Coldwater Beds | |
---|---|
Stratigraphic range: Ypresian (Wasatchian) ~ | |
Type | Formation |
Unit of | Kamloops Group |
Sub-units | Merritt & Quilchena coal basins |
Overlies | Nicola Group |
Thickness | 230 m (750 ft) |
Lithology | |
Primary | Mudstone |
Other | Shale, tuff, coal |
Location | |
Coordinates | 50°06′N120°30′W / 50.1°N 120.5°W |
Approximate paleocoordinates | 54°48′N103°30′W / 54.8°N 103.5°W |
Region | British Columbia |
Country | ![]() |
Extent | Okanagan Highlands |
Type section | |
Named for | Coldwater River |
Named by | Dawson |
Year defined | 1895 |
The Coldwater Beds are a geologic formation of the Okanagan Highlands in British Columbia, Canada. They preserve fossils dating back to the Ypresian stage of the Eocene period, or Wasatchian in the NALMA classification. [1]
The formation comprises mudstones, shales and tuffs deposited in a lacustrine environment and has provided many insect fossils, as well as indeterminate birds and fossil flora. [2]
The Coldwater Beds were defined by Dawson (1895) based on a section along the Coldwater River in the Okanagan Highlands. [3] The formation reaches a thickness of 230 metres (750 ft), [4] and comprises mudstones, shales and tuff deposited in a lacustrine environment. U-Pb dating of thick tephra, combined with Ar-Ar dates of sanidine from same bed provided an Early Eocene age. The tephra was deposited within insect-bearing shales. [1]
During the Early Eocene, the climate of much of northern North America was warm and wet, with mean annual temperatures (MAT) as high as 20 °C (68 °F), mean annual precipitation (MAP) of 100 to 150 centimetres (39 to 59 in), mild frost-free winters (coldest month mean temperature >5 °C (41 °F)), and climatic conditions that supported extensive temperate forest ecosystems. [5]
The Quilchena fossil locality is dated to 51.5 ± 0.4 Ma corresponding to the Early Eocene Climatic Optimum (EECO), and is reconstructed as the warmest and wettest of the Early Eocene upland sites from the Okanagan Highlands of British Columbia and northern Washington State. Mean annual temperature (MAT) is estimated from leaf margin analysis as 16.2 ± 2.1 °C (61.2 ± 3.8 °F) and 14.6 ± 4.8 °C (58.3 ± 8.6 °F). Using bioclimatic analysis of 45 nearest living relatives, a moist mesothermal climate is indicated (MAT 12.7 to 16.6 °C (54.9 to 61.9 °F); cold month mean temperature (CMMT) 3.5 to 7.9 °C (38.3 to 46.2 °F) and mean annual precipitation (MAP) of 103 to 157 centimetres (41 to 62 in)/yr. Leaf size analysis estimates a mean annual precipitation of 121 ± 39 centimetres (48 ± 15 in). [6]
A wide variety of fossils occur in the formation, including abundant fish remains, insects, and plants, and rare occurrences of molluscs, ostracods, and birds: [1]
Fossil plants were first reported from the Coldwater Beds at the Quilchena site and nearby by Penhallow (1908) [7] with an expanded taxonomic list given by Mathewes et al (2016). [6]
Mark Wilson (1987) noted, without taxonomic identification, that unidentified small bivalves are a component of the Quilchena invertebrate paleofauna. [10]
The insect fossils studied by Wilson (1987) showed Bibionidae dominating the paleoentemofauna, at 28% of all specimens examined at that time. An additional 13% of the fossils were other dipterans while up to 41% of all insects still had attached wings. The invertebrates trace fossils included two undescribed species of Trichoptera larval cases and burrowing or tracks in the sediment. [10]
The formation has been correlated with the Eocene Okanagan Highlands floras including the Allenby Formation, Kamloops Group, Horsefly shales, and Driftwood Canyon site of British Columbia, along with the Klondike Mountain Formation of Washington State. [5] Additionally its correlated with the Margaret Formation of Ellesmere Island, Nunavut, the Chickaloon Formation of Alaska, Wishbone, Chuckanut and Iceberg Bay Formations, all of similar age. [5] The flora of the Coldwater Beds has been correlated to the Chu Chua Formation of southeastern British Columbia. [7] The formation also correlates with the Springbrook, Kettle River and O'Brien Creek Formations in Washington, United States. [3]
Florissantia is an extinct genus of flowering plants in the Malvaceae subfamily Sterculioideae known from western North America and far eastern Asia. Flower, fruit, and pollen compression fossils have been found in formations ranging from the Early Eocene through to the Early Oligocene periods. The type species is Florissantia speirii and three additional species are known, Florissantia ashwillii, Florissantia quilchenensis, and Florissantia sikhote-alinensis.
