Fossils

[Tero]

I gave the seniors a class and as I am not a geologist, I did not have a good explanation of fossil content.

It looks like sedimentary rock, but what exactly?
https://www.enchantedlearning.com/subje ... ilhow.html

[Brian Peacock]

Jesus put fossils in the ground to test your faith Tero - that's why you can't explain them. Nobody can.

[Rum]

I thought this thread might be a suggestion for a new name for the forum.

[laklak]

We're not completely ossified. Yet.

[Tero]

I'm going to my coccoon now for an hour after the snow shoveling. How long will it take for me to fossilize?

[Tero]

Bone is apatite and organic matter. The organic marrow obviously decomposes
https://www.sciencedirect.com/science/a ... 2789900231
Calcite
https://english.fossiel.net/information ... %20fossils

[Clinton Huxley]

I thought this thread might be a suggestion for a new name for the forum.

Ha.

The Rationaliferous Era.

[Tero]

Bone is apatite and organic matter. The organic marrow obviously decomposes
https://www.sciencedirect.com/science/a ... 2789900231
Calcite
https://english.fossiel.net/information ... %20fossils

So expanding on that a bit, fossil bones are very heavy, as they are solid rock all the way through. There is a change from calcium salts of phsophate (apatatite) to calcium carbonate (calcite or lime stone even). The outside is solid enough in a bone, but porous just enough to let new salt seep in. The calcite may just be less soluble than the apatite that you start with. Bone marrow is rotted away and the hole filled up.

[JimC]

I remember with great fondness going with my father to sea cliffs on the Victorian coast - Miocene sediments, from memory. Dad would collect samples of the rock, take them home, gently break them up, sieve them, and prepare microscope slides of the most beautiful microscopic fossils, Foraminiferans. They are the remaining cases of single celled marine protozoans, and come in a huge variety of forms, many with great elegance. There are plenty of living examples, too, usually living in the first few cm of the ocean floor.

Dad, although an amateur, was a leading taxonomist of this group, and published dozens of scientific papers, often naming new species and even new genera.

[Brian Peacock]

You made me go looking for them Jim. Fascinating.



https://schaechter.asmblog.org/schaecht ... ifera.html

[NineBerry]

My bones sometimes already feel as heavy as stone.

[JimC]

Fantastic image, Brian! Dad used to make up mounted slides of forams, with a black background. He would use a paintbrush, slightly moistened, with a single fine hair, to position them. He would then do the most beautiful drawings using a stippling technique (he was trained as a draughtsman and architect), which became the basis for the plates of illustrations in his papers. He amassed a large collection, many of them type specimens, which went to the Melbourne Museum after he passed away. My eldest son worked there for a year, and was chuffed to find granddad's collection...

[Brian Peacock]

I've been playing with various images of formanifera...

[JimC]

The sheer variety of their forms is astounding. As an architect by profession, I suspect Dad found his amateur naturalist hobby a good fit...

[L'Emmerdeur]

Speaking of tiny fossils, a recent study points to a wider diversification among Precambrian testate amoebae (those with shells) than was known previously. This tends to demonstrate that the Cambrian explosion was not as abrupt an event as it had previously seemed. The vase-shaped microfossils that some species of testate amoebae left are nowhere near as visually interesting as the huge variety found in later foraminifera, but this finding is a step forward in understanding the Cambrian explosion, which I think is cool.

'Amoebas diversified much earlier than thought'

Amoebas diversified at least 750 million years ago, far earlier than previously thought, researchers have revealed.

The finding, from a team led by Daniel Lahr of the University of São Paulo in Brazil, challenges existing theory about life during the time. Known as the late Precambrian period, it was thought to feature only a small number of unicellular lineages, including undifferentiated proto-amoebae and photosynthetic algae known as stromatolites.

The new study revealed eight new ancestral lineages of Thecamoebae, the largest group in the amoeba domain. This newly discovered diversity has implications for understanding how microorganisms evolved on Earth.

"We show that diversification apparently already existed in the Precambrian and that it probably occurred at the same time as ocean oxygenation,” says Lahr.