<p> Concretions in a zone about 4 m. below the Tichenor Limestone formed just below the sediment water interface. Their growth was initiated about an
organic-rich fossil cluster and was probably completed before
they were more than 5 to 8 m below the sediment surface. Chemical
products of organic decay, notably bicarbonate ions and
ammonia, diffused outward, raising the pH and precipitating
calcite from connate waters already nearly saturated with
respect to calcium carbonate.
These conclusions derive from the shape of the concretions,
from their relation to the enclosing shales, and from their
overall structure , particularly the position of pyritic fossil
clusters. The relative volumes of soluble material (calcite)
in the concretions are consistent with relative pore volumes
through the upper 5 m. of recent, fine-grained, clayey sediments.
The postulated genetic sequence agrees with recent work
on carbonate diagenesis. Restriction of the concretions to
discrete layers was most probably due to a widespread comnbination
of high rates of organic productivity, high rates ·of sedimentation, and low rates of water circulation, that
lasted a short period of time and resulted in the rapid
burial.of much undecomposed organic material. </p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18473 |
| Date | 10 1900 |
| Creators | Jordan, Frank W. |
| Contributors | Beerbower, J. R., Geology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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