| 词条 | Strathcona Fiord |
| 释义 |
Strathcona Fiord is a fiord on the west central coast of Ellesmere Island, the most northern island within the Canadian Arctic Archipelago, Nunavut, Canada. GeographyStrathcona Fiord is a southern tributary of Bay Fiord. The landscape in the region is fragile and spectacular. The steep hills forming the sides of the valley rise about {{Convert|400|m|abbr=on}} above sea level. The striking arc of a terminal moraine marks the limit of the last ice advance in the area. Taggart Lake running eastward of the moraine drains Upper and Lower Taggart lakes into the head of the fiord. The Prince of Wales Icefield lies on the eastern flank of this valley. Human activityAlthough currently there is no permanent settlement in the Strathcona Fiord area, stone tent rings and other archaeological features indicate past human habitation. Eureka, about {{Convert|170|km|abbr=on}} to the northwest, is a weather station and staging point for scientific expeditions and for other visitors to Ellesmere Island and the Qikiqtaaluk Region. Grise Fiord is an Inuit community, located about {{Convert|250|km|abbr=on}} to the south, also on Ellesmere Island. A parcel of land located south of the head of Strathcona Fiord is designated Inuit Owned Land. The area is sometimes visited by hunters from the nearest Inuit community, Grise Fiord. CoalA large portion of the Strathcona Fiord area lies within a coal license area, owned by Canadian Sovereign Coal Corporation, a subsidiary of Weststar Resources Corporation.[1] The coal property is governed by three coal exploration licenses covering an area of {{Convert|37628|ha|abbr=on}}.[2] Coal deposits in the Strathcona Fiord area are ranked from lignite to sub-bituminous and have been estimated to comprise roughly 1 billion tonnes.[3] In January 2010, when the paleontological scientific community learned of Weststar's interest in exploring this area the Society of Vertebrate Paleontology issued a press release outlining the need to preserve the fossils in the area,[4] Within four days the Nunavut Impact Review Board received over 70 letters of concern from paleontologists and the public alike. PaleontologyThe vicinity of Strathcona Fiord has yielded a fossil record of tremendous international scientific significance. These fossils, including plant and animal remains, have provided a unique opportunity for understanding the effect of climatic change through the past 4 or 5 million years on the Arctic environment, and on its flora and fauna. Pliocene fossils (3-5 million years old)The only Pliocene High Arctic vertebrate fossil locality known is the Beaver Pond site at Strathcona Fiord. The Beaver Pond site was first noted by John Fyles of the Geological Survey of Canada in 1961. In 1988 he found the first vertebrate remains there. In 1992 vertebrate paleontologist, Richard Harington of the Canadian Museum of Nature, began 10 summers of excavations at the site. This fossil site includes the mummified remains of fossil plants, including trees such as an extinct larch (Larix groenlandii) and other trees indicative of a boreal forest.[5] Much of the wood preserved at the site has been gnawed by beavers[6] and some of it is fire-blackened. This exceptional site also has yielded remains of pollen, insects, mollusks, fish (a percid), frogs and mammals such as an unusual rodent, a deerlet (Boreameryx), 3-toed horse, an extinct beaver (Dipoides), a rabbit (Hypolagus), an unusual shrew (Arctisorex polaris), a primitive black bear (Ursus abstrusus), a badger (Arctomeles), and several other carnivores.[7][8][9][10][11][12][13][14] Paleoclimatic reconstruction suggests a mean annual temperature that was {{Convert|14|-|19|C-change|F-change|0}} warmer than present day Ellesmere Island.