The Minaret Formation is a Late Cambrian limestone

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

of the Heritage Group of Antarctica. The age of the formation is established to be

Guzhangian The Guzhangian is an uppermost stage of the Miaolingian Series of the Cambrian. It follows the Drumian Stage and precedes the Paibian Stage of the Furongian Series. The base is defined as the first appearance of the trilobite ''Lejopyge laevigat ...

Cambrian Stage 10 Stage 10 of the Cambrian is the still unnamed third and final stage of the Furongian series. It follows the Jiangshanian and precedes the Ordovician Tremadocian Stage. The proposed lower boundary is the first appearance of the trilobite '' Lotagnos ...

(or Merioneth to Dresbachian in the regional stratigraphy), dated at ranging from 500 to 488 Ma.Minaret Formation
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org The formation has provided the first known Late Cambrian archaeocyathid, and ''

Knightoconus antarcticus ''Knightoconus antarcticus'' is an extinct species of fossil monoplacophoran from the Cambrian Minaret Formation of Antarctica. It is thought to represent an ancestor to the cephalopods. It had a chambered conical shell, but lacked a siphuncle. ...

'', an ancestor to the

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

s.Yochelson et al., 1973

Description

The Minaret Formation forms a discontinuous limestone unit exposed from

Webers Peaks Webers Peaks () is a line of peaks on a ridge bounded by Splettstoesser Glacier on the north, Balish Glacier on the east and Dobbratz and Fendorf Glaciers on the west, in the Heritage Range, Ellsworth Mountains. They were named by the University ...

in the northern

Heritage Range The Heritage Range is a major mountain range, long and wide, situated southward of Minnesota Glacier and forming the southern half of the Ellsworth Mountains in Antarctica. The range is complex, consisting of scattered ridges and peaks of mod ...

to the Independence Hills in

Horseshoe Valley Horseshoe Valley may refer to: * Horseshoe Valley (Antarctica) * Horseshoe Valley (Peleliu) * Horseshoe Valley (Missouri) * Horseshoe Valley (North Dakota) * Horseshoe Valley (Nebraska) * Horseshoe Valley, North Dakota * Horseshoe Resort, formerly ...

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 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 webersi''Debrenne et al., 1984 *

Gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

s ** '' Strepsodiscus splettstoesseri''Webers et al., 1992 *

Conodont Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...

s ** '' Furnishina furnishi'' ** '' F. quadrata''Buggisch et al., 1992, p.172 ** '' F. ?asymmetrica''Buggisch et al., 1992, p.170 ** '' Proacodus tenuis'' ** '' Phakelodus sp.'' ** '' Westergaardodina bicuspidata'' ** '' W. moessebergensis''Buggisch et al., 1992, p.173 ** '' W. tricuspidata'' * Tergomya ** '' Aremellia batteni'' ** '' Ellsworthoconus andersoni'' ** '' Kirengella pyramidalis'' ** ''

'' ** '' Proconus incertis'' ** '' Proplina rutfordi'' * Rostroconchia ** '' Apoptopegma craddocki'' ** '' Cosminoconella runnegari'' * Paragastropoda ** '' Matherella antarctica'' ** '' Ribeiria australiensis'' ** '' Scaevogyra thompsoni'' ** '' ?Kobayashiella heritagensis''

References

Bibliography

* * * * * * {{doi, 10.1111/j.1502-3931.1973.tb01199.x Geologic formations of Antarctica Paleozoic Antarctica Furongian Guzhangian Limestone formations Shallow marine deposits Deep marine deposits Cambrian southern paleotemperate deposits Paleontology in Antarctica

Description

Fossil content

See also

References

Bibliography