Gnishik Formation
| Gnishik Formation | |
|---|---|
Ma | |
| Type | Alborz Mountains |
| Type section | |
| Named for | Gnishik River |
| Named by | Arakelyan |
| Year defined | 1964 |
  Gnishik Formation (Caucasus mountains) | |
The Gnishik Formation is a
period.[1]
The thin-bedded
Arpa River valley of Armenia. The sediments were deposited in an open marine setting at the northern edge of the Paleo-Tethys Ocean
.
The coral Wentzellophyllum gnishikense was named after the formation.
Description
The Gnishik Formation was first formally described by Arakelyan in 1964, based on a section in the
bituminous foraminiferal-algal biodetrital limestones. The occasional admixture of clayey and terrigenous material colors the limestones light grey and yellowish. The thin-bedded layers alternate with coarser-bedded compact varieties.[2]
The open marine limestones of the formation reach a thickness of 670 metres (2,200 ft) in the Julfa section of northwestern Iran. In Iran, the formation overlies the Dorud Formation and is overlain by the Khachik Formation,[3] while in Armenia the formation rests on top of the Asni Formation and is overlain by the Arpa Formation.[4] The Gnishik Formation represents an increase in subsidence rate in the Permian.[3] The sediments were deposited at the northern edge of the Paleo-Tethys Ocean.
The formation is dated to the late
Middle Permian.[1] The Gnishik Formation is correlated with the Ruteh and Nesen Formations,[6] and the Kuffengian stage of Chinese chronostratigraphy.[7]
Fossil content
Among many others, the following fossils have been reported from the formation:[1]
Invertebrates
- Trilobites
- Cephalopods
- Gastropods
- Pharkidonotus khairliensis[9]
- Naticopsis cf. spectatus[9]
- Bellerophon sp.[9]
- Naticopsis sp.[9]
- Straparollus sp.[9]
- ?Euphemites sp.[9]
- ?Platyceras sp.[9]
- Bellerophontidae indet.[9]
- Corals
- Ipciphyllum araxense[10]
- I. flexuosum[11]
- I. originale[11]
- I. ex gr. restriseptatum[11]
- I. simplex[11]
- I. subtimoricum[11][12]
- I. subelegans[11]
- Lonsdaleia aff. gracilis[12]
- L. aff. jenningsi[12]
- Lophocarinophyllum lophophyllidum[13]
- L. pulchrum[10][11]
- L. aff. zaphrentoideum[12]
- Michelinia vesiculosa[8]
- Paraipciphyllum transcaucasicum[11]
- Parawentzelella (Parawentzelella) canalifera[12]
- Pentaphyllum leptoconicum[13]
- Praetachylasma alternatum[12]
- Protomichelinia microstoma[13]
- Sinopora asiatica[13]
- Szechuanophyllum szechuanense[12]
- Ufimia elongata[8]
- Wentzelella armenica[12]
- Wentzelella (Wentzelella) densicolumnata[8]
- Wentzellophyllum gnishikense[10]
- W. parvus[10]
- W. volzi[12]
- Yatsengia asiatica[12]
- Lophophyllidium sp.[11]
- Wentzelella sp.[11]
- Crinoids
- Rhynchonellata
- Cryptospirifer omeishanensis[15]
- Septospirigerella baissalensis[15]
- Terebratuloidea davidsoni[8]
- Crenispirifer sp.[15]
- Septospirigerella sp.[15]
- Strophomenata
- Stenolaemata
- Fusulinina
- Sichotenella cf. sutschanica[8]
- Yangchienia cf. haydeni[8]
- Nankinella cf. ovata[8]
- N. orbicularia[8]
- Staffella sphaerica[8]
- S. suborientalis[8]
- Eoverbeekina cf. intermedia[8]
- Pisolina abichi[8]
- P. subsphaerica[8]
- Leella ex gr. bellula[8]
- Sphaerulina crassispira[8]
- S. ogbinensis[8]
- Verbeekina cf. heimi[8]
- V. verbeeki[8]
