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32-554: There are several notable fossil producing localities in the Princeton & Tulameen basins. Historical collection sites included Nine Mile Creek , Vermilian Bluffs , and Whipsaw Creek , while modern sites include One Mile Creek , Pleasant Valley , Thomas Ranch , and the Princeton Chert . The Allenby is estimated to have an overall extent of approximately 300 km (120 sq mi), though actual outcroppings of

64-438: A decade later, the older age of 48  ± 2 million years old was first suggested, with a younger age being suggested at 46.2  ± 1.9 million years old in 2000 and an older date of 52.08  ± 0.12 million years ago obtained from uranium–lead dating of zircons from Vermilion Bluffs shale in 2005. The Allenby is composed of cyclical sedimentation events that were deposited along

96-399: A freshwater fish, Amia (bowfin), have been found in the shale overlying the plant deposits, along with remains of the freshwater fishes Amyzon and Libotonius , plus a soft-shelled turtle. Pathogenic fungi have been recorded on the leaves and other organs of some vascular plants. Fossil Uhlia palms have tar spot fungi on their leaves described as Paleoserenomyces , which

128-602: A huge increase in ferns , such as Dennstaedtiopsis , after a huge ash fall, though few angiosperms occur in these layers. A large number of angiosperms have been found along with several types of conifers , ferns, and several unidentified fossils from various families. The array of floral and faunal fossils found in the Princeton Chert has offered unequivocal evidence that it was a lacustrine or lake environment. The plant fossils found show many structural and anatomical adaptations to an aquatic environment, including

160-546: A large transect of lakes recorded many of the earliest appearances of modern genera, while also documenting the last stands of ancient lines. The warm temperate uplands floras of the Allenby Formation and the highlands, associated with downfaulted lacustrine basins and active volcanism are noted to have no exact modern equivalents, due to the more seasonally equitable conditions of the Early Eocene. However,

192-489: A moist warm temperate climate with mean annual temperature 13.1 ± 3.1 °C, with mild winters (cold month mean temperature 5.3 ± 2.8 °C), and mean annual precipitation 114 ± 42 cm per year. Several of the smaller chert layers are separated by volcanic ash layers, indicating nearby volcanic activity. It is thought that fossils were pervaded with silicic acid due to this volcanic activity. Subsequently, water charged with minerals flowed from springs or geysers into

224-570: A reduced vascular system, aerenchyma in tissues (air spaces to provide buoyancy), and protoxylem lacunae surrounded by a ring of cells with thickened inner walls. Further evidence is provided by the fossils’ clear affinities with modern aquatic angiosperms. Many extant plants show these adaptations and are similar to the organisms found in the chert. For example, water lilies ( Allenbya , Nymphaeaceae ), water plantains ( Alismataceae ), arums ( Keratosperma , Araceae ) and rushes and sedges ( Ethela , Juncaceae / Cyperaceae ) are just some of

256-644: Is a fossil locality in British Columbia , Canada , which comprises an anatomically preserved flora of Eocene Epoch age, with rich species abundance and diversity. It is located in exposures of the Allenby Formation on the east bank of the Similkameen River , 8.5 km (5.3 mi) south of the town of Princeton, British Columbia . The Princeton Chert (Ashnola shale in older sources) and its fossils have been known since

288-425: Is an interbedded sequence consisting of coal , shale , volcanic ash , and chert in the Allenby Formation . 49 chert layers, ranging in thickness from 1 to 55 cm (0.39 to 21.65 in) have been recognized and described, though each is not unique in organisms preserved. Despite this, trends are evident throughout the outcrop , with certain taxa appearing and disappearing with time. The Princeton Chert

320-404: Is in turn parasitized by a mycoparasite , Cryptodidymosphaerites princetonensis . Symbiotic mycorrhizal relationships have also been preserved in roots of Pinus and Metasequoia milleri . In Metasequoia these associations have been compared to extant mycorrhizae , and found to be very similar. The mycorrhizal relationship with Pinus was the first documentation of ectomycorrhizae from

352-519: The Himalayas and the Tibetan plateau due to the collision of tectonic plates. Also at the time, Australia , which was joined to Antarctica , was beginning to move northwards. The Princeton Chert fossils indicate that the area was an aquatic ecosystem , growing in tropical to subtropical conditions. More recent analysis of the fossil flora, however reconstructs for the Princeton Chert flora

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384-430: The 1950s, but have attracted increased attention in the late 1970 and on. This may be due to the rare type of silica permineralized fossil Lagerstätten found, which has preserved plants and animals in minute 3D detail, with exceptional internal cellular detail. This has meant anatomical descriptions and reconstruction of whole plants from isolated parts has been possible in many species. Few plant fossils elsewhere in

