Category: Web Resources

The US Geological Survey has made publicly available a large repository of geochemical data (63 of the 91 naturally occurring elements) that it has acquired through a continuing nation-wide survey of stream sediments (available at http://tin.er.usgs.gov/geochem/doc/home.htm).  The data coverage is incomplete and involves several generations of previous surveys.  The most revealing stream sediment surveys involve collection of panned sediment samples in every small stream that has no upstream tributary, but that is a daunting task for such a vast area as the USA.  That method allows the analyses to be treated as accurate representations of stream sediment composition in upstream catchments around 1 x 1 km in size.  The USGS data are a mixed bunch, some dating from the National Uranium Resource Evaluation (NURE) of the 1970s when there was a scramble to find new uranium ore bodies.  The NURE survey involved a sample density based on a 17 x 17 km grid, and made no distinction between stream order.  The latest USGS survey is based on sample collection that uses 10 x 10 km grids drawn in the UTM co-ordinate system. Each 10 x 10 km cell is divided into four quadrants, and one is selected at random for sampling.  In that one small stream selected at random is chosen for analysis.  The data set is too coarse and too varied to create meaningful gridded interpolations that can be displayed as continuous tone images, unlike comparable geochemical atlases based on systematic, small-stream sampling, such as that developed for commercial leasing by the British Geological Survey. The NGS data will be a useful resource for scanning broad geochemical features of the country, such as for high levels of potentially toxic elements in water, bearing in mind that the analyses are of solid minerals not the water itself.

“Plumeology” site

The last issue of EPN showed that the debate over mantle  plumes, their sources, and even their existence is hotting up (see Geoscience consensus challenged in EPN January 2004).  However that pans out, vast areas of continental and submarine flood basalts compel geoscientists to ponder over them, the more so because they represent events never witnessed by humans and are therefore unimaginable.  Now they have their own website (http://www.mantleplumes.org/) that has been compiled by Gillian Foulger of Durham University.  It is an impressive and highly useful resource, the outstanding feature being pages on most aspects of large igneous provinces written by experts who are also excellent communicators.  There is even a linked site at the Geological Society that hosts discussion on the Great Plume Debate, as well as a letters page, links and up to date news.  For information, without unnecessary frills, this is the place to go, especially if you have to write an essay!

If you like that frisson of fear that comes from contemplating the demise of the world as we know it, then the Near Earth Objects Dynamic Site (NEODyS) will give you hours of it (newton.dm.unipi.it/neodys).  The more than 2500 NEOs that orbit within 45 million km of the Earth’s are fully catalogued there, along with impact risk assessment.  The site also links to the on-line newletter Tumbling Stone, that has news on asteroidal matters, especially near misses…..and impending doom…..

They are all at www.dinodata.net, seriously!  Dutch enthusiast, Fred Bervoets puts a vast resource and copious links at anyone’s disposal, even including a forum and a chat rooms.  Technical drawings and artistic impressions of many species are there, together with guides to where specimens can be seen in museums, and major fossil sites.  Skin, eggs, diet, controversies, companion species and sources for replicas……

The Smithsonian Institute’s National Museum of Natural History has a new and evolving Earth science website at  www.mnh.si.edu/earth (Flash 6 and printable versions).  Currently only the Rocks and Mining section is up and running, but it is instructive at the introductory level.  To come are sections on gemstones, plate tectonics and the Solar System.  There are also downloads and a geogallery.  It is somewhat slow in Flash using a normal dial-up connection., but the printable version has no images.  With a fast connection, this is likely to become a favourite for elementary visualisation of Earth processes.

The University of New Brunswick, Canada, maintains an illustrated archive of information on terrestrial impact craters.  It lists 169, with exact co-ordinates for each and much other information besides.  Many have satellite, aerial and/or ground images, plus full lists of references for each.  The URL is http://www.unb.ca/passc/ImpactDatabase/

When directing The Greatest Story Ever Told George Stevens was unimpressed by John Wayne’s delivery of his only line at the very end of the film.  Stevens said, “You have to deliver with a little more awe, John”.  And so we have one of the great conclusions in cinema history, “Aw, he truly was…..”.  Astronauts have had a fair number of those “Aw” moments, and thankfully, most have them have carried cameras.  They captured a great many views of odd and awesome phenomena and features of the Earth as they passed over. There are a great many (around 400 thousand), and NASA has compiled the best views of Earth’s surface on its new site at  http://eol.jsc.nasa.gov/sseop/EFS/.  I put in “faults” to see what came up; there were 184 images from every continent.  Downloads are in two sizes, 300 kb and 13 Mb, so the images are of very high quality.   The entire archive is searchable at http://eol.jsc.nasa.gov/sseop/.

The US Geological Survey has placed 16 thousand of its archived field photographs on the web, at print-quality resolution.  They can be accessed at http://libraryphotos.er.usgs.gov and carry no copyright, so anyone can use them for illustration of lectures or textbooks (it would be polite to acknowledge the USGSs generosity).  The photos date back to the earliest days of geological research in the United States, and are in black and white, and colour.  Although still under development, the site’s search engine works well and quickly.  Putting in “unconformity” and “thrust” yielded 31 and 52 pictures, respectively.  However, trying to find the highly photogenic thrust of grey Cambrian limestones over Permian redbeds west of Las Vegas in Nevada drew a surprising blank.  Every geological survey holds enormous archives of photographs that never see the light, so the USGS initiative ought to encourage others to follow suit.  In particular, it would be great news if the British Geological Survey, the world’s oldest, did likewise, instead of just generating a meagre flow of funds by selling a minute proportion of its collection as postcards.

Dave Reay of the School of Geosciences at the University of Edinburgh has developed an extremely useful website that covers all the breaking news about “greenhouse” gases and climate change at www.ghgonline.org, which is easy to navigate and regularly updated.  It contains links to on-line publications and a comprehensive Links page.

The Digital Library for Earth Systems Education now has a site that can act as a gateway to thousands of Earth Science web sites that provide educational materials from school to professional level (www.dlese.org) .  There is a comprehensive range of topics, and a potentially useful enhancement is part which announces conferences and discussion groups.

Devonian art

The Devonian Period witnessed sudden diversification of vertebrate animals, including the first amphibians.  The oceans were teeming with other life forms.  Museums have for a long while commissioned artists to create dioramas of ancient seas that express part of their diversity.  Using gaming software, British artist Christian Darkin is in the process of developing an interactive Devonian diorama, eventually intended for museum use.  His work in progress can be viewed at   www.geocities.com/christiandarki/fish.htm .  You will need the Macromedia Shockwave plug in, downloadable direct from Darkin’s site, and a higher speed connection than with a normal modem.  However, the experience is dramatic and informative.

If so, the site to visit is at NASA’s Jet Propulsion Laboratory ( www.jpl.nasa.gov/temlates/flash/neo/neo.htm ).  The Near Earth Objects team has designed the site for general education about the kinds of space chunks that might strike, the risks involved and what will probably happen when we get very unlucky.