MAGMA

MAGMA (yun. magma — khamira), moddai gudokhtai tarkibash asosan silikati, ki dar qari zamin hosil meshavad. Tarkibash asosan az oksigen, Si, Al, Fe, Ms, Sa, Na va K iborat. Bazan Magma to yakchand foiz komponenthoi bukhorshavanda, asosan ob, kamtar oksidhoi karbon, gidrogensulfid, gidrogen, ftor, khlor va g. dorad. Harorati Magma 900—1100° S, bazan 700—1350° S. Aksari tadqiqotchiyon chunin meshumorand, ki dar tabaqahoi poyonii qishri Zamin yo mantiyai boloii on (dar chuqurihoi taqriban 50—700 km) dar natijai kohishi elementhoi radioaktivi va harakathoi tektoniki harorat baland shuda, moddahoi sakht ba holati moe, yane ba Magma tabdil meyoband. Magma hangomi az qar ba qabathoi boloii litosfera harakat kardanash ba qismhoi gunoguntarkib taqsim shuda, moddahoi bukhorshavandai khudro gum mekunad. Badi khunuk shuda kristall bastani Magma dar qishri Zamin jinshoi intruzivi, pas az tarkishhoro pur kardani on jinshoi ragi va hamchun lava ba rui zamin rekhta khunuk shudani Magma jinshoi effuziey (vulqoni) hosil meshavand. Tarkib va khususiyati Magmaro bo rohi omukhtani jinshoi kuhii magmavi muayyan kardan mumkin ast. Az rui tarkibi khimiyavi Magma ba yakchand tiphoi asosi va guruhho taqsim meshavad: 1) Magmai ultraasosi, ba miqdori ziyod Fe, Mg va khele kam Si03 dorad, az on jinshoi peridotit, dunit hosil meshavad; 2) Magmai asosi yo bazalti va jinshoyash bazalt, gabbro, norit; 3) Magmai tursh yo graniti va jinshoi on granit, granodiorit, liparit; 4) Magmai ishqori, jinshoyash sionit va sienithoi nefelindor. Magmahoi ultraasosi va asosi dar qabathoi boloii mantiya va Magmai graniti dar qari qishri Zamin ba vujud meoyand. Yak guruh olimon (N. A. Bouen, A. N. Zayaarnskiy va digar) mavjudiyati yagona nakhustmagmai bazaltiro etirof karda, chunin meshumorand, ki az on bo rohi differensiasiya yo assimilyasiya tamomi tiphoi boqmondai Magma ba vujud meoyand. Ba aqidai F. K). Levinson-Lessing va digar tamomi jinshoi magmavi az du nakhustmagma — asosi (bazalti) va tursh (graniti) hosil shudaand, ki paydoishi onho dar mantiyai beloi va tabaqahoi gunoguni qishri Zamin ba amal omadaast. Paydoishi bisyor konhoi sarvathoi zerizamini bo Magma aloqamand ast. Hangomi differensiasiya va kristallbandii Magma konhoi gunoguni magmavi va az hisobi komponenthoi bukhorshavandai on konhoi gidrotermali, greyzeni, skarni va g. paydo meshavand. Nig. niz Konhoi magmavi.

Ad.: Zavariskiy A. N, Izverjennie gornie porodi, M., 1961; Magma maloglubinnikh kamer, M., 1070; Problemi magmi i genezisa izverjennikh gornikh porod, M., 1963.

U. Olimov.