Pegunungan Rockies di Kanada sangat berbeda dalam penampilan dan batuan geologinya dari pegunungan Rockies di Amerika. Rockies Kanada terdiri dari batuan sedimen berlapis seperti batu gamping dan shale, sedangkan Rockies Amerika sebagian besar terdiri dari batuan metamorf beku seperti gneiss dan granit. Rockies Amerika, rata-rata, lebih tinggi di ketinggian dari Rockies Kanada, tetapi Rocky Kanada terlihat lebih dramatis karena lebih tegak dengan dindingnya yg curam, dan puncak2nya sambung menyambung seperti bergerigi.

The Canadian Rockies are quite different in appearance and geology from the American Rockies. The Canadian Rockies are composed of layered sedimentary rock such as limestone and shale, whereas the American Rockies are made mostly of metamorphic and igneous rock such as gneiss and granite. The American Rockies are, on average, higher in elevation than the Canadian Rockies, but have less vertical relief, which is to say they are shorter from base to summit because the mountain valleys are higher.

The Canadian Rockies are more jagged than the American Rockies, because the Canadian Rockies have been very heavily glaciated, resulting in sharply pointed mountains separated by wide, U-shaped valleys gouged by glaciers, whereas the American Rockies are more rounded, with river-carved V-shaped valleys between them. The Canadian Rockies are cooler and wetter, giving them moister soil, bigger rivers, and more glaciers. The tree line is much lower in the Canadian Rockies than in the American Rockies (Gadd, Ben).

The Rocks that Make Up the Rockies
Many people, upon first seeing the Rockies assume they are made of very hard rocks like granite. They believe (mistakenly) that the mountains are either volcanic in origin, or that the rocks (like granite) had a molten genesis. With the exception of a few isolated pockets of igneous (formerly molten) rocks, the Canadian Rockies are composed exclusively of layered sedimentary rocks. These include limestone, dolomite, sandstone and shale, amongst others. Worldwide, sedimentary rocks cover approximately 75% of the worlds surface. Of this, approximately 50% are shales, 30% sandstone and 20% limestone.

Sedimentary rocks have a unique method of deposition – one layer on top of another. This seemingly simple arrangement can be extrapolated to assume that the rocks nearest the surface will always be younger than rocks deeper down. Digging through the layers, geologists can analyze their composition, and determine much about the climate and landscape during the time of their formation.

In the mountains, this organized arrangement has been shattered. Older rocks have been piled up on top of their younger neighbours. They have been bent, folded, cracked, and eroded. The original order is often impossible to determine, however geologists have done an amazing job of reconstructing the various layers. By knowing the formations, they can estimate the age of the rocks, anticipate how they will react to erosion, and get a better understanding of why the landscape looks the way it does.

Sedimentary rocks result from compression of the layered sediments on the bottom of a large body of water. Differences in parent material, along with the effects of weathering, erosion, transportation and deposition can have a large impact on the resulting layers. They can be divided into two major groupings: inorganic and organic.

Inorganic rocks are those formed by the deposition of inorganic matter. This includes minerals as well as the remains of other older rocks that were eroded away, only to have their individual grains deposit as layered sediments.

Organic rocks are further broken down into chemical and organic origins. This group combines rocks formed from the remains of living organisms along with rocks resulting from several chemical processes. These include the limestones and dolomites that form many of our mountain summits, along with other valuable resources like coal.

In the Canadian Rockies, limestone forms most of the resistant ridges and summits. Often interspersed with layers of shale and sandstone, limestone is more resistant to erosion. This leaves it forming the upper-most layer on most of our peaks (Ward Cameron - Mountain Nature)




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