What is the difference between original horizontality and lateral continuity?
The Law of Original Horizontality suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed. The Law of Lateral Continuity suggests that all rock layers are laterally continuous and may be broken up or displaced by later events.
What principle states that a geologic feature that cuts another geologic feature is younger than the cut feature?
cross-cutting relationships
What are continuous rock layers?
The principle of lateral continuity states that layers of sediment initially extend laterally in all directions; in other words, they are laterally continuous. As a result, rocks that are otherwise similar, but are now separated by a valley or other erosional feature, can be assumed to be originally continuous.
What type of unconformity occurs when sedimentary rocks overlie either igneous or metamorphic rocks?
Nonconformities occur where rocks that formed deep in the Earth, such as intrusive igneous rocks or metamorphic rocks, are overlain by sedimentary rocks formed at the Earth’s surface. The nonconformity can only occur if all of the rocks overlying the metamorphic or intrusive igneous rocks have been removed by erosion.
Is Disconformity dating absolute or relative?
1) Relative dating–places geologic events into a sequence and refers to them in their order of occurrence. This is typically determined from their position in the rock record or from comparison of fossils. Studying the fossil record of life is called PALEONTOLOGY. 2) Absolute dating–results in an absolute age.
What is an unconformity in rock layers?
Put simply, an unconformity is a break in time in an otherwise continuous rock record. Unconformities are a type of geologic contact—a boundary between rocks—caused by a period of erosion or a pause in sediment accumulation, followed by the deposition of sediments anew.
What are the 5 types of unconformities?
Types
- Disconformity.
- Nonconformity.
- Angular unconformity.
- Paraconformity.
- Buttress unconformity.
- Blended unconformity.
What is a nonconformity?
1a : failure or refusal to conform to an established church. b often capitalized : the movement or principles of English Protestant dissent. c often capitalized : the body of English Nonconformists.
Which rock unit is the youngest?
The principle of superposition states that the oldest sedimentary rock units are at the bottom, and the youngest are at the top. Based on this, layer C is oldest, followed by B and A.
What do Unconformities represent in the rock record how do they form?
Unconformities are gaps in the geologic record that may indicate episodes of crustal deformation, erosion, and sea level variations. Unconformities represent times when deposition stopped, some of the previously deposited rock was removed by an erosion interval and finally resumed deposition.
How is the principle of original horizontality describe?
The Principle of Original Horizontality states that layers of sediment are originally deposited horizontally under the action of gravity. It is a relative dating technique. The principle is important to the analysis of folded and tilted strata.
What is the name of the process in which rock layers in different regions are matched?
CORRELATION
What is correlation of rock layers?
The process of showing that rocks or geologic events occurring at different locations are of the same age is called correlation. Geologists have developed a system for correlating rocks by looking for similarities in composition and rock layer sequences at different locations.
What does it mean if two or more rock layers are in correlation?
If two rock layers have the same index fossils, then they’re probably about the same age. Rock layers with the same index fossils must have formed at about the same time. The presence of more than one type of index fossil provides stronger evidence that rock layers are the same age.
Where is the youngest rock layer present in original horizontality?
The many horizontal layers of sedimentary rock illustrate the principle of original horizontality (Figure below). The youngest rock layers are at the top and the oldest are at the bottom, which is described by the law of superposition.
Is the fault older or younger than rock layer A?
A fault is a break in Earth’s crust. A fault is always younger than the rock it cuts through. The surface where new rock layers meet a much older rock surface beneath them is called an unconformity. An unconformity is a gap in the geologic record.
What is an intrusion intrusions are always younger than what?
Magma that cools and pushes into. bodies of rock and hardens is called an. Intrusion. An intrusion is always younger than the rock layers around and beneath it. The intrusion (in red) is now younger than the surrounding rocks.