Description
dating methods to place events
Posting
ve four rocks Granite, Slate Limestone, and Shale or Mudstone.
Field setting of the rocks is as follows
On the bottom is Granite either side of the granite is Slate, on top of Slate is Limestone, the top layer is
Shale or Mudstone
In the field setting of the above rocks there is a selection of of possible events in the history of the rocks
listed
Relative dating methods will place the list in the correct chronological order, some of the events may be
used more than once.
a time gap in depostition
deposition of shale
Intrusion of granite pluton
folding of shale
metamorphism of shale
deposition of limestone
Uplift, weathering and erosion
I have done this answer, need to know if its ok, as I am not very knowledgable in geology.
Regards
Sandie
Subject:
Topic:
Geology
Environmental Geology.
Level:
Bid Amount:
Other
1 Credit(s)
Your question is this:
1. “I have done this answer, need to know if its ok, as I am not very knowledgeable in geology”.
It is kind of difficult to tell where the question ends and your answer begins. I am assuming that
the following list is your answer (and not a given and part of the question) that you want me to
check:
 a time gap in depostition
 deposition of shale
 Intrusion of granite pluton
 folding of shale
 metamorphism of shale
 deposition of limestone
 Uplift, weathering and erosion
A. First, relative dating methods involve placing geological events in a sequential order as
determined from their position in the rock record. Relative dating will not tell us how long ago a
particular event occurred; only that one event preceded the other. Four principles of relative
dating are of importance for this question:
1. Principle of superposition: Nicolas Steno realized that correct relative ages of horizontal
(undeformed) strata could be determined by their position in a sequence of rock.
2. Principle of cross-cutting Relationship: holds that an igneous intrusion or a fault must be
younger than the rocks it intrudes or displaces. This principle is very important in relative dating
of geologic events and interpreting Earth history.
3. Principle of lateral continuity states that sediment extends laterally in all directions until it
thins and pinches out or terminates against the edge of the depositional basin.
4. Principal of original horizontality: Steno reasoned that sediment is deposited in essentially
horizontal layers
B. The four rocks are as follows:
Shale-Mudstone is a detrital sedimentary rock
Limestone is a chemical sedimentary rock
Granite is an igneous rock
Slate is a low-grade metamorphic rock
C. The relative dating of your field study using the relative dating principles are as follows:
The detrital sedimentary rocks (Shale-Mudstone) in your field study were originally deposited
horizontally (principal of original horizontality). The oldest rocks (i.e., slate) are therefore at the
bottom and the youngest rocks (shale-mudstone) are therefore at the top (principle of
superposition). Limestone, a chemical sedimentary rock (i.e., developed through chemical
weathering), is the next strata and is, therefore, the second oldest rock next to that of shalemudstone (principle of superposition and principal of original horizontality). Because the granite
has slate on either side, obviously the granite is an igneous intrusion and must be younger than
the rocks (i.e., slate) it intrudes or displaces (principle of cross-cutting relationship). The oldest
rock (i.e.,) is at the bottom (principle of superposition).
As you can see, some of your answers fit nicely into this geological relative dating analysis.
However, it is important to use the geologic principles in your analysis. I hope this helps. Good
work and take care.
Source: Wicander, R. & Monroe, J. S. (1995). Historical Geology: Evolution of the earth and life
through time (2nd ed.). New York: West Publishing Company