earth science

Gnishik Formation

Gnishik Formation is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Gnishik Formation rather than just read about it. In short: The Gnishik Formation is a geologic formation in Armenia, Azerbaijan and Iran. It preserves fossils dated to the Wordian age of the Permian period.

Key takeaways

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Reference excerpt

The Gnishik Formation is a geologic formation in Armenia, Azerbaijan and Iran. It preserves fossils dated to the Wordian age of the Permian period. The thin-bedded limestones of the formation reach a thickness of 670 metres (2,200 ft) in the Julfa section of northwestern Iran and 300 metres (980 ft) in the 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 Gnishik River valley, after which the formation was named. The formation is mostly represented by thin-bedded, occasionally shaly, dark grey and black 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. 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, while in Armenia the formation rests on top of the Asni Formation and is overlain by the Arpa Formation. The Gnishik Formation represents an increase in subsidence rate in the Permian. The sediments were deposited at the northern edge of the Paleo-Tethys Ocean. The formation is dated to the late Murgabian, which belongs to the Wordian stage of the Middle Permian. The Gnishik Formation is correlated with the Ruteh and Nesen Formations, and the Kuffengian stage of Chinese chronostratigraphy.

Fossil content Among many others, the following fossils have been reported from the formation:

Invertebrates Trilobites Pseudophillipsia armenica Pseudophillipsia (Carniphillipsia) paffenholzi Acropyge sp. Cephalopods Orthocerida indet. Gastropods Pharkidonotus khairliensis Naticopsis cf. spectatus Bellerophon sp. Naticopsis sp. Straparollus sp. ?Euphemites sp. ?Platyceras sp. Bellerophontidae indet. Corals Ipciphyllum araxense I. flexuosum I. originale I. ex gr. restriseptatum I. simplex I. subtimoricum I. subelegans Lonsdaleia aff. gracilis L. aff. jenningsi Lophocarinophyllum lophophyllidum L. pulchrum L. aff. zaphrentoideum Michelinia vesiculosa Paraipciphyllum transcaucasicum Parawentzelella (Parawentzelella) canalifera Pentaphyllum leptoconicum Praetachylasma alternatum Protomichelinia microstoma Sinopora asiatica Szechuanophyllum szechuanense Ufimia elongata Wentzelella armenica Wentzelella (Wentzelella) densicolumnata Wentzellophyllum gnishikense W. parvus W. volzi Yatsengia asiatica Lophophyllidium sp. Wentzelella sp. Crinoids ?Poteriocrinites ardjichensis Rhynchonellata Cryptospirifer omeishanensis Septospirigerella baissalensis Terebratuloidea davidsoni Crenispirifer sp. Septospirigerella sp. Strophomenata Chonostegoides baissalensis C. ogbinensis Edriosteges poyangensis Leptodus sp. Stenolaemata Mackinneyella dzhulfensis Rhabdomeson floriferum Septopora lineata Fusulinina Sichotenella cf. sutschanica Yangchienia cf. haydeni Nankinella cf. ovata N. orbicularia Staffella sphaerica S. suborientalis Eoverbeekina cf. intermedia Pisolina abichi P. subsphaerica Leella ex gr. bellula Sphaerulina crassispira S. ogbinensis Verbeekina cf. heimi V. verbeeki Eopolydiexodina darwasica E. persica Polydiexodina chekiangensis Chusenella abichi C. doraschamensis Dunbarula sp. Foraminifera Globigaetania angulata

Flora Dasycladophyceae Atractyliopsis fecundus Diplopora americana Endoina stellata Epimastopora nipponica Gyroporella tenuimarginata Johnsonia spinosa Macroporella spinosa Mizzia velebitana Pseudogyroporella grandis Pseudovermiporella serbica Stolleyella yabei Rhodophyceae Succodium ambiguum S. difficile Gymnocodium bellerophonte G. novum Permocalculus forospinus P. fragilis P. piai Ungdarella stellata

See also

References

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, retrieved 2020-08-01 Saidi, Abdollah; Brunet, Marie-Françoise; Ricou, Luc-Emmanuel (1997), "Continental accretion of the Iran Block to Eurasia as seen from Late Paleozoic to Early Cretaceous subsidence curves", Geodinamica Acta, 10 (5): 189–208, doi:10.1080/09853111.199 (inactive 12 July 2025){{citation}}: CS1 maint: DOI inactive as of July 2025 (link) Paleontology Gennari, Valerio; Rettori, Roberto (2019), "Globigaetania angulata gen. n. sp. n. (Globivalvulininae, Foraminifera) from the Wordian (Middle Permian) of NW Iran", Rivista Italiana di Paleontologia e Stratigrafia, 125 (1): 1–11, doi:10.13130/2039-4942/11054 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, Series IV, 23: 53–146 Kotlyar, G. V.; Zakharov, Y.u. D.; Kropatcheva, G. S.; Pronina, G. P.; Chedija, I. O.; Burago, V. I. (1989), Evolution of the latest Permian biota: Midian regional stage in the USSR, ., pp. 1–184 Nakamura, K.; Golshani, F. (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.; Golshani, F.; Stöcklin, J. (1969), "Upper Permian and Permian-Triassic boundary in north Iran", Geological Survey of Iran Report, 12: 1–72 Ruzhentsev, V. E.; Sarycheva, T. G. (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 Zhurnal, 1964: 52–57

Worked examples

Example 1 — a first encounter with Gnishik Formation

Start with the simplest possible case. Write down what Gnishik Formation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Gnishik Formation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Gnishik Formation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Gnishik Formation

In research: Gnishik Formation appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Gnishik Formation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Gnishik Formation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geologic formations of Armenia, Geologic formations of Azerbaijan, Geologic formations of Iran, so understanding it makes those chapters shorter.
In everyday life: Look for Gnishik Formation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Gnishik Formation in 20 minutes

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Frequently asked questions

What is Gnishik Formation in simple terms?

The Gnishik Formation is a geologic formation in Armenia, Azerbaijan and Iran. It preserves fossils dated to the Wordian age of the Permian period.

Why does Gnishik Formation matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Gnishik Formation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Gnishik Formation.