#microfossil

[geologyjohnson]

This is an acritarch from my mid Proterozoic sediments, it's usually found in association with the weird textures I've been posting. This image is a stack and stitch of 100+ images at 100x mag. It was an early attempt hence the glitches.

[intelligentliving]

Ancient Microfossil Reveals Missing Link In The Evolution Of Animals

Scientists, led by the UK’s University of Sheffield and Boston College in the USA, discovered a microfossil in the Scottish Highlands, which could be the oldest fossil of its kind on record. The tiny fossil, dated to around one billion years ago, contains two distinctly different cell types and appears...

[earthstory]

Zone Fossils (Index Fossils) The recognition and use of zone fossils is fundamental to biostratigraphic correlation. Fossil groups that were (i) rapidly evolving, (ii) widespread across different facies and biogeographic provinces (facies are the rocks that represent a particular life environment), (iii) relatively common, and (iv) easy to identify make the ideal zone fossils. In the Early Paleozoic macrofauna, graptolites are the closest to being ideal zone fossils, whereas during the Mesozoic, the ammonites(http://on.fb.me/1LYL0Lm) are most useful.

The use of efficient zone fossils ensures that relatively short intervals of geological time can be correlated, often with a precision of a few hundred thousand years, over long distances through different facies belts around the world. In practice there are no ideal zone fossils. Most long-range correlations involve use of intermediate faunas with mixed facies. For example, in Ordovician and Silurian rocks, deep-water facies are correlated by means of the rapidly-evolving and widespread graptolites; these fossils are rare in shallow-water shelf deposits where trilobites and brachiopods are much more common. Nevertheless, facies with both graptolite and shelly faunas may interdigitate in deep-shelf and slope sequences, allowing correlation through these mixed facies from deep to shallow water. Parallels can be drawn with a neritic ammonites and benthic bivalves and gastropods of the Mesozoic seas. Microfossils are widely used for correlation in hydrocarbon exploration; the amount of rock available in drill cores or cuttings is usually limited and a range of fossil microorganisms including foraminiferans (members of a phylum or class of amoeboid protists), and radiolarians (protozoa) together with dinoflagellates (flagellate protists), spores and pollen form the basis of the correlation schemes used by petroleum companies. ~ JM Image Credit: http://bit.ly/1grt7ZC Labelled for re-use. More Info: Index Fossils: https://pubs.usgs.gov/gip/geotime/fossils.html http://abt.cm/1dPEOY3

[fissurina]

So...after many years of work and to my great delight, my book was published this year just before christmas. Above is my favourite plate of specimens out of the 25 pages of illustrations. Forams are cool and beautiful.

[geologyjohnson]

Fossil Microbial Mats

Extreme close ups of 1.3 billion year old microbial mats in muddy OM rich chert. Fossils are the dark filaments and spheres, surrounded by a pale coating of phosphate and silica. Some fossils have been replaced by silica, phosphate, or pyrite. The little spheres and long filamentous structures are the fossil microbes. The scale bar at the side says 20 microns, which is a bit thinner than a human hair. So that gives you an idea of how tiny these microbes where.

Each sphere and filament was a tiny colony of individual microbes. So each sphere and filament is like a tower block full of apartments the microbes lived in, and the mat is like a city.

But these mats were so dense and thick, that if you scaled up one of the fossil microbes to the size of an average human, the mat would be 25 km high and cover all of Europe and most of Asia.

Mats like this covered the floor of Earths shallow seas long before animals and plants evolved. The tops of the mats were photo synthesisers, below them live microbes that could convert sulphur and iron into energy.

These microbial communities worked nonstop for billions of years, changing the chemistry of the Earths oceans and atmosphere, pumping out oxygen, and making the world habitable to more complex life like the first simple animals, and eventually humans.

They were here long before even the simplest animals and plants, and they will be here long after we have gone. Microbial mats like this will probably be some of the last life on Earth, and I wouldn't be surprised if they were common on warm, wet, rocky planets throughout the universe.

[earthstory]

What have fossils ever done for us?

Palaeontology has provided the inspiration for many great works. But just what is it that palaeontologists actually do with fossils once they’ve got them out of the ground? Of course, you can clean them up and show them off in a museum, and this is the side of palaeontology that the vast majority of the public sees. Nothing is quite as eye-catching as a dinosaur, and the beauty of ammonites is undeniable. This is the realm of curating, though and although it’s the dream job of many palaeontologists, there are only so many museums in the world. Instead, many palaeontologists work on micro-fossils.

As the name suggests, micro-fossils are fossils which are especially small. Whilst they can be spectacular to look at, their main use is for biostratigraphy. Biostratigraphy is the use of fossils to divide rock sequences into time zones. This is done using what are known as index fossils: fossils that are abundant, wide-ranging, and went extinct relatively fast.

Graptolites, an enigmatic group unique to the Palaeozoic, are a fantastic example of this. These organisms can be found in almost all deep-water deposits in the Ordovician and Silurian. Many individual species last for little more than a million years, with some having ranges as short as 300,000 years. Though an incredibly long time from a human perspective, in geological timescales it’s simply the blink of an eye.

But why do we want to know how old rocks are, and how do we know that? Knowing the age of rocks is important for multiple reasons; for example, oil deposits in some areas of the world occur within shales of certain ages. While radiometric dating is an incredibly useful technique for both igneous and metamorphic rocks, it is not a technique that can be reliably used with sedimentary rocks. As such, other methods need to be found. Microfossils can be extracted from boreholes with very little risk of damage and, by determining the biozone of the species, can be used to determine rock age. Microfossils like these can be extracted from rocks sampled through boreholes and matched with microfossils from other areas; matching index fossils would mean the rocks have the same age!

Biozone ranges are determined by radioactively dating overlying and underlying igneous deposits. This gives a maximum and minimum age for the deposit, though the boundaries are difficult to define beyond this. By finding a good biozone defining species entirely within the deposit, it can be correlated across the world with deposits that have not had the good fortune to be bounded by volcanic layers. Once you have a matching age, you can do all sorts of other comparisons, such as figuring out where shorelines were or where units might have generated resources.

Dale

Image Credit of various Graptolites - http://geolmag.geoscienceworld.org/cgi/content-nw/full/147/2/253/FIG2 Read More - http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8447431 - http://www.stratigraphy.org/upload/bak/bio.htm - http://the-earth-story.com/post/90435946398/whos-been-writing-on-the-rocks-although-theres

[earthstory]

Ossicle This ring-shaped feature is a piece of calcium carbonate that, about 150 million years ago, was part of a Sea Cucumber. These animals are actually echinoderms – the same phylum as starfish and crinoids, but with a completely different body plan. They are often elongate and mostly fleshy tissue – hence their nickname as “Sea cucumbers”. They secrete a tiny internal skeleton in the form of these tiny, calcite “ossicles” (the term for very small parts of a skeleton or very small bones like those of your ear). In sea cucumbers, the tissues and muscles attach to these tiny rings, helping to provide support for the whole body. When the organism dies, those ossicles are released as mineralized “microfossils” – this one is about half a millimeter across and comes from a limestone from the Tethys Seaway, today found in the Czech Republic. It was photographed using an electron microscope -JBB Image credit: Petr Hykš https://flic.kr/p/DSpxju Reference: http://tolweb.org/Holothuroidea

[earthstory]

jenebauerSome days are spent creating digital forams! Foraminifera are microfossils and are hard (sometimes impossible) to see with just your eyes. We are scanning large palm sized models to create digital fossils to share with everyone!!!