1. Field measurements Preparation to field work
Field observations prior to any structural measurements
Measurements at the outcrop scale
Measurements on maps

2. from The Earth - An Introduction to Physical Geology (2nd ed
from The Earth - An Introduction to Physical Geology (2nd ed.), by Tarbuck & Lutgens, Merrill Publishing Co., 1984)
Grenerally topography reflect structures (because of differential erosion). This
Provide clues about the orientation of structures (strike, dip) and guidance to help interpolating of extrapolating outcrop observations

4. Intersection with topography
Intersection of planar structures with topography
Beds that are horizontal will have contacts at constant elevations. The contacts will coincide with or be parallel to topographic contours (above left).
When structures are vertical, a map view looks along the surface of the structure. Structures cross topography without deviating (above right).
Dipping planes fall somewhere in between these two extremes. The shallower the dip, the more the contacts follow contours. The steeper the dip, the less the influence of topography.

5. Determining strike and dip from geologic maps

6. -Topography slopes generally southeast and the contact dips northwest.
Topographic contours and structure contours on the contact are at 100-meter intervals. The contact is in green and the rocks below the contact are in yellow.
The strike of the plane is 045 degrees and the location of the 700-meter structure contour is the same.
Horizontal
Dip 9 NW
3. Dip 17 NW
4. Dip 32 NW

7. Dip 79 NW (Contour Interval 100 and 200 meters) Dip Vertical

8. South Tianshan Piedmont
Courtesy of John Suppe
erosional surface

9. Hinge zone or axial surface at the front of Quilitak relief
Courtesy of John Suppe

10. I. Basic Techniques in Structural Geology
Fundamental principles
Field measurements and mapping
Terminology on folds
Stereographic projections
Preparing maps and constructing cross-sections
Seismic Imaging

11. Folds tend to be cylindrical (an implication of rheological layering).

12. Fold terminology anticline
Anticline: fold that that has the older strata in the core and younger strata farther out (convex toward the younger strata).
Syncline: Fold that has the younger strata in the core and older strata farther (convex toward the older strata)
Note that Identifying an anticline or a syncline requires knowing the polarity of the stratigraphy. If the bed polarity is not known then use the terms
Antiform: for a convex up fold.
Synform: for a convex down fold.
syncline

13. Fold terminology anticline synformal anticline syncline
antiformal syncline

14. The Quilitake Anticline
South Tian Shan Piedmomt, near Kuqa (Hubert-Ferrari et al, JGR, 2007; Daeron et al, JGR, 2007)
The Quilitake Anticline

15. Fold terminology Folds come in three basic types:
Folds can generally be subdivided in dip domains, and may have angular or curved fold hinge:

16. Fold terminology
Dip domains are separated by axial surfaces, imaginary planes which viewed in two dimensions form axial traces. Anticlinal axial surfaces occupy concave-downward fold hinges; synclinal axial surfaces occupy concave-upward fold hinges.
Anticlinal axial surface
Synclinal axial surface

17. Fold terminology
Axial surfaces often occur in pairs that bound fold limbs, which are also called kink bands:

18. Vertical axial surfaces: Symmetric folds

19. The Quilitak anticline (South Tianshan Piedmont)
Put here Quilitake core
Maybe add something about Quilitak Location: New Slide ?

20. Fold terminology Symmetric upright Overturned Asymmetric Recumbent
Overturned
Asymmetric
Recumbent
NB: Here the folds axis are all assumed horizontal