Whoomph.. the volcano blew its top and left a crater. The big hole, shaped like an ice-cream cone, then filled with water. There was nothing to disturb the sediment at the bottom of the lake (described as “anoxic” i.e. no oxygen). Around the lake an evergreen rainforest, a “vine forest”, supported all sorts of plant and animal life. When did the eruption occur? 23 MILLION years ago!
As a rough idea the “maar” lake would have looked a bit like in this photo… and if you wonder why I’ve picked a photo of Lake Eacham in North Queensland (Australia) that’s because Dr Paula Peeters observed that it would’ve been similar, in her excellent blog-post Drawing on Queensland’s present to recreate New Zealand’s past.
Then over time things in the lake would die and fall to the bottom. Other stuff would fall into the lake, one way or another, and sink to the bottom. This stuff, these things, didn’t decompose (no oxygen), and there was nothing living there to disturb them… so they’d just sit on the bottom and were preserved. For a period of 120,000 years, there was a bloom of diatoms on the surface every spring/summer and these would sink to the bottom and form a 1mm blanket, covering whatever was there… every year. Diatoms contain silica and the stuff/things were preserved in “exquisite” condition.
Things like this leaf (photo via Assoc Prof Daphne Lee, University of Otago)
Click on the photo to enlarge
What other things? Examples:
- numerous leaves, entire cell structure preserved and you can look at, for example, stomata
- flowers with petals and pollen still on the anthers
- fish Galaxias – some with preserved soft tissue; a species of eel
- insects with eyes and antennae
- bird poo (!)
And there’s a wealth of other things and stuff waiting to be found! The maar is 1000m x 800m. It’s also been drilled down through the middle to the bottom and a 183m core removed and stored frozen at the University of Otago. University staff and students visit Foulden Maar 3 or 4 times a year and retrieve items of interest to take back for research BUT the quantity of what they’ve looked at is described as being like a teaspoon from a rugby field. If they examined closer to the edges they might find some more really cool things, like moa remains and crocodiles.
AND I haven’t even touched on leaf fossils and changes in CO2 levels that scientists can correlate with ancient ice melt, aiding our understanding of climate change.
Over the last few days I’ve been reading and learning more about this situation at Foulden Maar and the very real possibility that we could LOSE this TREASURE TROVE to commercial interests who plan to mine the lot.
If you don’t know why these fossils are under threat, you haven’t read my post They Don’t Bat an Eyelid – please do!
YOU CAN SIGN THE PETITION TO SAVE FOULDEN MAAR !!!
Everybody… this includes readers outside of New Zealand
Add your name to the Petition to Save Foulden Maar.
— there’s already over 6000 people signed up to this —
References (not already linked to above)
The radio interviews below are really good as the interviewees explain things in a much simpler way than what you normally read.
— Radio New Zealand interviews with:
Assoc Prof Daphne Lee University of Otago (15 May 2019)
Daphne Lee has written 40 papers on Foulden Maar and has a long association with the site, regularly taking field trips there over the years.
Dr Nic Rawlence director, paleogenetics lab, Uni of Otago (13 May 2019)
Dr Beth Fox 20 October 2016
Leaf fossils, CO2 levels and correlation with ancient ice melt
— Wikipedia Article (being regularly updated)
There are many references to earlier news articles on my previous post They Don’t Bat an Eyelid
The Science Media Centre published a summary of news headlines about Foulden Maar on its page of 16 May 2019: Proposal to mine Foulden Maar – In the News
Are you on Twitter? … https://twitter.com/savefouldenmaar
Disclaimer: I am not a scientist. I’ve given you plenty of references in my blog-posts so that you can check these things out for yourself, by reading or listening to what the experts are saying about Foulden Maar
Posted by Liz; Exploring Colour (2019)