Washington:
A strong relationship exists between global and local climate change and a mountain's internal tectonic plate shifts and topographic changes, researchers have found.
Researchers led by geologist Eva Enkelmann from University of Cincinnati in US found that the way a mountain range moves and behaves topographically can also change and create its local climate by redirecting wind and precipitation.
The repercussions of these changes can in turn, accelerate the erosion and tectonic seismic activity of that mountain range.
"There are two primary processes that result in the building and eroding of mountains and those processes are interacting," said Enkelman.
Enkelmann noted that the northern part of the St Elias mountain range - located along the Pacific coastal region of North America - is dry. But the precipitation is very high in the southern area, resulting in more erosion and material coming off the southern flanks.
As the climate change influences the erosion, that can produce a shift in the tectonics.
Enkelmann synthesised several different data sets to show how a rapid exhumation occurred in the central part of the mountain range over four to two million years ago.
This feedback process between erosion and internal tectonic shifting resulted in a mass of material moving up toward the surface very rapidly.
Enkelmann's model suggests that global climate shifts triggered a change in the rheology - the way material behaves.
While the Earth was much warmer millions of years ago, glaciers still existed in the high altitudes.
However, 2.6 million years ago the Earth experienced a shift to a colder climate and glaciation intensified. Glaciers grew larger, froze solid, covered the area and did not move.
Enkelmann said the glaciers today are wet-based and are moving, very aggressively eroding material around and out, and in the case of her observation, into the Gulf of Alaska.
The tectonic forces continue to move towards Alaska, get pushed underneath and the sediment on top is piling up above the Yakutat plate. These processes work against each other.
The movement of glaciers can compete with the internal buildup. Scientists have suggested that the Himalayas, European Alps and mountains in Taiwan were caused by the same competing reactions as those Enkelmann has observed in southeastern Alaska.
According to Enkelmann, the climate-driven erosion can influence the tectonics and change the motion of the rocks in that area.
The study was published in the journal Geophysical Research Letters.