Look....when I said I wanted a 'whiskey on the rocks', this isn't exactly what I had in mind.

Welcome to a new weekly feature here at Otters Oddities And Steam Cleaning Services LLC. It is something that will be gracing your computer every Friday morning in lieu of the normal oddity you've all come to expect. This new feature is called:

Friday Rocks!

For those of you who are feeling a bit slow today, allow me to explain. It's Friday, and these posts will be about rocks. Fossils to be exact.

What is a fossil?

A fossil is the preserved remains of an organism from the past.

How is a fossil made?

There is no easy answer to this as there are many different types of fossilization. They include:

  • Adpression - These are compression/impression fossils. For example, a leaf from a tree. The original material undergoes a chemical transformation. The original material is still present in a altered form. When the rock that contains the fossil is split open, one side contains the actual materiel while the other shows just an impression of the original item.
  • Bioimmuration - This happens when the skeletal remains of one organism grows around another organism and an impression of the second organism is left. A common type would be if a brachiopod fell onto a colony of bryozoans and the bryozoans grew around the brachiopod. When the brachiopod decays, an impression is left in the bryozoan.
  • Carbonization - Most living organisms are primarily carbon based. When decomposition occurs, sometimes a trace of the carbon remains creating a silhouette of the original organism.
  • Casts and Molds - This happens when an organism is totally encased in some sort of sediment. When the organism decays away, a cavity in it's shape is left. This is a cast. If this void is filled with another mineral, this is a mold.
  • Permineralization - This happens when the dead organism is buried shortly after death before the decaying process has had a chance to really begin. Mineral rich water permeates all the empty spaces of the organism.
  • Replacement and Recrystallization - This is when the original organism is replaced by a different element, such as calcite or pyrite. The original form of the organism is still present, even though all the original materiel has been replaced.
  • Soft Tissue, Cellular and Molecular Preservation - This is actually a subsection of Adepression. Soft tissue fossils are exceedingly rare. Generally, fossils are made up of shells, bones, or something more solid like vegetation. Soft tissue generally decomposes too fast to be preserved. However, if the proper conditions are met, such as the soft tissue being encased in a mineral-rich, anoxic materiel, the soft tissue can be replaced by other minerals.


But we'll go more into exactly what fossils are as I show them. Let's move on to the first fossil in the series. But before we do, I should note that I have made a couple posts about fossils in the past. These posts have included examples from my own collection. I may show some that you have seen before. Oh well. I'll be going into more detail in these posts, so I think I can get away with it.

The first fossil I'm going to profile is also the oldest fossil I own. That's it, pictured above. It's called a Stromatolite. And how old is it? That's very hard to determine with any sort of accuracy. About all I can say for sure is it's between 1,000,000,000 and 1,500,000,000 years old. (that's between 1 and 1.5 billion years)

Stromatolites are the remains of the first known organisms that inhabited the world. In fact, without these first organisms, we wouldn't be here. These first organisms were known as cyanobacteria. These were a blue-green algae. The oldest ones found date back about 3.5 billion years. The crust of the Earth first solidified about 3.8 billion years ago. That means that in the space of only 300 million years, water collected to form the primordial seas and life first emerged.


We don't really know how that happened. There is speculation, but who can say for certain. (not gonna get into a debate about creationism, panspermia, or spontaneous life)

These cyanobacteria discovered what could be called the most amazing thing to ever happen: photosynthesis. This is the process that allows plants to convert light into energy. And it turned out to be a good thing. Because as a result of this, the cyanobacteria produced oxygen as a waste product.

This oxygen, over the course of several billion years, permeated the atmosphere and the seas and allowed all other life.


Another byproduct of the conversion of light to energy caused the cyanobacteria to become slightly tacky. This allowed them to stick together in large colonies, and also to have small particulate matter attach to them.

As a result of this, the colonies of cyanobacteria began to form structures that supported themselves. As the top layer of bacteria died, the layers underneath kept reproducing, and also producing oxygen. As the colony grew, they would grow into pillars, some reaching 100 meters tall.


In this picture, you can see the different layers of each generation of bacteria that lived. You aren't actually seeing the cyanobacteria, as they were microscopic. Bacteria is all single celled. What you are seeing is, the sediment that attached to the sticky substance the bacteria exuded.

Eventually the cyanobacteria all over the world supplied enough oxygen to the world that other organisms could survive. And for a long time, these other organisms had nothing to eat but cyanobacteria. As a result, cyanobacteria doesn't form into stromatolites any longer. Other organisms eat them too quickly.

Actually, Shark Bay in Australia still has living stromatolites. Scientists estimate that they are about 30,000 to 100,000 years old. The reason they are still around is because the salinity of the bay is too high to support the predators that would eat the cyanobacteria. If you travel to Shark Bay, you can walk out on wooden docks to see the stromatolites. And if you look closely, you will occasionally see a small stream of bubbles rise up from one of them. This is the oxygen the bacteria are 'pooping' out. And it's those little streams of bubbles that took the Earth from having no oxygen at all to having enough to support life today.


These stromatolites would be an example of a mold type fossil.

*Authors Note*

Since this is a new feature, I am still working on the exact format I will follow for these posts. I realize I used a lot of words that you most likely have no idea about what they mean. (bryozoan, brachiopod, panspermia...). This is a problem I didn't really think about until I started typing out this post. As a result, I wasn't prepared to supply definitions. (bryozoan = tiny marine filter feeders that gather in colonies; brachiopod = have hard valves or shells on the upper and lower segments, not to be confused with bivalves which have valves on the left/right; panspermia = the theory that life began somewhere else and then seeded the Earth)


As these posts continue, I will be more prepared with more detailed definitions. I will also not be as rushed writing the posts as I am tonight. Also, most of the fossils I feature will be cooler than a stromatolite. I felt I needed to start with this one because the cyanobacteria that make up stromatolites are responsible for all the oxygen we breathe today.

If there is a way you would like to see the details of the fossils laid out, feel free to post suggestions in the comments.