Coldwater Beds Explained

Coldwater Beds should not be confused with Coldwater Sandstone.

Coldwater Beds
Type:	Formation
Age:	Ypresian (Wasatchian) ~
Period:	Ypresian
Prilithology:	Mudstone
Otherlithology:	Shale, tuff, coal
Namedfor:	Coldwater River
Namedby:	Dawson
Year Ts:	1895
Region:	British Columbia
Coordinates:	50.1°N -120.5°W
Paleocoordinates:	54.8°N -103.5°W
Unitof:	Kamloops Group
Subunits:	Merritt & Quilchena coal basins
Overlies:	Nicola Group
Thickness:	230m (760feet)
Extent:	Okanagan Highlands

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]

Description

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 230m (760feet),^[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]

Climate

During the Early Eocene, the climate of much of northern North America was warm and wet, with mean annual temperatures (MAT) as high as 20C, mean annual precipitation (MAP) of 100cmto150cmcm (00inchesto60inchescm), mild frost-free winters (coldest month mean temperature >5C), and climatic conditions that supported extensive temperate forest ecosystems.

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 16.2C2.1C and 14.6C4.8C. Using bioclimatic analysis of 45 nearest living relatives, a moist mesothermal climate is indicated (MAT 12.7C16.6C; cold month mean temperature (CMMT) 3.5C7.9C and mean annual precipitation (MAP) of 103cmto157cmcm (41inchesto62inchescm)/yr. Leaf size analysis estimates a mean annual precipitation of 121cm±39cmcm (48inches±15inchescm).^[5]

Fossils

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]

Flora

Fossil plants were first reported from the Coldwater Beds at the Quilchena site and nearby by Penhallow (1908)^[6] with an expanded taxonomic list given by Mathewes et al (2016).^[5]

Pteridophytes

• Azolla^[5]

Ginkgophytes

• Ginkgo^[5]

Pinophytes

• Abies^[5]
• cf Amentotaxus^[5]
• Calocedrus^[5]
• Chamaecyparis^[5]
• Glyptostrobus^[5]
• Keteleeria^[5]
• Metasequoia^[5]
• Picea^[5]
• Pinus^[5]
• Pseudolarix^[5]
• Sequoia^[5]
• Taxodium^[5]
• Thuja^[5]
• Tsuga^[5]

Angiosperms

• Acer^[5]
• cf. Aesculus^[5]
• †Alnus parvifolia^[5]
• †Betula leopoldae^[5]
• Bignoniaceae^[5]
• †Castaneophyllum^[5]
• †Comptonia columbiana^[5]
• Cornus ^[5]
• Corylopsis^[5]
• Dipteronia^[5]
• cf. Disanthus^[5]
• †Eucommia montana^[7]
• †Eucommia rolandii^[7]
• cf. Exbucklandia^[5]
• Fagus^[5]
• †Florissantia quilchenensis^[8]
• Fraxinus^[5]
• Hovenia^[5]
• †Joffrea/Nyssidium^[5]
• Nyssa^[5]
• Pieris^[5]
• †Plafkeria^[5]
• cf. Pterocarya^[5]
• Rhus^[5]
• cf. Sambucus^[5]
• Sassafras^[5]
• Ternstroemia^[5]
• cf. Gordonia^[5]
• Tilia^[5]
• Trochodendron^[5]
• †Ulmus okanaganensis^[6]

Pollen taxa

Ginkgophytes

• Ginkgo^[5]

Pinophytes

• Picea^[5]
• Pinus^[5]
• cf Sciadopitys^[5]
• Tsuga^[5]

Angiosperms

• Alnus^[5]
• Carya^[5]
• †Liliacidites^[5]
• Liquidambar^[5]
• †Pistillipollenites mcgregorii^[5]
• cf. Platanus^[5]
• Pterocarya^[5]
• †Sabal ?florisanti^[6]
• Tilia^[5]
• Ulmus^[5]

Molluscs

Mark Wilson (1987) noted, without taxonomic identification, that unidentified small bivalves are a component of the Quilchena invertebrate paleofauna.^[9]

Insects

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.^[9]

Blattaria

• Diplopterinae indet.^[10]

