Permtida

Permtida 299–251 millionar år sidan PreЄ Є O S D C P T J K Pg N
Gjennomsnittleg O₂-innhald i perioden	ca. 23 vol %^[1] (115 % av dagens nivå)
Gjennomsnittleg CO₂-innhald i atmosfæren i perioden	ca. 900 ppm^[2] (3 gonger førindustrielt nivå)
Middeltemperaturen ved jordoverflata i perioden	ca. 16 °C ^[3] (2 °C over dagens nivå)
Viktige hendingar i perm sjå • diskuter • endre -300 — – -295 — – -290 — – -285 — – -280 — – -275 — – -270 — – -265 — – -260 — – -255 — – -250 — Karbon Asselium Sakmarium Artinskium Kungurium Roadium Wordium Capitanium Wuchia- pingium Changhsin… Trias ← Masseutrydding P e r m Mesozoikum Paleozoikum Lopingium (Øvre perm) Guadalupium (Mellomperm) Cisuralium (Nedre perm) Ei tilnærma tidsskala for hendingar i perm. Skala: Millionar år sidan.

Perm er ein geologisk periode som strekkjer seg frå tida 299,9 ± 0,8 millionar år sidan til 251,0 ± 0,4 millionar år sidan.^[4] Han er den siste perioden i paleozoikum. Perioden vart etterfølgd av trias, den første delen av mesozoikum.

Perm vart kalla opp etter kongedømet Permia i Russland av den skotske geologen Roderick Murchison i 1841, og ikkje den vesle byen Perm som mange ofte trur.^[5]

Permsystemet er bergartar som er avsette i perm.

↑ Fil:Sauerstoffgehalt-1000mj.svg
↑ Fil:Phanerozoic Carbon Dioxide.png
↑ Fil:All palaeotemps.png
↑ F.M. Gradstein, F.M, J.G. Ogg, A.G. Smith, & al. (2004): A Geologic Time Scale 2004. Cambridge University Press PDF Arkivert 2013-11-01 ved Wayback Machine.
↑ Murchison, R.I.; de Verneuil, E.; von Keyserling, A. (1845). Geology of Russia in Europe and the Ural Mountains. Vol. 1: Geology. London: John Murray. s. 138–139. «...Convincing ourselves in the field, that these strata were so distinguished as to constitute a system, connected with the carboniferous rocks on the one hand, and independent of the Trias on the other, we ventured to designate them by a geographical term, derived from the ancient kingdom of Permia, within and around whose precincts the necessary evidences had been obtained. ... For these reasons, then, we were led to abandon both the German and British nomenclature, and to prefer a geographical name, taken from the region in which the beds are loaded with fossils of an independent and intermediary character; and where the order of superposition is clear, the lower strata of the group being seen to rest upon the Carboniferous rocks.»

[1] Fil:Sauerstoffgehalt-1000mj.svg

[2] Fil:Phanerozoic Carbon Dioxide.png

[3] Fil:All palaeotemps.png

[4] F.M. Gradstein, F.M, J.G. Ogg, A.G. Smith, & al. (2004): A Geologic Time Scale 2004. Cambridge University Press PDF Arkivert 2013-11-01 ved Wayback Machine.

[Murchison_etal_1845-5] Murchison, R.I.; de Verneuil, E.; von Keyserling, A. (1845). Geology of Russia in Europe and the Ural Mountains. Vol. 1: Geology. London: John Murray. s. 138–139. «...Convincing ourselves in the field, that these strata were so distinguished as to constitute a system, connected with the carboniferous rocks on the one hand, and independent of the Trias on the other, we ventured to designate them by a geographical term, derived from the ancient kingdom of Permia, within and around whose precincts the necessary evidences had been obtained. ... For these reasons, then, we were led to abandon both the German and British nomenclature, and to prefer a geographical name, taken from the region in which the beds are loaded with fossils of an independent and intermediary character; and where the order of superposition is clear, the lower strata of the group being seen to rest upon the Carboniferous rocks.»

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