Chapter 6 Glaciers, Deserts And Wind

Front 1

Glacier formations

Back 1

100s to 1000s years to form

accumulation, compaction and recrystallization of snow

important record of time

Front 2

Types of Glaciers (2 types to know for exam)

Back 2

Continental/Ice sheets (only Greenland and Antarctica)

Alpine or Valley Glaciers (Alps, Alaska, Northern Rockies, Southern Andes, Himalayas)

Front 3

Erosion and Landforms

Back 3

1. Plucking and Abrasion

2. Glacial Trough - U shaped valley

3. Glacial Striations

Front 4

Plucking

Back 4

Occurs when melt water penetrates the cracks and joints along the rock floor of the glacier and freezes

Front 5

Abrasion

Back 5

As the ice and its load of rock fragments slide over bedrock, they function like sandpaper to smooth and polish the surface below.

Front 6

Glacial Trough

Back 6

The result during glaciation, narrow valleys undergo a transformation as the glacier widens and deepens them creating a U-shaped glacial trough

Front 7

Glacial Striations

Back 7

scratches and grooves made when ice contains large rock fragments

Front 8

Glacial Deposits

Back 8

Glacial Drift - sediments of glacial origin no mater how where or what form they were deposited (Till or Stratified Drift)

Moraines - Layers or ridges of till

Front 9

Glacial Drift - two distinct types

Back 9

Till and Stratified Drift

Front 10

Till

Back 10

Materials deposited directly by the glacier. Till is deposited as glacial ice melts and drops its load of rock debris

Front 11

Stratified Drift

Back 11

Sediments laid down by glacial meltwater. It is sorted according to the size and weight of the fragments.

Front 12

Effects of Glaciation

Back 12

1. Lithospheric Subsidence - Greenland

2. Lowering of Sea Level

3. Pluvial Lakes and Drainage Basins

4. Climate

Front 13

Causes of Glaciation

Back 13

1. Plate Tectonics

2. Variations of Earth's orbit

Front 14

Three types of Variations to Earth's orbit

Back 14

1. Eccentricity- elliptical orbit

2. Obliquity- 22.5 - 24.5 degrees

3. Precession - wobble of axis rotation

Front 15

How much of Earth's surface is desert?

Back 15

30%

Front 16

What are some misconceptions of deserts?

Back 16

1. Deserts are lifeless

2. Deserts are always hot (snow in Sonoran desert and Antarctica is a desert)

3. Deserts are vast expanses of sand

4. Desert erosion is caused by wind ~ it's caused mostly by water.

Front 17

How do climatologists define "dry climate"

Back 17

A climate in which yearly precipitation is less than the potential loss of water by evaporation.

Front 18

Ephemeral Streams

Back 18

Streams in response to specific episodes of rainfall. May only flow for a few days or hours

Front 19

Interior Drainage

Back 19

A discontinuous pattern of ephemeral streams that do not flow out of the desert to the ocean.

Front 20

Alluvial Fans

Back 20

A cone of debris at the mouth of a canyon

Front 21

Bajada

Back 21

Over time Alluvial fans enlarge and connect with fans from adjacent canyons to produce an apron of sediment along the mountain foot.

Front 22

Playa Lakes

Back 22

Streams may flow across the alluvial fans to the center of the basin converting the basin floor into a shallow lake lasting only a few days or weeks before evaporation and infiltration remove the water.

Front 23

Desert pavement and deflation

Back 23

Over time, deflation lowers the surface and coarse particles become concentrated

Front 24

Saltation

Back 24

Sediment moving appears to jump or skip along

Front 25

Abraison

Back 25

Windblown sand cuts and polishes exposed rock surfaces.