Perm, d a v r a i (s i s t e m a i) perm, davrai okhirii (shashum)-i erai paleozoy. Davrai Perm 285 mln sol muqaddam ogoz yofta, 55 mln sol davom kardaast. Tahnishasthoi sistemai Permro bori nakhust soli 1841 geologi anglis R. I, Murchison dar Ural Zay (gub. Perm) va hamvorii Rus judo kard. Davrai Perm ba zamonhoi avval va okhir, sistemai Perm boshad, ba qismhoi poyon va bolo taqsim meshavand. Dar davrai Perm harakathoi tektoniki khele shiddat yoftand. In harakatkhho, ki marhilai okhirini chindorshavii gersini budand, makhsusan dar zonahoi geosinklinali — Uralu Tiyonshoi (SSSR), Gersin (Evropai Garbi) va Annalachi (Amerikai Shimoli) avj girifta, boisi paydo shudani kuhhoi baland gardidand. Dar nimai duyumi davra nohiyahoi pahnovari platformaho niz baland shudand. Dar natija bahrho az platformaho kuchida, dar joi onho qitahoi kaloni khushki ba vujud omadand. Va tufayli regressiyai perm, ki dar tarikhi Zamin yake az kalontarin bud, bahrhoi bekanori ibtidoi Perm dar okhiri davra ba kulu bahrhoi nimkushod tabdil yoftand. Bahrho tanho dar baze nohiyahoi geosinklinali (masalan, dar Tetis, Verkhoyane) boqi mondand. Dar davrai Perm magmatizm ham nihoyat avj girift. Vulqonho chi dar zeri ob va chi dar khushki amal mekardand; dar qishri Zamin massahoi intruzivi ba vujud meomadand.
Iqlimi Perm kharakteri mintaqavi doshta, on toraft khushktar megardid. Materikhoi hamonvaqta ba yakchand mintaqahoi iqlimi — qutbi, mutadili sernami nimkurahoi shimoli va janubi, garmu khushki Nimkurai shimoli va tropikhoi sernam taqsim shuda budand. Sardshavii iqlim dar avval va okhirhoi davra mushohida shudaast.
Olami organikii davrai Perm ba olami organikii davrai karbon shabohat dosht. Dar bahrho fuzulinidho, marjonho, mshankaho, brakhiopodaho, foraminiferaho va gayraho, az muhradorho mohihoi panjabolu nahangmonand va digar mohiho bisyor budand. Ba sababi vusat yoftani masohati khushki namudi hanvonot va rastanihoi khushki niz afzud. Hayvonhoi khushki asosan obkhokiho (stegosefalho), khazandaho (pareozavrho, dinasefalho) va hasharotho budand. Dar okhiri davra baze guruhhoi hayvonhoi bemuhra (marjonhoi chorparra, trilobitho, fuzulinidho, tabulyataho, khorpushthoi bahrii qadima) va bisyor namudhoi florai davrai karbon (sigillyariyaho, qalamitho va gayraho) tamoman barham khurdand.
Tahnishinsthoi sistemai Perm dar SSSR beshtar vusat yoftaand. Chunonchi tahnishasthoi lagunagiyu kontinenti dar Urali Garbi, koptinenti dar pastkhamihoi Oltoyu Sayan va nohiyai chindori Qazoqiston, kontipenti angishtdor va tabaqai jinshoi vulkoni dar platformai Sibir, tahnishasthoi bahri dar platai (hamvorii) Rus va Sibiri Shimolu Sharqi, Zabaykaliya, Primoriya, takhhnishasthoi beshtar bahri va tabaqai jinshoi vulqoni dar Kavkaz va Osiyoi Miyona maydonhoi vasero ishgol kardaand. Tahnishasthoi kontineitiyu lagunagi asosan az formasiyahoi jinshoi shikastanorai surkhrangu khokistarrang, jinshoi terrigenii angishtdor, formatsiyai namakdori lagunaho va tahnishasthoi bahrhoi Perm az formatsiyahoi jinshoi karbonati (ohaksanghoi gunogun, az jumla rifogeni), jinshoi shikastanora va shikastaporayu vulkonogeni iboratand. Dar Tojikiston tahnishasthoi davrai Perm dar qatorkuhi KhHisor (havzai daryohoi Luchob, Khonaqoh, Qarotog va gayra) va nohiyahoi Darvozu Pomir malumand. Inho asosan tabaqahoi jinshoi terrigeniyu vulkonogeni buda, gafsiashon az chand sad metr to 6000 m va az on ziyodtar ast.
Dar takhhishasthoi sistemai Perm ashyoi khomi minerali farovon ast.
Yak qator havzahoi angishti SSSR (Pechora, Kuznetsk, Minusa va Tunguska), mamlakathoi Evropai Garbi, Amerikai Shimoli, Khitoy, Hinduston va mamlakathoi Nimkurai janubi dar davrai Perm paydo shudaand (24,3% zakhirai angishti jahoni). Bisyor konhoi neftu gaz dar SSSR (nohiyai Volgayu Ural, pastkhamihoi Pechora, Donetsk) va Amerikai Shimoli az tahnishasthoi Perm yoft shudaand. Zakhirahoi kaloni namaksang va namaki kaliy bo tahnishasthoi Permi poyop (havzahoi Nazdiural, Nazdikaspiy, Donetsk va gayra) va Permi bolo (konhoi namaki Evropa, Amerikai Shimoli) aloqamandand. Tahnishasthoi Perm mis, fosforit va zakhirahoi ziyodi gips, angidrit niz dorand. Bo massivhoi intruzivii in davra bisyor koni madanhoi gunogun vobastaand (dar Ural, Qazoqiston va digar mahalho).
Ad.: Geologiya SSSR, t. 24— Tadjikskaya SSR. M., 1959; M i k l u kh o-M a k- l a y A. D., Verkhniy paleozoy Sredney Aaii, L., 1963; Geologicheskoe stroenie SSSR, t. 1, M., 1968; Permskaya sistema, M., 1966 (stratigrafiya SSSR).