W2 - Stratigraphy Flashcards
Who was Clair Patterson?
In 1956, showed the Canyon Diablo Meteorite to be - established age of planetary formation in solar system
How old is the solar system?
4.55by +/- 70my
How was the age of the solar system formation estimated?
Determined by Clair Patterson who developed the first clean labs to measure lead isotopes
In 1956, determined the age of the Canyon Diablo Meteorite
What is absolute geologic age?
Understanding of when events actually happened
Asks how old it is
What is tephra?
Volcanic ash layer
Helpful for dating
What is relative geologic age?
Understanding when events occurred relative to one another
Asks what came first
What is stratigraphy?
Study of layered rocks in order to understand their composition, origin, and changes in space and time
What are layers of rock called?
Strata (pl.) or stratum (s.)
Sedimentary rocks are usually layered or “bedded”
Stratigraphic succession is the vertical sequence of layering
Who was Nicolas Steno?
Danish Catholic monk and famed renaissance anatomist
Tried to understand the connection between inorganic and organic material
What was Nicolas Steno’s big discovery?
Recognized that fossil shark’s teeth were entombed in sedimentary rock rather than grown within the rock
Reasoned that rock was originally fluidized and that crystals in igneous rocks formed in original liquid state - indicated that Earth’s geology recorded complex processes of sedimentation and transformation of sediments to rocks
Also invented the basic laws of stratigraphy
What is the Principle of Original Horizontality?
Sedimentary layers laid down in water are deposited nearly horizontal and parallel to the Earth’s surface
Layers now eroded were once continuous (ex: Tapeats sandstone layer in the Grand Canyon has been eroded by the Colorado River)
What is the Principle of Superposition?
In any undisturbed series of sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top
What is the Principle of Lateral Continuity?
Strata extend continuously in all directions until they are terminated by thinning at the edge of a basin, end abruptly at a barrier to sedimentation, or grade laterally into a different sediment type
Who was Charles Lyell?
Came up with the Principles of Geology
What is uniformitatianism?
The theory that present is key to the past
