Stretched belemites Found in Jr - K strata Hard parts of a marine animal related to squid Preseved calcite fibers

When stretched, the conical rod breaks into separate pieces Spaced filled by calcite or quartz during deformation Stretched belemites office a means of measuring extension (e).

Determing extension (e) Measure total length by reconstructing the separated pieces. Knowing the length before (l o ) and after (l f ), Evaluate e, and ' and construct a Mohr strain diagram.

Stretching direction Mineral lineation produced by calcite grains. Lineation marks the extension direction Measure the angle  between overall trend of the belemite fragments and the strain ellipse long axis for each fossil.

A:  = 33°, ' = 0.62 B:  = 62°, ' = 0.75 The stretch direction allows us to determine the q value for belemnite A and B. How do we construct a Mohr circle using the values for these deformed fossils, and determine the ' 1 and ' 3 (the principal quadratic elongation values).

Draw the circle first on graph paper and don't worry about the scale initially. Plot the 2  angles, draw the Mohr circle, and now make your scale, given values for fossil A and B

Draw the circle first on graph paper and don't worry about the scale initially. Plot the 2  angles, draw the Mohr circle, and now make your scale, given values for fossil A and B