Relative dating rock layers activity, introduction
Scientists also use direct evidence from observations of the rock layers themselves to help determine the relative age of rock layers.
In reading earth history, these layers would be "read" from bottom to top or oldest to most recent. Which fossil organisms could possibly be used as index fossils?
WHO'S ON FIRST? A RELATIVE DATING ACTIVITY
All of the fossils represented would be found in sedimentary rocks of marine origin. Once an organism disappears from the sequence it cannot reappear later.
When you complete this activity, you will be able to: Arrange them from oldest to youngest with the oldest layer on the bottom and the youngest on top. The cards in Set B represent rock layers containing various fossils.
It is recommended that students complete Procedure Set A and answer the associated Interpretation Questions correctly before proceeding to Set B. Scientific measurements such as radiometric dating use the natural radioactivity of certain elements found in rocks to help determine their age.
This also means that fossils found in the lowest levels in a sequence of layered rocks represent the oldest record of Green dating sites there.
The Grand Canyon and Relative Dating
This would also mean that fossils found in the deepest layer of rocks in an area would represent the oldest forms of life in that particular rock formation.
It is good at this time to remind them that these letters represent fossils in a rock layer and that one fossil next to another within a rock layer implies no particular sequencing; they both are approximately the same age as that particular rock layer.
Locally, physical characteristics of rocks can be compared and correlated. Use this information to sequence the cards in a vertical stack of fossils in rock strata.
Return to top To enhance this activity, have students match the fossil sketches to real fossils. When you finish, you should have a vertical stack of cards with the top card representing the youngest fossils of this rock sequence and the "TC" card at the bottom of the stack representing the oldest fossils.
The nonsense syllables or letters sometimes overlap other cards and are being used to introduce the students to the concept of sequencing. Use this information to sequence the cards in a vertical stack of fossils in rock strata.
In a "normal" horizontal sequence of rocks, the oldest rock layers will be on the bottom with successively younger rocks on top.
Name three organisms represented that probably could not be used as index fossils and explain why.