Logo for the Journal American Rhododendron Society

Journal American Rhododendron Society

Current Editor:
Dr. Glen Jamieson ars.editor@gmail.com


Volume 61, Number 3
Summer 2007

DLA Ejournal Home | JARS Home | Table of Contents for this issue | Search JARS and other ejournals

Two Summers in the Canadian Rockies
Peter Kendall
Portland, Oregon

Map showing location of Canmore, Alberta
Map showing location of Canmore, Alberta, approximately 60 mile
 west of Calgary on the cusp of the Front Range of the Rocky Mountains.

        The stretch of the Rocky Mountains (from west and slightly south of the resort town of Canmore) in Assiniboine Provincial Park to the northern reaches of Yoho National Park in the province of British Columbia yields so much in the way of geological and horticultural intrigue. The geological spectacle of the Canadian Rockies takes away one’s breath. It invites the question: from when, where and how did such magnificence come to be? To ever so briefly respond to the query, I offer the following sketch.

Mt. Assiniboine: rock, ice 
and Lake Magob.    Mt. Assiniboine, the Matterhorn 
of the southern Canadian Rockies.    Block faulting below Mt. Yukness at 
Lake O'Hara
Mt. Assiniboine: rock, ice
and Lake Magob.
Photo by Peter Kendall
   Mt. Assiniboine, the Matterhorn of the
southern Canadian Rockies.
Photo by Peter Kendall
   Block faulting below Mt. Yukness at Lake O'Hara.
Photo by Peter Kendall

        Some 180 million years ago, with the break up of Pangea, the North American Plate consisted of the granitic Canadian Shield in the east and a rather rolling, non-descript western rampart ending where the Rockies’ main range is today. To the west lay the Pacific Oceanic Plate with its far-flung terranes (major island land masses) moving inexorably east and eventually into and under the North American Plate. This occurred between 120-60 million years ago during the Cretaceous Period and represents the orogeny (mountain building) of the Canadian Rockies we see today.

Mt. Rundle, Banff's signature mountain, 
in Canadian Rockies Front Range - a classic thrust fault.    Lake MacArthur and Mt. Biddle at 
Lake O'Hara area in Yoho National Park in the Canadian Rockies Main Range.
Mt. Rundle, Banff's signature mountain, in Canadian Rockies
Front Range - a classic thrust fault.
Photo by Peter Kendall
   Lake MacArthur and Mt. Biddle at Lake O'Hara area in
Yoho National Park in the Canadian Rockies Main Range.
Photo by Peter Kendall
 
Rock Island in Sunshine Meadows, approximately 
west/northwest of Banff in Canadian Rockies Front Range.    Three Sisters mountains at dawn, Canmore's 
signature peaks.
Rock Island in Sunshine Meadows, approximately west/northwest
of Banff in Canadian Rockies Front Range.
Photo by Peter Kendall
   Three Sisters mountains at dawn, Canmore's signature peaks.
Photo by Peter Kendall

        It was only relatively recently (from some 2 million years to 10,000 years ago) during the ice ages of the Pleistocene that the present-day sculpture emerged. The 700 million-year-old rock or substrate that was uplifted was primarily sedimentary and came from ocean sediments to the west, chiefly organic carbonate (calcium and magnesium carbonate from precipitating marine organisms) and from clastic, nonorganic sediments (colloidal clay particles to large rocks) to the east. Two parallel ranges were thrust upward to heights approaching 10,000 to 12,000 feet. To the east, we see the slip faulting of the Front Range; to the west we observe the block faulting of the Main Range. Over the years, with the breakdown and deposition of materials into rudimentary soil and the ensuing climatic shifts, we find the wealth of plant material extant today.

Rhododendron groenlandicum 
(formerly Ledum groenlandicum) at Lake O'hara.    Rhododendron albiflorum on 
Iceline Trail.
Rhododendron groenlandicum (formerly Ledum groenlandicum) at Lake O'hara.
Photo by Peter Kendall
   Rhododendron albiflorum on Iceline Trail.
Photo by Peter Kendall

        With forests of spruce, fir and larch, with many species of willow and similar deciduous and evergreen colonizing species (think ericaceous - including rhododendrons probably 40-50 million years ago - among them), many niches for plant material were created. From high alpine reaches to lower meadow environments, the disparate flora is astounding. Accompanying this article are photographs of some of the more spectacular geological sites and remarkable flora from locations I visited.

Draba paysonii    Bronze bells (Stenanthium occidentale)
Draba paysonii
Photo by Peter Kendall
   Bronze bells (Stenanthium occidentale).
Photo by Peter Kendall

Peter Kendall is a frequent contributor to the Journal and a member of the Portland Chapter.


Volume 61, Number 3
Summer 2007

DLA Ejournal Home | JARS Home | Table of Contents for this issue | Search JARS and other ejournals