[15] The assemblage of Pliocene plant macrofossils (wood, leaves, cones and seeds) is typical of present-day boreal forest, as it includes alder (Alnus), birch (Betula), bogbean (Menyanthes trifoliata), larch (Larix), sweet gale (Myrica gale), spruce (Picea), pine (Pinus), and lingonberry (Vaccinium vitis-idaea), as well as the southern boreal tree, the white cedar (Thuja occidentalis).[5][16] Eocene fossils (about 50 million years old)The first High Arctic terrestrial fossil vertebrates were discovered in 1975, in the Strathcona Fiord by a team led by Mary Dawson from the Carnegie Museum. These earliest finds include the fossil remains of an alligator, considered to be Allognathosuchus, and also small arboreal mammals called plagiomenids. Since then, field expeditions in Strathcona Fiord have yielded a much more complete picture of the biodiversity of the Eocene Arctic. Although, Eocene fossil vertebrates are known from other areas on Ellesmere Island (e.g., Stenkul Fiord), and Axel Heiberg Island, Strathcona Fiord has yielded the richest vertebrate fossil record. The fossil vertebrate record of the Eocene Arctic includes giant tortoises, varanid lizards, and boid snakes.[17] Mammal fossils are extremely diverse, including the rhino-like brontotheres, the hippo-like Coryphodon, a tapir like relative (Thuliadanta), an early horse (Hyracotherium?), carnivores (e.g., Viverravus, Miacis), meat-eating creodonts (e.g. Paaeonictis), a mesonychid (Pachyaena), a small swimming carnivore (Pantolestid), a leptictid and at least five rodents (including Paramys and Microparamys).[18][19][20] There are over 40 fossil vertebrate sites in the Strathcona Fiord region. There are numerous Eocene plant fossil sites, including shale units that are rich with leaves as compression fossils.[21][22][23] Very notable are the petrified tree stumps, some of which are preserved in their original growth position. The trees show wide growth rings indicating favorable growth conditions.[24] The fossil flora indicates the presence of rich floodplain forests dominated by dawn redwood (Metasequoia glyptostroboides), together with ginkgo (Ginkgo adiantoides), walnut family (Juglans and other Juglandaceae), elms (Ulmus spp.), birch and alder (Betulaceae), and katsura (Cercidiphyllum).[22][23] Analysis of nearby fossil leaf sites from central Ellesmere Island of the same age indicate that these forests grew under very high rainfall, and can be considered to have represented a polar rainforest.[25] This lush Eocene ecosystem thrived under a polar light regime. Like today, the region would have seen 24-hour sun in the summer and 24-hour darkness in the winter as it was positioned at almost the same latitude in the Eocene as it is today. Despite an early Eocene climate with generally mild frost-free temperatures, the polar light regime likely forced these plants to be deciduous.[22] Notes1. ^Canadian Sovereign Coal Corporation 2. ^Strathcona Fiord Property 3. ^Kalkreuth, McIntyre, Richardson 1993 4. ^Concern Over Possible Loss of Fossil Resources 5. ^1 Matthews, Fyles 2000 6. ^Rybczynski 2008 7. ^Harington 1997 8. ^Harington 2001 9. ^Hulbert, Harington 1999 10. ^Tedford, Harington 2003 11. ^Zakrzewski, Harington 2001 12. ^Hutchison, Harington 2002 13. ^Dawson, Harington 2007 14. ^Murray, Cumbaa, Harington, Smith, Rybczynski 2009 15. ^Ballantyne, Greenwood, Damste, Csank, Eberle & Rybczynski 2010 16. ^Matthews, Ovenden 1990 17. ^Estes, Hutchison 1980 18. ^Eberle, McKenna 2002 19. ^Dawson 1991 20. ^Eberle 2004 21. ^Hickey, West, Dawson, Choi 1983 22. ^1 2 Basinger, Greenwood, Sweda 1994 23. ^1 McIver, Basinger 1999 24. ^Francis 1988 25. ^Greenwood, Basinger, Smith 2010 References
