✅✅✅El MODELADO KÁRSTICO✅✅✅ y sus formas de relieve

Understanding Karst Modeling

Introduction to Karst Modeling

• The video introduces the concept of karst modeling, highlighting its complexity and various manifestations in different landscapes.

• A color-coded map of Spain illustrates the predominant rock types, specifically limestone areas marked in pink, which are primarily composed of calcium carbonate.

Geological History of Spain

• To understand the prevalence of sedimentary rocks in Spain, one must consider its geological history during the secondary era when Pangaea began to fragment.

• The Iberian microplate formed and separated from surrounding plates while many peripheral areas were submerged under the sea, leading to significant sediment deposition.

Formation of Sedimentary Rocks

• Under high pressure and temperature, sediments underwent diagenesis—compacting and crystallizing into sedimentary rocks like sandstones and conglomerates.

• During the Tertiary era, tectonic movements caused by the African plate colliding with European plates led to mountain formation known as Alpine orogeny.

Elevation of Marine Sediments

• This tectonic activity resulted in the elevation of previously submerged marine sediments into mountain ranges such as the Pyrenees and Cantabrian Mountains.

• Fossils found inland indicate that these marine sediments were uplifted thousands of meters above their original seabed locations.

Types of Relief Formed by Limestone

• Once elevated through folding processes, limestone can create various relief forms including Jurassic relief characterized by undulating shapes and alpine relief with thrust sheets.

• The focus shifts to how water interacts with these limestone formations through chemical weathering rather than just physical or biological processes.

Chemical Weathering in Karst Areas

Mechanism of Chemical Weathering

• Rainwater combines with atmospheric carbon dioxide to convert calcium carbonate into soluble bicarbonate, leading to rock dissolution—a key process in karst development.

Classification of Karst Relief

Endokarst (Internal Relief)

• Internal features shaped by underground water circulation include dolines—rounded depressions resulting from limestone dissolution or cave ceiling collapse.

Examples and Characteristics

• When flooded, dolines are referred to as cenotes; while rare in Spain, they are abundant in Yucatán. An example is Torcas de Palancares consisting of multiple dolines and cenotes.

Uvalas and Poljes

• Uvalas are large dolines formed from several smaller ones. Poljes are elongated depressions created by tectonic forces often filled with sediments.

Vauclusian Springs

• These springs emerge from cracks allowing groundwater discharge; rivers like Guadiana may disappear into sinkholes before re-emerging later at a different location.

Conclusion on Water's Role

Understanding Karst Formations and Their Characteristics

Formation of Caves and Galleries

• Some caves connect to the surface while others link different levels, such as the famous "Cima de los Huesos" in Atapuerca. These galleries are formed by the dissolution of underground limestone layers.

• Initially, these were simple cracks where water seeped through; over thousands of years, calcium carbonate dissolved, creating vast spaces within the caves.

Stalactites and Stalagmites

• When water drips from cave ceilings, some calcium carbonate precipitates back onto the rock, forming stalactites.

• If drops fall to the ground carrying minerals, they create stalagmites. Stalagmites are less common than stalactites due to this process.

Unique Geological Features

• Kárstic flows occur when water runs over surfaces and deposits layers of calcium carbonate. The most impressive examples are found in Turkey.

• Exokarst formations shape external rock surfaces primarily through chemical weathering by water but also involve other geological factors like wind and mechanical erosion.

Erosion Patterns: Lapiaz and Tomos

• Lapiaz or lunar features are grooves carved by runoff on flat limestone surfaces that grow larger over time due to rock dissolution.

• Tomos form through differential erosion affecting lower areas more than higher ones; they appear as large mushroom-shaped rocks.

Arches and Canyons

• Arches result from similar erosional processes but are rarer due to their structural vulnerability; they tend to collapse over time.

• Canyons like "Cañón del Río Lobos" feature steep walls shaped by intense water dissolution. Streams feeding into canyons are called springs.

Conclusion: Importance of Geographical Education