SES4U
Earth and Space Science
Reference: ArcGIS Online
Weathering and Erosion Activity
Aging Impact Craters Using ArcGIS Online
Weathering and erosion act to wear down the earth’s surface while plate
tectonics and other geologic forces act to “build it up”. If plate tectonics were not
creating new mountains, highlands or rift valleys the processes of weathering and
erosion would create a featureless flat surface to the Earth.
For the same reason that we know a shorter, rounded more eroded mountain is
older than a mountain with tall jagged peaks, we can apply this reasoning to
determine the relative age of impact craters.
Characteristics of a Crater:
Diameter (determined by the size and velocity of the impacting object)
Depth (a function of the crustal composition as well as size/velocity of object)
Definition (how visible/defined the walls, depth and overall shape of the crater
are. Indicates age of crater)
What to Do:
1) Log into your ArcGIS Online account that you created and click MAP along
the top bar.
2) In the
tool choose the satellite imagery layer to view a
composite image of the entire world.
3) To add the location and information about world impact craters click the
Icon and choose “search for layers”
4) In the Find: bar type “impact craters” and in the In: bar choose ArcGIS
Online.
5) Find the title “world impact craters” and click add.
6) For each of the craters listed on the next page use the Measure tool to
estimate its diameter. For extensively eroded craters click on the symbol to
show diameter.
7) Fill in the rest of the chart in an attempt to place all craters in order of age.
SES4U
Earth and Space Science
Reference: ArcGIS Online
Find the Following Craters:
Location and Name
Diameter &
estimate of
object size
Interesting
Features/landform
Level of Weathering &
Erosion: minimal, moderate,
Extensive
Relative Age
Southwestern USA:
Barringer
Central USA:
Manson
Central USA:
Decaturville
Northern Quebec:
Clearwater East and
West
Central France :
Steinhelm
Northern Quebec:
Manicouagan
Northern Ontario:
Sudbury Basin
Central India:
Lonar
Questions:
1. What aspects associated with climate might impact how quickly a crater weathers and
erodes?
2. What role do you think wind (aeolian) could play in the visibility of impact craters?
3. Moving glaciers shape the earth’s surface by weathering and eroding huge amounts of
rock over large areas (sometimes entire continents). How might observing impact
craters that have experienced glaciation affect our ability to relative date them
accurately?
4. The substrate (bedrock) where an impact occurs plays a role in the overall size,
definition and preservation of a crater. Suggest an environment where a crater may
weather and erode quickly vs. an environment where a crater would erode slowly.
Age
Ranking