|author1=Ballantyne, A.P. |author2=Greenwood, D.R. |author3=Sinninghe Damsté, J.S. |author4=Csank, A.Z. |author5=Eberle, J.J. |author6=Rybczynski, N. |date=July 2010 | title = Significantly warmer Arctic surface temperatures during the Pliocene indicated by multiple independent proxies | journal = Geology | volume = 38 | pages = 603–606 | doi = 10.1130/G30815.1 }}
|author1=Basinger, J.F. |author2=Greenwood, D.R. |author3=Sweda, T. |editor1=Boulter, M.C. |editor2=Fisher, H.C. | date = 1 December 1994 | title = Arctic terrestrial biota - Paleomagnetic evidence of age disparity with mid-northern latitudes during the Late Cretaceous and Early Tertiary | journal = Cenozoic Plants and Climates of the Arctic, NATO ASI Series | volume = 271 | issue = 4616 | pages = 175–198 | publisher = Springer-Verlag | isbn = 9780387586168 | accessdate = 15 October 2012 | url = http://www2.brandonu.ca/academic/environmental/images/Basinger_et_al_1994.PDF }}
| last1 = Dawson | first1 = Mary R | authorlink1 = Mary Dawson (paleontologist) | year = 1991 | title = Early Eocene rodents (Mammalia) from the Eureka Sound Group of Ellesmere Island, Canada | journal = Canadian Journal of Earth Sciences | volume = 28 | issue = 3 | pages = 364–371 | doi = 10.1139/e91-033 }}
| author = Dawson, Mary R | last2 = Harington | first2 = Charles Richard | year = 2007 | title = Boreameryx, an unusual new artiodactyl (Mammalia) from the Pliocene of Arctic Canada and endemism in Arctic fossil mammals | journal = Canadian Journal of Earth Sciences | volume = 44 | issue = 5 | pages = 585–592 | doi = 10.1139/e06-111 }}
| author = Eberle, Jaelyn J; McKenna, Malcolm C | year = 2002 | title = Early Eocene Leptictida, Pantolesta, Creodonta, Carnivora, and Mesonychidae (Mammalia) from the Eureka Sound Group, Ellesmere Island, Nunavut | journal = Canadian Journal of Earth Sciences | volume = 39 | issue = 6 | pages = 899–910 | doi = 10.1139/e02-001 }}
| author = Eberle, Jaelyn J. | date = 10 November 2005 | title = A new 'tapir' from Ellesmere Island, Arctic Canada - Implications for Northern High-latitude Palaeobiogeography and Tapir Palaeobiology | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 227 | issue = 4 | pages = 311–322 | doi = 10.1016/j.palaeo.2005.06.008 }}
|author1=Estes, Richard |author2=Hutchison, J. Howard | year = 1980 | title = Eocene Lower-Vertebrates from Ellesmere Island, Canadian Arctic Archipelago | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 30 | pages = 325–347 | doi = 10.1016/0031-0182(80)90064-4 }}
| author = Francis, Jane E. |date=December 1998 | title = A 50-Million-Year-Old Fossil Forest from Strathcona Fiord, Ellesmere Island, Arctic Canada: Evidence for a Warm Polar Climate | journal = Arctic | volume = 41 | issue = 4 | pages = 314–318 | accessdate = 15 October 2012 | url = http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/view/1738/1717 }}
|author1=Greenwood, D.R. |author2=Basinger, J.F. |author3=Smith, R.Y. |date=December 2010 | title = How wet was the Arctic Eocene rainforest? Estimates of precipitation from Paleogene Arctic macrofloras | journal = Geology | volume = 38 | issue = 1 | pages = 15–18 | doi = 10.1130/G30218.1 }}
| last = Harington | first = Charles Richard | authorlink = Charles Richard Harington | date = 20 November 1997 | title = Life at a 3.5 million year old beaver pond in the Canadian Arctic Islands | journal = Canadian Museum of Nature Science Forum | volume = Abstracts | pages = 57–58 }}
| last = Harington | first = Charles Richard | year = 2001 | title = Life at a 3.5 million-year-old beaver pond in the Canadian Arctic Islands and the modern scene | journal = Meridian | issue = Fall/Winter | pages = 11–13 }}
|author1=Hickey, Leo J. |author2=West, Robert M. |author3=Dawson, Mary R. |author4=Choi, Duck K. | date = 16 September 1983 | title = Arctic terrestrial biota - Paleomagnetic evidence of age disparity with mid-northern latitudes during the Late Cretaceous and Early Tertiary | journal = Science | volume = 221 | issue = 4616 | pages = 1153–1156 | pmid = 17811507 | doi = 10.1126/science.221.4616.1153 }}
