The Kidluit Formation is a significant geological formation located in the Beaufort-Mackenzie Basin, primarily within the Mackenzie Delta and offshore areas of the Northwest Territories, Canada. It constitutes part of the larger Beaufort Group, a major Cenozoic sedimentary sequence in the Arctic region.
Geological Setting and Age: The formation dates from the Late Miocene to Pliocene epochs. It represents a period of substantial sedimentation following the main phase of Neogene deltaic progradation in the Beaufort-Mackenzie Basin.
Lithology: The Kidluit Formation is predominantly composed of dark grey to greenish-grey mudstone and silty mudstone. Minor interbeds of fine-grained sand, siltstone, and occasional lignite (a low-rank coal) are also common. Towards the upper parts of the formation, especially in more northern or younger sections, glacial erratics and glaciomarine sediments may be present, indicating the increasing influence of glacial activity during the Pliocene.
Depositional Environment: The sediments of the Kidluit Formation were primarily deposited in a prodelta to outer-shelf marine environment. This suggests accumulation on the submerged fringes of a large delta system, under relatively low-energy conditions. In some areas, particularly closer to the ancient Mackenzie River delta mouth, the environment might have transitioned to inner-shelf or even delta-front settings. The presence of glacial influence later in its history points to a shift towards colder, potentially ice-proximal marine conditions.
Stratigraphic Relationships: The Kidluit Formation typically conformably overlies the Kugmallit Formation, another unit within the Beaufort Group, which generally represents more proximal deltaic to fluvial environments. It is generally overlain unconformably by Quaternary glacial and post-glacial sediments.
Significance: The Kidluit Formation is important for understanding the late Cenozoic geological evolution of the Canadian Arctic. It provides insights into paleoenvironmental conditions, sediment transport pathways, and the onset and progression of glaciation in the region. Furthermore, like other units of the Beaufort Group, it is of interest in petroleum exploration due to its potential as source rock or seal rock, and its association with occurrences of natural gas hydrates.