Klondike Mountain Formation

The Klondike Mountain Formation is an Early Eocene (Ypresian)[1][2] geological formation located in the northeast central area of Washington state. The formation, named for the type location designated in 1962, Klondike Mountain north of Republic, Washington,[3] is composed of volcanic rocks in the upper unit and volcanics plus lacustrine (lakebed) sedimentation in which a lagerstätte with exceptionally well-preserved[4] plant and insect fossils has been found, along with fossil epithermal hot springs.[5]

Klondike Mountain Formation Stratigraphic range: Ypresian 50.1–48.9 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Klondike Mountain Formation outcrop at site A0307
Type	Geological formation
Unit of	Okanagan Highlands
Sub-units	Tom Thumb Tuff, Lower & Upper Members
Underlies	Glacial deposits
Overlies	Sanpoil Volcanics & others
Thickness	up to 3,200 ft (980 m)
Lithology
Primary	Variable
Other	See text
Location
Coordinates	48.7°N 118.7°W / 48.7; -118.7
Approximate paleocoordinates	54.4°N 101.9°W / 54.4; -101.9
Region	Okanagan highlands
Country	United States
Extent	Okanagan highlands
Type section
Named for	Klondike Mountain
Named by	Muessig
Year defined	1962
Klondike Mountain Formation (the United States) Show map of the United States Klondike Mountain Formation (Washington (state)) Show map of Washington (state)

The formation is the youngest in a group of formations which belong to the Challis Sequence rocks. The formation unconformably overlies rocks of the Eocene Sanpoil Volcanics and much older Triassic and Permian formations. The formation is bounded on its edges by a series of high-angle strike slip faults, which have contained the Klondike Mountain Formation in a series of graben structures, such as the Republic Graben.[6]

Extent

The formation is located in northern Ferry County, Washington, with the majority of the sedimentation in the Republic and Curlew Basins on the east and in the Toroda Creek area to the north west. The town of Republic, Washington is situated at the southern end of the formation, with outcrops within the city itself. The Curlew basin is situated north of Republic, with the northern edge along the Kettle River and the community of Curlew, Washington near the northeastern edge.[7]

The formation is the southernmost of a string of preserved Eocene highland lakebeds in Washington state and British Columbia.[8] The lake system, within the Okanagan highlands, extends from the Klondike Mountain Formation north approximately 1,000 kilometres (1,000,000 m) in to southern central British Columbia.[1]

Age

Early dating of the formation was based primarily on identification and correlation of the fossils found in the Tom Thumb Tuff, with Joseph Umpleby in 1910 reporting a putative age of Early Miocene. This date was based in examination of fossils by C. R. Eastman, who thought them to be similar to those found in the Florissant Formation of Colorado, which at the time was also considered Miocene. This age was retained in the 1928 work of Edward W. Berry, who included the Klondike Mountain Formation fossil lakebeds as part of the Latah Formation.[9] The age of the Formation has been revised in the following hundred years, with Roland W. Brown identifying the deposits as being older than the Latah Formation in 1936.[10] In a later written communication circa 1958, Brown again revised the age still older, stating the fossils found in the area of Mount Elizabeth indicated an Oligocene age. This age was used by R.L. Parker and J. A. Calkins in their 1964 work on the Curlew Quadrangle of Ferry County.[11] Since then the fossil-bearing strata of the Formation have been radiometrically dated, to give a current estimate of the Ypresian, the mid stage of the early Eocene,49.4 ± .5 million years ago.[1]

Lithology

Parker and Calkins in 1964 noted the association of the Klondike Mountain Formation with the gold and silver deposits of the Republic District and suggested it as a potential host to more ore deposits in the Curlew Quadrangle.[11] The epithermal gold deposits occurring in the Sanpoil volcanics terminate directly below the unconformity where the volcanics contact the base of the Klondike Mountain Formation[12] or sometimes penetrate into the Formation's lowest unit.[5] Hydrothermal sinter deposits are known from the lowest portions of the Formation and are thought to represent hydrothermal eruption areas.[5] In general the lower portions of the Formation have a large amount of hydrothermal alteration, and areas around vents are rich in pyrite and silica. two products of natural hydrothermic sintering. The areas above that show a transition to mudstones, siltstones and sandstones grading from fine-grained material into coarser materials moving up the strata column. The finely-bedded stones show the greatest numbers of fossils and the finest preservation of details.[13]

