Mount Cap formation
{{Infobox rockunit
| name = Mount Cap Formation
| image =
| caption =
| type = Formation
| age = Cambrian
| period = Cambrian
| prilithology = Shale, siltstone
| otherlithology = Sandstone
| namedfor =
| namedby =
| region = Northwest Territories
| country = Canada
| coordinates = {{coord|63|24|23|N|123|12|22|W|region:CA-NT_type:mountain_source:kolossus-dewiki|display=title}}
| unitof =
| subunits =
| underlies =
| overlies =
| thickness =
| extent =
| area =
| map = {{Location map+ | Canada
| relief = 1
| width = 300
| float = center
| places =
{{Location map~ | Canada
| lat_deg = 63.5
| lon_deg = -123.2
| mark = Dark Green 004040 pog.svg
| marksize = 12
}}
}}
| map_caption =
}}
The Mount Cap Formation is a geologic formation exposed in the Mackenzie Mountains, northern Canada. It was deposited in a shallow shelf setting in the late Early Cambrian,{{Cite journal| doi = 10.1038/369477a0| title = Burgess Shale-type fossils from a Lower Cambrian shallow-shelf sequence in northwestern Canada| year = 1994| last1 = Butterfield | first1 = N. J.| journal = Nature| volume = 369| pages = 477–479|bibcode = 1994Natur.369..477B | issue=6480| s2cid = 4326311}} and contains an array of Burgess Shale-type microfossils that have been recovered by acid maceration.{{Cite journal| doi = 10.1038/nature06724| pmid = 18337723| year = 2008| last1 = Harvey | first1 = T.| last2 = Butterfield | first2 = N.| title = Sophisticated particle-feeding in a large Early Cambrian crustacean| volume = 452| issue = 7189| pages = 868–871| journal = Nature|bibcode = 2008Natur.452..868H | s2cid = 4373816}}
Description
The formation is {{convert|100|to|300|m|ft}}, and comprises shales, siltstones and sandstones with a high glauconite content. It has been exposed to remarkably little metamorphic activity given its great age; it is dated to the Bonnia–Olenellus Trilobite Zone. This zone lies within the Lower Cambrian Waucoban stage in North America, which is equivalent to the Caerfai in Wales, and thus the Comley of England,{{Cite journal| doi = 10.1144/gsjgs.152.2.0221| title = An early Cambrian assignment for the Caerfai Group of South Wales| year = 1995| last1 = Siveter | first1 = D. J.| last2 = Williams | first2 = M.| journal = Journal of the Geological Society| volume = 152| issue = 2| pages = 221–224| bibcode = 1995JGSoc.152..221S| s2cid = 140607675}} and has yet to be formally ratified. Nevertheless, this makes it just younger than the earliest trilobites,{{dubious|how can it be in a trilobite zone if it's pre-trilobite?|date=August 2014}} and thus the earliest known Burgess Shale-type deposit, though this is disputable when considering the age of Chengjiang County fauna. Its organic-walled fauna, known as the "Little Bear biota", includes both non-mineralized and originally-mineralized taxa, including hyolith and trilobite fragments, anomalocaridid claws, arthropod carapaces and brachiopods.{{Cite journal| last1 = Butterfield | first1 = N. J.| last2 = Nicholas | first2 = C. J.| title = Burgess Shale-Type Preservation of Both Non-Mineralizing and 'Shelly' Cambrian Organisms from the Mackenzie Mountains, Northwestern Canada| jstor = 1306492| journal = Journal of Paleontology| volume = 70| issue = 6| pages = 893–899| year = 1996| doi = 10.1017/S0022336000038579| bibcode = 1996JPal...70..893B| s2cid = 133427906}}
See also
{{Portal|Earth sciences|Canada|Paleontology}}
References
{{reflist}}
External links
- {{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date=July 8, 2014}}
Category:Geologic formations of the Northwest Territories
Category:Shale formations of Canada
Category:Siltstone formations of Canada
Category:Sandstone formations of Canada
Category:Shallow marine deposits
Category:Cambrian Northwest Territories