Glaciers and Landscapes Review Session 5 Glaciers and Landscapes

WHERE DO GLACIERS FORM? This graph shows the places on earth where winter accumulation can exceed summer melting. Notice that glaciers can exist at the equator, at elevations above 5200 meters, as well as in the arctic.

Alpine Glaciers Continental Glaciers

Glacial Erosion The rocks frozen to the bottom act like sandpaper to form GLACIAL GROOVES and GLACIAL PARALLEL SCRATCHES on the bedrock underneath the glacier. These are called STRIATIONS

Glacial Erosion Over time, a glacier is going to carve a valley out of that rock underneath. A GLACIER WILL ALWAYS CARVE OUT A U-SHAPED VALLEY!

Erratic Boulder-sized rock dumped by a glacier Rock is different type than surrounding rocks

Unsorted Materials- all sizes mixed together (called Till)

Drumlins A drumlin forms when a glacier moves over a hill or deposits and shapes a large group of sediments. Drumlins have a steep side and a gradual side Drumlins tell you which direction the glacier moved The direction of motion is always from the steep side to the gradual side Direction of motion

The Finger Lakes During the last ice age (~10,000 years ago), most of the Northeast USA was covered in glaciers When the ice age ended, the glaciers melted, carving u-shaped valleys in upstate NY Some of these valleys filled with water, forming the Finger Lakes.

Three Major Landscape Types A. Mountains 1. High elevation compared to surrounding areas or sea level. 2. Distorted rock layers (folds, tilts, faults) 3. Often composed of metamorphic rock. (Regional Metamorphism)

Three Major Landscape Types

Three Major Landscape Types B. Plateaus 1. High elevations above sea level. 2. Undistorted rock layers (flat bedrock). (Sedimentary!) 3. Streams may have cut deep canyons.

Three Major Landscape Types C. Plains or Lowlands 1. Level surface with little change in slope. 2. Often horizontal rock structure.

Influences of Climate Arid or Dry Climates 1. Little vegetation to hold sediments in place on slopes. 2. Wind and Water rapidly carry sediments away. 3. Characterized by steep slopes and sharp, angular landscapes.

Influences of Climate Humid Climates 1. Sediments are held in place by vegetation. 2. Characterized by smoother and more rounded landscape. 3. Chemical weathering also contributes to rounded landscapes.

Drainage Patterns the general shape or pattern that is formed by tributaries as a result of different topography.  Four examples of drainage patterns  

Dendritic looks like the branches of a tree.  -found on flat uniform strata.

Annular circular pattern resulting from a   dome with upturned layers. 

Radial flowing outward from a central high point like a volcano or a mountain.

Rectangular tributaries flow at right angles to the main stream channel. - form where the strata is folded and faulted.