Development of the GTS Flashcards
How did the time scale work in it’s early days and which period is still used today
Primary, Secondary, Tertiary and Quaternary
Quaternary is the only one used today
How were rock varieties described in 1809
Primitive Rocks
Transition
Secondary
Albduvial
How did William smiths map impact the world
He has the oldest rocks and the bottom and youngest at the top in his legend.
How did Murchisons 5th edition map impact the time scale
Named the Silurian in 1835 and the Permian in 1841
How many eons are there and what are they
3 eons
Phanerozoic
Proterozoic
Archean
What did Lord Kelvin do for the time scale
He considered that earth started off hot and has cooled since.
Using the geothermal gradian and thermal conductivity he came up with 98Myrs + or - (20-400MA)
This was ultimately wrong
Define the Hadean
Hadean=no rocks
while Archean = oldest rocks
Why was the GST constructed
In the beginning of the Industrial Revolution, In order to understand where coal deposits are, by understanding the time scale it was easier to predict where certain deposits were located.
How does heat work within the earth
Heat is constantly being generated by radioactivity and then is constantly being circulated and recycled by convection
Define Proterozoic
About 2 billion years of time, (hadean and Archean put together). Started off as a GSSAs eventually called a GSSPs
What is the problem with the pre-Cambrian
Has no official place within the gts anymore,
What events happened in the Proterozoic
First multicellular animals
Snowball earth or slushball earth
Grenville orogeny in North America(NA)**
GOE**
What is the GOE*** possible question
Biological 02 accumulates in atmosphere
What is the Grenville Orogeny in North America(NA)
Massive mountain range that has since eroded
What is an orogenic event
Mountain Building event
What is the Cryogenian
earth was completely covered in ice, snowball earth
What does the term phanerozoic mean
Manifestation of life
Development of the Phanerozoic time scale
base of Phanerozoic is defined by a trace fossil
Define GSSPs ***test question
Global Boundary Stratotype sections and points
When was the First of the big 5 extinctions
Ordovician
Why do Adam sedgwick and sir roderick Murchsion matter
Sedgwick named the cambrian in 1835
Murchison named the Silurian in 1835
When they created these periods they realized there was overlap between the two periods, and ended up arguing over this until they died. Then Charles Lapworth named the Ordovician in 1879
When did the second of the big five extinctions
also called The reef killer, occurred in the dovonian
what are the precision arrows on the gst
they indicate levels of precision in determing approximately when time occurred.
What are bases and tops on GST
base is the start of a new period and the end of the old while the top is not defined as the base of the next period is defining the top, as to prevent overlap
How is the GST divided into different subsections
Eons, eras, periods, epochs,