416-809: The Thomas ranch site by Dillhoff et al. (2013) resulted in the identification of 32 pollen and spore types that were assignable to family or genus level, with a total number of distinct pollen and spore types, including unassignable morphotypes, number over 70. The predominant pollens of the site are conifers , which make up between 85%–97% of the total pollens, while the angiosperm pollens are dominated by members of Betulaceae . Several pteridophyte families and genera are represented as spore fossils alone, without corresponding megafossil records, including Lycopodiaceae , Osmundaceae , and Schizaeaceae . Similarly, at least three additional conifer genera are only present as pollen fossils and up to 12 angiosperms are present in

448-424: The angiosperms found both today and in the Princeton Chert. Seeds have also been found which share adaptations with living aquatics. On the other hand, terrestrial fossils have rarely been found. The few that are, are represented mainly by seeds, some of which may have been transported by birds. Additional support for the aquatic nature of the Princeton Chert deposits comes from animal fossils. Several fossils of

480-401: The basin allowed peat to re-accumulate each time, producing the multiple layers. Sampling into the Princeton Chert has been carried out, but presently the data has not been analysed in detail. Across the outcrop, trends in taxa can be seen; in the topmost layers fossil organs of Metasequoia milleri cease to be represented, yet Pinus (pine) and monocotyledons increase in number. There is

512-763: The basin place the hanging wall Allenby strata in contact with much older foot wall strata of the Nicola Formation which dates to the Upper Triassic . The Allenby Formation is the southern-most of the Eocene Okanagan Highlands lakes in British Columbia, and second most southern site after the Klondike Mountain Formation of Republic, Washington and northern Ferry County . In British Columbia,

544-493: The cherts, while slowly moving waters and gently subsiding terrains would be needed for the peats and fens to accumulate. Rates of organic deposition in swamps have been estimated at 0.5–1 mm (0.020–0.039 in) in modern temperate climates, this suggests the time needed for each 10–20 cm (3.9–7.9 in) chert layer would be at least 100 years or more, with the full sequence of cycles taking place over no more than 15,000 years. Palynological analysis of samples from

576-410: The coal seams are sections of chert which formed during silica rich periods. The rapid cyclical changes from coal to chert and back are not noted in any other fossil locality in the world. An estimated 49 coal-chert cycles are known, though the exact conditions for this process are not well understood. Silica rich volcanic episodes in the region during deposition would have been needed for formation of

608-464: The course of a river-system in conjunction with depositional areas from nearby lakes and wetlands. Coeval volcanic eruptive events are recorded as interbeds of tephras and lavas, while the riverine course is marked with depositional areas of conglomerates and sandstones. The quieter environments are noted for finer layers of shales and coalified layers. The coal seams throughout the formation are typically sub-bituminous . Notable in conjunction with

640-638: The formation has been compared to the upland ecological islands in the Virunga Mountains within the Albertine Rift of the African rift valley . The earliest work in the region was on exploratory expeditions in 1877 and 1878, with fossils collected in the areas of Nine-Mile Creek, Vermilian Bluffs on the Similkameen River , and Whipsaw Creek . While reporting on additional plant fossils collected from British Columbia, Penhallow (1906) noted

672-713: The formation is coeval to the Tranquille Formation , known from the McAbee Fossil Beds and Falkland site , the Coldwater Beds , known from the Quilchena site , and Driftwood Canyon Provincial Park . The highlands, including the Allenby Formation, have been described as one of the "Great Canadian Lagerstätten " based on the diversity, quality and unique nature of the biotas that are preserved. The highlands temperate biome preserved across

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704-455: The formation make up less than 1% of the formation, while other exploratory contact is via boreholes and mines. The half-graben which contains the formation is separated into two major depositional basins, the Princeton basin around Princeton, British Columbia and the Tulameen basin centered approximately 17 km (11 mi) west. The grabens extensional faults at the eastern side of

736-1031: The fossil record, with the fungi suggested as close to the modern pine symbiotics Rhizopogon and Suillus Undescribed Undescribed Undescribed A lepidopteran forewing Not described to family/genus/species Undescribed Undescribed undescribed A turtle , Bones preserved in the Princeton Chert † Dickwhitea † Dickwhitea allenbyensis An athyriaceous fern † Makotopteris † Makotopteris princetonensis An athyriaceous fern † Trawetsia † Trawetsia princetonensis A blechnacious fern † Dennstaedtiopsis † Dennstaedtiopsis aerenchymata A dennstaedtioid fern Osmundaceae Osmunda Undescribed An osmundaceous fern Not identified to species Cupressaceae Metasequoia † Metasequoia milleri A dawn redwood † Pinus allisonii A 2-needled Pine † Pinus andersonii A 3-needled Pine † Pinus arnoldii A basal Pine , First described for ovulate cones A whole plant reconstruction includes

