mountain and later showed me some outcrops along the northern and western face of the mountain.



The stratigraphy of Tale Mountain (Western Cape Province, South Africa) always seemed to be a perfect example of "layered cake" stratigraphy: the base is Malmesbury Shale and Cape Granite with the famous Sea Point Contact between the two. Both are truncated at the top by an unconformity. The succession continues upwards with some basal conglomerate in places, the tidal or fluvial Graafwaater Formation, followed by the fluvial quartzites of the Peninsula Formation and topped by some glacial till, remnants of the Pakhuis Formation. This package of Graafwater Fm. and Peninsula Fm. can be found in the Cape Mountains where it is highly deformed.

The contact between the Graafwater Fm. and the Peninsula Fm. had always been interpreted as a conformable contact. By coincidence John Rogers noticed an angle between the Graafwater Fm. and the overlying Peninsula Fm., prompting the question, whether the contact between these two formations is actually conformable. Dating on zircons by Rogers et al. points to a significant hiatus between the two formations.

The picture above shows Cape Point and Rooikrans at the southern tip of the Cape Peninsula. It is one of the prime tourism and field-trip stops. I had been here a few times before in the past twenty years, but neither me, nor seemingly anybody else, had noticed the prominent syncline/anticline in the Graafwater Fm. beneath an undeformed Peninsula Fm.

My guess is that the folding is due to compression along a north-south axis because all observed folds dip along this axis. The quartzites of the Peninsula Fm. seem to be more competent. Instead of ductile deformation they show brittle deformation, e.g. a prominent reverse fault under Constantiaberg, the fault plain dipping to the south.

This puzzles me and I will have to do more reading on the regional geology of the Western Cape. Why is the principal stress from the south if the nearby Cape Mountains were folded by a main stress from the west? How far did the Graafwater Fm. extend? Is there an angular unconformity at Lekkranskloof (near Heerenlogement and Graafwater)? Interesting new detail about the assemby of Gondwana.

Neogene Chaos

The Tertiary is gone since 2003 but the discussion on the stratigraphic classification of the Neogene is still ongoing. For example, the International Stratigraphic Commission decided to ban the Quaternary from the official time scale, but geologists have sucessfully fought to keep this system (see for example this document). Both, Quaternary as well as Tertiary were regarded as 'remnants of the Neptunist concept of stratigraphy'. Strange, as recently, the 'Anthropocene' was proposed in 2007 by the Stratigraphic Commission of the Geological Society (UK) which also caused some blog echo for example here and here.

These 'outs' and' ins' are hard to follow, therefore the International Comission of Stratigraphy quite frequently provides updates on their stratigraphic chart at http://www.stratigraphy.org/cheu.pdf. Every time I visit this page this 'standard chart' looks different and unfortunately the stratigraphy.org page does not archive older versions of the chart for comparison.
Fortunately there is the Internet Archive which never forgets! Just visit http://web.archive.org/web/*/http://www.stratigraphy.org/cheu.pdf and you can download older versions of the stratigraphic chart back to 2004: a 'sequence of stratigraphic charts'.

Are you an old-fashioned geologists and still keep on using terms like 'Tertiary'? You are not alone ;) Indeed the Commission itself was not really sure how to deal with these Neptunistic concepts even after their 2003 decision. A closer look at these old charts quite nicely illustrates the discussion which followed:

1. 2004 The Tertiary and the Quaternary ... both gone ...
   
   
2. December 2005: The Quaternary is back! looks strange, but it's there..
   The * is a placeholder for the following footnotes:
   
   • until April, 2006: 'Proposed by ICS'
   • from October 2006 on: 'Formal chronostratigraphic unit sensu joint ICS-INQUA taskforce (2005) and ICS.'
   
   
3. October 2006: The Tertiary is back!
   Footnote:' Informal chronostratigraphic unit sensu Aubry et al. (2005, Episodes 28/2).'
   
   
   
   
4. September 2007: Tertiary off again.. and a strange line from Quarternary to the base of Gelasian..
   Footnote: The status of the Quarternary is not yet decided.
   
   
   
   


5. Current version (Nov. 2008): Quaternary has two potential bases?
   
   
   

What comes next? The International Stratigraphic Comission provides an interesting pdf which is named: 'A Proposal for Simplifying the International Geological Time Scale Chart' ... and this is the simplification for the Cenozoic:

No comment...

Dublin Core for stratigraphic units

This is a first draft which shows how I would encode metadata on stratigraphic units.
The usage of the coverage and subject (which both now contain the chronostratigraphic position of the unit) tag is still preliminary. I have to look up the DC specifications, as far as I remember there was the possibility to specify spatial as well as temporal coverage..

<metadata>
<oai_dc:dc xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
<dc:format>text/html</dc:format>
<dc:rights>
Licensed under a Creative Commons Attribution 2.5 License
</dc:rights>
<dc:publisher>
Stratigraphy.Net http://www.stratigraphy.net</dc:publisher>
<dc:type>Stratigraphic Unit</dc:type>
<dc:title>Ammergauer Schichten</dc:title>
<dc:date>1855</dc:date>
<dc:creator>Studer</dc:creator>
<dc:identifier>http://some_URL</dc:identifier>
<dc:relation>Wetzstein-Schichten</dc:relation>
<dc:subject>Malm</dc:subject>
<dc:coverage>Malm</dc:coverage>
<dc:coverage>Germany</dc:coverage>
<dc:coverage>Ammergebirge</dc:coverage>
</oai_dc:dc>
</metadata>