Eureka Sound Formation

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Eureka Sound Formation
Stratigraphic range: Paleogene
Type Formation
Region Nunavut
Country Canada
This is a map of the Canadian Territory of Nunavut

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]

Sediments and Geology[edit]

On Southern Ellesmere Island, the Eureka Sound Formation is up to 480 meters thick and consists of a sequence of prediminantly 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 anounts of the rocks of the Eureka Sound Formation on Western Ellesmere Island are marine in origin.[5]

See also[edit]