vocab
The preserved remains or traces of living things are called___
fossils
rock layer in a standard diagram is the oldest
the bottom layer
What is a geologic time scale?
a system used by scientists to describe the timing and relationships of events in Earth's 4.6-billion-year history
Approximately how old is the Earth
4.6 billion years
Journey
a rock is its age compared to the ages of other rocks.
relative age
Which is younger an intrusion or the rock it cuts
The intrusion is younger because it must exist after the rock layers it pushes into.
How do geologists develop the geologic time scale?
studying rock layers and fossils with absolute dating to organize Earth's history in order.
What event directly caused the Great Oxidation Event roughly 2.4 billion years ago
The evolution of photosynthetic cyanobacteria
What is my favorite animal
giraffe
a rock is the number of years that have passed since the rock formed.
absolute age
What does a geologist look for to determine the absolute age of a rock
They measure the relative amounts of radioactive elements in it
Why are sedimentary rocks most useful for relative dating
They form in distinct layers, whereas igneous or metamorphic rocks are usually formed by heating and cooling, which often destroys older structures
Which event is known as the deadliest mass extinction in Earth's history, wiping out roughly 96% of marine life
The Great Dying
how many animals do i have
5
a gap in the geologic record.
unconformity
What kind of clue do geologists use from faults
A fault is always younger than the rock it cuts through
What is the longest part of Earth's history
It makes up the vast majority of Earth's history about 4.6 billion to 542 million years ago.
Approximately how long ago did modern human emerge
300,000 years ago
What city am i from (or were is my old house located)
Tee
to determine the relative ages of sedimentary rock layers.
law of superposition
Why can't scientists use the Law of Superposition on overturned rock layers
Tectonic forces can fold or flip layers completely over, putting older rocks on top of younger ones
what are the 4 ages of earth
dominant forms of life, major evolutionary shifts, and significant mass extinctions
Which celestial event occurred roughly 4.5 billion years ago and resulted in the formation of Earth's Moon
A Mars-sized body collided with the early Earth
what is my dads name
Brock