This week’s episode discusses the latest rumbling, shaking and eruptions in Tonga, global warming and the ozone layer and dinosaurs – small and feathered. Plus a reading recommendation.

Participants (links in brackets are Twitter feeds)

Chris - goodSchist (@yorrike)

Chris –  Highly Allochthonous (@allochthonous)

Julia – The Ethical Palaeontologist (@morphosaurus)

Eruptions of  Hunga Tonga Hunga Ha’apai and Earthquakes in Tonga

The Big Picture has some beautiful pictures of the eruptions, including a sequence of photos showing an eruption in progress.

Eruptions has details on the M7.9 quake in Tonga and details on the eruption plus some pictures and video of the eruption.

Maria at Green Gabbro assures us that the eruptions and earthquakes are probably unrelated.

The BBC has a pretty sweet video of the eruption too.

Here’s the NOAA map of seafloor age.

Ozone Modelling

Universe Today tells of the Ozone Success Story: NASA Video of Enviro Action That Worked.

The Nanoraptor

Geology.com talks about this Cat-Size Dinosaur Found in Alberta.

Science Centric tells of how Mini dinosaurs prowled North America.

Featured Dinosaurs

Not Exactly Rocket Science has the scoop on the Tianyulong confuciusi and has a word to say about the 4-wing microraptor.

Extras

The Kraken Wakes by John Wyndham, as recommended by Chris R and Julia.

del.icio.us/podclast

We have a del.icio.us account which can be found at http://del.icio.us/podclast. All the web pages and resources we’ve found and used in the discussions on the podclast can be found here. A convenient way to browse per episode is to go to, for example, http://del.icio.us/podclast/episode9 (for this episode).

If you find a link to a topic that you’d like to hear discussed on the podclast, or have a link to a topic that’s already been discussed, you can add links to the podclast page through your own del.icio.us account.

When saving a link, include the tags for:podclast and episodeX (where X is the episode number – for example episode8). You can add more than one episode tag if the link applies to multiple episodes.

Next Episode

We like to have a new episode of the podClast every fortnight, so the next episode will be recorded on Sunday the 5th of April at 2000 GMT.

Contributing

If you’re keen to hear a specific topic talked about, or would like to join the discussion during the next episode, either leave a comment below or email chris [the at symbol] goodschist.com. You’ll probably also do well reading the details on joining the podclast. If you don’t have the time to join us but would like to contribute a 3-5 minute audio clip to the show simply record it, make sure it’s an mp3, and send it to the address above.

Credit

The intro and exit music was Roots Fi Cool by Burning Babylon.

Text Addresses

The post that accompanies this podcast can be found at http://www.goodschist.com/2009/03/21/the-podclast-episode-9/ or http://is.gd/otDZ and an archive of all  podClasts can be found at http://www.goodschist.com/category/podclast/

Episode 7 of the podClast is ready for download. You can grab the mp3 here (42.5 Mb, 46:24), or subscribe through iTunes here. Or you can listen to it right here:

This week’s episode discusses the ancient sponge biomarkers recently described in a formation in Oman, palaeomagnatism, geology on Google Earth and more. This is the first episode in 7 months and it’s the longest podClast ever at just over 46 minutes.

Participants (links in brackets are Twitter feeds)

Chris - goodSchist (@yorrike)

Ron – Ron Schott’s Geology Home Companion Blog (@rschott)

Chris –  Highly Allochthonous (@allochthonous)

Dave – Geology News (@rockbandit or @geologynews)

Jess - Magma Cum Laude (@tuff_cookie)

Ryan – Staff Geologist (@staffgeologist)

Sponges, Palaeomagnetism and Ophiolites

You can read this brief article on the ancient sponge biomarkers or read through the Google News results regarding these ancient Omani trace fossils.

Chris’s post at Highly Allochthonous on Magnetic Polar Reversals

Wikipedia on Ophiolites

Google Earth and Geology

Ron’s blog article on Building  a Google Earth Geology Layer

Jess on Using Google Earth to Visualize Volcanic and Seismic Activity

Kim on similar matters in Google Earth Explosion

The OneGeology project

Chris’s post on Geoaggregation

And a few other links

The Dibblee Geological Foundation

The HMS Beagle Project which Chris mentioned.

Ryan’s Staff Geologist page

Ron’s Geoblogosphere Search Engine

del.icio.us/podclast

We have a del.icio.us account which can be found at http://del.icio.us/podclast. All the web pages and resources we’ve found and used in the discussions on the podclast can be found here. A convenient way to browse per episode is to go to, for example, http://del.icio.us/podclast/episode7 (for this episode).

If you find a link to a topic that you’d like to hear discussed on the podclast, or have a link to a topic that’s already been discussed, you can add links to the podclast page through your own del.icio.us account.

When saving a link, include the tags for:podclast and episodeX (where X is the episode number – for example episode8). You can add more than one episode tag if the link applies to multiple episodes.

Next Episode

We like to have a new episode of the podClast every fortnight, so the next episode will be recorded on Sunday the 8th of March at 2000 GMT.

Contributing

If you’re keen to hear a specific topic talked about, or would like to join the discussion during the next episode, either leave a comment below or email chris [the at symbol] goodschist.com. You’ll probably also do well reading the details on joining the podclast. If you don’t have the time to join us but would like to contribute a 3-5 minute audio clip to the show simply record it, make sure it’s an mp3, and send it to the address above.

