Sedbergh is known as England's Book Town. Have a wander through and there is lots to see.
This EarthCache involves looking down at what there is on the floor, namely the flagstones. The flagstones were originally sediment in a marine environment, such as a lake, lagoon or sea. Over millenia, layers built up,and over time stone was formed. It was also full of marine life, and whilst it was millions of years ago, it is still possible to see fossils which show what the lifeforms were like. Now, fossils are the preserved remains of plants and animals, but these tend just to show a structure such as a shell, bone or part of a tree. There is a type of fossil known an ichnofossil here, indeed it is abundant here.
🤔 What is an Ichnofossil?
An ichnofossil is a trace of a biological activity, preserved in the form of a geological record. They are also known as trace fossils, and thus show a trace of an impression made on the substrate, and can be root cavities, burrows, feeding marks, footprints, and remains of excretia, such as fossilized droppings.
🤔 Bioturbation.
Here there is evidence of bioturbation. We imagine that when sediment is deposited, it just forms layers, and eventually limestone is formed. Though a marine environment is not just the lifeforms in the water, there is also animals living on and in the sediment itself. These animals included shellfish, worms, crabs and prawns. In the process of moving about, and firming burrows, they bioturbated the sediment. Basically it was moved about by their actions. The ichnofossil here is evidence of bioturbation occuring. The specific ichnofossil type is a burrow, but what type of burrow?
🤔 Types of burrows.
➡️ Domichnia burrows.
➡️ Thalassinoides burrows.
➡️ Chondrites burrows.
This being an EarthCache, in order to log it, I ask that you answer some questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. What type of burrows are there here?
2. In what type of environment was the original sediment deposited?
3. How wide are the burrows? How wide do you think the creatures that created the burrows was ? (Allow for 1mm each side of the creatures).