Liam Fitzgerald


B.Sc. (Honours) Thesis

Sedimentology, Stratigraphy, and Depositional History of the Coal Measures Near Cottam Settlement, Debert-Kemptown Basin, Nova Scotia

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The study utilizes detailed core descriptions of two closely-spaced drill holes and a measured section of continuous outcrop along the Debert River to assess the sedimentology, stratigraphy, and depositional history of Westphalian C coal measures within the Debert-Kemptown Basin near Cottam Settlement, Nova Scotia. Five facies assemblages are recognized based on lithology, sedimentary structures, and fossilized plant and faunal remains. They include: open lacustrine deposits comprising organic-rich mudstone; lacustrine delta deposits comprising planar-bedded to cross-laminated sandstone, laminated siltstone, and mudstone successions; distributary channel deposits comprising massive to trough cross-bedded sandstone; overbank deposits comprising rooted mudstone, siltstone and sandstone; mire deposits comprising coaly shale and high volatile A bituminous coal. The coal seams are economically significant with low sulfur (< 1%) and variable ash (10-30%) contents, although structural complications may hamper any future coal mining.

The relatively restricted study interval records a five-stage depositional history characterized by alternating periods of delta plain, mire, and freshwater lake/lacustrine delta development. The Cobequid fault produced subsidence generating accommodation space, and might have provided a means for regionally sourced drainage systems to be diverted into the Debert-Kemptown Basin. Changes in the availability of sediment from regionally sourced rivers may have produced periods of high and low sediment supply, although climatic and eustatically driven factors may have exerted a significant control on sediment supply, as well as mire development. Coals could have formed during low stands and lakes/lacustrine deltas during high stands. Mires may have been nourished by groundwater discharge from alluvial fan deposits sourced from the paleo-Cobequid Highlands. Orographic climate change and differential subsidence may have also played a role in basin-fill development, although more evidence is required to prove or disprove either of these controls.

Pages: 92
Supervisors: Rob Naylor / Martin Gibling