Deserts, Glaciers and Climate

Deserts, Glaciers, and Climate

Jeff Christison

SCI 245 / Physical Geology

Jonathon Drasdis

November 28th, 2010

1. Desert and Glacial Landforms

Deserts are formed where dry stable air masses maintain arid conditions throughout the year. These desert climates have precipitation that is highly variable, and are characterized by low humidity and high temperatures. Some desert environment characteristics have significant effects on the major processes of weathering, transportation, erosion, and deposition. Sparsely vegetated, or bare, areas result in rapid water run-off when intense rain occurs allowing high winds to erode and transport the sand and dust. The sand accumulates in areas where the wind has a lower velocity and forms dune fields, and sand seas. These formations consist mainly of crescent, linear, and star dunes. The forces governing the formation of dunes are the availability of sand and the variation of wind direction from season to season. Regional geological and tectonic environments can also have an effect on desert landforms.

Glaciers are large bodies of ice that form on land by snow that compacts, recrystallizes, and shows signs of movement downhill due to gravity. It is important to note that glaciers themselves are not landforms, but their actions create landforms. This is a process known as glaciations and as these glaciers move they scour the landscape carving out landforms. There are two types of glaciers: relatively small glaciers form in higher elevations and are referred to as mountain glaciers, and glaciers that form over large areas of the continents are referred to as continental glaciers, or ice sheets. There are currently only two continental glaciers: one that covers 85% of Greenland, and the other covers roughly 95% of Antarctica. Glaciers have two zones within them. The first is the ablation zone, and this is where their mass is lost due to melting and evaporation at a higher rate than the accumulation of snow...