Petrology Lecture Notes Flashcards

Vocabulary flashcards covering the classification, types, and industrial uses of rocks as discussed in the PTE 1252 Petrology lecture.

Igneological classification

The classification of rocks into three major groups based on their origin: igneous, sedimentary, and metamorphic.

Igneous rocks

Rocks solidified from molten or partly molten magma, also referred to as primary rocks.

Sedimentary rocks

Rocks resulted from the consolidation of loose sediments derived by mechanical and chemical weathering of pre-existing rocks, also termed secondary rocks.

Metamorphic rocks

Rocks derived from pre-existing igneous, sedimentary, or metamorphic rocks that undergo mineralogical, chemical, and/or structural changes.

Lithosphere Composition

According to Clarke and Washington, the lithosphere consists of $95\%$ igneous rocks and $5\%$ sedimentary rocks.

Stratified rocks

Rocks consisting of different layers in their structure separated by planes of stratification, such as sandstone, limestone, and shale.

Unstratified rocks

Rocks that possess a crystalline or compact granular structure throughout their whole body, such as granite and marble.

Foliated rocks

Rocks possessing a layered or banded structure obtained by exposure to pressure and heat, such as gneiss and schist.

Argillaceous rocks

Rocks in which clay content is predominant; they are soft in nature and can be crumbled easily with the presence of water.

Calcareous rocks

Rocks in which calcium carbonate is the major ingredient, such as marble, limestone, and dolomite.

Siliceous rocks

Rocks containing a predominant amount of silica, which makes them hard, durable, and resistant to weathering.

Magma

The molten fluid or material inside the Earth that is the source of all igneous rocks.

Principle of Uniformitarianism

A basic concept of geology stating "the present is the key to the past," given by Hutton in $1785$.

Ore

A mineral deposit from which valuable metals can be recovered profitably.

Diatomite

A silica mineral formed from fossilised algae used to filter water and purify drinks such as beer and wine.

Glauconitic sandstone

A sedimentary rock that is directly crushed and used as fertilizer in agricultural fields.

Ballast

Aggregate consisting of crushed rock, sand, and gravel upon which railway tracks are laid.

Depth of Earth's Crust

The outermost layer of the Earth's internal structure, spanning from $0$ to $100\,km$.