GLG455/598
Advanced Field Geology
Mecca Hills’ Painted Canyon
Structural geology of deformed
sedimentary and basement rocks
within the San Andreas Fault zone
View southeast over the Mecca Hills
Mecca Hills
Painted Canyon
Tent camping on the
beach: $7/night x 2 camps
=$28/11 people ~ $3 each
????
Forecast from weather.com
Logistics
• Depart Fwing loading dock at 4 pm on
Friday.
• Return early evening on Sunday night
• Bring camping gear and field gear
• We will provide kitchen system
• Organize food groups (if desired) and
purchase items before Friday
Mapping exercise: Produce a geologic map along this transect which
is mostly perpendicular to the major structures.
-Many strike and dips of faults and bedding plotted on the map
-Major stratigraphic contacts and basement contacts
-Rock descriptions
Generalized stratigraphy in the Mecca Hills
Basement: Highly sheared gneiss and granite of the
Chuckawalla complex; Orocopia Schist
Unconformity or fault along Box Canyon
Nice folds and
faults in
Painted
Canyon
Sedimentary structures in Plio-Pleistocene units
Some basement rocks are involved in the deformation
Structural planes
• See handouts and a couple of movies
• See also Reynolds’ web sites:
– http://geology.asu.edu/%7Esreynolds/blocks/0_
start_here.htm
– http://geology.asu.edu/%7Esreynolds/apparent_
dip/apparent_dip_gallery.htm
Davis and Reynolds, 2000
Ragan and Arrowsmith, 2002
Ragan and Arrowsmith, 2002
Ragan and Arrowsmith, 2002
Strike and dip notation
• Azimuthal
• Quadrant
• Dip/dip direction
Measuring strike and dip
Ragan and Arrowsmith, 2002
Ragan and Arrowsmith, 2002
Davis and Reynolds, 2000
Davis and Reynolds, 2000
Davis and Reynolds, 2000
Ragan and Arrowsmith, 2002
Davis and Reynolds, 2000
Davis and Reynolds, 2000
Basic steps in the preparation of a
geologic cross section:
1) Choose appropriate line of
section
2) Produce topographic profile
along it.
3) Transfer marker attitudes
(contacts and within units)
4) Correct for apparent dip in line of
section (if line <75 degrees from
strike)
5) Draw units; maintain
stratigraphic thickness where
possible; use deformation
patterns observed from field to
guide interpretation. Continue
lines into air and below ground
Davis and Reynolds, 2000
Ragan and Arrowsmith, 2002
Davis and Reynolds, 2000