5980 x 4092 px | 50,6 x 34,6 cm | 19,9 x 13,6 inches | 300dpi
Data acquisizione:
9 aprile 2016
Ubicazione:
Big Rock, Campbell River, Georgia Straits, South Island Highway, Vancouver Island, BC, Canada.
Altre informazioni:
Where did the Big Rock originally come from? The scientific explanation is that it is a glacial erratic left over from the most recent ice age. This is referred to as the “Wisconsin” ice age and was the last of three major glacial stages. During this stage (about 26, 000 to 13, 300 years ago) the ice sheet that covered North America was 3 to 4 km thick and extended down to the 45th parallel north (northern Oregon). The glacial sheets took so much water from the oceans that the sea level was lowered by 100-120 meters and the weight was so intense that it deformed the Earth’s mantle and crust and even altered the Earth’s gravitational field! Huge expanses of coastal plain opened up the coast as the sea level dropped. At one point you could walk from Vancouver Island to Haida Gwaii. In fact, underwater archaeology has revealed the presence of permanent human habitations at the 100 metre mark. On the west coast, the glacial sheet flowed towards the ocean. It is possible that the Big Rock originated hundreds of miles North-East of its present position. The most likely explanation of its origin is that it was plucked off of the top of the landscape and dragged along under the glacier, the pressure and friction scouring and polishing it into its present shape.
