Daily Archives: April 25, 2008

Sedimentary Processes and Rocks

Sedimentary rocks form by the breakdown (both physical and chemical) of pre-existing rocks (these may be of igneous, metamorphic or sedimentary origin). The main factors that control this breakdown are: climate topography vegetation properties (physical and chemical) of the rock. … Continue reading

Posted in earth, interior of the Earth, rocks | 4 Comments

Classification of Igneous Rocks

Igneous rocks are classified by using grainsize, silica content, and/or silica saturation. Other methods of classification include the International Union of Geological Sciences (IUGS) scheme and the Total Alkalies vs Silica scheme. Grain Size Based on the predominant grainsize that … Continue reading

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Limestone Topography

Limestone caves Caves form in limestone (calcium carbonate), and occasionally in dolomite (calcium magnesium carbonate), when water containing dissolved carbon dioxide (carbonic acid) seeps into rock crevices and joints. The carbon dioxide comes from decaying organic matter in soil, and … Continue reading

Posted in interior of the Earth | 3 Comments

Limestone Caves

Limestone has a peculiar quality in that whilst pure water cannot dissolve it rain water can because it has picked up carbon dioxide from the air and soil and turns the limestone into calcium bicarbonate. That process of dissolving becomes … Continue reading

Posted in interior of the Earth, Landforms | 3 Comments