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What does the principle of superposition tell you about the relative ages of sedimentary rock layers?
Wiki User
∙ 11y ago
Younger layers are deposited on top of older layers, whether the layer is sedimentary or volcanic. Occasionally faults may result in overthrusts, where a series of older layers may be pushed over the top of younger layers. But this is rare. In general, the older layers will be the lower layers.
Wiki User
∙ 12y ago
Wiki User
∙ 11y agoThere are two types of age determinations. Geologists in the late 18th and early 19th century studied rock layers and the fossils in them to determine relative age. William Smith was one of the most important scientists from this time who helped to develop knowledge of the succession of different fossils by studying their distribution through the sequence of sedimentary rocks in southern England. It wasn't until well into the 20th century that enough information had accumulated about the rate of radioactive decay that the age of rocks and fossils in number of years could be determined through radiometric age dating.
Principle of superposition: Younger sedimentary rocks are deposited on top of older sedimentary rocks.
Principle of cross-cutting relations: Any geologic feature is younger than anything else that it cuts across.
The dating of fossils was originally done by their placement in a geologic column of rock strata. Because of the Law of Superposition, the deeper the stratum, the older it is (in an undisturbed body of rock or sediment). Fossils which were evident in a particular stratum, but missing from other strata were noted as "index" fossils. The presence of these fossils indicated the age of the stratum relative to other layers. The layers of stratum were placed in a geologic column, subdivided, and assigned names based on the presence of different types of fossil organisms.This is the basis of "relative dating" of rock layers and fossils, a dating technique that was in effect until the advent of radiometric techniques in the twentieth century.
Wiki User
∙ 14y agoThe Law of Superposition in geology states that "Sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top."
Most sedimentary rocks show evidence of distinct layers or strata. If you find a fossil in a lower layer then generally it is older than one found in a higher layer.
A good demonstration of this principle is the KT-Boundary. It is believed that the KT-Boundary is a layer of rock and debris from a huge asteroid impact from 65.5 million years ago. Because of high concentrations of a rare element, Iridium, this layer is recognisable all over the world. All non-avian dinosaurs fossils are found below this level and none are found above. This has lead scientist to believe that all non-avian dinosaurs became extinct at the end of the cretaceous.
Wiki User
∙ 15y agoThe law of superposition says that oldest strata is on the bottom and the youngest is on top in undisturbed strata.
Wiki User
∙ 11y agoSuperposition refers to new layers being added on top of older layers. So, barring disturbances after deposition, rock layers nearer the surface are younger than rock layers further down.
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Which scientific principle states that younger rock layers are generally deposited on top of older rock layers and why?
Superposition
How is the law of superposition is used to date fossils?
Superposition is the methodology of younger sediments being deposited over older rocks. Paleontologists can determine the evolution or extinction of a species by looking at what fossils are either present or absent in a particular sedimentary layer.
What layer of rock would you most likely find a fossil?
Is at the bottom of course! Since sedimentary rock is formed when layers build up and then harden. So the younger would be at the top.!
What is the Arrangement of rock layers based on their ages?
A geologic column is an arrangement of rock layers in which the oldest rocks are at the bottom. The upper part of the column is rich in fossils.
Describe two ways that fossils can form?
By fossilisation and permineralisation. Fossilisation is caused by layers upon layers of sediment burying the bones. As the layers of sediment above the buried bones increases, so does the pressure on the layers of sediment lower down. The pressure becomes so great that the bones and the sedimentary rock fuse. Permineralisation occurs when mineral rich water trickles in through the sedimentary rock reaching the dinosaur bones. The minerals fill in the cracks and spaces within the bone. Sometimes the calcium in the bones may be replaced with these minerals. The new minerals in the bone make them even harder and more likely to be preserved.
How do a geologist use the principle of superposition?
A geologist uses the principle of superposition to determine the relative ages of rocks and sedimentary layers. This principle states that in undisturbed layers of rock, the youngest layers are at the top while the oldest layers are at the bottom. By observing the order in which different rock layers are stacked, a geologist can infer the sequence of events that happened over time in a particular location.
How do geologist use the principle of superposition?
The principle of superposition states that a rock layer on top of another is younger than the one beneath it. Geologists use the principle of superposition to determine the relative ages of rock layers.
what principle applies to sedimentary layers that are laid down level on top of each other?
Law of Superposition.
One of the key principles of relative dating is the law of superposition which states that?
Younger layers of sedimentary rock are deposited on older layers
What is the oldest sedimentary rock?
In an undisturbed strata, the oldest layers are at the bottom. It's called the law or principle of superposition.
What two things did 19th century scientists do to determine the relative age of sedimentary rock all over the world?
They studied fossils and applied the principle that old layers of rock are below young layers! -
What suggests relative age?
The position of a layer of rock or sediments in relation to the other layers in undisturbed strata suggests its relative age, according to the principle of superposition and the law of horizontality.
How the principle of superposition was used in determining the relative ags of the cross sections?
The principle of superposition states that the higher layers are younger because they must be laid down on a layer below, which is therefore older, can be used in cross-sections. Each layer, going up, is younger than all the previous layers.
The idea that the oldest rocks will always be the bottom layer of a series of rock layers is called the principle of?
The priciple of 'superposition'. Layers closer to the surface are younger. Age increases with depth.
Describe how the principle of superposition was used in determining the relative ages of the cross sections?
The principle of superposition states that the higher layers are younger because they must be laid down on a layer below, which is therefore older, can be used in cross-sections. Each layer, going up, is younger than all the previous layers.
The term for dating fossils based on the relative positions of different rock layers is?
Ether the principle of superposition(also called the law of superposition- concept that the layer of sediment that is deepest is the oldest) or stratigraphy which is the study of layers, when using knowledge of when certain species existed and remains of those species while also studying the layers it is called biostratigraphy.
What is the Law of Superposition?
Superposition is the principle that states that, in undisturbed strata, newer layers will be deposited over older layers; thus, in a core sample, those samples of earth and rock nearest the surface will be newer in age than those beneath them.
