The origins and evolution of the basin are attributed to the east-west movement of earth's surface along the Minas Fault Zone during the late Devonian period 419 million years ago, referred to as the fish and fossil period, to the Carboniferous period, 358 million years ago, the swamp and coal period. A Basin begins as a low lying area or depression in the earth’s surface(sometimes below sea level), where rock and sediment are trapped as they move along by forces of weathering or erosion, shifting of the earth’s crust and gravity. There is evidence of an abundance of Sedimentary rock in the St. Mary’s Basin. This type of rock results from deformation, or alteration in shape and size of pieces of pre-existing rocks, loosened by exposure to wind, ice and water. As the rock and sediment become trapped, it can become compacted and cemented into sedimentary rock. The four types of sedimentary rock are Conglomerate, Breccia, Sandstone and Shale. Conglomerate rock features a coarse make up of predominately round grains of 64mm to 256m in size. Breccia contains angular grains of course material about 2mm to 4 mm in size. Sandstones grains range in size from 1/16mm to 2 mm. Shale grains are less than 1/16 mm, mainly mud and flakes of clay silt sized particles, fine grained quartz or calcite. Sedimentary rocks are the only rocks that contain fossils or indicators of climate, such as ripple marks, mud cracks and raindrops, that were present when the rock formed. At GZ and several locations along the TCT (the great trail), you will see a Sedimentary rock deposits un earthed during construction of the Guysborough Railway 80 years ago.
To log this Earthcache, please answer the following questions and e-mail to cache owner. You must answer all questions and e mail cache owner before logging.
1. What type of sedimentary rock is abundant at GZ?
2. Identify the characteristic and colour of the rock which leads you to conclude what type of rock it is?
3. What are THREE uses for this type of rock?
4. What is the sea level at GZ?
5.[REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please post a photo in your log of yourself or a personal item at the outcrop to prove you visited the site.