lithology

geology

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June 30, 2026

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Lithology is the study of rocks, or the specific characteristics of a rock formation. It can also refer to a rock formation with a particular set of traits.1

Rocks are broadly categorized into three main types: igneous, sedimentary, and metamorphic. Igneous rocks form from molten rock (magma or lava), sedimentary rocks are created from accumulated sediment, and metamorphic rocks are transformed by heat and pressure.2

The process of freshly deposited sediment turning into rock is called lithification. This involves cementation, where minerals bind the grains together, and authigenesis, where chemical reactions form new minerals within the sediment. Compaction also plays a role, reducing pore space and expelling fluids.3

Geologists classify igneous rocks based on their mineralogy, chemistry, and texture. For volcanic rocks, which often have fine grains, chemical composition is frequently used for classification. The study of rock successions and their correlation, often using fossils, has been crucial in understanding Earth's history.45

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river
Determining factors
Lithology is significant mainly in connection with permeability. The capacity of karst to swallow and to reissue water is well known, as is the role of permeable strata generally in absorbing water into groundwater tables. An extreme case of a special kind is represented by…
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Lithology is significant mainly in connection with permeability. The capacity of karst to swallow and to reissue water is well known, as is the role of permeable strata generally in absorbing water into groundwater tables. An extreme case of a special kind is represented by…
Read More

Devonian Period
Occurrence and distribution of Devonian deposits
…has taken place, all rock lithologies occur, from those characteristic of continental and desert conditions to the varied lithologies associated with continental shelf and deep-sea accumulation. Contemporary igneous activity was widespread in the form of extrusive lavas, submarine pillow lavas, tuffs, agglomerates, and bentonites, as well as igneous intrusions. Extrusive…
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…has taken place, all rock lithologies occur, from those characteristic of continental and desert conditions to the varied lithologies associated with continental shelf and deep-sea accumulation. Contemporary igneous activity was widespread in the form of extrusive lavas, submarine pillow lavas, tuffs, agglomerates, and bentonites, as well as igneous intrusions. Extrusive…
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geochronology
The emergence of modern geologic thought
…classification was that each unique lithology in a succession implied its own unique time of formation during the Noachian flood and a universal distribution. As more and more comparisons were made of diverse rock outcroppings, it began to become apparent that Werner’s interpretation did not “universally” apply. Thus arose an…
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…classification was that each unique lithology in a succession implied its own unique time of formation during the Noachian flood and a universal distribution. As more and more comparisons were made of diverse rock outcroppings, it began to become apparent that Werner’s interpretation did not “universally” apply. Thus arose an…
Read More