The Brigus Fault EarthCache
Hidden : 5/9/2013
Difficulty:
1.5 out of 5
Terrain:
1.5 out of 5

Size: Size: not chosen (not chosen)

Join now to view geocache location details. It's free!

Watch

How Geocaching Works
Looking for a different adventure?

Please note Use of geocaching.com services is subject to the terms and conditions in our disclaimer.

Geocache Description:

This is an earthcache which provides an educational opportunity to learn about the Brigus Fault.

The Brigus Fault – an EarthCache
 
Travel to the coordinates listed above and you will find yourself standing along the southern shoreline of Brigus Harbour in Newfoundland and Labrador.  This area is often referred to as Frog Marsh. Here you will learn of the two very large rock formations that cover the Brigus area.
 
More than 500 million years ago, during the late Neoproterozoic Era, two major rock formations came together, forming the Brigus Fault. The Drook Formation (part of the Conception Group) formed the western side of the Brigus Fault. The Harbour Main Group formed the eastern side. The contact between these two rock formations is referred to in geological terms as conformable, meaning there is no distinct break or interruption between these two rock formations. The following diagram shows the Brigus Fault dividing the Drook Formation and the Harbour Main Group.


Reference: http://www.nr.gov.nl.ca/mines&en/geosurvey/maps/nl/html_nf/images/88-01.pdf
 
Each of these rock formations has physical characteristics and composition, which make them distinctly different. The Drook Formation is made up of green silicious siltstone and sandstone, and silicified tuff (consolidated volcanic ash). The Harbour Main Group consists of pink to gray felsic tuff and conglomerate; pink to red rhyolite and welded tuff; minor mafic volcanic and clastic sedimentary rocks; green to purple basaltic flows and pyroclastic rocks.
 
Stand at the published coordinates and look northward, across Brigus Bay. You should note the steep coastline on that side of the bay. That area of Brigus Bay forms a point of land called Gallows Cove Point. This is an important landmark as the Brigus Fault lies just east of that area, in the small cove. Look closely and you will see the difference in color and texture of the rocks on either side of the fault.




The westerly outcrop makes up the Drook Formation. It has sedimentary rock that is a greenish grey color and forms vertical layers that are angled eastward at about 60 degrees. You should also note the large vein of quartz that is compressed between these layers, just above the cove.



The rock face east of the cove is more of a purple color with the consistency of large blocks of volcanic looking material. This is the Harbour Main Group.



 
The Brigus Fault crosses Brigus Bay and intersects the area close to the coordinates of this earthcache. It crosses through Frog Marsh , following a southerly direction to Colliers Bay. Spend some time exploring the area and examining the outcrops.  A good example of the Drook Formation can be found at GC4BG0D , and the Harbour Main Group at GC4BEZK.
 
To claim this EarthCache please log your remarks at geocaching.com and send me a separate email of the answers to the following:
1.     In which direction do the stratified layers of the Drook Formation lean ( East or West)?
2.     When looking across Brigus Bay to Gallows Cove Point, what is the predominant color of the Harbour Main Group nearest the water’s edge?
3.     What is the name of the area where the Brigus Fault lies on the south coast of Brigus Bay?
4.     The Brigus Fault runs in what general direction?
5.     What are you standing on when at the published coordinates?
 
 

Additional Hints (No hints available.)



Advertising with Us