Description:
Logging requirements are included in the first part of the description. PLEASE make sure you answer all questions. You may log the earthcache as a find once you have completed the logging requirements. I will contact you if I have questions or need clarification.
Driving Directions:
“From route 470, follow Route 470-10 (Margaree-Fox Roost Road) bou 2.5 kilometers toward the coast. In margaree, turn left towards Fox Roost. About 600 meters further, a side road leads to the shore; you may see a small sign for the Misery Point Livyer’s Point Station. Follow the side road to the shore, about 150 meters.” (Geology of Newfoundland)
Hike:
There is a short walk (0.2 km) through grasses to the rock formation. It is best viewed at low tide.
Introduction:
When you first see the fine outcrop of gneiss (pronounce “nice”) it probably simply looks like gray swirls on the beach cliff. However, if you look closer, you will notice a LOT of different minerals. It looks kinda like taffy, the yummy gooey treat kids and adults alike love!
Logging Requirements:
You are looking for THREE things:
Quartz & Feldspar – these are the white (you should see milky as well as a pink/translucent type) bands and sworls you see. The quartz “sweats out” of molten rock first and has coalesced in the Margaree Gneiss. You are looking for the WIDEST band and the THINEST band and contrasting their size (Logging requirement #1).
Amphibolite – these rocks are dark black. You will see two types A) those that intruded (crosses the folds of gneiss in straight lines, often thick, like logs through the taffy, they are called dikes) and B) folded into the “taffy” of the gneiss. Which of these forms do you to believe to be younger? Why? (Logging Requirement #2)
Folding – the gneiss “taffy” has been folded multiple times. Identify at least one “fold” and state its length and width. (Logging requirement #3)
Geology:
There has been a lot of action on this tip of Newfoundland that was responsible for making this formation:
Ordovician Period –The molten igneous rock intruded (squeezed through cracks) into the Gander zone formed as the ancient Iapetus ocean opened. As the Iapetus ocean opened, all the raw ingredients for what you now see as Gneiss arrived on the scene (for the first time). They looked very different back then though!
How these minerals became what they are today involved Subduction (one plate sliding under another) during the late Ordovician period and into the Silurian period. There are two theories on what this process looked like. 1) Shallow Supra-subduction -- the rocks in this "zone between the continent shelves" slid shallowly downward getting "melted like taffy" rather than like butter (Whalen) citing geochemical analysis of the minerals present at this site 2) Others (Hickman-Hild) differ and say that a deep subduction happened, citing evidence in that nearby Port aux Basques garnets and kynite are present, both of whichcan form only underhigh heat and pressure. All this to say, this part of Newfoundland shows a LOT of action!
Silurian Period – The raw materials that were present now undergo a series of metamorphic processes. First, since this area was on the edge between TWO ancient continents (Laurentia and Gondwana) and both of these continents had peninsular areas that collided here, the rocks in the area collided at incredible force. The rocks you see here were forced deep underground. The Iapetus Ocean closes as the continents collided and folded
Much more recently – Dikes of Amphibolite intruded (crossed) the folded Gneiss.
Hild mentions that since these events, that are evidenced here, the Atlantic Ocean has "opened" in a spot SIMILAR (but not the same) as the Iapetus ocean of geologic antiquity. As a result we see rocks up on the surface that were once buried deep underground. We see rocks on the surface that originated from BOTH the ancient Laurentia and Gondwana within the same region (19).
Reference:
Hild, Martha Hickman., and Stephanie Porter. Geology of Newfoundland: Touring through Time at 48 Scenic Sites. Portugal Cove-St. Philip's, N.L.: Boulder Publications, 2012. Print.
Whalen, Joseph B. "Insights Into Tectonostratigrafic Zone Identification in Southwestern Newfound Based on Isotopic and Geochemical Data." Electronic Text Centre Journals. Acadiensis, 28 Nov. 1997. Web. 01 Jan. 2014. .