..... A component of loess

..... Travertine

..... In rocks affected by karstification

..... If occurs in low proportion, the viscosity of lava is higherk

..... Builds 45% of rhyolite

..... Stromboli, Etna

..... Stalactite

..... Chert

..... Produced by solfataras

..... Typical component of Andean rocks

..... Chert

..... Travertine

..... Rock affected by karstification

..... SiO₂ is a main component

..... Piping (suffosion) is a major process of its erosion

..... Clastic sedimentary rock

..... Includes CaCO₃

..... Wind action is important in formation

..... Formed in great thicknesses (several thousands of metres) in the Triassic

..... Typical in Alpine rocks

..... Preparatory process to surface planation

..... H₂CO₃ + CaCO₃ = Ca (HCO₃)₂

..... Typical of cold polar areas

..... End product is clay

..... Temperature is an important condition for its operation

..... Influenced by pH

..... Involves chemical transformation

..... May be caused by pressure release

..... Its product can be transported by mass movements

..... Typical in the tropical belt

..... Mid-latitudes

..... Fluvial erosion typical in summer

..... Fluvial erosion typical in winter

..... Along the western coasts of continents

..... Rivers have broad gravel beds almost dry in summer

..... Typical soil type is terra rossa

..... Mechanical weathering is only intensive in high mountains

..... Brown forest soils are typical

..... Fiumara type streams are typical

..... In summer under the influence of the ascending limb of trade winds

..... Formed by gelisolifluction

..... Horns point against wind direction

..... Landform of partly stabilized sand areas

..... Also occurs in Hungary

..... Merge to form transversal dunes

..... Vegetation contributes to its development

..... Average height is more than 100 m

..... Landform of areas of free sand movement

..... Aeolian landform

..... Dark stripes are due to ovrag formation