Vortex? The “Westport Vortex?” I’ve already alarmed the good citizens of Westport with the news that you live on a fault line. Now, “You live beside a vortex!” Will a bass boat on the Upper Rideau suddenly eddy into a Bermuda Triangle vortex? Will a plane from the Township airstrip mysteriously spiral into a Black Hole at Galactic Central? Have I been watching too many Sci-fi movies?
But what is this Westport Vortex? Decades ago, Dr. Wynne-Edwards did the primary study of the intricate pre-Cambrian geology of Eastern Ontario. He documented more different kinds of minerals within 100 km of Kingston than any other place on the planet. He documented the only place in the world where you can experience three very distinctive geological provinces within few hours drive from Ottawa to Kingston, or canoe them in several days on the Rideau Canal, or hike them on the Rideau Trail. Wynne-Edwards became a renowned geologist and head of Queen’s University’s Department of Geology. In his 1967 Interpretive Structural Map of the Westport Area, he defined Westport Mountain as the ‘Westport Vortex’. Through this term, he attempted to explain the dynamics that created this amazing structure in granite. His theory has not found favour with some of his peers. They now see ‘vortex’ as too simplistic to adequately explain all mountains of granite. But the term ‘vortex’ does invoke a sense of the enormous energy and dynamics of mountain-building that has left us this legacy in enduring pink granite, a marvel to be appreciated when you look out from Spy Rock on Westport’s Vortex or from Rock Dunder on the Lyndhurst Vortex.
Some similar formations in granite, be they pink, gray or even black are called ‘laccoliths’. To me, laccolith does not invoke the same awe as ‘vortex’. But we might think of Westport Mountain as a blister, a gigantic blister born in fire, of beautiful granite rock over 6 km. across and unmeasured meters thick The next time you hit your finger with a hammer, watch quietly and in the interest of science as your blood collects between layers of your skin or under your finger nail. There will likely be some pain and distortion. As kids, Mom often would soothe us with the explanation that we had a “blood blister”. In a day or three, the pain would subside. In a week or two, layers of skin would erode to expose your very own personal hardened blood blister circled by dermal rings, your personal laccolith.
On a grand and highly simplified scale, Westport Mountain formed when seething hot magma under intense pressure formed a “blister” within our planet’s thin and fragile skin. That blister slowly cooled within its cocoon of surrounding host rock. As with the layers of skin around your blood blister, the surrounding host rock was distorted and changed by intense heat and pressure. The host rock was metamorphosed by the experience. Along the shore of Duck Bay on the north side of the Upper Rideau Lake you can find rock that was deformed by Mother Nature’s “Shake and Bake”. Minerals such as mica, graphite and crystallized limestone give evidence that once there was a lot of heat and pressure in the neighborhood. Over the intervening billion years, much of the softer rock that hosted the Westport’s granite laccolith has been eroded away to form the basin of Duck Bay.
Other sources define Westport Mountain as a granite pluton. A pluton must have something to do with Pluto, God of Hades to the ancient Greeks. Indeed the Westport Pluton did originate deep in the “underworld” of our Earth’s crust where plutonic rocks like granite found their fiery birth in the roots of mountains. About a billion years ago, giant waves of rock were pushed up when Laurentia (Canadian Shield) collided with Amazonia (Brazilian Shield). Canada once collided with Brazil? Boggles the mind! But many things about our amazing place in the universe boggle the mind.
The crust of Planet Earth is very thin, relatively much thinner than an egg’s shell. Moreover, it’s a cracked shell. The fragile crust of our blue-green planet is divided into many plates; some plates provide basins for oceans; a few bear continents. These plates wander about the surface of our planet accumulating new real estate, sometimes colliding and occasionally gathering into super-continents. Sometimes plates tear apart. They are swept along at about the same speed your fingernail grows (one that you didn’t hit with a hammer). They are propelled from beneath by great currents in the “white” of our giant egg, the Earth’s mantle. These convections are heated by the heavy metal and radio-active “yolk” or core of our planet. For instance, the India subcontinent was once joined to far-away Antarctica. But after a long voyage across the Indian Ocean, it is now colliding and wedging under the southern flank of Asia. In this collision, Mt. Everest and its sister Himalayas are being heaved high into the sky. Tibetans and their yaks live on our planet’s highest plateau. And China is being invaded from below by seismic waves that quake cities and demolish schools. Earthquakes are percussions in the symphonic music of our sphere. It is a bit of geological irony that a mere hundred years ago during the era of “Rule Britannia”, India was called “the sub-continent” of Asia.
