Friday, 11 April 2014

You Never Forget Your First Marine Reptile

I heard back from my friend at the museum - I can't believe my luck: a bona fide marine reptile vertebrae from the late Jurassic!

It's only one bone. It's not even one complete bone, but I found it, and it's mine.

A fossil reptile? Yes please-iosaur!

From the article Plesiosaur Peril

Monday, 7 April 2014

Taking to the Skye

I do occasionally go on holidays but, being slightly science-crazed, these often resemble ill-advised naturalist expeditions rather than relaxing getaways. No lazing on beaches sipping margaritas for the Science Lady. I enjoy treks up mountains, carrying basalt slabs back to the car with a crazed gleam in my eyes muttering "quartz bubbles"; negotiating slippery algae-clad shorelines to the base of unstable cliffs to fill my pockets with chunks of ammonite graveyard;  or hunched over clay beds with my cold fingers knuckle-deep in the Jurassic, and smears of diatom streaked over my cheeks like war paint.

So it was on the Isle of Skye this week, when my partner and I followed the recommendation of a palaeontologist friend and explored the Jurassic coastline there.

Driving north into the trap topography of Trotternish. This ridge is the edge
of basalt lava flows, the Old Man of Storr is visible on the right.
Skye has some wonderfully unique geology for Scotland. In the south it rests it's knees along the staggeringly ancient rocks of the moine thrust, the fault-line that runs the length of the west coast of Scotland. There, on the Sleat peninsula, the topography appears much the same as the nearby mainland. Most of the rest of the Island is far younger, a mere 50-65 million years old - a geological toddler one might say - and quite different in character. In the centre of the island are the Cuillins, famously ragged peaks formed from the remnants of a giant volcanic magma chamber. This chamber sat between Greenland/North America and Scotland/Europe, as the two halves pulled apart to form the Atlantic Ocean.
Looking south from the base of Old Man of Storr (behind me).
See the layers of basalt rock tilted in the middle-ground.

Break ups are always hard. The Skye volcanoes wept floods of basalt for millions of years over this one. These floods are known as traps, and form distinctive layered platforms of the north of the island. They are quite resistant to erosion, but imperfections and cracks allow beautiful jutting formations to form. Google 'Skye', and the images you get are all of the iconic Old Man of Storr. He's so famous, he's even been to Hollywood. We trekked up and sat at the Old Man's feet for a while to enjoy the spring sunshine and try and count the lava layers in the cliffs behind us (apparently there are 32 lava flows visible here).

The basalt is peppered with little bubbles, each one filled
with quartz crystals. This one has broken open.
As well as the Tertiary traps, there are numerous remnants of older Mesozoic rock, or as I tell my non-geological friends, dinosaur-age rock.

Palaeontology is pretty much a synonym for dino-studies to most folk, but these wonderful creatures are just a tiny slice of the palaeo-science pie. Although the Mesozoic rock in Skye is the right age for dinosaurs, I had no illusions about finding T-Rex buried there. (Firstly, the areas we were visiting were marine sediments, so unless T-Rex had a penchant for scuba, it was unlikely. Secondly the strata are too early - like all the fashionable dinosaurs, Mr. Rex arrived late to the party). I expected to find ammonites and belemnites: not sexy or unusual, but I reckon digging up anything that was alive 150 million years ago is pretty impressive.


Our first fossil collection site. Opposite, the flood basalt
is sitting on top of a thick layer of Jurassic rock.
Two big belemnites, surrounded by
little marine creatures
Various shelled marine creatures
Ammonites, belemnites and other marine beasties abound in the Jurassic sediments of Skyes eastern shore. These were my first belemnites (or dolomites, as the man in the pub in Portree called them), so I was suitably chuffed about claiming a few of their little dead bodies for my collection. Most were peaking coyly from the edges of herculean boulders, and as much of the coastline here is designated SSSI (Site of Special Scientific Interest), it is protected from over-zealous collectors who might take a hammer to the lot. Any hammering here and you can expect to be prosecuted. However there were a few small rocks and fossil pieces to fit in the pocket.

The biggest ammonite we could
find, but far from portable!

This site contrasted sharply with the squidgy second visit further long the coast, where Kimmeridgian and Oxfordian clays meet one other, and the sea. Slowly, these late Jurassic layers spill their guts across the high tide line, belching out belemnites like a child who ate his crayons. The ammonites however, are soft white ghosts here, disappearing into a chalky smudge under your fingertips. Harder sediment packed with millions of shells and fragments can be found, including the ominous 'devils toenail' (Gryphaea), an ancient bivalve mollusc said to resemble Satan's tootsies.

Our second site near Flodigarry.

An ammonite, plucked gentle from
the clay. It is squidgy.
We struggled not to get covered in the dense clays, marvelling at how such ancient rock can be soft (chemistry, alas, my weakness). After collecting the best little specimens we could find, we were taking a last look along the shore when I spotted... could it be? A bone? I reminded myself not to go totally bananas with excitement, after all, I'm not an expert (yet) so I could be wrong, but I think it is...

I've taken it home, taken pictures and sent them off for an informed second opinion.

Could I really have found my first fossil reptile?