UNIVERSITY OF SOUTH ALABAMA
GY 111: Physical Geology
Lecture 18: Geological Time
Instructor: Dr. Douglas W. Haywick
Last Time
1) Deep Marine Environments
2) Groundwater
Web notes 17
Deep Marine Environments
The deepest part of the ocean floor is relatively flat and is called
the abyssal plain.
http://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStrat%207/SedStrat7.html
Submarine Fans
Submarine fans:
accumulations of siliciclastic
sediment from the shelf break
onto the base of the
continental slope
http://www.dkimages.com/discover/previews/851/20117924.JPG
Submarine Fans
Submarine fans can also
be divided into 3 zones
1
2
3
http://www.geol.umd.edu/~jmerck/geol100/lectures/31.html
1: Proximal (upper)
2: Middle
3: Distal (lower)
Deep Marine Transport Mechanisms
Density currents have long been studied by geologists and
engineers. Ultimately they produce one of the most diagnostic
rock types in geology…
The turbidite.
http://serc.carleton.edu/
http://instruct.uwo.ca/earth-sci/200a-001/07turbidity.jpg
Turbidites
Turbidites are formed
due to sedimentation
from a gradually
slowing density current
and are primarily
recognized on the basis
of their fining-upward
nature.
http://regentsprep.org/Regents/earthsci/units/weathering/gradedbedding.gif
Chalk
Siliciclastic sediment is not the only deep water deposit on the
seafloor.
You also get chalk (it
tends to form on the
abyssal plane in areas
free of siliciclastic
input)
The “white cliffs” of Dover,
England
http://farm1.static.flickr.com/119/290719612_5a27cbaf61.jpg
Chalks
You can only see these “beasties” (coccoliths) under an electron
microscope. There are estimated to be 40 billion of them in every
sugar cube-sized piece of chalk on the planet (that’s a lot!).
http://www.physicalgeography.net/fundamentals/images/chalk.jpg
0.001mm
Hydrosphere
The hydrosphere is
defined as all the
water above, on and
in the Earth
hydrosphere
Hydrological Cycle
Water in the
hydrosphere is
circulated within the
hydrological cycle
http://www.coloradocollege.edu/dept/ev/courses/EV211WWW/hydrological%20cycle.jpg
Groundwater
Groundwater is water that infiltrates below the Earth’s surface
Porosity: percent void
space in a material
Permeability: degree of
connectivity of pores
(ability of a material to
transmit a fluid)
Common permeable
geological material
includes the sandstones,
limestone, marble, fault
breccia
http://www.belmont.sd62.bc.ca/teacher/geology12/photos/erosion-water/permeability.gif
Water Table
Undersaturated zone (Vadose)
Straight down water movement
Saturated zone (Phreatic)
Lateral? water movement
http://myweb.cwpost.liu.edu/vdivener/notes/water_table.gif
The water table is a planar surface that separates
the saturated and undersaturated zones
Water Table
Porous layers that are capable of passing water and releasing
it at springs and/or wells are called aquifers.
http://www.tol.ca/files/web_images/engineering/environment/WebImages/unconfined.jpg
Water Table
Clay layers may act as aquicludes and generate a perched
water table (a localized water table).
Terminology
Potentiometric
Surface: elevation
to which the
pressurized water
in a confined
aquifer will rise
Artesian Well: water
rises to an
elevation above the
aquifer
Flowing Artesian
Well/Spring:
potentiometric
surface is above the
ground surface
http://www.douglas.co.us/water/images/Denver_Basin_Aquifers_clip_image004.jpg
Groundwater Issues
• Contamination of groundwater supply
Karst Topography
Limestone dissolution features
are abundant and diverse both
at the surface and
underground
Karst Topography
Like meandering rivers, the degree
of karstification can be related to
“age”
Assignment 3
Water table contours
Ground water flows
according to
elevation differences
of the water table....
which is a surface,
It can be contoured
Assignment 3
Water table contours
Flow direction is down gradient
Assignment 3
Water table contours
Flow direction is down gradient
Assignment 3
Water table contours
Flow direction is down gradient
Today’s Agenda
A) How long is long?
B) Geological time divisions
Web notes 18
Geological Time
The problem is that we have to deal with a lot of time.
Geological Time
The problem is that we have to deal with a lot of time.
4.6 GA = 4,600,000,000 years
Geological Time
Time
0 MA (today)
4.6 GA
Geological Time
Time
Eon
0 MA (today)
Eons: the largest division
of geological time
4.6 GA
Geological Time
Time
Eon
Time
0 MA (today)
4.6 GA
Hadean
4.6 Ga to 4.2* Ga
* the upper age boundary varies as the oldest rocks on the
planet change. The shift from 4.1 to 4.2 GA occurred in
October 2008 following the discovery of really old rocks
in northern Canada.