Tilia johnsoni is an extinct species of flowering plant in the family Malvaceae that, as a member of the genus Tilia, is related to modern lindens. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and a similar aged formation in British Columbia, Canada.
Halictus? savenyei is an extinct species of sweat bee possibly in the halictid genus Halictus. The species is solely known from the Early Eocene, Ypresian stage, Coldwater Beds, part of the Princeton Group, in the Quilchena area, Nicola Country, British Columbia, Canada.
The McAbee Fossil Beds is a Heritage Site that protects an Eocene Epoch fossil locality east of Cache Creek, British Columbia, Canada, just north of and visible from Provincial Highway 97 / the Trans-Canada Highway. The McAbee Fossil Beds, comprising 548.23 hectares, were officially designated a Provincial Heritage Site under British Columbia's Heritage Conservation Act on July 19, 2012. The site is part of an old lake bed which was deposited about 52 million years ago and is internationally recognised for the diversity of plant, insect, and fish fossils found there. Similar fossil beds in Eocene lake sediments, also known for their well preserved plant, insect and fish fossils, are found at Driftwood Canyon Provincial Park near Smithers in northern British Columbia, on the Horsefly River near Quesnel in central British Columbia, and at Republic in Washington, United States. The Princeton Chert fossil beds in southern British Columbia are also Eocene, but primarily preserve an aquatic plant community. A 2016 review of the early Eocene fossil sites from the interior of British Columbia discusses the history of paleobotanical research at McAbee, the Princeton Chert, Driftwood Canyon, and related Eocene fossil sites such as at Republic.
The Allenby formation is a sedimentary rock formation in British Columbia which was deposited during the Ypresian stage of the Early Eocene. It consists of conglomerates, sandstones with interbedded shales and coal. The shales contain an abundance of insect, fish and plant fossils known from 1877 and onward, while the Princeton Chert was first indented in the 1950s and is known from anatomically preserved plants.
Aphaenogaster longaeva is an extinct species of ant in formicid subfamily Myrmicinae known from a solitary Eocene or Oligocene fossil found in North America. A. longaeva was one of five insect species described by the paleoentomologist Samuel Hubbard Scudder in an 1877 paper.
Wesmaelius mathewesi is an extinct species of lacewing in the neuropteran family Hemerobiidae known from an Eocene fossil found in North America
Comptonia columbiana is an extinct species of sweet fern in the flowering plant family Myricaceae. The species is known from fossil leaves found in the early Eocene deposits of central to southern British Columbia, Canada, plus northern Washington state, United States, and, tentatively, the late Eocene of Southern Idaho and Earliest Oligocene of Oregon, United States.
Palaeopsychops is an extinct genus of lacewing in the moth lacewings family Ithonidae. The genus is known from Early Eocene fossils found in Europe, and North America and is composed of ten species. The ten species can be informally separated into two species groups based on veination of the forewings, the "European" and "North American" groups. When first described, the genus was placed in the family Psychopsidae, but later was moved to Polystoechotidae, which itself is now considered a subgroup of the moth lacewings.
The paleoflora of the Eocene Okanagan Highlands includes all plant and fungi fossils preserved in the Eocene Okanagan Highlands Lagerstätten. The highlands are a series of Early Eocene geological formations which span an 1,000 km (620 mi) transect of British Columbia, Canada and Washington state, United States and are known for the diverse and detailed plant fossils which represent an upland temperate ecosystem immediately after the Paleocene-Eocene thermal maximum, and before the increased cooling of the middle and late Eocene to Oligocene. The fossiliferous deposits of the region were noted as early as 1873, with small amounts of systematic work happening in the 1880-90s on British Columbian sites, and 1920-30s for Washington sites. A returned focus and more detailed descriptive work on the Okanagan Highlands sites revived in the 1970s. The noted richness of agricultural plant families in Republic and Princeton floras resulted in the term "Eocene orchards" being used for the paleofloras.