Coleoptera

• cf. Amara sp.^[10]
• †Buprestis saxigena ^{[11] [12]}
• †Buprestis sepulta ^{[11] [12]}
• †Buprestis tertiaria ^{[11] [12]}
• Carabidae indet.^[10]
• †Cercyon? terrigena ^[11]
• Curculionidae indet.^[10]
• cf. Erotylidae indet.^[10]
• †Nebria paleomelas ^[11]
• Omaliinae indet.^[10]
• Pachymerina sp.^[5]
• Scarabaeoidea indet.^[10]

Dermaptera

• Forficulina indet.^[10]

Diptera

• Plecia angustipennis^[13]
• Plecia canadensis^[13]
• Plecia pictipennis^[14]
• Mycetophilidae indet.^[10]
• Pipunculidae indet.^[10]
• Pipunculinae indet.^[15]
• Pleciinae indet.^[10]
• Syrphidae indet.^[10]
• Tipulidae indet.^[10]

Hemiptera

• Telmatrechus defunctus^[14]
• Aphididae indet.^[10]
• Cercopoidea indet.^[10]
• Cicadellidae indet.^[10]
• Cydnidae indet.^[10]
• Gerridae indet.^[10]
• Megymeninae indet.^{[10] [5]}
• cf. Pentatomidae indet.^[10]

Hymenoptera

• Eosphecium naumanni^[16]
• Halictus? savenyei^[17]
• Braconidae indet.^[18]
• Formicidae indet.^[10]
• Ichneumonidae indet.^[10]
• Tenthredinidae indet.^[18]
• Trigonalidae indet.^[18]
• Vespidae indet.^[10]

Mecoptera

• Eorpa jurgeni^[19]
• Eorpa sp.^[19]
• Panorpoidea sp.^[5]

Neuroptera

• Polystoechotites sp.^[20]
• Palaeopsychops dodgeorum^[21]
• Palaeopsychops douglasae^[20]
• Wesmaelius mathewesi^[22]

Orthoptera

• Prophalangopsidae indet.^[10]

Trichoptera

• Phryganeidae indet.^[10]
• Trichoptera indet.^[10]

Fish

• Amia sp. scales^[5]
• Amyzon brevipinne^[5]

Birds

• Aves indet. feathers^{[5] [23]}

Mammals

• Insectivorous mammalian indet. tooth^[5]

Correlations

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. 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. The flora of the Coldwater Beds has been correlated to the Chu Chua Formation of southeastern British Columbia.^[6] The formation also correlates with the Springbrook, Kettle River and O'Brien Creek Formations in Washington, United States.^[3]

