@mastersthesis {35433,
	title = {Erosion surfaces and gravel shoreface deposits: The influence of tectonics on the sedimentology of Carrot Creek member, Cardium Formation (Turonian, Upper Cretaceous), Alberta, Canada},
	year = {1987},
	month = {04/1987},
	pages = {404 pages },
	school = {McMaster University},
	address = {Hamilton, ON },
	abstract = {The Raven River Member of the Cardium Formation (Turonian, Upper Cretaceous) in the Carrot Creek -- Cyn-Pem area of Central Alberta, contains two coarsening upward sequences of marine mudstones into sandstones, separated by a gritty siderite . The gritty siderite is believed to represent a pause in deposition in the basin. The sandstones of the upper sequence contain hummocky cross stratification suggesting deposition below fair weather wave base in a storm-dominated setting. The two sequences are scoured to a variable depth by a major erosion surface with a relative relief of about 20 m. Structure maps and 3-D mesh diagrams suggest that the erosion surface can be divided into four topographic areas: a relatively high, flat TERRACE, a BEVEL where underlying sediments are truncated, and an erosional remnant topography of BUMPS and HOLLOWS, which gradually fades basinwards into a relatively flat BASIN PLAIN. The erosion surface is covered by conglomerates with localized thicknesses of up to 20 m. These conglomerates are assigned to the Carrot Creek Member of the Cardium Formation. The thick conglomerates occur in relatively elongate northwest-southeast trending pools. They are overlain by the transgressive marine mudstones of the Dismal Rat Member of the Cardium Formation. At first sight the coarsening upward sequence capped by conglomerates (Carrot Creek Member) appears to be similar to other coarsening upward sequences encased in marine mudstones described from the Western Interior Seaway. These deposits have "traditionally" been interpreted as "offshore ridges", forming many tens of kilometres from the time equivalent shoreline. The Carrot Creek conglomerates, however, are separated from the Raven River Member coarsening upward sequence by an erosion surface, and thus are not genetically part of it. The erosion surface is believed to have formed during a rapid relative lowering of sea level. During maximum lowstand a new shoreface profile (the bevel) was established in the basin. Also during this lowstand, gravel was supplied to the shoreface by incised rivers, and reworked along the shelf by marine processes. Both upper and lower shoreface deposits can be recognized in the conglomerate pools. Subsequent transgression reworked gravel southwestwards across the terrace, while storms transported gravel stringers northeastwards into the transgressive muds accumulating in the hollows. Similar erosion surfaces of this type have been described from Alberta at the Cardium, Viking, and Badheart horizons. The Gallup-Tocito Formation in New Mexico also invoke a similar erosion surface. The presence of these surfaces may be more widespread than presently documented. The results of this thesis suggest that sea level changes and shoreface incision should be considered as a possible alternative for other long, narrow, "offshore ridges", particularly when the offshore deposits are coarser than the proposed time equivalent shoreline deposits},
	keywords = {erosion, gritty siderite, sedimentology},
	url = {https://macsphere.mcmaster.ca/bitstream/11375/12930/1/fulltext.pdf},
	author = {Bergman, Katherine Mary}
}
