Millions of Years of Green Point Geology

Monday, July 29, 2013


Late morning we set out on the oceanside trail that ran from the campground to a river and parking area 3 km north. It was originally the path that linked the fishing village at Green Point with the next one down the coast. In the winter, until 1952, the mail was delivered on the trail by dogsled. We started out in a forested area and came out on a pond. Shortly we came onto a large bouldered beach and walked the length of it to a river flowing into to ocean where we saw a flyfisherman. On the way down we saw a mama bird (probably a Willet or a Greater Yellowlegs) trying to coax a fluffy baby back into a nest among the boulders. It kept wandering farther away. Poor thing, the boulders were like mountains to the fuzz-ball.

Coastal Trail

Through Balsam Fir and Black Spruce

A Barachois Pond

Giant Dragonfly

It was hard to get the Black Backed gull and the Gannets to pose together

Beach Pea

On the way down we also stopped to check out a “tuckamore”, which is a group of low lying spruce trees stunted by the salt spray and winds. There was a small cave like opening in the spruce, but shortly after getting inside we could stand up and farther in, the trees were more normal height and shape. It would make a great fort for kids!

NOT Sequoia National Park

Walking back we continued on the boulder beach. It was really tough going. We had a good view of the Green Point Fishing village across the cove that we were going to visit in the afternoon. After lunch we set out on a wildflower covered meadow across the headland to the fishing village. We walked through the working village, the cod “food fishery” was just finishing up until September, and tried to stay out of their way. Around the bend we came upon the cliffs of Green Point. The park service had posted a geologist there for the afternoon to answer questions.

As we arrived at the cliffs, the geologist was discussing Appalachian geology with a man from Illinois. When she saw Greg's shirt with a geologic map of Pennsylvania on it, she exclaimed, “Just what we need!”, and proceeded to point to Greg's shirt for examples of what they were discussing.

Green Point - Global Stratotype for the Cambrian-Ordovician Boundary

Finally - Someone appreciates my fashion sense

Ripple casts in Limestone

Graptolite fossil in shale

Paper-thin shale beds sandwiched between limestone tilted vertically - NOT a barefoot beach.

Small scale folds in the white limestone

Greg's commentary on Green Point-
Green Point consists of sedimentary rocks (mostly limestone with interbeds of sandstone and shale) that are very similar to the rocks of western Pennsylvania and Ohio bordering the west side of the Appalachian Mountains. The Long Range mountains that extend north-south along the west coast of Newfoundland are considered the northernmost extent of the Appalachians. The mountains consist of very old and very hard igneous and metamorphic granites and gneisses (continental basement rocks) that were pushed westward up and over the younger sedimentary rocks during the collision of North America with the plates of Europe and Africa. The older and harder rocks resisted the several glaciations of the last 150,000 years, resulting in a mountain wall that rises suddenly out of the glacial lowlands formed by the softer limestones.
Green Point is most famous for the occurrence of various rare conodont fossils. Conodonts are tiny hard structures that are thought to be the chewing tools or teeth remaining from small animals that had no other hard parts to be preserved. Conodonts are widespread and common across the world in rocks formed from sediments in shallow oceans about 500 to 550 million years ago. The shales at Green Point contain an unusual record of uninterrupted deposition and evolution of the conodont fossils that are used to estimate the age of rocks that are older than those that contain more complex fossils. This location is considered the world's defining site for the boundary between the Cambrian and Ordovician Periods of geologic time (510 million years ago). At Green Point, the soft shales are preserved between layers of thicker and harder limestone that protects them from the surf that pounds on the cliff and ledges where the rocks are folded into almost vertical beds.

The Cambrian - Ordovician boundary is defined by the fossils in this series of shales

Kathleen sitting on the Cambrian Ordovician Boundary

Limestone conglomerate, maybe formed from a collapsed reef

Green Point was amazing! To look at one cliff face and see so many different layers was fascinating, especially the mud ripples from the ancient sea floor. The boulders in the water and the cliffs in the distance kept drawing my eyes away from the equally fascinating geology. We walked back along the boulder beach, through the discarded fish carcasses, very fresh, so not smelly, and back up the cliff stairs to the campground. No sunset this evening, the overcast had come in, but we could still see and hear the surf.

Tide coming in

Cod Fishermen coming home

Campground stairs

View from our camp