768-498: The likely coeval status of the Princeton basins with many of the sites now considered the Okanagan Highlands. Modern collecting has centered on the areas around One Mile Creek, Pleasant Valley, and Thomas Ranch. The age estimates for the Allenby Formation have varied a number of times since the first explorations happened in the 1870s. Shaw (1952) dated the formation as Oligocene , an age followed by Arnold (1955). Half

800-438: The low lying basin where the Princeton chert was located. Here, the water surrounded organisms as they grew, along with plant debris which had been accumulated. Many organisms were preserved in situ, in the lake or small pond environment in which they lived. The preservation must have been rapid, due to the minute cellular detail which has been conserved. This sequence of events is thought to have been replicated up to 50 times, as

832-1066: The pollen record. Sometimes considered a Biostratgraphic index fossil , the angiosperm palynospecies Pistillipollenites macgregorii has been recovered from several sites in the Allenby Formation, while the palynospecies Erdtmanipollis pachysandroides is rare, having only been reported from the formation twice. Aquifoliaceae Ilex Unidentified Pollen A holly palynomorph Arecaceae Sabal Cf. † Sabal granopollenites Pollen A palm palynomorph Buxaceae † Erdtmanipollis † Erdtmanipollis pachysandroides Pollen A box family palynomorph Betulaceae Alnus Unidentified Pollen & macrofossils An alder palynomorph Betulaceae Betula Unidentified Pollen & macrofossils A birch palynomorph Betulaceae Carpinus Unidentified Pollen A hornbeam palynomorph Betulaceae Corylus unidentified Pollen A hazelnut palynomorph Cupressaceae Cunninghamia unidentified Princeton Chert The Princeton Chert

864-764: The second-highest grade of coal. Sub-bituminous coal is primarily used as a fuel for steam-electric power generation . Sub-bituminous coals may be dull, dark brown to black, soft and crumbly at the lower end of the range, to bright jet-black , hard , and relatively strong at the upper end. They contain 15-30% inherent moisture by weight and are non- coking (undergo little swelling upon heating). The heat content of sub-bituminous coals range from 8300 to 11,500 BTu / lb or 19.3 to 26.7 M J / kg . Their relatively low density and high water content renders some types of sub-bituminous coals susceptible to spontaneous combustion if not packed densely during storage in order to exclude free air flow. A major source of sub-bituminous coal in

896-490: The synonymized P. similkameenensis . † Pinus princetonensis A pinaceous cone Alismataceae † Heleophyton † Heleophyton helobieoides An aquatic or emergent water-plantain Sub-bituminous coal Sub-bituminous coal is a lower grade of coal that contains 35–45% carbon . The properties of this type are between those of lignite , the lowest grade of coal, and those of bituminous coal ,

928-621: The world exhibit such excellence in both preservation and diversity. Similar aged fossil beds in Eocene lake sediments are found elsewhere in British Columbia , including in Driftwood Canyon Provincial Park near Smithers in northern British Columbia, the McAbee Fossil Beds west of Kamloops , about 160 km (160,000 m) NNW of the Princeton Chert beds, and the Klondike Mountain Formation around Republic, Washington , south of Princeton. The Princeton Chert

960-462: Was originally considered to be Middle Eocene based on data from mammals , freshwater fish, and potassium-argon dates. Recently, more accurate radiometric techniques provided a date of 48.7 mya, placing the Princeton Chert in the Ypresian stage (47.8–56.0 mya), consistent with the whole Allenby Formation being now dated radiometrically as being Early Eocene . The climate at this time

992-476: Was small. This long term warmth is thought to be due to increased greenhouse gases, particularly CO 2 trapping more heat. The reason for this sudden increase in CO 2 is unknown, but it is hypothesised that it was due to an increase in ocean floor being recycled via volcanic arcs and metamorphic decarbonation reactions. This happened because the ocean between India and Asia was disappearing and being replaced by

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1024-608: Was warm; it had reached a maximum during a series of warming events during the Early Eocene with the Princeton Chert likely deposited after the Eocene Thermal Maximum 2 and during the Early Eocene Climatic Optimum. During this time the sea warmed approximately 4 °C and terrestrial temperatures were several degrees warmer than today, meaning little or no ice was present at the poles. The temperature difference between poles and equator

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