Paleobiota

Rhus hybrid leaf with lobed terminal leaflet

The lake bed sediments preserve a diverse array of plants, insects, and fishes, notably the biota called the Republic flora. The Okanagan lake system, which includes the Klondike Mountain Formation, has been classified as one of the great Canadian lagerstätten.[4] The paleoenvironment preserved in the lake deposits is that of a mesic forest, similar in rainfall to that found today along the modern Washington State and British Columbia coast. The climate of the region offered a moderate amount of summer heat, with chilly winters not cold enough to sustain snow cover (a lower mesothermal to upper microthermal climate).[4]

Over a dozen different Rosaceae genera, both extant and extinct, have been identified in the formation. These fossils are some of the oldest reliable macrofossils (excluding ancient fossil pollen) for the family.[14] Fossils of Sorbus genus and Rhus genus leaves that show evidence of being interspecies hybrids have been noted from the formation. Flynn, DeVore and Pigg in 2019 described four species of sumac which formed multiple hybrids.[15] The neuropteran insects (lacewings and their allies) identified as of 2014 include species from the families Berothidae, Chrysopidae, Hemerobiidae, Ithonidae (including Polystoechotidae), Nymphidae, Osmylidae, and Psychopsidae.[1] A number of mecopteran species belonging to the families Cimbrophlebiidae, Dinopanorpidae, Eorpidae, and Panorpidae are also known.[16]

Conifers, ferns, and ginkophytes

Name	Authority	Year	Family	Notes	Images
Abies milleri[17]	Shorn & Wehr, 1986	1986	Pinaceae	Oldest true fir described	Abies milleri
Azolla primaeva[18]	Arnold, 1955	1955	Salviniaceae	A mosquito fern	Azolla primaeva
Ginkgo biloba[19]	Linnaeus	2002	Ginkgoaceae	A ginkgo	Ginkgo biloba
Ginkgo dissecta[19]	Mustoe, 2002	2002	Ginkgoaceae	A ginkgo	Ginkgo dissecta
Metasequoia occidentalis[20][21]	(Newberry) Chaney	1987	Cupressaceae	A dawn redwood	Metasequoia occidentalis
Pinus latahensis[9]	Berry, 1929	1929	Pinaceae	A 5 needle pine
"Pinus macrophylla"[9]	Berry, 1929	1929	Pinaceae	A 3 needle pine, jr homoym to Pinus macrophylla Lindley 1839	"Pinus macrophylla"
Pinus monticolensis[9]	Berry, 1929	1929	Pinaceae	A pine seed morphogenus
Pinus tetrafolia[9]	Berry, 1929	1929	Pinaceae	A possible 4 needled pine, Noted by Berry as "highly improbable that this should represent a distinct botanic species"
Sequoia affinis[20]	Lesquereux	1935	Cupressaceae	A coast redwood, Reported as "Sequioa langsdorfii" by Brown, 1935	Sequoia affinis
Taxodium dubium[9][20]	(Sternberg) Heer, 1855	1929	Cupressaceae	A bald cypress
Torreya bonseri[9][22]	(Knowlton) LaMotte, 1926	1929	Taxaceae	A plum-yew relative