Plecia canadensis is an extinct species of Plecia in the fly family Bibionidae. The species is solely known from Early Eocene sediments exposed in central southern British Columbia. The species is one of twenty bibionid species described from the Eocene Okanagan Highlands paleofauna.
The Eocene Okanagan Highlands or Eocene Okanogan Highlands are a series of Early Eocene geological formations which span a 1,000 km (620 mi) transect of British Columbia, Canada, and Washington state, United States. Known for a highly diverse and detailed plant and animal paleobiota the paleolake beds as a whole are considered one of the great Canadian Lagerstätten. The paleobiota represented are of an upland subtropical to temperate ecosystem series immediately after the Paleocene–Eocene thermal maximum, and before the increased cooling of the middle and late Eocene to Oligocene. The fossiliferous deposits of the region were noted as early as 1873, with small amounts of systematic work happening in the 1870–1920s on British Columbian sites, and 1920–1930s for Washington sites. Focus and more detailed descriptive work on the Okanagan Highland sites started in the late 1960s.
The paleofauna of the Eocene Okanagan Highlands consists of Early Eocene arthropods, vertebrates, plus rare nematodes and molluscs found in geological formations of the northwestern North American Eocene Okanagan Highlands. The highlands lake bed series' as a whole are considered one of the great Canadian Lagerstätten. The paleofauna represents that of a late Ypresian upland temperate ecosystem immediately after the Paleocene-Eocene thermal maximum, and before the increased cooling of the middle and late Eocene to Oligocene. The fossiliferous deposits of the region were noted as early as 1873, with small amounts of systematic work happening in the 1880-90s on British Columbian sites, and 1920-30s for Washington sites. Focus and more detailed descriptive work on the Okanagan Highlands site started in the last 1970's. Most of the highlands sites are preserved as compression-impression fossils in "shales", but also includes a rare permineralized biota and an amber biota.
Promastax is a genus of "monkey grasshoppers" belonging to the extinct monotypic family Promastacidae and containing the single species Promastax archaicus. The species is dated to the Early Eocenes Ypresian stage and has only been found at the type locality in east central British Columbia.
Alnus parvifolia was an extinct species of flowering plant in the family Betulaceae related to the modern birches. The species is known from fossil leaves and possible fruits found in early Eocene sites of northern Washington state, United States, and central British Columbia, Canada.
Plecia avus is an extinct species of Plecia in the March fly family Bibionidae and is solely known from Early Eocene sediments exposed in central southern British Columbia. The species is one of twenty bibionid species described from the Eocene Okanagan Highlands.
Polystoechotites is an extinct parataxon of lacewings in the moth lacewing family Ithonidae. The taxon is a collective group for fossil polystechotid giant lacewing species whose genus affiliation is uncertain, but which are distinct enough to identify as segregate species. Polystoechotites species are known from Eocene fossils found in North America and is composed of four named species Polystoechotites barksdalae, Polystoechotites falcatus, Polystoechotites lewisi, and Polystoechotites piperatus, plus two unnamed species. Three of the described species are known from fossils recovered from the Eocene Okanagan Highlands of Washington State, while the fourth is from Colorado.
The Paleobiota of the Klondike Mountain Formation comprises a diverse suite of Early Eocene plants and animals recovered from North Central Washington State. The formation outcrops in locations across the north western area of Ferry County, with major sites in Republic, north west of Curlew Lake, and on the Toroda Creek area. The formation is the southern most of the Eocene Okanagan Highlands, sharing much of the paleoflora and paleofauna with site across Central and southern British Columbia.
Palaeorehniidae is an extinct family of katydid-like orthopterans that has been described from the fossil record. The family is known from the Paleocene to the end of the Eocene and has been described from North America and Scotland. Circumscription and placement of the group has changed several times since it was first described in 1939, with the group currently treated as a family that is incertae sedis in the suborder Ensifera. Five monotypic genera are assigned to the family.
Allenbya is an extinct odonate genus possibly in the damselfly-like family Dysagrionidae with the single included species Allenbya holmesae. The genus was first described in 2022 from an Early Eocene Okanagan Highlands site in western North America. The species is known from the late Ypresian sediments exposed around Princeton in Central British Columbia.