April 18, 2023 GLG510 Advanced Structural Geology

Fold analysis and cross sections

Marshak and Mitra

Marshak and Mitra

Beta diagram: fold axis at intersection of bedding planes

Marshak and Mitra

Marshak and Mitra

Marshak and Mitra

Marshak and Mitra

Cross sections

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 groundDavis and Reynolds, 2000

Construction: Busk method

Marshak and Mitra

Construction: Busk method

Marshak and Mitra

Construction: Kink band method

Marshak and Mitra

Construction: Kink band method

Marshak and Mitra