Textural evidence, high carbonate concentration and septarian cracks in dolomite and calcite concretions and beds of the Middle Ordovician Cloridorme and Cow Head formations indicate early carbonate precipitation during very shallow burial in uncompacted or little compacted host-sediments. These carbonates started to form at a depth not exceeding 5 m from the seafloor, where porosities were as high as 90%, and continued to grow in the sediment column to subsurface depth of 150 meters. Concretions of the Silurian La Vieille Formation and Lower Ordovician Levis Formation started to form at somewhat greater depths of 50 and 350 meters, when porosities amounted to 65 and 25%, respectively, and continued to grow to depths of 350 and 600 meters, respectively. / Covariation between $ delta sp{13}$C and $ delta sp{18}$O values of these carbonates further supports early diagenetic concretion growth. / Variation of major and minor elements (i.e., Ca, Mg and Sr) observed along AAS traverses in the Cloridorme, Levis and Cow Head carbonates indicate that they grew in continually changing chemical environments.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.59231 |
| Date | January 1989 |
| Creators | Shah, Jehangir A. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Geological Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001066228, proquestno: AAIMM63402, Theses scanned by UMI/ProQuest. |
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