<p> Bioherm growth within the Edgecliff Member of the Onondaga Formation in the vicinity of Port Colborne, Ontario is represented by a broad low-lying coralliferous mound, trending approximately north-south. The mound displays a progressive pattern of faunal and lithologic succession which can be broken down into four stages. The Basal and Coral-Rich Basal Facies represents deposition in a shallow to deep shelf lagoon, below fair weather wave base and above storm wave base. Stage I of mound development is initiated in response to a slight regression near the top of these facies, corresponding to the deposition of the Transitional Facies, a shoaling upwards sequence reaching above the surrounding substrate. stage II is represented by the colonization and stabilization of the mound by solitary and colonial corals within fair weather wave base. Stage III results in the diversification of the mound upwards into a high energy zone, corresponding to the deposition of the Core Facies. At this time, sea-level remains stable and intermound areas are filled in by the Biostrome, Flank, and Flank/Cap Facies. The final stage, Stage IV represents the termination of mound growth by deposition of a crinoidal cap due to, either a fall in sea-level, or growth of the mound into the surf zone.</p> <p> The inferred paleocurrent direction from facies relationships, and a measured coral orientation, suggest currents direction from the southeast to northwest.</p> <p> Thus, the Edgecliff Member of the Onondaga Formation in the vicinity of Port Colborne, Ontario represents deposition in a shallow shelf lagoon, and displays evidence for two possible sea-level fluctuations; one near the top of the Basal and Coral-Rich Basal Facies, and the second corresponding the Flank/Cap and Cap Facies, terminating mound development.</p> / Thesis / Bachelor of Science (BSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19528 |
| Date | 04 1900 |
| Creators | Johnston, Craig Thomas |
| Contributors | Risk, Michael J., Geology |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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