In May and September, the Tintina Trench is a dramatic avian flyway. It is a migration corridor for sandhill cranes, tundra swans, peregrine falcons and numerous other bird species. The riverside cliffs, wetlands, marshes and muskegs provide suitable nesting sites for some of these species as well as offering plenty of food.
The flight of the sandhill cranes is the most obvious and spectacular of the migrations. It is an awesome sight as over 200,000 of these large birds pass through here on their way to and from their tundra nesting grounds, the clamour of their calls filling the valley.
All Creatures Great & Small
The Tintina Trench is home to a large number of wildlife species year-round, with a particularly large population of lynx.
The numerous river tributaries that drain into the trench provide migration routes and spawning grounds for salmon.
The Yukon Plateau (North)
From this vantage point, you are facing the Yukon Plateau (North) ecoregion, which the Tintina Trench traverses from southeast to northwest.
The Yukon plateau has deep valleys, rounded mountains, and areas of permafrost giving rise to tilted or "drunken" forests.
The vegetation is rich and diverse, including hardwood and softwood forest species, grasslands, over a half dozen edible berries, and uncommon species such as yellow pond lillies. Unique hot springs with their own microclimates are also found in this ecoregion.
A continental climate predominates in this area. Extremes of winter cold and summer heat are accentuated by the low, wide valleys, which experience some of the Yukon's record temperatures.
Mineral deposits are a by-product of the plate tectonic forces that shape the continents. When two tectonic plates come together, one is often pushed beneath the other where it melts deep within the earth. Some of the melted rock floats to the surface as lava, while more of it cools within the crust to form granites.
A modern example of this activity is the tectonic plate under the Pacific Ocean that is sliding beneath Alaska. Some of it reappears as Aleutian Island volcanoes. Volcanic rocks and granites are common in the Yukon. Many of them carried gold and other minerals out of the earth. Erosion eventually uncovered the gold bearing rocks. The gold was washed into the Tintina Trench and buried in river sediments like the famous "White Channel gravels" of the Klondike region. Tectonic movements, volcanism, glaciation, erosion and sedimentation have combined to bring these gravels and their gold within human reach. It was just a matter of time before they were discovered.
Just a Matter of Time
And discovered they were, in 1896, in a tiny tributary of the Klondike River. This led to one of the greatest human sagas the world has ever seen - the Klondike Gold Rush of 1898.
Thousands of people and their machinery changed the landscape in and around Dawson. Other minerals such as copper, silver, lead, zinc and coal have been discovered and mined along the length of the Tintina Trench.
From Dawson City to Watson Lake, the Tintina Trench continues to host much of the mining and mineral exploration activity that plays such a vital role in the economy of the Yukon.
The Tintina Trench
The Tintina Trench is a linear valley, extending into Alaska and south across the Yukon. It was first recorded as a geological feature in the early 1900s by R.G. McConnel, a geologist with the Geological Survey of Canada. The GSC named it the "Tintina (meaning Chief) Trench"
Beneath the Tintina Trench is a fault line along which the bedrock has shifted a minimum of 450 km laterally. Some 65 million years ago, the rocks presently beneath Dawson City were adjacent to those of Ross River! About 8 million years ago, the earth's crust separated along the fault, creating a wide valley or trench.
Changing the Course of Rivers
The Tintina had a dramatic impact on the river drainage system. The formation of the trench created a channel for the rivers draining the interior to the south. Later, blockages due to ice build-up during the first glacial period around 3 million years ago, caused the Yukon River system to be re-routed.
Water, which once drained in a southerly direction, was forced northwest into Alaska. The mighty Yukon River itself, which now flows to the Bering Sea, once flowed south to the Gulf of Alaska! Evidence of the ancient river can be seen as old terraces along the redirected river north and south of Dawson. These remnant shores contain gravel types from the Ogilvie Mountains 40 km to the north, which could only have been deposited if the river once flowed south.
It Continues Today
Geological processes continue to shape the Tintina Trench to this day. The most significant activity is "landsliding" generally caused by erosive action. Presently, landslides occupy 35% of the surficial deposits within the Tintina Trench north of Dawson - one of the highest such concentrations in the Yukon. For further information on geology of the region, visit the Dawson City Museum.