* Peter Knights Photos of Landscapes and Glaciers (Keele University)
FORMS OF ICE• GLACIER – a moving mass of ice on a land surface• NICHE ICE – ice which has accumulated in a hollow high up on the mountain side• CIRQUE GLACIER – deepened hollow filled with ice• ICE CAP – large area of ice, which has spread outwards from a central area.• VALLEY GLACIER – large mass of ice from a cirque or ice field, which follows existing valleys• ICE SHEET – huge areas of ice which spread outwards from central domes
Niche glaciersThe smallest scale ofglaciation: Niche glaciersand ice aprons in the GrandTetons, Wyoming, USA.Small glaciers such as theseare often the most sensitiveto local climate change.
The summit ice cap of the volcano, Cotopaxi, EcuadorThe ice cap extends further on one side of the mountain. The sideof the mountain facing the moisture-bearing winds has highersnowfall and hence more extensive glaciation. The deep channelscarved by meltwater and by volcanic mudflows (lahars) caused bymelting of snow and ice during eruptions.
As a glacier slides over its bed, it picks up rock fragments that act as abrasive and scouring agents. As a result bedrock surfaces, such as this limestone outcrop, commonly bearpolished and scratched (‘striated’) surfaces, as well as various gouge-marks.!!!!!