Geological Time
Time
Eon
Time
0 MA (today)
4.6 GA
Archean
4.2 Ga to 2.5 Ga
Hadean
4.6 Ga to 4.2 Ga
Geological Time
Time
Eon
Time
0 MA (today)
Proterozoic 2.5 GA to 550 Ma
4.6 GA
Archean
4.2 Ga to 2.5 Ga
Hadean
4.6 Ga to 4.2 Ga
Geological Time
Time
Eon
0 MA (today)
Phanerozoic
550 MA to 0 MA
Proterozoic
2.5 GA to 550 Ma
Archean
4.2 Ga to 2.5 Ga
Hadean
4.6 Ga to 4.2 Ga
4.6 GA
Time
Geological Time
Time
Eon
0 MA (today)
Phanerozoic
Era
Time
Proterozoic
Archean
Hadean
4.6 GA
Eras: the 3-fold division of the eons
Geological Time
Time
Eon
0 MA (today)
Phanerozoic
Era
Time
Proterozoic
Archean
4.6 GA
Hadean
Early,
Middle,
Late
4.2 Ga to 2.5 Ga
4.6 Ga to 4.2 Ga
Geological Time
Time
Eon
0 MA (today)
Phanerozoic
Proterozoic
Era
Time
Neoproterozoic
900 MA to 550 Ma
Mesoproterozoic
1.6 GA to 900 MA
Paleoproterozoic
2.5 GA to 1.6 GA
Archean
4.2 Ga to 2.5 Ga
Hadean
4.6 Ga to 4.2 Ga
4.6 GA
Geological Time
Time
Eon
0 MA (today)
Phanerozoic
Proterozoic
Era
Time
Cenozoic
65 MA to 0 MA
Mesozoic
245 MA to 65 MA
Paleozoic
550 MA to 245 MA
Neoproterozoic
900 MA to 550 Ma
Mesoproterozoic
1.6 GA to 900 MA
Paleoproterozoic
2.5 GA to 1.6 GA
Archean
4.2 Ga to 2.5 Ga
Hadean
4.6 Ga to 4.2 Ga
4.6 GA
Geological Time
Time
Eon
0 MA (today)
Phanerozoic
Proterozoic
Era
Time
Cenozoic
65 MA to 0 MA
Mesozoic
245 MA to 65 MA
Paleozoic
550 MA to 245 MA
Neoproterozoic
900 MA to 550 Ma
Mesoproterozoic
1.6 GA to 900 MA
Paleoproterozoic
2.5 GA to 1.6 GA
Archean
4.2 Ga to 2.5 Ga
Hadean
4.6 Ga to 4.2 Ga
4.6 GA
Geological Time
Era
Period
Cenozoic
(0 to 65 Ma)
Quaternary
(0 to 2 Ma)
Tertiary
(2 MA to 65 Ma)
Periods: the most
useful subdivisions of
(mostly) the
Phanerozoic eon
Mesozoic
(65 to 251 Ma)
Cretaceous (65 to 144 Ma)
Jurassic (144 to 208 Ma)
Triassic (208 to 251 Ma)
Paleozoic
(251 to 542 Ma)
Permian (251 to 286 Ma)
Pennsylvanian (286 to 320 Ma)
Mississippian (320 to 362 Ma)
Devonian (362 to 418 Ma)
Silurian(418 to 441 Ma)
Ordovician (441 to 505 Ma)
Cambrian (505 to 542 Ma)
Proterozoic
(2500 Ma to 542 Ma)
Geological Time
Era
Period
Cenozoic
(0 to 65 Ma)
Quaternary
(0 to 2 Ma)
Tertiary
(2 MA to 65 Ma)
Periods: the most
useful subdivisions of
(mostly) the
Phanerozoic eon
Mesozoic
(65 to 251 Ma)
Cretaceous (65 to 144 Ma)
Jurassic (144 to 208 Ma)
Triassic (208 to 251 Ma)
Paleozoic
(251 to 542 Ma)
Permian (251 to 286 Ma)
Pennsylvanian (286 to 320 Ma)
Mississippian (320 to 362 Ma)
Devonian (362 to 418 Ma)
Silurian(418 to 441 Ma)
Ordovician (441 to 505 Ma)
Cambrian (505 to 542 Ma)
Proterozoic
(2500 Ma to 542 Ma)
Ediacarin*
(600 to 542 Ma)
Cryogenian* (850 to 600 Ma)
Geological Time
Era
Period
Epoch
Cenozoic
(0 to 65 Ma)
Quaternary
(0 to 2 Ma)
Holocene (0 to 10 Ka)
Tertiary
(2 MA to 65 Ma)
Pleistocene (10 Ka to 2 Ma)
Pliocene (2 Ma to 5 Ma)
Miocene (5 Ma to 24 Ma)
Oligocene (24 to 37 Ma)
Eocene (37 Ma to 58 Ma)
Paleocene (58 to 65 Ma)
Periods: the most
useful subdivisions of
(mostly) the
Phanerozoic eon
Mesozoic
(65 to 251 Ma)
Cretaceous (65 to 144 Ma)
Jurassic (144 to 208 Ma)
Triassic (208 to 251 Ma)
Paleozoic
(251 to 542 Ma)
Permian (251 to 286 Ma)
Pennsylvanian (286 to 320 Ma)
Mississippian (320 to 362 Ma)
Devonian (362 to 418 Ma)
Silurian(418 to 441 Ma)
Ordovician (441 to 505 Ma)
Cambrian (505 to 542 Ma)
Proterozoic
(2500 Ma to 542 Ma)
Ediacarin*
(600 to 542 Ma)
Cryogenian* (850 to 600 Ma)
Lots of
Epochs in
All
Periods
Today’s Homework
1.
Organize your notes (Lecture test 2 coming up soon)
2. Groundwater Assignment due next Thursday
3. Compose a symphony in 3-part harmony
Next Time
Bedding, Attitude and Geological maps
GY 111: Physical Geology
Lecture 18: Geological Time
Instructor: Dr. Doug Haywick
dhaywick@southalabama.edu
This is a free open access lecture, but not for commercial purposes.
For personal use only.