Rocks factsGeology quiz
Dry Falls is thought to be the greatest known waterfall that ever existed. Where is it?
In the United States. Dry Falls is a 3.5 mile long scalloped precipice in central Washington. According to the current geological model, catastrophic flooding channeled water over this 400-foot (120 m) rock face at the end of the last ice age. At this time, it is estimated that the flow of the falls was ten times the current flow of all the rivers in the world combined.
What kind of rock is marble?
Metamorphosed limestone. Marble is a metamorphic rock. It is formed deep under the Earth surface, under high pressure and temperature between 500 and 700°C. Under such conditions calcite recrystallises and limestone is transformed into marble.
What is karst?
A kind of chemical decomposition. Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions.
What is the literal meaning of the name Gibraltar?
The Mountain of Tariq. The name "Gibraltar" is the Spanish derivation of the Arabic name Jabal Ṭariq, meaning "Mountain of Ṭariq". Following a raid in 710, a predominately Berber army under the command of Tariq ibn Ziyad crossed from North Africa in April 711 and landed somewhere in the vicinity of Gibraltar (though most likely not in the bay or at the Rock itself). Tariq's expedition led to the Islamic conquest of most of the Iberian peninsula.
What is the oldest rock in the world?
Gneiss. The Acasta Gneiss in the Canadian Shield in the Northwest Territories, Canada is composed of the Archaean igneous and gneissic cores of ancient mountain chains that have been exposed in a glacial peneplain. Analyses of zircons from a felsic orthogneiss with presumed granitic protolith returned an age of 4.031 ±0.003 Ga.