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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 ...
Cross-cutting relationships between contacts and formations can be used to determine the geological history of an area. Events are in order, from oldest to youngest, A to F. Identifying and understanding the relationship between contacts is important in determining relative ages of rocks and formations. [ 6 ]
Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. [1] The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
The principle of cross-cutting relationships that states a rock that cuts across another rock must be younger than the rock it cuts across. [ 8 ] [ 9 ] [ 10 ] [ 7 ] The law of included fragments that states small fragments of one type of rock that are embedded in a second type of rock must have formed first, and were included when the second ...
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 dyke (cutting through A, B & C); E – even younger rock strata (overlying C & D); F – normal fault (cutting through A, B, C & E).
A cross section or cross-section, in geology, is a diagram representing the geologic features intersecting a vertical plane, and is used to illustrate an area's structure and stratigraphy that would otherwise be hidden underground. The features described in a cross section can include rock units, faults, topography, and more.
For example, there is a common misconception that having many smaller earthquakes can somehow 'relieve' a major fault such as the San Andreas Fault, and reduce the chance of a major earthquake. [1] It is now known (using paleoseismology) that nearly all the movement of the fault takes place with extremely large earthquakes.
Cross-joints – Joints which are approximately perpendicular to fold axes. Diagonal joints – Joints which typically occur as conjugate joint sets that trend oblique to the fold axes. Strike joints – Joints which trend parallel to the strike of the axial plane of a fold. Cross-strike joints – Joints which cut across the axial plane of a ...