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Green Gardens Trail lies within the boundaries of Gros Morne National Park, Newfoundland. Leading hikers from a dry, desert-like roadside to a powerful and windswept coast, this trail provides every tourist with an assortment of Newfoundland sights. We spent the morning of our seventh day meandering along the dry cracked rocks, lush mountains, and jagged coastline that Green Gardens offers, finding much to study, admire, and, of course, photograph!

Geologically, Gros Morne National Park lies within the Western Zone (also called Humber Zone) of North America, an area that consists of a sequence of Eocambrian and Ordovician sediments deposited on top of a crystalline basement of late Grenvillian age (~1240 Ma). The Taconic and Acadian orogenies deformed and metamorphosed these sediments to variable degrees.


What We Saw of Geologic Importance
The beginning of our hike lead us through a flat plain of dusty brown rocks. Though insignificant in appearance, these rocks actually have a great deal of geologic importance! They are from the "center of the Earth," or, more specifically, the Earth's mantle, and are discussed in further detail at the Tablelands site.

At the hightest elevation on the trail, large granite-like masses composed mainly of quartz, plagioclase feldspar and mica were revealed. Because the rocks don't contain any potassium feldspar, they are called plagiogranites, which represent a part of the ophiolite complex. These rocks, unlike the first dusty-brown rocks we saw, can support life because they are high in important life-giving elements such as calcium, sodium, and aluminum. For this reason, this mountaineous part of our hike exhibited plenty of trees, shrubbery and other small plants, as well as small ground animals, birds, and the rare moose. Though we constantly scanned the ground below us, we didn't see any moose!

After hiking some more, we finally reached the coast. There, we observed wave refraction, including an interesting case of almost circular refraction; the cliffs and numerous sea stacks; diverse rocky beaches; and the magnificent displays of the ophiolite complex.

The cliffs of Newfoundland exist because of the passive margin that makes up the Atlantic Coast of North America. During glaciation of this area, these coastal rocks were depressed to below the present day sea level by the extreme weight of the ice. Since the ice melted at the end of the last ice age (~10 Ka), the land has risen and uplifted to its present height above sea level. The sea stacks here have been carved by water erosion for thousands of years.

At the beach, we found various samples, including many colors of micro-crystalline quartz, a few pieces of olivine, and some nice amydaloidal cobbles (Alisha's favorite sample).


The Ophiolite Complex
The ophiolite complex at Green Gardens Trail proved to be as "spectacular" as the trail brochure claimed. The photograph at right shows Jocelyn standing near an enourmous example of the complex. The lower layer shows columns of vertical fractures; these fractures were created when a sheet of hot lava intruded between two stacks of pillow basalts and cooled rapidly. The upper layer of circular and rounded masses represents the uppermost layer of the complex: the pillow basalts. These basalts formed when lava erupted under water, and like the material inside a lava lamp, formed bubble-like masses. Before these bubbles could flatten or flow, the cold water rapidly cooled and froze them in these ellipsoidal shapes.


A Beautiful Day
The cloudless sky and bright sun allowed for an expansive view of sloping mountains terminated by jagged cliffs and ocean waves. In less than 10 kilometers, we experienced the low and dusty mantle rocks, the high and lush mountains, and an amazing windswept coast overflowing with wild vegetation and grazing sheep. This hike and all its wonderful sights serve as a highlight of Newfoundland for many tourists, including some in our own group.