|author1=Hulbert, R. C. |author2=Harington, C. R. | year = 1999 | title = An early Pliocene hipparionine horse from the Canadian Arctic | journal = Palaeontology | volume = 42 | pages = 1017–1025 | doi=10.1111/1475-4983.00108 }}
| last1 = Hutchison | first1 = J. Howard | last2 = Harington | first2 = Charles Richard | year = 2002 | title = A peculiar new fossil shrew (Lipotyphla, Soricidae) from the High Arctic of Canada | journal = Canadian Journal of Earth Sciences | volume = 39 | issue = 4 | pages = 439–443 | doi = 10.1139/e01-078 }}
|author1=Kalkreuth, W. D. |author2=McIntyre, D. J. |author3=Richardson, R. J. |date=December 1993 | title = The Geology, Petrography and Palynology of Tertiary Coals from the Eureka-Sound-Group at Strathcona Fjord and Bache Peninsula, Ellesmere Island, Arctic Canada | journal = International Journal of Coal Geology | volume = 24 | issue = 1-4 | pages = 75–111 | doi=10.1016/0166-5162(93)90006-v }}
|author1=McIver, E.E. |author2=Basinger, J.F. | year = 1999 | title = Early Tertiary floral evolution in the Canadian High Arctic | journal = Annals of the Missouri Botanical Garden | volume = 86 | issue = 1 | pages = 523–545 | accessdate = 15 October 2012 | url = https://www.biodiversitylibrary.org/item/89037#page/529/mode/1up | doi=10.2307/2666184 }}
|author1=Matthews, John V. Jr. |author2=Ovenden, Lynn E. |date=December 1990 | title = Late Tertiary plant macrofossils from localities in Arctic/Subarctic North America | journal = Arctic | volume = 43 | issue = 4 | pages = 301–414 | accessdate = 15 October 2012 | url = http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/view/1631/1610 | doi=10.14430/arctic1631 }}
|author1=Matthews, J V, Jr. |author2=Fyles, J G | year = 2000 | title = Late Tertiary plant and arthropod fossils from the high-terrace sediments on Fosheim Peninsula, Ellesmere Island, Nunavut | journal = Geological Survey of Canada Bulletin | volume=529 | series = | pages = 295–317 | publisher = Natural Resources Canada }}
| author = Murray, Alison M.; Cumbaa, Stephen L.; Harington, C. Richard; Smith, Gerald R., Rybczynski, Natalia |lastauthoramp=yes | year = 2009 | title = Early Pliocene fish remains from Arctic Canada support a pre-Pleistocene dispersal of percids (Teleostei: Perciformes) | journal = Canadian Journal of Earth Sciences | volume = 46 | issue = 7 | pages = 557–570 | doi = 10.1139/E09-037 }}
| last = Rybczynski | first = Natalia | authorlink = Natalia Rybczynski |date=August 2008 | title = Woodcutting behavior in beavers (Castoridae, Rodentia): estimating ecological performance in a modern and a fossil taxon | journal = Paleobiology | volume = 34 | issue = 3 | pages = 389–402 | doi = 10.1666/06085.1 }}
| last1 = Tedford | first1 = Richard H. | authorlink1 = Richard H. Tedford | last2 = Harington | first2 = Charles Richard | date = 25 September 2003 | title = An Arctic mammal fauna from the Early Pliocene of North America | journal = Nature | volume = 425 | pages = 388–390 | pmid = 14508486 | doi=10.1038/nature01892 | issue=6956 }}
| last1 = Zakrzewski | first1 = R. J. | last2 = Harington | first2 = Charles Richard | year = 2001 | title = Unusual Pliocene rodent from the Canadian Arctic Islands. 61st Annual Meeting, Society of Vertebrate Paleontology | journal = Journal of Vertebrate Paleontology | volume = 21, Supplement to Number 3 | pages = 116A-117A | location = Bozeman, October 3–6, 2001 | doi = 10.1080/02724634.2001.10010852 }}{{Fjords of Nunavut}}{{Coord|78|41|N|82|40|W|region:CA-NU_type:waterbody_scale:200000|display=title}} 3 : Fjords of Qikiqtaaluk Region|Canadian Arctic Archipelago|Ellesmere Island |
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