- Eopolydiexodina darwasica[8]
- E. persica[8]
- Polydiexodina chekiangensis[8]
- Chusenella abichi[8]
- C. doraschamensis[8]
- Dunbarula sp.[8]
- Foraminifera
Flora
- Dasycladophyceae
- Atractyliopsis fecundus[8]
- Diplopora americana[8]
- Endoina stellata[8]
- Epimastopora nipponica[8]
- Gyroporella tenuimarginata[8]
- Johnsonia spinosa[8]
- Macroporella spinosa[8]
- Mizzia velebitana[8]
- Pseudogyroporella grandis[8]
- Pseudovermiporella serbica[8]
- Stolleyella yabei[8]
- Rhodophyceae
- Succodium ambiguum[8]
- S. difficile[8]
- Gymnocodium bellerophonte[8]
- G. novum[8]
- Permocalculus forospinus[8]
- P. fragilis[8]
- P. piai[8]
- Ungdarella stellata[8]
See also
References
- ^ a b c Gnishik Formation in the Paleobiology Database
- ^ Leven, 1998, p.302
- ^ a b Saidi et al., 1997, p.198
- ^ Leven, 1998, p.301
- ^ Leven, 1998, p.308
- ^ Leven, 1998, p.314
- ^ Leven, 1998, p.320
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw Ruzhentsev & Sarycheva
- ^ a b c d e f g h i j Stepanov et al., 1969
- ^ a b c d Kropatcheva, 1999
- ^ a b c d e f g h i j Kotlyar et al., 1989
- ^ a b c d e f g h i j k Morozova, 1970
- ^ a b c d Ezaki, 1991
- ^ Stukalina, 1999
- ^ a b c d e f Nakamura & Golshani, 1981
- ^ a b c Shishova, 1964
- ^ Gennari & Rettori, 2019
Bibliography
- Geology
- Leven, Ernst J.A. 1998. Permian fusulinid assemblages and stratigraphy of the Transcaucasia. Rivista Italiana di Paleontologia e Stratigrafia 104(3). 299–328. Accessed 2020-08-01.
- Saidi, Abdollah; Marie-Françoise Brunet, and Luc-Emmanuel Ricou. 1997. Continental accretion of the Iran Block to Eurasia as seen from Late Paleozoic to Early Cretaceous subsidence curves.
- Paleontology
- Gennari, Valerio, and Roberto Rettori. 2019. Globigaetania angulata gen. n. sp. n. (Globivalvulininae, Foraminifera) from the Wordian (Middle Permian) of NW Iran.
- Kropatcheva, G. S. 1999. Novie vidi pozdnepermski rugoz zakavkaziya - New materials of Late Permian rugosans from the Caucasus. Voprosy Paleontologii 11. 24–32. .
- Stukalina, G. A. 1999. The Late Permian crinoids from Primorye, Transcaucasia, and North Caucasus. Paleontological Journal 33. 139–146. .
- Ezaki, Y. 1991. Permian corals from Abadeh and Julfa, Iran, West Tethys. Journal of the Faculty of Science, Hokkaido University 23. 53–146. .
- Kotlyar, G. V.; Y.u. D. Zakharov; G. S. Kropatcheva; G. P. Pronina; I. O. Chedija, and V. I. Burago. 1989. Evolution of the latest Permian biota: Midian regional stage in the USSR, 1–184. ..
- Nakamura, K., and F. Golshani. 1981. Notes on the Permian brachiopod genus Cryptospirifer. Journal of the Faculty of Science, Hokkaido University, Series 4, Geology and Mineralogy 20. 67–77. .
- Morozova, I. P. 1970. Mshanki Pozdnei Permi. Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta 122. 1–346. .
- Stepanov, D. L.; F. Golshani, and J. Stöcklin. 1969. Upper Permian and Permian-Triassic boundary in north Iran. Geological Survey of Iran Report 12. 1–72. .
- Ruzhentsev, V. E., and T. G. Sarycheva. 1965. The Development and Change of Marine Organisms at the Palaeozoic-Mesozoic Boundary. Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta 108. 1–431. .
- Shishova, N. A. 1964. Novyye Pozdnepermskiye Rabdomezonidy Sovetskogo Soyuza. Paleontologicheskii Zhurnal1964. 52–57. .