Flowering plants

Name	Authors	Year	Family	Notes	Images
Acer arcticum[23]	Heer, 1876	1987	Sapindaceae	A maple
Acer hillsi[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Acer republicense[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Acer spitzi[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Acer stonebergae[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Acer toradense[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Acer washingtonense[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Acer wehri[23]	Wolfe & Tanai, 1987	1987	Sapindaceae	A maple
Alnus parvifolia[21]	(Berry) Wolfe & Wehr, 1929	1929	Betulaceae	An Alder	Alnus parvifolia
Barghoornia oblongifolia[21]	Wolfe & Wehr, 1987	1987	Burseraceae	An extinct Bursera relative	Barghoornia oblongifolia
Betula leopoldae[21]	Wolfe & Wehr, 1987	1987	Betulaceae	A birch	Betula leopoldae
Bohlenia americana[21]	(Brown) Wolf & Wehr, 1935	1935	Sapindaceae	An extinct sapindale	Bohlenia americana
Cercidiphyllum obtritum[21]	(Dawson) Wolfe & Wehr, 1890	1935	Cercidiphyllaceae	A katsura	Cercidiphyllum obtritum
Comptonia columbiana[21]	Dawson, 1890	1890	Myricaceae	A Comptonia	Comptonia columbiana
Concavistylon wehrii[24]	Manchester et al., 2018	2018	Trochodendraceae	A Trochodendrale
Corylopsis reedae[2]	Radtke, Pigg, & Wehr, 2001	2001	Hamamelidaceae	A winter-hazel
Corylus johnsonii[25]	Pigg, Manchester, & Wehr, 2003	2003	Betulaceae	A hazel nut	Corylus johnsonii
Cruciptera simsonii[26]	(Brown)	1991	Juglandaceae	A walnut family relative.
Dillhoffia cachensis[27]	Manchester & Pigg, 2008	2008	incertae sedis	A flower of unknown relationships	Dillhoffia cachensis
Dipteronia brownii[28]	McClain & Machester, 2001	2001	Sapindaceae	A Dipteronia	Dipteronia brownii
Eucommia montana[29]	Brown, 1940	1997	Eucommiaceae	A "hard rubber tree"	Eucommia montana
Fagopsis undulata[21]	(Knowlton) Hollick, 1899	1987	Fagaceae	A beech	Fagopsis undulata
Fagus langevinii[30]	Manchester & Dillhoff, 2004	2004	Fagaceae	A beech
Florissantia quilchenensis	(Mathewes & Brooke) Manchester		Malvaceae	A chocolate relative	Florissantia quilchenensis
Fothergilla malloryi[2]	Radtke, Pigg, & Wehr, 2005	2005	Hamamelidaceae	A witch alder	Fothergilla malloryi
Koelreuteria dilcheri[31]	Wang et al., 2012	2012	Sapindaceae	A Koelreuteria species	Koelreuteria dilcheri
Langeria magnifica[21]	Wolfe & Wehr, 1987	1987	Hamamelidaceae	A witch hazel relative	Langeria magnifica
Macginitiea gracilis[21]	(Lesquereux) Wolfe & Wehr	1929	Platanaceae	A plane tree	Macginitiea gracilis
