Disconformity
A disconformity occurs between two sedimentary rock layers that are parallel but separated by an erosional surface. This geological feature indicates a period of erosion or non-deposition that interrupts the continuous sedimentary record. Disconformities can be identified by an abrupt change in fossil content or rock type, marking a gap in geological time. Essentially, it highlights a break in the depositional history of the rock sequence.
unconformity
The type of unconformity you are referring to is a nonconformity. It occurs when an erosional surface separates younger sedimentary rocks above from older igneous or metamorphic rocks below, indicating a period of erosion and non-deposition.
sedimentary rock
The principle that indicates rock layers separated by a valley were once continuous is called the Principle of Original Continuity. This principle suggests that sedimentary layers are deposited in continuous sheets over large areas. When a valley forms, it can erode through these layers, but the original continuity of the layers prior to erosion implies they were once part of a larger, uninterrupted sequence.
There are three main types of unconformities in geology: angular unconformities, disconformities, and nonconformities. Angular unconformities occur when sedimentary layers are tilted or folded and then eroded before new layers are deposited on top. Disconformities represent a gap in the geological record where sedimentary layers are parallel but separated by an erosional surface. Nonconformities occur where sedimentary rock overlays igneous or metamorphic rock, indicating a significant period of erosion or non-deposition.
unconformity
A disconformity occurs between two sedimentary rock layers that are parallel but separated by an erosional surface. This geological feature indicates a period of erosion or non-deposition that interrupts the continuous sedimentary record. Disconformities can be identified by an abrupt change in fossil content or rock type, marking a gap in geological time. Essentially, it highlights a break in the depositional history of the rock sequence.
unconformity
The type of unconformity you are referring to is a nonconformity. It occurs when an erosional surface separates younger sedimentary rocks above from older igneous or metamorphic rocks below, indicating a period of erosion and non-deposition.
The igneous rock could have been erupted as lava on the surface, or intruded into the sedimentary rock layers as magma underneath the surface (a sill).
Sedimentary rock layers. your welcome
Factors such as wind, ice, and warder contribute to sedimentary build up. As this occurs older layers of sedimentary rock are driven lower while newer layers replace them closer to the surface.
A line of weakness in which sedimentary rocks can be separated is called a bedding plane. This is where layers of sediment have accumulated and can be easily split or eroded along this plane due to variations in sedimentary deposition.
These thin layers are called sedimentary rocks, which are formed from the accumulation and compression of sediments over time. Sedimentary rocks are one of the three main types of rocks found on Earth's surface, along with igneous and metamorphic rocks.
Angular unconformity is not a type of unconformity. The three main types of unconformities are nonconformity, disconformity, and paraconformity. A nonconformity occurs when sedimentary rock is deposited on igneous or metamorphic rock, disconformity is an erosion surface between parallel sedimentary layers, and paraconformity is a buried erosion surface within sedimentary layers.
Sedimentary rocks are separated by lines of weakness called bedding planes. These planes represent the original horizontal layers in which the sediments were deposited, and they often serve as zones of weakness along which rocks may break or deform.