Earth History Flashcards
What is angular nonconformity?
Indicates deposition of sediments, tectonic uplift, and deformation, erosion and deposition of new sediments
What are Carbonaecous films?
Thin silhouettes of carbon. Result from high temp and press. as sediments deposit on top. Carbon of organism undergoes chemical change to produce thin carbon film
What are climate proxy records?
Historical records of crop productivity and other phenomena that imply the nature of past climate. Ex: Tree rings
Principle of Superposition
In any sequence of sedimentary strata the order in which the strata were deposited is from bottom to top
A.k.a Older rocks on bottom, younger rocks on top
What are embedded fragments?
The law of included fragments is a method of relative dating in geology. Essentially, this law states that clasts in a rock are older than the rock itself. One example of this is a xenolith, which is a fragment of country rock that fell into passing magma as a result of stoping.
How may volcanoes have helped to cause the relative warmth in the Cretaceous Period?
Increased volcanic activity, may have contributed to more climate warming and sea level rising
How recent did Humans exist?
One hundred thousand years ago
What are index fossils and what are their characteristics?
Fossilized organism remains and can can be used to correlate rock layer.
Must be abundant, widespread, unique and brief period existence
In what period did dinosaurs become completely extinct?
Cretaceous period
In what period did mammals first appear?
Jurassic Period
In what period did reptiles first appear?
Carboniferous period
In what period did the first amphibians appear?
Devonian Period
In what period did the first flowering plants appear?
Cretaceous Period
Principle of Cross-cutting relationships?
That the geologic feature which cuts another is the younger of the two features. It is a relative dating technique in geology.
How does Radioactive dating work?
By measuring the amount of parent and daughter isotope within a rock or mineral and use the ratio of the two to find age of rock