Fossiliferous Tyndall Stone in Downtown Peterborough
To log this earthcache it is advisable to use the images below on the cache page to identify log requirements. This is a neat winter and public friendly Earthcache in the Heart of Peterborough's Downtown Core. For this Earthcache you will only need to walk along the perimeter of the building and can answer all questions by remaining on the sidewalk as outlined in the provided overhead image. GZ should provide parking if you're visiting after normal business hours.
Where does this rock get quarried? Tyndall Stone is quarried at Garson, Manitoba. Geologically, it is referred as the Upper Mottled Limestone of the Red River Formation of the Ordovician System. Due to the beauty of the stone as well as notoriety among architecs, this stone has been exported and used all over Canada.
How did this stone form?Four hundred and fifty million years ago, what is now southern Manitoba was part of a warm, shallow, inland sea. During this time, which geologists call the Ordovician Period, many different types of animals lived in this ocean. Some, such as corals, sponges, molluscs, and algae, we would recognize today. Others, such as trilobites and stromatoporoids, are extinct. All of these creatures lived on or above the soft, muddy sea floor. After they died, their remains became part of it. The calcium carbonate in their skeletons made the mud limey, so that when it hardened into rock it became limestone. Fossils of these animals and plants are visible today in Tyndall Stone. Other animals burrowed in the mud of the sea floor for food or protection.And it is the preserved burrows of these creatures that make the beautiful mottling which gives Tyndall Stone its unique appearance. Nobody knows what exactly these animals were, because the traces of their burrows are all that they left behind.But shrimp in the Caribbean Sea make similar burrows today, so it's possible these creatures were shrimp-like.
What are some of the fossils present? Two major types of fossils occur in Tyndall Stone. The first are body fossils. These are the calcite shells of a variety of marine animals and plants that lie scattered through the stone -- like raisins suspended in a pudding. The second are trace fossils in the form of a network of burrows that extends through the entire rock. Body fossils are evident as shells in random cross-section on surfaces of Tyndall Stone. Brachiopods and trilobites are present but difficult to identify. With their thicker shells and distinctive internal septae, small solitary rugose corals are easier to see. Large mollusks, such as gastropods and cephalopods, are preserved as internal moulds. The most conspicuous fossils are mounds of colonial tabulate corals and stromatoporoids. The largest and most enigmatic of the Tyndall fossils is the so-called "sunflower coral" which occur as circular "colonies" the size of a basketball. These fossils are assigned to Receptaculites which is thought to be an extinct type of calcareous algae.
To complete this Earthcache, You will be required to fill in this form.
To Log This Earthcache, Please email us with the answers to the following questions:
1- Include with your log, a photo that clearly demonstrates that you visited this Earthcache. You do not have to be in the photo as per policies. However, including a picture of the area, although optional, is the best way to display your visit.
2- Fill in the above table and submit where you find the fossils (North or West side).
3- Using an instrument or tool of your choice, measure the size of one fossil to provide a reference scale. Take pictures or remember this fossil and Identify it using this online gallery! Give it your best shot and explore all the various fossils that are within this great rock.
4- Tell us which fossils you believe are body fossils and which are trace fossils.
BONUS- What is the name of the building which you are visiting? and do you know the story behind their legacy in the Peterborough region?
Many thanks to NeoDorcet and Junglehair for their guideance in placing this earthcache.
Other notable Tyndall Earthcache's:
Tyndall Stone: Manitoba Rocks! - GC2F770
La tapisserie de Tyndall- The tapestry - GC2JEH6
Manitoba Tyndall Stone - GC12TPF
Reference Material:
http://www.tyndallstone.com/companyindex.html
http://www.gac.ca/PopularGeoscience/factsheets/TyndallStone_e.pdf
http://gsc.nrcan.gc.ca/paleochron/17_e.php
http://dfp.mediacooks.com/fossils/index.html