Reference no: EM133407017
1. Stratigraphy:
a. What is the oldest geologic unit exposed at the surface in your map area? What is the youngest geologic unit exposed at the surface in your map area?
b. Show a stratigraphic column that includes all of the formations in your map area, colored consistently with your map.
c. Are there are any key unconformities associated with your structure? If so,
is it associated with growth of the specific structure featured in the map area?
Show where the unconformity is in the stratigraphic column and on the map.
You may also find it helpful to show a perspective map/Google Earth view to demonstrate how this is an angular unconformity, for example.
d. Which parts of the stratigraphy are pre-tectonic, syn-tectonic, and post- tectonic relative to the first-order structures depicted in your map area?
e. Are there key formations that relate to the structural style (e.g., that define the detachment level in a fold and thrust belt)? What lithology are these rocks?
2. First-order structures:
What are the first-order geologic structural features illuminated by the geology exposed in this map? Through a combination of map view and cross section view (using the cross section published with your map, if available), demonstrate your detailed understanding of structural geology concepts to describe the features, using the guidance given below:
a. Folds:
What are the average strike a dip of the fold limbs? What is the trend and plunge of the fold axis?
Is the fold symmetric, asymmetric, overturned?
Is layer thickness preserved in folding, or varying systematically in some way? Point to the observations on your map during your presentation that allow you to make these interpretations.
b. Faults: What is the average strike and dip of the first-order faults? Are they strike-slip, thrust, normal, or oblique slip faults (and how do you know)? Do the faults dip the same, or differently, than the adjacent bedding?
Is the faulting thin-skinned (detached in the sedimentary section) or thick-skinned (involving basement rocks)?
Point out the observations that lead you to this conclusion. How many thrust sheets are there?
Are they fore-thrusts, or back-thrusts, relative to the overall fold-and- thrust belt?
What is the deepest layer exhumed in the fault, and what does that tell you about the detachment level?
c. Fault-related folds: Are the faults exposed at the surface, or blind/inferred from the location of associated folds?
What styles of fault-related folds are present (fault-bend folds, fault- propagation folds, detachment folds, imbricates, etc.)?
3. Second-order structures:
What types of second-order (smaller-scale) folds or faults are present? (E.g., Normal, strike-slip, or thrust faults? Regional Joints? Disharmonic folds?)
Are they confined to specific stratigraphic layers (e.g., are they related to accommodating shortening differently in mechanically distinct layers) or extend across multiple layers?
How are they related to the first order structures-did they form at the same time as part of the same system (e.g., strike-slip tears associated with lateral transitions in thrust belts) or did they form at an entirely different time due to a different tectonic event?
Point out the specific observations that lead you to these conclusions.
4. Evidence for activity/inactivity of the structures present:
Are these faults active? I.e., does topography in the map area reflect the geometry of actively-growing, or recently-active structures, or, in the case of inactive structures, does topography reflect the relative erodibility of different stratigraphic layers?
Show examples using your map overlain on topography in Google Earth using your KMZ file.