Minaret Formation
{{Short description|Limestone formation in Antarctica}}
{{Infobox rockunit
| name = Minaret Formation
| image = {{Location map+ | Antarctica
| relief = 1
| width = 250
| float = center
| places =
{{Location map~ | Antarctica
| lat_deg = -79.4
| lon_deg = -84.8
| mark = Dark Green 004040 pog.svg
| marksize = 10
}}
{{Location map~ | Antarctica
| lat_deg = -79.8
| lon_deg = -84.5
| mark = Dark Green 004040 pog.svg
| marksize = 10
}}
}}
| type = Geological formation
| age = Guzhangian-Cambrian Stage 10
(Merioneth-Dresbachian)
~{{fossil range|500|488}}
| period = Cambrian
| prilithology = Limestone
| otherlithology =
| namedfor =
| namedby =
| year_ts =
| region = Ellsworth Land
| country = Antarctica
| coordinates = {{coord|79.4|S|84.8|W|display=inline,title}}
| paleocoordinates =
| unitof = Heritage Group
| subunits =
| underlies = Crashsite Group
Howard Nunataks Formation
| overlies = Liberty Hills & Springer Peak Formations
| thickness = Up to {{convert|600|m|ft|abbr=on}}
| extent = Ellsworth Mountains, Yochelson Ridge & Heritage Range
| area =
| map = Panotiaggg.jpg
| map_caption = Paleogeography of the Cambrian with the supercontinent Pannotia and Antarctica south of the paleo-equator
}}
The Minaret Formation is a Late Cambrian limestone formation of the Heritage Group of Antarctica. The age of the formation is established to be Guzhangian to Cambrian Stage 10 (or Merioneth to Dresbachian in the regional stratigraphy), dated at ranging from 500 to 488 Ma.[https://paleobiodb.org/classic/displayStrata?geological_group=Heritage&formation=Minaret&group_formation_member=Minaret Minaret Formation] at Fossilworks.org
The formation has provided the first known Late Cambrian archaeocyathid, and Knightoconus antarcticus, an ancestor to the cephalopods.Yochelson et al., 1973
Description
The Minaret Formation forms a discontinuous limestone unit exposed from Webers Peaks in the northern Heritage Range to the Independence Hills in Horseshoe Valley of the Ellsworth Mountains. At Mount Rosenthal, at the head of Horseshoe Valley, the Minaret Formation is formed predominantly of white to pale grey micritic limestone with thin, discrete interbeds of oolitic and oncolithic grainstones.Curtis & Lomas, 1999, p.66
The Minaret Formation is the uppermost formation of the Heritage Group, overlying the Liberty Hills and Springer Peak Formations. The formation is overlain by the Howard Nunataks Formation of the Crashsite Group.Curtis & Lomas, 1999, p.65 The formation reaches a thickness of {{convert|600|m|ft}} in the south of its extent.Webers & Splettstoesser, 2007, p.3 The formation ranges from shallow to deep marine.Curtis & Lomas, 1999, p.71 The Minaret fauna contains the first known Late Cambrian archaeocyathid.Webers & Splettstoesser, 2007, p.5 During the final stages of Gondwanian deformation, structureless and stratified post-cleavage breccia bodies formed in the carbonate lithologies of the Minaret Formation, due to cave-like dissolution processes and contemporaneous low temperature hydrothermal activity.Curtis & Lomas, 1999, p.64
Fossil content
The reefal limestones of the formation have provided fossils:
- Antarcticocyathus webersiDebrenne et al., 1984
- Gastropods
- Strepsodiscus splettstoesseriWebers et al., 1992
- Conodonts
- Furnishina furnishi
- F. quadrataBuggisch et al., 1992, p.172
- F. ?asymmetricaBuggisch et al., 1992, p.170
- Proacodus tenuis
- Phakelodus sp.
- Westergaardodina bicuspidata
- W. moessebergensisBuggisch et al., 1992, p.173
- W. tricuspidata
- Tergomya
- Aremellia batteni
- Ellsworthoconus andersoni
- Kirengella pyramidalis
- Knightoconus antarcticus
- Proconus incertis
- Proplina rutfordi
- Rostroconchia
- Apoptopegma craddocki
- Cosminoconella runnegari
- Paragastropoda
- Matherella antarctica
- Ribeiria australiensis
- Scaevogyra thompsoni
- ?Kobayashiella heritagensis
See also
- List of fossiliferous stratigraphic units in Antarctica
- Geology of Antarctica
- Shackleton Limestone, Cambrian fossiliferous limestone of Antarctica
References
{{reflist|20em}}
= Bibliography =
- {{citation |last1=Webers |first1=G.F. |last2=Splettstoesser |first2=J.F. |year=2007 |title=Review of the geology and paleontology of the Ellsworth Mountains, Antarctica |url=https://pubs.usgs.gov/of/2007/1047/srp/srp107/of2007-1047srp107.pdf |journal=USGS and the National Academies; USGS OF-2007-1047, Short Research Paper |volume=107 |pages=1–5 |accessdate=2020-07-11}}
- {{citation |last1=Curtis |first1=Michael L. |first2=Simon A. |last2=Lomas |year=1999 |title=Late Cambrian stratigraphy of the Heritage Range, Ellsworth Mountains: implications for basin evolution |url=https://www.researchgate.net/publication/231801100 |journal=Antarctic Science |volume=11 |issue=1 |pages=63–77 |doi=10.1017/S0954102099000103 |bibcode=1999AntSc..11...63C |accessdate=2020-07-11}}
- {{citation |last1=Buggisch |first1=Werner |first2=Gerald F. |last2=Webers |first3=John E. |last3=Repetski |first4=Linda |last4=Glenister |year=1992 |title=Cambrian conodonts from the Springer Peak and Minaret Formations, Ellsworth Mountains, West Antarctica |url=https://www.researchgate.net/publication/296064090 |journal=Geological Society of America Memoir |volume=170 |pages=169–179 |doi=10.1130/MEM170-p169 |accessdate=2020-07-11}}
- {{citation |last1=Webers |first1=G.F. |first2=J. |last2=Pojeta |first3=E.L. |last3=Yochelson |year=1992 |title=Cambrian Mollusca from the Minaret Formation, Ellsworth Mountains, West Antarctica |journal=Geological Society of America Memoir |volume=170 |pages=181–248|doi=10.1130/MEM170-p181 }}
- {{citation |last1=Debrenne |first1=F. |first2=A. Y. |last2=Rozanov |first3=G. F. |last3=Webers |year=1984 |title=Upper Cambrian archaeocyatha from Antarctica |journal=Geological Magazine |volume=121 |issue=4 |pages=291–299|doi=10.1017/S0016756800029186 |bibcode=1984GeoM..121..291D }}
- {{citation |first1=E.L. |last1=Yochelson |first2=R.H. |last2=Flower |first3=G.F. |last3=Webers |year=1973 |title=The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda |journal=Lethaia |volume=6 |issue=3 |pages=275–309 |doi=10.1111/j.1502-3931.1973.tb01199.x|bibcode=1973Letha...6..275Y }}
Category:Geologic formations of Antarctica
Category:Shallow marine deposits