| Assistance Formation | |
|---|---|
| Stratigraphic range: Permian (Roadian) | |
| Type | Formation |
| Location | |
| Region | Nunavut |
| Country | Canada |
The Assistance Formation is a geologic formation located on Devon Island and Ellesmere Island in Nunavut. It preserves fossils dating back to the Permian period. The formation rides along the southeastern edges of the Sverdrup Basin, as well as on Melville Island and Grinnell Peninsula.
The Assistance Formation was discovered in 1955 by Raymond Thorsteinsson, during Operation Franklin. Although the Trold Fiord Formation and Degerbols Formation were generally recognized as part of the Assistance Formation, Thorsteinsson clarified various terminology problems and cleared any naming discontinuities.
Fine grained, green/gray sandstone and mudstone compose a large part of the formation. The lower portions and beds of the stone are generally recessive, with and occur in beds up to .6 meters in length and depth. Outside of sandstone and rust-colored rocks, the loose components of the fiord usually include limestone and a plethora of perpetually eroding organic debris. In the upper half of the formation, oxidized, calcareous ironstone buildups remain abundant. On Melville Island and Grinnell Peninsula, the depth of the fiord is usually its lowest, averaging around 60 meters. The thickest parts of the fiord occur on Ellesmere Island.
In 2009, fossil fauna of Assistance Formation was used to confirm the invalidity of the Ufimian stage in the Russian geologic time scale. Conodonts Mesogondolella gracilis and ammonoids Sverdrupites harkeri from this formation are characteristic of the Roadian (Kazanian) stage, while Mesogondolella idahoensis and ammonoids Epijuresanites from the underlying Sabine Bay Formation are typical for Upper Kungurian stage. Such correspondence to the stages completely excludes the presence of a "gap" between Sabine Bay and Assistance Formations for an additional Ufimian stage. [1]
In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian Epoch or Series. The Roadian lasted between 273.01 and 266.9 million years ago (Ma). It was preceded by the Kungurian and followed by the Wordian.
The Bjorne Formation is a formation of sandstones and shales in the Canadian Arctic Archipelago. The southern edge of the formation includes petroleum reserves in Melville Island. The basin also includes Mackenzie King Island, Lougheed Island and portions of Prince Patrick Island, Borden Island, Ellef Ringnes Island, Amund Ringnes Island, and Cornwall Island.
Strathcona Fiord is a fiord on the west central coast of Ellesmere Island, the most northern island within the Arctic Archipelago, Nunavut, Canada.
The Canyon Fiord Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Carboniferous period.
The Otto Fiord Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Carboniferous period.
The Blue Fiord Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Devonian period.
The Disappointment Bay Formation is a geologic formation in Nunavut, extending from Ellesmere Island in the east to Bathurst Island in the west. It preserves fossils dating back to the Devonian period, primarily of invertebrates.
The Eureka Sound Formation is a geologic formation found in the Canadian Territory of Nunavut on Ellesmere Island, which is part of the Canadian Arctic Archipelago. The Eureka Sound Formation is Tertiary in age.
The Dana Bay Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Degerböls Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Feilden Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Sabine Bay Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Early Permian period.
The Trappers Cove Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Trold Fiord Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Hare Fiord Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Nansen Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Permian period.
The Blind Fiord Formation is a geologic formation in Nunavut. It preserves fossils dating back to the Triassic period.
The Margaret Formation is a geologic formation of the Eureka Sound Group in the Sverdrup Basin in Northwest Territories and Nunavut, Canada. The unit belonging to the Eureka Sound Group which crops out at Ellesmere Island preserves fossils dating back to the Early Eocene period, or Wasatchian in the NALMA classification.
The Devon Island Formation is a geologic formation in the Canadian Arctic. It preserves fossils dating back to the late Silurian and Devonian periods.
The Goose Fiord Formation is a geologic formation in Nunavut, Canada. It preserves fossils that date back to the Silurian period. It is located on the southern portion of the Ellesmere Island in Canada. It also lies on the northern portion of Devon Island.
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