Nuphar carlquistii[32]	DeVore, Taylor, & Pigg, 2015	2015	Nymphaeaceae	A waterlily	Nuphar carlquistii seeds
Oemleria janhartfordae[14]	Benedict, DeVore, & Pigg, 2011	2011	Rosaceae	An Osoberry
Orontium wolfei[33]	Bogner, Johnson, Kvaček & Upchurch, 2007	2007	Araceae	A golden club	Orontium wolfei
Palaeocarpinus barksdaleae[25]	Pigg, Manchester, & Wehr, 2003	2003	Betulaceae	A birch relative	Palaeocarpinus barksdaleae
Paleoallium billgenseli[34]	Pigg, Bryan, & DeVore, 2018	2018	Amaryllidaceae	An onion relative	Paleoallium billgenseli
Pentacentron sternhartae[24]	Manchester et al., 2018	2018	Trochodendraceae	A Trochodendrale
Photinia pageae[21]	Wolfe & Wehr, 1987	1987	Rosacaea	A Christmas-berry relative	Photinia pagae
Populus lindgreni[9]	Knowlton, 1898	1929	Salicaceae	A cottonwood
Prunus cathybrownae[14]	Benedict, DeVore, & Pigg, 2011	2011	Rosaceae	A cherry relative	Prunus cathybrownae
Pteronepelys wehrii[35]	Manchester	1994	incertae sedis	A samara of uncertain affinities.	Pteronepelys wehrii
Republica hickeyi[21]	Wolfe & Wehr, 1987	1987	incertae seids	An incertae sedis angiosperm possibly of Hamamelididae affiliations	Republica hickeyi
Rhus boothillensis[15]	Flynn, DeVore, & Pigg, 2019	2019	Anacardiaceae	A sumac, formed hybrids with the other Rhus species in the Klondike Mountain Formation	Rhus boothillensis
Rhus garwellii[15]	Flynn, DeVore, & Pigg, 2019	2019	Anacardiaceae	A sumac, formed hybrids with the other Rhus species in the Klondike Mountain Formation
Rhus malloryi[21][15]	(Wolfe and Wehr) Flynn, DeVore and Pigg	1987	Anacardiaceae	A sumac, formed hybrids with the other Rhus species in the Klondike Mountain Formation	Rhus malloryi
Rhus republicensis[15]	Flynn, DeVore, & Pigg, 2019	2019	Anacardiaceae	A sumac, formed hybrids with the other Rhus species in the Klondike Mountain Formation
Sassafras hesperia[21]	Berry, 1929	1929	Lauraceae	A sassafras	Sassafras hesperia
Schoepfia republicensis[21]	(LaMotte) Wolfe & Wehr, 1944	1929	Schoepfiaceae	A Schoepfia relative	Schoepfia republicensis
Tetracentron hopkinsii[24]	Pigg et al., 2007	2018	Trochodendraceae	A Trochodendrale, possibly the leaves of Pentacentron sternhartae	Tetracentron hopkinsii
Tilia johnsoni[21]	Wolfe & Wehr, 1987	1987	Malvaceae	A Linden	Tilia johnsoni
Trochodendron nastae[36]	Pigg, Wehr, & Ickert-Bond, 2001	2001	Trochodendraceae	A Trochodendron	Trochodendron nastae
Tsukada davidiifolia[21]	Wolfe & Wehr, 1987	1987	Nyssaceae	A dove-tree relative	Tsukada davidiifolia
Ulmus chuchuanus[37]	(Berry) LaMotte, 1926	2005	Ulmaceae	An elm species
Ulmus okanaganensis	Denk & Dillhoff, 2005	2005	Ulmaceae	An elm species	Ulmus okanaganensis

