| Eureka Sound Formation | |
|---|---|
| Stratigraphic range: Paleogene | |
| Type | Formation |
| Location | |
| Region | Nunavut |
| Country | Canada |
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. [1]
During the early Tertiary period, marine beds began forming in the Eureka Sound Formation within an area that was previously thought to be almost exclusively non-marine. [1] This discovery indicates that this region of the Arctic had been mild, temperate, and ice-free during the early to middle Eocene, despite being well above the Arctic Circle. As of May 2014, this discovery had been restricted to the easternmost regions of the Canadian Arctic on Ellesmere Island. [2] Because the Eureka Sound Formation contains the largest accumulation of Arctic Paleogene deposits, studying its marine deposits is key in gaining a better understanding of the early Tertiary history of the Arctic Ocean. [1]
Some fossils discovered in the Eureka Sound Formation were Paleogene land vertebrates that include fish, turtles, and several types of mammals. [3] Other types of fossils found were reptilian species and several types of birds. [4] Fresh water molluscs were also found. [5]
On Southern Ellesmere Island, the Eureka Sound Formation is up to 480 meters thick and consists of a sequence of predominantly non-marine sandstones, mudstones, coal and minor siltstones. Sandstone petrography and heavy mineral analyses indicate that the Eureka Sound sediments were derived mainly from Precambrian granulite-grade metamorphic rocks of the Canadian Shield located to the southeast of the Formation. [6] Another finding states that significant amounts of the rocks of the Eureka Sound Formation on Western Ellesmere Island are marine in origin. [5]
Ellesmere Island is Canada's northernmost and third largest island, and the tenth largest in the world. It comprises an area of 196,236 km2 (75,767 sq mi), slightly smaller than Great Britain, and the total length of the island is 830 km (520 mi).
Axel Heiberg Island is an uninhabited island in the Qikiqtaaluk Region, Nunavut, Canada. Located in the Arctic Ocean, it is the 32nd largest island in the world and Canada's seventh largest island. According to Statistics Canada, it has an area of 43,178 km2 (16,671 sq mi). It is named after Axel Heiberg.
Plotopteridae is an extinct family of flightless seabirds with uncertain placement, generally considered as member of order Suliformes. They exhibited remarkable convergent evolution with the penguins, particularly with the now extinct giant penguins. That they lived in the North Pacific, the other side of the world from the penguins, has led to them being described at times as the Northern Hemisphere's penguins, though they were not closely related. More recent studies have shown, however, that the shoulder-girdle, forelimb and sternum of plotopterids differ significantly from those of penguins, so comparisons in terms of function may not be entirely accurate. Plotopterids are regarded as closely related to Anhingidae (darters) and Phalacrocoracidae (cormorants). On the other hand, there is a theory that this group may have a common ancestor with penguins due to the similarity of forelimb and brain morphology. However, the endocast morphology of stem group Sphenisciformes differs from both Plotopteridae and modern penguins.
Mary R. Dawson was a vertebrate paleontologist and curator emeritus at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.
Presbyornis is an extinct genus of presbyornithid bird from North America during the Paleogene period, between the Late Paleocene and Early Eocene.
The Fram Formation is an Upper Devonian (Frasnian) sequence of rock strata on Ellesmere Island that came into prominence in 2006 with the discovery in its rocks of examples of the transitional fossil, Tiktaalik, a sarcopterygian or lobe-finned fish showing many tetrapod characteristics. Fossils of Laccognathus embryi, a porolepiform lobe-finned fish, and Qikiqtania, a close relative of Tiktaalik, were also found in the formation. The Fram Formation is a Middle to Upper Devonian clastic wedge forming an extensive continental facies consisting of sediments derived from deposits laid down in braided stream systems that formed some 375 million years ago, at a time when the North American craton ("Laurentia") was straddling the equator.
Pachyaena was a genus of heavily built, relatively short-legged mesonychids, early Cenozoic mammals that evolved before the origin of either modern hoofed animals or carnivores, and combined characteristics similar to both. The genus likely originated from Asia and spread to Europe, and from there to North America across a land bridge in what is now the North Atlantic ocean. Various described species of Pachyaena ranged in size from a coyote to a bear. However, recent work indicates that Pachyaena is paraphyletic, with P. ossifraga being closer to Synoplotherium, Harpagolestes and Mesonyx than to P. gigantea.
The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane.
The Chuckanut Formation in northwestern Washington, its extension in southwestern British Columbia, and various related formations in central Washington are fluvial sedimentary formations of Eocene age, deposited from about 54 million years ago to around 34 million years ago. The nature of the deposits and included plant fossils indicate a low-lying coastal plain with a subtropical climate; the nature of the sediments indicates metamorphic sources in northeastern Washington.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1999.
The Paleocene, or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek παλαιός palaiós meaning "old" and the Eocene Epoch, translating to "the old part of the Eocene".
Hat Island is an uninhabited island located in the Qikiqtaaluk Region of Nunavut, Canada. It is situated in Eureka Sound, at the confluence of Bay Fjord, east of Ellesmere Island's Raanes Peninsula and 19.6 km (12.2 mi) west of Stor Island. It is a member of the Sverdrup Islands group and the Arctic Archipelago. It is also a member of the Queen Elizabeth Islands and the Arctic Archipelago.
Strathcona Fiord is a fiord on the west central coast of Ellesmere Island, the most northern island within the Arctic Archipelago, Nunavut, Canada.
The Willwood Formation is a sedimentary sequence deposited during the late Paleocene to early Eocene, or Clarkforkian, Wasatchian and Bridgerian in the NALMA classification.
The La Meseta Formation is a sedimentary sequence deposited during the Eocene on Seymour Island off the coast of the Antarctic Peninsula. It is noted for its fossils, which include both marine organisms and the only terrestrial vertebrate fossils from the Cenozoic of Antarctica.
The Sharps Formation is a geologic formation in South Dakota. It preserves fossils dating back to the Paleogene.
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 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 Canadian Arctic Rift System is a major North American geological structure extending from the Labrador Sea in the southeast through Davis Strait, Baffin Bay and the Arctic Archipelago in the northwest. It consists of a series of interconnected rifts that formed during the Paleozoic, Mesozoic and Cenozoic eras. Extensional stresses along the entire length of the rift system have resulted in a variety of tectonic features, including grabens, half-grabens, basins and faults.
The Eurekan orogeny was a Phanerozoic mountain building event that affected the eastern portion of the Arctic Archipelago and, to a lesser extent, northern Greenland. Deformation initiated in the Late Cretaceous, during which time the Sverdrup Basin began to fragment and fold in response to the counterclockwise rotation of Greenland, caused by seafloor spreading in the Canadian Arctic Rift System. Isostatic uplift was most pronounced in the Grantland Mountains and Victoria and Albert Mountains on Ellesmere Island and in the Princess Margaret Range on Axel Heiberg Island, as evidenced by the current physiography. Compression in a broad zone on Ellesmere Island resulted in the formation of the Eurekan Fold Belt.
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