| 摘 要： | Experiments have been conducted over a wide range of temperature and pressure(300--950℃, 500--2000 bars) in attempting to gain some better understanding of the geological features of Precambrian migmatite granite and banded iron formation (BIF)widespread in Northeast China. Results indicate that BIF of Anshan type is unstable under the action of sufficient alkaline solutions with some iron or aluminum silicates formed at the expense of quartz. Rock melting experiments show that the beginningof-melting temperatures of phyllite, biotite plagioclase gneiss and migmatite granite range from 680 to 640℃, but that of BIF and plagioclase amphibolite are 150-200℃ higher. The authors suggest that migraatite in this region has been resulted from partial melting and metasomatizm. With respect to the relation between migmatization and iron deposits, it has been experimentally revealed that migmatite will not “digest” the BIF if they are separated by other country rocks. But melting to various extent will take place in BIF where migmatite is in direct contact with it. Additionally, the BIF will even become richer in iron under favorable conditions. This information may probably help in guiding our efforts to prospect for Precambrian iron deposits in. regions with extensive occurrence of migmatite.
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