ERA
|
PERIOD
|
AGE
(of start)
|
Cenozoic
|
|
1.6 my
|
|
65 my
|
Mesozoic
|
|
140 my
|
|
205 my
|
|
250 my
|
Paleozoic
|
|
290 my
|
|
355 my
|
|
410 my
|
|
438 my
|
|
510 my
|
|
540 my
|
|
Quaternary 1.6 million years
ago - Today
Life
Dominant life includes:
Mammals, humans
First Homo Sapiens
The climate is relatively cool with ice
at the poles. There were dramatic glaciers (permanent
bodies of ice that move due to its heavy weight) that
covered much of the continents, including much of the Lehigh
Valley.
Continuation of weathering and erosion,
forming the current landscape.
The main rock types/ deposits in PA
are silt, clay, gravel and sand.
|