Argentina: Landforms and Environment

• The summary is about Argentina's landforms

Environment Definition and Elements

• The environment includes both natural and social elements.
• The natural environment comprises air, water, land, flora, and fauna, which interact and are essential for life.
• Key elements are:
  • Landforms, including plains, mountains, and plateaus
  • Climate factors, such as temperature and precipitation
  • Hydrography, including river basins
• These elements interact and regulate each other, creating environmental variations.

Landform Definition

• Landforms are the heights and depths of the Earth's surface (crust and lithosphere).
• Landforms are products of the combined action of internal (endogenous) and external (exogenous) processes

Geological Time Scale in Argentina

• Earth's age is approximately 4.6 billion years; the Precambrian period took place between 4.6 billion and 570 million years ago.
• The Precambrian period involved the formation of shields and massifs (ancient landforms).
• The geological time scale is divided into eras, periods, and epochs.
• Paleozoic Era
• Mesozoic: Formation of the Andes Mountains, Patagonian Plateaus, and Sierras Madres.
• Cenozoic: Formation of plains.

Landform Formation Process

• Argentina is part of the South American plate, which constantly interacts with the Nazca plate.
• Orogenic movements have occurred along the western edge of the plate for millions of years, adding new structural units.
• Mountains in the west are younger, taller, and more seismically and volcanically active.
• The Brasilia massif in the east fractured and modified due to changes and erosion in the west, forming the Puna, Misiones Plateau, Tandil, and Pampeanas ranges.
• Depressed areas became the basement of the Pampeana Plain, covered in sediments.
• The Patagonian massif in the south acquired a stepped shape, descending from the Andes to the Argentine Sea.

Geological Periods

• The Tertiary period was dominated by the Andean orogeny, which folded and uplifted the Principal Cordillera, Subandean ranges, Patagonian-Fueguinos Andes, and Famatina system, modifying previous structures.
• During the Quaternary period, erosion formed new sediment layers, creating the Pampeana Plain and various valleys and basins.
• The Cimmerian orogeny involved intense sedimentation and erosion, forming the Ventania and Patagonides systems.
• The Caledonian folding uplifted sediments accumulated during the Precambrian, forming the Precordillera of La Rioja, San Juan, and Mendoza, and the Famatina system.
• The Variscan folding later uplifted the Eastern Cordillera and Frontal Cordillera.
• Mountains formed by the Huronian folding have been deeply eroded due to their age and are now shields or massifs like the Brasilia and Patagonico massifs.

Natural Conditions of Argentina

• Natural conditions include natural resources and environments (landforms, climates, hydrography).
• Environments can be modified by human actions.
• Environments are diverse and harbor varied flora and fauna.

Natural Base of Argentina

• Argentina develops over two geological structures: the Brasilia and Patagonian massifs.
• It has a variety of landforms: Andes Mountains (west), plains, plateaus, and ancient ranges.
• It consists of the Andean and extra-Andean systems.
• Natural bases are made up of:
  • Relief
  • Climate
  • Bodies of water
  • Plant and animal-life
• These elements are related to social activities
• The main feature of the relief layout is the Andes Mountains in the west, the plains in the east and the Patagonian plateau in the south.
• The Andes mountain range, parallel to the Pacific coast, conditions wind circulation, precipitation patterns and river runoff.
• Relief, soils, water, and climates determine the presence of living beings, both animal and plant.
• The use that the diverse societies of the Argentinian territory have made of natural elements configures the different environments of Argentina.

Importance of the Andes Mountains

• The Andes mountain range contains a great diversity of ecosystems and endemic species.
• Therefore, making it a key region for the conservation of biological diversity

Natural Resources in Argentina

• Rich in mineral resources like copper and lithium.
• It contains important sources of water for agriculture and human supply

Climate and Hydrology

• It influences the climate of the countries it crosses, creating micro-climates and regulating precipitation patterns.
• The mountains act as barriers that affect the winds and distribution of rainfall

Endogenous and Exogenous Processes

• Endogenous processes: Geological phenomena inside the Earth that shape the land.
• Endogenous processes are fundamental for understating the dynamics of the Earth's surface and evolution through time.
  • Plate Tectonics: Movement of tectonic plates can cause mountain formation, earthquakes, and volcanoes; movement can be divergent, convergent, or transform.
  • Volcanism: Volcanic activity results in the ascension of magma, leading to eruptions, mountains, and landscapes.
  • Earthquakes: Earthquakes are releases of energy accumulated in tectonic faults. They can have devastating effects.
• Exogenous processes: Forces on the Earth's surface are caused by external forces, like water, wind, or ice.
• These processes are responsible for shaping the Earth's surface.
  • Erosion: Wearing away rock and soil by wind, water, or ice.
  • Weathering: Decomposition of rocks due to temperature changes, pressure, or organisms.
  • Sedimentation: Accumulation of transported particles by water, wind, or ice in new locations.

Exogenous Processes

• Exogenous processes use erosion, weathering and accumulation to model terrain from the outside of the Earth.
• Erosion occurs by water, glaciers, seas, and wind, which wear, transport, and accumulate sediments.
• Rivers form valleys in mountainous areas like the Desaguadero basin. Water erosion affects the Pampeana region due to soil undulation, precipitation, and agricultural practices.
• Glacial erosion significantly shapes the Patagonian landscape, creating lakes and moraines.
• Wind erosion is prominent in arid and semi-arid regions; human activities such as overgrazing and deforestation can worsen it.
• Over 70% of Argentina has arid or semi-arid climates, affecting Patagonian region and sectors of Mendoza, San Juan, La Rioja, Catamarca, Salta, and Chaco.

Weathering

• Weathering on Earth's surface occurs from climatic factors affecting the components of the rocks. It can be physical or chemical.
• Mechanical weathering: it does not alter the rock's chemical composition, but fracture it into small parts, which can be carried by wind or water.
• Mechanical weathering occurs with the dilation and contraction of the rock weakening the structure of it, and occurs in arid climates.
• Mechanical weathering occurs in cold weather, caused by the freezing of water in cracks, expanding their size until the rocks break.
• Chemical weathering: Chemical weathering changes the rock's chemical composition, and it occurs by oxidation and dissolution.
• Oxidation occurs between the oxygen and minerals in the soil, which weakens the structure of the rocks, and also favoring formations like the red soil in Misiones
• Dissolution: Dissolution occurs when the soluble materials go into contact with water. For example, when water with calcium filtrates the soil, forming caves
• Areas with this trait known as "karst"
• The karst formations consists of stalactites made of constant dripping, dissolving calcium minerals.
• Some of the formations can be found in San Juan, Salta and Mendoza regions

Overview of Argentina's environment, including natural and social elements. Key components like landforms (plains, mountains, plateaus), climate factors, and hydrography are discussed. The evolution of landforms through geological time is also examined.