The word "quartz" is derived from the German word "Quarz" and its Middle High German ancestor "twarc", which probably originated in Slavic (cf. Czech tvrd? ("hard"), Polish twardy ("hard")).Crystal h ...
Metamorphic minerals are those that form only at the high temperatures and pressures associated with the process of metamorphism. These minerals, known as index minerals, include sillimanite, kyanite, ...
The setting in which a sedimentary rock forms is called the sedimentary environment. Every environment has a characteristic combination of geologic processes and circumstances. The type of sediment th ...
Based on the processes responsible for their formation, sedimentary rocks can be subdivided into four groups: clastic sedimentary rocks, biochemical (or biogenic) sedimentary rocks, chemical sedimenta ...
The word "basalt" is ultimately derived from Late Latin basaltes, misspelling of L. basanites "very hard stone," which was imported from Ancient Greek βασαν?τη? (basanites), from β?σανο ...
Magmatism in island arc regions (i.e., active oceanic margins) comes from the interplay of the subducting plate and the mantle wedge, the wedge-shaped region between the subducting and overriding plat ...
Granite is classified according to the QAPF diagram for coarse grained plutonic rocks and is named according to the percentage of quartz, alkali feldspar (orthoclase, sanidine, or microcline) and plag ...
The change of rock composition most responsible for the creation of magma is the addition of water. Water lowers the solidus temperature of rocks at a given pressure. For example, at a depth of about ...
Igneous and metamorphic rocks make up 90–95% of the top 16 km of the Earth's crust by volume.Igneous rocks are geologically important because:their minerals and global chemistry give information abou ...
Because the surface of continental crust mainly lies above sea level, its existence allowed land life to evolve from marine life. Its existence also provides broad expanses of shallow water known as e ...
Coral reefs are dying around the world. In particular, coral mining, agricultural and urban runoff, pollution (organic and inorganic), overfishing, blast fishing, disease, and the digging of canals an ...
In The Structure and Distribution of Coral Reefs, published in 1842, Darwin described how coral reefs were found in some areas of the tropical seas but not others, with no obvious cause. The largest a ...
Most of the coral reefs we can see today were formed after the last glacial period when melting ice caused the sea level to rise and flood the continental shelves. This means that most modern coral re ...
An example of a cliffed coast is in north-south Wales where over years of the sea beating at the cliffs the houses on top have begun collapsing into the sea. With some of them you can even see inside ...
Within the Quaternary glaciation (2.58 Ma to present), there have been a number of glacials and interglacials.Last glacial period Main article: Last glacial periodThe last glacial period was the most ...
