Dale Conrod

B. Sc. Honours Thesis

Fluvial Sedimentation in the Lower Member of the Cheverie Formation at Blue Beach, Nova Scotia

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The lower member of the non-marine Cheverie Formation that is exposed at Blue Beach, Nova Scotia, represents fluvial strata that were deposited during the late Tournaisian. The Blue Beach strata are composed of a coarse-grained facies assemblage and an alternating facies assemblage. The coarse-grained assemblage consists of massive to trough cross-stratified granule conglomerate and sandstone, and massive to laminated sandstone. This assemblage represents channel lag and fill units that were deposited by periodic flash-flooding. The alternating assemblage displays the following three distinct patterns of sediment distribution: 1) coarsening upward sequences of laminated to trough cross-stratified sandstone; 2) thin interbedded siltstone and sandstone units which commonly display laminae and trough cross-stratification; and 3) thick, massive, red coarse-grained siltstone deposits. These distinct patterns represent proximal splay, distal splay, and flood basin deposits, respectively.

The original channels exhibited high sinuosity, moderate width/depth ratios, lateral migration, a moderate percentage of overbank material, and vertical and lateral amalgamation, indicative of alternating period of confined channel flow and channel switching caused by periodic flooding. Climatic conditions were semi-arid to sub-humid and strongly seasonal in the depocenter, and more humid in the elevated source region. Paleocurrents indicate that the source region was located to the southeast and petrographic data suggest it contained a substantial granitic component.

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Pages: 101
Supervisor: Martin Gibling