Brad O’Neal
Professor Wilhelm
AST 191 001
21 September
Write Up #3
3a) Given a picture of the moon I need to give an age sequence at least three maybe more
of the formations present in the picture. This is made possible from Steno’s laws which are: Law
of Original Horizontality, Law of Lateral Continuity, Law of Superstition, and the Law of CrossCutting Relations. Each law gives a logical explanation as to why a crater on the moon cam
before the rift the runs across the crater. I plan to use Steno’s Laws to relatively age date
formations on the moon.
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Law of Original Horizontality-infers that sedimentary rock layers were originally
deposited as flat-lying (horizontal) layers.
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Law of Lateral Continuity-states that sedimentary rock layers are deposited over large
areas
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Law of Superposition-states that, in a cross-section view, rock layers are oldest at the
bottom and become progressively younger upwards.
•
Law of Cross-Cutting Relations-infers that a rock body (e.g. igneous dike) cutting
through another rock body (sandstone beds) is younger than the layers it intrudes.
The picture above has four formations marked: the red circle is a crater, the yellow line is
a rift, the white circle is another crater, and the black arrows are pointing to the Mare of the
Moon. From using Steno’s laws I can relatively put the formations in chronological order from
youngest to the oldest. Starting with the oldest, the crater encircled with red. I can say that the
crater is the oldest using Steno’s Law of Original Horizontality. The crater is filled with Mare,
which is pointed out with the black arrows, so I can make an educated guess that the crater came
first and then the sedimentary layer covered it. It is a clear sign of age. The crater came first and
the Mare came second. From the Mare we can see the rift, outlined in yellow, in the sedimentary
layer right above the crater. I can tell from the Law of Cross-Cutting Relations that the rift came
after the Mare and the crater because it cut through the Mare. The youngest feature compared
with the others is the crater outlined in white. I came to this conclusion because the crater,
outlined in white, interrupts the rift that is outlined in yellow. This is the Law of Lateral
Continuity at work. To sum everything up; A meteor impacted the Moon, then a lava flow
rushed over the crater, the rift formed, and then another meteor hit interrupting the rift’s
formation.
Dating the formations on the Moon is relatively easy. I was able to make an educated
guess using some of Steno’s Laws. Most everything on the surface of many planets can be dated
if the viewer knows Steno’s Laws. Using the Steno’s Laws of Original Horizontality, CrossCutting Relations, and the Law of Lateral Continuity I was able to date the four formations I
have outlined in the picture above on the Moon.
3b) These images was taken of the moon Europa. Europa is one of many moons of Jupiter in
our Solar system. Having geological activity, Europa’s surface formations can be dated in
chronological order from the oldest formation to the youngest formation. It can also shed some
light onto what is happening on the surface of Europa. The two images below are examples of
this. Dating the formation and figuring out the activity of Europa is made possible by using
Steno’s Laws: Law of Original Horizontality, Law of Lateral Continuity, Law of Superstition,
and the Law of Cross-Cutting Relations. I plan on using Steno’s Laws to relatively date these
linear formations on the surface of Europa on image one and to explain what is happening in
image two.
In image one the stress fracture outlined in red on Europa’s surface is the oldest. I can
come to this conclusion using Steno’s Law of Cross-Cutting Relations. “Law of Cross-Cutting
Relations infers that a rock body (e.g. igneous dike) cutting through another rock body
(sandstone beds) is younger than the layers it intrudes.” Now the original sedimentary layer of
Europa is the oldest but the oldest geological activity is the stress fracture outlined in red. Then
the next formation to occur was the stress fracture outlined in black. I also came to that
conclusion by using the same law of Cross-Cutting Relations. The black outlined stress fracture
is younger because it interrupts the red outlined one. Continuing on, the yellow outlined fracture
interrupts the black outlined stress fracture so I can conclude that this one is younger than both
the red and the black one. If you were to continue on following the stress fracture outlined in
black you would come across the fracture outlined in purple. From the law of Cross-Cutting
Relations I can tell that the purple one is younger than the black one because it interrupts the
black outlined fracture. Following the purple outlined fracture you can see that it is interrupted
by the green outlined fracture. I can tell this all by using the law of Cross-Cutting Relations all
of the interruptions are cutting through the previous formation and is intruding. From start to
end it went like this: The Red stress fracture, black, and then yellow. Then with the second
chronological order it went: The red stress fracture, black, purple, and then green.
In image number two I can tell that what I think to be as ice chunks are moving. I can tell
this because of the helps of the Steno Laws that were mentioned earlier. Specifically, the law of
Cross-Cutting Relations lets me know this. I have circled three examples that help prove the
point. The circles in red, yellow, and black all show a chunk of the ice that has broken off. I can
tell that they have moved from their first location from looking at the interruption in the stress
fractures. This interruption is what tells me the chunk of ice use to be one big chunk of ice until
it broke off. Now if that were just the case the stress fracture would have just had another
interruption in itself. I can tell that the chunks of ice are moving because it doesn’t match up.
The puzzle piece to this bizarre array of fractures is slightly out of place. From this conjecture I
can make a guess and say that maybe Europa has tectonic plates. There might possibly be a
heating and re-cooling effect that is making the chunks of ice slip with the liquid away from the
main body.
Using Steno’s Laws I was able to relatively date the stress fractures on Europa as well as
explain the features in the chaotic region of Europa. Europa is one of Jupiter’s moons that have
geological activity. The stress fractures and the chaotic region are just a few of many examples
of the geological activity that can be dated and explained by using Steno’s laws. I used Steno’s
law of Cross-Cutting Relations to prove the chronological order of age of these stress fracture
formations and help explain what was happening in the chaotic region on Europa.