Search results
Results from the WOW.Com Content Network
Identifying and understanding the relationship between contacts is important in determining relative ages of rocks and formations. [6] Contacts are a key feature used to create geological maps. Cross-cutting relationships of these contacts can be used to determine the relative geological history of an area or of an outcrop.
The principles of lithostratigraphy were first established by the Danish naturalist, Nicolas Steno, in his 1669 Dissertationis prodromus. [1] A lithostratigraphic unit conforms to the law of superposition, which in its modern form states that in any succession of strata, not disturbed or overturned since deposition, younger rocks lies above older rocks. [2]
This is caused by rapid solidification of the melt near the contact with the surrounding low temperature environment. In an intrusive case, the crystallized chilled margin may decrease in size or disappear by later remelting during magma flow, depending on magma heat flux .
Cross-cutting relationships can be used to determine the relative ages of rock strata and other structures. Explanations: A – folded rock strata cut by a thrust fault; B – large intrusion (cutting through A); C – erosional angular unconformity (cutting off A & B) on which rock strata were deposited; D – volcanic dike (cutting through A, B & C); E – even younger rock strata (overlying ...
The principle of Uniformitarianism states that the geologic processes observed in operation that modify the Earth's crust at present have worked in much the same way over geologic time. [2] A fundamental principle of geology advanced by the 18th century Scottish physician and geologist James Hutton, is that "the present is the key to the past ...
Contact metamorphism occurs typically around intrusive igneous rocks as a result of the temperature increase caused by the intrusion of magma into cooler country rock. The area surrounding the intrusion where the contact metamorphism effects are present is called the metamorphic aureole, [44] the contact aureole, or simply the aureole. [45]
Map of isothermal lines across North America and Europe from Lyell's Principles of Geology (6th edition). Published in three volumes in 1830–1833 by John Murray, the book established Lyell's credentials as an important geological theorist and popularized the doctrine of uniformitarianism (first suggested by James Hutton in Theory of the Earth published in 1795). [3]
Geology – one of the Earth sciences – is the study of the Earth, with the general exclusion of present-day life, flow within the ocean, and the atmosphere. The field of geology encompasses the composition, structure, physical properties, and history of Earth's components, and the processes by which it is shaped.