Credit

The intro and exit music was Roots Fi Cool by Burning Babylon.

I a geologist have illdefined notion of land covered with ocean, former animals, slow force cracking surface &c truly poetical (V. Wordsworth about science being sufficiently habitual to be poetic)

Darwin defined himself as a geologist. His seminal publication On The Origin of Species relied on what would later be known as the Theory of Plate Tectonics in order to geographically isolate and then force adaptation in species. (You can try and read Darwin’s hand written notebook M here or read the plain text version here).

So from one geologist to another, happy bicentennial Charles.

Sandra Herbert has written a book called Charles Darwin, Geologist, which is definitely on my “to read” list between now and the 24th of November, the sesquicentennial of the publication of “Origin”. Which I should probably read through again before that date too. If you’re up for reading through some superb 19th century scientific literature, On  The Origin of Species by Means of Natural Selection (here’s the pdf) can be read at Darwin Online (or at Google Books), along with all of Darwin’s other works (and there are plenty).

Now my gushing is out of the way, I’ve often been interested in the evolution of Darwin’s immense beard. Here to hopefully inspire your own interest in the growth of this fascinating creature, I present Darwin’s beard through the ages (all images can be clicked and embiggened);

Every species but one (the first one) requires some sort of ancestor. Here we observe Darwin’s beard in early, primitive forms (left to right ages 7, 29 and 32). Not so much covering the chin, as framing it. Natural selection had obviously not required an adaptation requiring complete chin coverage in this environment, but the genesis is obvious.

At this stage of evolution (aged 45 and 51), the beard not so much as changes, but finds itself the in a changing environment where previous domination by head hair has come and gone. The time seems appropriate to fill the vacated niches. But how? Only natural selection will bear fruit on this mystery. A appearance of the clade known as “the crazy eyes”is brief and not well preserved in the fossil record.

Finally the last and most developed specimens of the Darwin beard (age 60 and 72). Here it makes its finest and most dominating appearance in its natural environment. Had suitable conditions continued, imagine the great evolutionary frontiers the mighty Darwin beard could have reached. Perhaps natural geographical isolation could have formed between hair of neck and hair of chin, resulting in speciation the likes of which the world has never seen.

Next year will mark both Darwin’s 200th birthday and the 150th anniversary of the first publication of The Origin of Species, so get to thinking about your celebrations.

But to be clear, what defines an epoch, an age, a period and era or an eon in the geological sense is reasonably arbitrary. There is nothing in particular one must consider as a marker between two periods. Time periods can be determined as the time when a particular large group of biota become extinct (like the P-T extinction event) or when there’s enough cooling for rocks to form and then for some of those rocks to still exist (like the Hadean-Archean boundary). A geological time is defined by geologists saying “that’s a good point right there because of this”, and nothing more. Brain at Clastic Detritus has an article expressing how annoyingly wrong a news article got this particular point.

In his latest article, The Anthropocene revisited, Andrew Alden takes another look at the concept of recognising the remarkable changes the human species has had on the geological record as a new geological epoch (Universe Today also has a good article up on this topic). The concept of the Anthropocene, as originally suggested by Nobel Prize-winning chemist Paul Crutzen in 2002 is discussed in a (freely available) GSA Journal paper entitled “Are we now living in the Anthropocene“, which I quote below;

A case can be made for its consideration as a formal epoch in that, since the start of the Industrial Revolution, Earth has endured changes sufficient to leave a global stratigraphic signature distinct from that of the Holocene or of previous Pleistocene interglacial phases, encompassing novel biotic, sedimentary, and geochemical change.
Zalasiewicz et. al., 2008

The current “sixth mass extinction” event we are causing started in the Holocene, the epoch that is defined as the 10,000 carbon years preceding 1950 (Zalasiewicz et. al. 2008, Wikipedia). This was the end of the Younger Dryas, the name given to the last ice age, and saw the beginning of the widespread extinction of mega fauna such as the Mammoth and the last Saber Tooth Tiger species. This, much like the extinction event at the Cretaceous-Tertiary boundary, began and continued slowly (in human terms) until a single event established it as a true geological boundary (and I’ve discussed this particular point before). It was a slow process. It began slowly (say, over a period like 10,000 years), and then ended suddenly (over a few months, but a few decades is basically the same in geological terms).

Though establishing a new epoch is probably best in terms of scientific enquiry, it would make the dawn of human domination of the Earth (the Holocene) a separate epoch from the widespread changes that domination brought with it. And if you consider the human phenomenon as a single natural process, it may make more sense to consider the beginning, duration and end as a single time period. And not to put too finer point on it, I think the amount of change currently occurring is so dramatic that establishing a new epoch maybe underplaying it. Should we begin to consider the establishment of a new Period once we can no longer sustain ourselves to cause as much change as we are currently? That being said, I’m in favour of considering everything since a yet-to-be decided point (and by point, I mean a very precise, slightly un-geological point, like new years eve 1850), as a new epoch, even if it does make the Holocene the shortest geological epoch ever. To be fair, I’m more interested in pre-Hadean events than the latter parts of the Quaternary.

References

• Zalasiewicz J, Williams M, Smith A, Barry TL, Coe AL, et al. (2008) Are we now living in the Anthropocene. GSA Today: Vol. 18, No. 2 pp. 4–8