Go back a billion years in G-time. Laurentia was colliding with Amazonia right here. Akin to the Himalayas of today, snow-capped peaks once soared over our proto-continent from present-day Labrador to mid-U.S.A. This mighty range is now referred to as the Grenville Mountains. In the seething high-temperature, high pressure roots of the Grenvilles were blisters filled with oxygen, silicon, aluminum, iron and magnesium, the five most common elements in the crust of our planet. Traces of other elements added spice to these vortices of magma; pressure cookers many times hotter than stove-top cooking, even Thai cooking. Westport Mountain was one of those vortices born in fire. Then it slowly cooled. Molecules gathered into minerals such as hornblende, biotite mica, orthoclase and quartz; minerals that crystallized or gelled within this womb in our earth’s crust. From this wondrous mix of minerals was born a beautiful intrusive rock called granite. Conversely liquid rock that is extruded onto the Earth’s surface is commonly seen as lava, usually black in colour. This is the stuff of volcanoes like Mtns.Vesuvio in Italy and Fuji in Japan.
A billion years of erosion by ice, water and wind has removed the Grenville peaks that once towered over Rideau country. We now see the Westport Vortex / Laccolith / Pluton exposed as a massive ridge of beautiful pink granite from Spy Rock to Kanes Bay along the north shore of Upper Rideau Lake. It is largely cloaked in patches of organic soil and beautiful forest. The Westport Mountain Vortex was not born alone. It is a triplet. To the west, Dr. Wynne Edwards identified the Wolfe Lake Vortex. Edged by the Rideau Lakes Fault, you can see its flank as the spectacular north shore of Westport Sand Lake. To the east is the Rideau Lake Vortex. Its edge can be seen from the Narrows to Horseshoe Bay as you cruise the Big Rideau. A nearby cousin, the Lyndhurst Vortex extends from Lyndhurst for about 10 km to Rock Dunder and Morton Bay. Diamond drilling has proven its depth or thickness to be several hundreds meters through exquisite monument-quality pink granite.
Vortex. Laccolith. Pluton. These are terms that attempt to define the formation and form of these magnificent natural structures in granite, the rock that ancient Egyptians carved into their eternal obelisks. Each of this trinity of terms attempts to define Westport Mountain from a different perspective. How many perspectives do we humans have for “tree”, for the colour “red”, for “black”? We even wage warfare over such differences in perspective. Maybe we can learn from geologists to wage friendly debate instead.
There are other plutons across our continent. Some of these granite formations have been suggested as safe and stable repositories for our nuclear waste. One of particular fame stands high as the core of the Black Hills of the Dakotas. During the heat and drought of prairie summers, the Lakota Sioux found relief and religion among its high cool forest of pines. Gutzon Borglum spent decades carving four giant faces into its massive gray granite. Alfred (the Great) Hitchcock filmed Eva Marie Saint in high heels and horror scaling down those faces (actually at a Hollywood sound stage). Formed about 1.6 billion years ago, this particular dome of enduring granite is now exposed to view and to human use and abuse. It is Mount Rushmore.
So I leave you with a final question. Which four Canadian Prime Ministers would you elect to see carved into the beautiful pink granite of Rock Dunder born from the Lyndhurst Vortex or of Spy Rock from the Westport Vortex? Keep in mind that in this year 2009, Washington, D.C. would probably not allow Mr. Borglum to mega-sculpt presidential visages, even that of Honest Abe onto a mountain that is sacred to their native people. In this year 2009, Ottawa’s environmental regulations would probably not allow Colonel By to build the Rideau Canal.
Geology/Natural History tours are sponsored annually by the Bastard and S. Burgess Heritage Society on the third Sunday afternoon of September (subject to weather) when we look at some of the sites of significance in our local and very rich natural history.