3 and a half years.
Index fossils are fossils of organisms that lived for a relatively short period of time but were widespread geographically. By identifying these index fossils in a particular layer of rock, scientists can determine the age of the rock and correlate it with other rock layers containing the same index fossils. This allows for the relative dating of rock layers based on the presence of specific index fossils.
Index fossils are used to date rocks by correlating the fossils found in the rock layers with known ages of those fossils. Index fossils are distinctive, widespread, and lived for a relatively short period of time. By identifying these fossils in a rock layer, scientists can infer the age of the rock based on the age range of the known fossil.
Perhaps by carbon dating and by comparing with the evolution and dominance of various organisms in the geological time scale.
Fossils found in the same rock layer or strata are assumed to be of similar age and were likely deposited during the same time period. This allows scientists to infer the relative ages of the fossils based on the layer they were found in. Fossils within the same layer can provide valuable information about the environment and species that existed during that specific time period.
The rock samples collected from the bottom of the drill hole likely came from the Earth's crust or upper mantle layer, as drill holes typically do not penetrate beyond the uppermost layers of the Earth's lithosphere. To determine the exact layer, further analysis of the composition and characteristics of the rock samples would be necessary.
to date a rock layer and other fossils within that layer
layer rocks
The fossils are typically found in the uppermost layer of rock, as sedimentary rock is formed from the accumulation of materials over time. Newer layers are deposited on top of older layers, meaning that the youngest fossils would be located in the most recent (top) strata. Therefore, the youngest fossils are in the layer that is highest in the sequence shown.
people who specialize in rock fossils are called paleontologists
Index fossils are very important to geologists because they identify geological time periods. Index fossils are found within a specific layer of rock- So when one finds the age of the rock layer, that is also the age of the index fossil.
Fossils found in the rock layer are the most accurate method for pinpointing a time period on the geologic time scale. By identifying the specific types of fossils present, scientists can determine the age of the rock layer relative to the known age ranges of those fossils.
The age of the rock layer
Geologists can use index fossils from rock layer B to correlate the age of the rocks in another location by matching the presence of these unique fossils. Index fossils are widely distributed and lived for a short period of time, making them useful for dating rock layers. By identifying the same index fossils in both rock layers, geologists can infer that they are of similar age.
It can be assumed that the organisms that created the fossils were a part of the same depositional environment and process, and roughly from the same time span of the rock that comprises the layer.
A fossil fuel
If the same types of fossils are found in two separate rock layers, it's likely that the two rock layers ____.
The Adirondack rocks have been both severely folded and sheared by ductile deformation and shattered by brittle.