<p> 49 beds of ripple-drift cross-lamination were
measured in the Ordovician Cloridorme Formation of Gaspe, Quebec.
Most of the beds are Bouma C (cross-laminated), some are BC (parallel
lamination pas sing up into cross-lamination) and a few are AC and ABC
types (graded bedding passing up into parallel and cross-lamination). </p> <p> Six climbing patterns have been recognised in the ripple-drift
beds, namely: concave -upward, straight, sigmoidal, convex-upward,
sinuous, and disconnected-irregular. Angles of climb range from 1 to
44 degrees. Commonly the angle of climb steepens up through the coset
to about 1/2 or 3/4 of the coset thickness and then gradually flattens
out until the bed is plane. </p> <p> Measurements of wave length, amplitude, stoss -angle, lee-angle, angle of climb and ratio of lee- to stoss-lamina thicknesses show
that the wave length continues to increase upward, and the lee/stoss thickness ratio decreases upward through the coset. The amplitude, and
stoss- and lee-angles increase upward through that portion of the coset
in which the angle of climb increases upward. Simultaneously with the
increase in amplitude and angle of climb, the shape of the foreset laminae
becomes progressively more and more sigmoidal. </p> <p> Down-current changes in lamination types were recorded in
several beds. The most interesting change is from parallel lamination
down-current into ripple-drift, continuing downcurrent back into parallel
lamination. </p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19742 |
| Date | 10 1900 |
| Creators | Bhattacharjee, Shyama |
| Contributors | Walker, R.G., Geology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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