#acritarch

[geologyjohnson]

Weird Precambrian Microfossils

Here is one of the weird fossils I've been working on since getting back to Belgium. It's about 60 microns long, or 0.06 millimetres and 1.4 billion years old and no one in the lab has seen anything like it before. The texture is not just a surface pattern, the light areas are pits, the dark areas are raised tubes. There are multiple layers of tissue and structures that look like pore that could open and close. These features indicate the fossil is probably from a eukaryotic organism - those with complex nucleated cells. I don't think this level of detail has ever been preserved in a fossil this old before. Additionally, you normally need to look at rocks less than a billion years old to find fossils with this level of complexity.

This fossil is significant because it lived at a time when we did not think life this complex existed yet. This is a period of time called "The Boring Billion" where the Earths environment and biology were thought to have entered a period of stasis - e.g. nothing changed for a billion years. My work will join a growing body of research that shows this interval was anything but boring, and was actually a pivotal period in the development of our planet and the life that inhabits it.

[goodrichthyseskdalensis]

Which Proterozoic acritarch is your favourite?

Dictyosphaera

Leiosphaeridia

Satka favosa

Valeria lophostriata

Tappania

Other (Comment)

Voting ended onApr 21, 2025

[geologyjohnson]

One of my proterozoic mudstone samples. The red arrow points to an organic walled Acritarch with 3D preservation, the green arrow points to an unusual net-like texture that is common in these samples

[geologyjohnson]

This is a high resolution photo of one of the rocks I study. The weird textures and shapes you can see were left on the seabed by microscopic organisms over a billion years ago. Not sure if the compression will ruin the image, but on the full version you can see structures as small as 0.05 mm. The photo is a stack of 30 separate photos taken with a macro lens then blended together. When we dissolved this rock in acid, we could extract the microbial fossils because they are made of organic matter which is what makes the rock look black. The little fossils look like tiny versions of the structures we can see in the photo.

[geologyjohnson]

Detail of a bedding plane with lovely textures on a carbonaceous clay lamination in a Paleoarchean sandstone. FOV is about 5 mm across.

[geologyjohnson]

Ancient Microbial Mat

#ThinsectionThursday An extreme close up of a #Precambrian microbial mat. This sample is over 1 billion years old. Dirty grey-brown is silt and silica cement with amorphous organic matter. Orange brown is titanite, and the dark grey brown to black is filamentous organic matter. The image is about 0.25 mm across #Geology #Paleontology.

[geologyjohnson]

1.5 Billion year old Eukaryote microfossil

Proterozoic #acritarch photographed in high res. This taxa appears to bud while undergoing torsion. This is made from focus stacking many images at high mag. Fossil is ~50 x 85 microns. The smallest resolvable objects on the full res version are ~ 500 nm. #Geology #Paleontology #Fossils #precambrian #tiny #geologyjohnson

[geologyjohnson]

FossilFriday a 3.22 Ga #acritarch from the Moodies Group, South Africa. These were first described by Javaux et al in 2010. But they've not been found since. I'm looking for more of them using new unweathered sample material. Details in alt text #Geology #Paleontology

greyscale microscope image of a circular microfossil with a surface that is wrinkled and speckled, and has radial cracks at the edges. These features indicate that the fossil was probably a 3D vesicle that has been compacted. There is a black arrow that points to one of the larger folds, and a black 50 micron scale bar that shows the fossil is about 300 microns wide. original paper: https://www.nature.com/articles/nature08793