See also

• List of fossiliferous stratigraphic units in British Columbia

Notes and References

1. http://www.fossilworks.org/cgi-bin/bridge.pl?action=displayStrata&geological_group=&formation=Coldwater%20Beds&group_formation_member=Coldwater%20Beds Coldwater Beds
2. http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&collection_no=31677 Quilchena
3. Pearson . R. C. . D. . Obradovich . 1977 . Eocene Rocks in Northeast Washington- Radiometric Ages and Correlation . . 1433 . 9–10.
4. Book: Tribe, Selina . 2004 . Cenozoic Drainage History of Southern British Columbia - PhD thesis . . 41, 67, 112.
5. Mathewes . R. W. . Greenwood . D. R. . Archibald . S. B. . 2016 . Paleoenvironment of the Quilchena flora, British Columbia, during the Early Eocene Climatic Optimum . Canadian Journal of Earth Sciences . 53 . 6 . 574–590. 10.1139/cjes-2015-0163 . 2016CaJES..53..574M . 1807/71979 . free .
6. David R. . Greenwood . Kathleen B. . Pigg . James F. . Basinger . Melanie L. . DeVore . 2015 . A review of paleobotanical studies of the Early Eocene Okanagan Highlands floras of British Columbia, Canada and Washington, USA . . 15, 18–19.
7. Call . V.B. . Dilcher . D.L. . 1997 . The fossil record of Eucommia (Eucommiaceae) in North America . American Journal of Botany . 84 . 6 . 798–814 . 21708632 . 10.2307/2445816 . 2445816 . 20464075 .
8. Manchester . S. R . 1992 . Flowers, fruits, and pollen of Florissantia, an extinct Malvalean genus from the Eocene and Oligocene of western North America . . 79 . 9 . 996–1008. 10.1002/j.1537-2197.1992.tb13689.x .
9. Wilson . M. . 1987 . Predation as a source of fish fossils in Eocene lake sediments . PALAIOS . 2 . 5 . 497–500. 10.2307/3514620 . 3514620 . 1987Palai...2..497W .
10. Archibald . S. B. . R. W. . Mathewes . 2000 . Early Eocene insects from Quilchena, British Columbia, and their paleoclimatic implications . . 78 . 8 . 1441–1462. 10.1139/z00-070 .
11. Scudder . S. H . 1879 . Appendix A. The fossil insects collected in 1877, by Mr. G.M. Dawson, in the interior of British Columbia . Geological Survey of Canada, Report of Progress for . 1877-1878 . 175–185.
12. Scudder . S. H . 1895 . Canadian fossil insects, myriapods and arachnids, Vol II. The Coleoptera hitherto found fossil in Canada . Geological Survey of Canada Contributions to Canadian Palaeontology . 2 . 5–26.
13. Rice . H. M. A . 1959 . Fossil Bibionidae (Diptera) from British Columbia . . 55 . 1–36.
14. Handlirsch . A . 1910 . Canadian fossil Insects. 5. Insects from the Tertiary lake deposits of the southern interior of British Columbia, collected by Mr. Lawrence M. Lambe . . 2 . 93–129.
15. Archibald . S. B. . C. . Kehlmaier . R. W. . Mathewes . 2014 . Early Eocene big headed flies (Diptera: Pipunculidae) from the Okanagan Highlands, western North America . . 146 . 4 . 429–443. 10.4039/tce.2013.79 . 55738600 .
16. Pulawski . W. J. . A. P. . Rasnitsyn . D. J. . Brothers . S. B. . Archibald . 2000 . New genera of Angarosphecinae: Cretosphecium from Early Cretaceous of Mongolia and Eosphecium from Early Eocene of Canada (Hymenoptera: Sphecidae) . . 9 . 34–40.
17. Engel . M. S. . S. B. . Archibald . 2003 . An Early Eocene bee (Hymenoptera: Halictidae) from Quilchena, British Columbia . . 135 . 63–69. 10.4039/n02-030 . 1808/16473 . 54053341 . free .
18. Archibald . S. B. . A. P. . Rasnitsyn . D. J. . Brothers . R. W. . Mathewes . 2018 . Modernisation of the Hymenoptera: ants, bees, wasps, and sawflies of the early Eocene Okanagan Highlands of western North America . . 150 . 2 . 250–257. 10.4039/tce.2017.59 . 90017208 .
19. Archibald . S. B. . R. W. . Mathewes . D. R. . Greenwood . 2013 . The Eocene apex of panorpoid scorpionfly family diversity . . 87 . 4 . 677–695. 10.1666/12-129 . 2013JPal...87..677A . 88292018 .
20. Archibald . S. B. . V. N. . Makarkin . 2006 . Tertiary Giant Lacewings (Neuroptera: Polystoechotidae): revision and description of new taxa from Western North America and Denmark . . 4 . 2 . 119–155. 10.1017/S1477201906001817 . 2006JSPal...4..119A . 55970660 .
21. Makarkin . V. N. . S. B. . Archibald . 2003 . Family affinity of the genus Palaeopsychops Andersen with description of a new species from the Early Eocene of British Columbia, Canada (Neuroptera: Polystoechotidae) . . 96 . 3 . 171–180. 10.1603/0013-8746(2003)096[0171:FAOTGP]2.0.CO;2 . 84362010 . free .
22. Makarkin . V. N. . S. B. . Archibald . J. D. . Oswald . 2003 . New Early Eocene brown lacewings (Neuroptera: Hemerobiidae) from western North America . . 135 . 5 . 637–653. 10.4039/n02-122 . 53479449 .
23. Mayr . G. . Archibald . S.B. . Kaiser . G.W. . Mathewes . R.W. . 2019 . Early Eocene (Ypresian) birds from the Okanagan Highlands, British Columbia (Canada) and Washington State (USA) . Canadian Journal of Earth Sciences . 56 . 8 . 803–813 . 10.1139/cjes-2018-0267. 2019CaJES..56..803M . 135271937 .