Insects

Name	Authors	Year	Family	Notes	Images
Adamsochrysa wilsoni[38]	Makarkin & Archibald	2013	Chrysopidae	A green lacewing
Ainigmapsychops[1]	Makarkin & Archibald	2014	Psychopsidae?	A possible psychopsid lacewing	Ainigmapsychops inexspectatus
Allorapisma chuorum[39]	Makarkin & Archibald	2009	Ithonidae	A moth lacewing	Allorapisma chuorum
Antiquiala snyderae[40]	Archibald & Cannings	2019	Aeshnidae	A darner dragonfly
Cimbrophlebia brooksi[16]	Archibald	2009	Cimbrophlebiidae	A Cimbrophlebiid scorpionfly	Cimbrophlebia brooksi
Cimbrophlebia westae[16]	Archibald	2009	Cimbrophlebiidae	A Cimbrophlebiid scorpionfly	Cimbrophlebia westae
Dinokanaga andersoni[41]	Archibald	2005	Dinopanorpidae	A scorpion fly species	Dinokanaga andersoni
Dinokanaga dowsonae[41]	Archibald	2005	Dinopanorpidae	A scorpion fly species
Dinokanaga sternbergi[41]	Archibald	2005	Dinopanorpidae	A scorpion fly species
Eoceneithycerus carpenteri[42]	Legalov	2013	Brentidae	An Ithycerinae weevil
Eoprephasma hichensi[43]	Archibald & Bradler	2015	Susumanioidea	A stick insect species
Eorpa elverumi[44]	Archibald, Mathewes, & Greenwood	2013	Eorpidae	A mecopteran scorpionfly	Eorpa elverumi
?Eorpa ypsipeda[44]	Archibald, Mathewes, & Greenwood	2013	Eorpidae	A mecopteran scorpionfly, tentatively identified	Possible E. ypsipeda[44]
Idemlinea versatilis[40]	Archibald & Cannings	2019	Aeshnidae	A darner dragonfly
Klondikia whiteae[45]	Dlussky & Rasnitsyn	2003	Formicidae	An ant
Metanephrocerus belgardeae[46]	Archibald, Kehlmaier, & Mathewes	2014	Pipunculidae	A pipunculid	Metanephrocerus belgardeae
Myrmeciites[47]	Archibald, Cover, & Moreau	2006	Formicidae	A bulldog ant form genus	Myrmeciities sp.
Neoephemera antiqua[48]	Sinitchenkova	1999	Neoephemeridae	A mayfly
Nymphes georgei[49]	Archibald, Makarkin, & Ansorge	2009	Nymphidae	A nymphid lacewing	Nymphes georgei
Oecophylla kraussei[50]	(Dlussky & Rasnitsyn)	1999	Formicidae	An ant, described as Camponotites kraussei, Moved to Oecophylla kraussei in 2017[51]
Palaeopsychops marringerae[52]	Archibald & Makarkin, 2006	2006	Ithonidae[53]	A giant lacewing	Palaeopsychops marringerae
Palaeopsychops timmi[52]	Archibald & Makarkin, 2006	2006	Ithonidae[53]	A giant lacewing	Palaeopsychops timmi
Polystoechotites barksdalae[47]	Archibald & Makarkin, 2006	2006	Ithonidae[53]	A giant lacewing	Polystoechotites barksdalae
Polystoechotites falcatus[47]	Archibald & Makarkin, 2006	2006	Ithonidae[53]	A giant lacewing	Polystoechotites falcatus
Polystoechotites lewisi[47]	Archibald & Makarkin, 2006	2006	Ithonidae[53]	A giant lacewing	Polystoechotites lewisi
Proneuronema wehri[54][55]	Makarkin, Archibald, & Oswald	2003	Hemerobiidae	A hemerobiid lacewing, originally placed in Cretomerobius, moved to Proneuronema in 2016
Propalosoma gutierrezae[50]	Dlussky & Rasnitsyn	1999	Formicidae	An ant, described as a Rhopalosomatidae wasp, moved to myrmeciinae in 2018[56]	Propalosoma gutierrezae
Ulteramus republicensis[57]	Archibald & Rasnitsyn	2015	Pamphiliidae	A parasitic wasp
Ypshna brownleei[40]	Archibald & Cannings	2019	Aeshnidae	A darner dragonfly

Vertebrates

Name	Authors	Year	Family	Notes	Images
"Amia" hesperia	Wilson	1977	Amiidae	A bowfin
Amyzon aggregatum	Wilson	1977	Catostomidae	A sucker	Amyzon aggregatum
Eosalmo[58]	Wilson	1977	Salmonidae	A Salmon	Eosalmo driftwoodensis
Hiodon woodruffi	Wilson	1978	Hiodontidae	A mooneye	Hiodon woodruffi
Libotonius pearsoni	Wilson	1979	Percopsidae	A trout perch

References

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3. Muessig, Siegfried (1962). "Tertiary volcanic and related rocks of the Republic area, Ferry County, Washington". Geological Survey Research 1962. 450 D: D56–58.
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35. Manchester, S.R. (1994). "Fruits and Seeds of the Middle Eocene Nut Beds Flora, Clarno Formation, Oregon". Palaeontographica Americana. 58: 30–31.
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