Spatial Variations Vegetation and soils.

The Andes

The Andes Mountain range is a chain of mountains 7000km long and up to 700 km wide. It provides the sediment for the Amazon basin. The Andes are fold mountains that have an average height of 4000m. They have sandstone as their bedrock and also show evidence of volcanism as evidenced by Mt. Sangay. Glacial and fluvial processes provide the main form of transport. The Andes consist of thin Alpine soil. The vegetation that exist here is mosses and shrubs on the higher slopes and rainforest on the lower slopes. Erosion: Freeze thaw action dominates on the upper slopes. This has created scree slopes which doesn’t allow soil to settle. This is where rivers start to form and many v-shaped valleys are present. Some glaciation is present and this is another way in which eroded material gets transported. Glaciers and rivers provide the main form of transportation as the sediment is suspended due to the fast flowing steep rivers in this area. Very little deposition occurs here. Chemical erosion is occurring as carbon dioxide is moving into rocks and corroding them. Erosion process are called denudation processes. Tundra is another prominent landscape.

The Amazon Basin

Amazon Basin: The Amazon Basin is a region created by fluvial processes. The dominant rivers the rio Negro and of course the Amazon river. The Amazon river has transported eroded material from the Andes and other parts of the Amazon basin. The material that is suspended in the river systems begins to get deposited as the river slows down. This has created alluvial plains. The Amazon basin is extremely flat and only changes 100 metres in elevation. The basin contains a large floodplain called the Varzea where soils are fertile due to the seasonal deposition of new alluvial material. The Amazon basin contains clear stratification of vegetation as species contest for light. Rose wood and Kapok trees grow up to 65 metres tall and contain epiphytes and are surrounded by lianas. The humus layer provides substantial amounts nutrients for the buttressed tree’s as the fertility from the alluvial soil has been leached out leaving podsol soils.

The Ancient Plateau’s

The Coastal regions

The Zones