Fracture orientations and densities
in the Orella Member sandstones at Toadstool Geologic Park - Summer
2004.
This is a suggested question outline - you
can and should adapt it, reorganize, revise it.
Introduction:
- What is the larger project this report is
a part of?
- Where is Toadstool?
- Why might the fracture orientations and densities
be of interest?
Previous work and background:
- What is the stratigraphic context these fractures
occur within?
- What controls the orientations and densities
of fractures in rocks?
- What have other researchers said about fracture
directions and joint sets in NW Nebraska?
Methodology:
- How, when and by whom was the data collected?
- How has the data been plotted, analyzed and
why was this method chosen?
Results:
- What are the preferred directions the fractures
show?
- What geometries are seen consistently (cross
vs. longitudinal joints)?
- What is the average fracture density?
- What is the variation in fracture density?
- In a map view is there any pattern to the
orientation or density of the fractures?
Discussion:
- How do the orientations of the fractures
compare to other orientations documented during the Toadstool
project (e.g. of the faults and veins)?
- What can be inferred from the orientations
of the fractures about the stress field at the time?
- How do your results compare with those of
others who have worked in the area?
- What are factors that seem to influence fracture
density in the sandstones?
- Is there any constraint on the age of fracturing?
- What work could be done in the future to
clarify understanding?
Conclusions:
- What are the three to four main points the
reader should take away with them?
References cited:
Figures and tables:
A table showing the data, and computed data
densities.
Diagrams of representative fracture density
patterns.
A rose diagram of weighted orientations.
A map showing the fracture density amounts
in relation to faults.