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AN EXPERIMENTAL-DETERMINATION OF LOW-SANIDINE -] MICROCLINE TRANSITIONстатья
Информация о цитировании статьи получена из
Web of Science
Дата последнего поиска статьи во внешних источниках: 27 мая 2015 г.
- Авторы: BYCHKOV AM, RUSAKOV VS, MESHALKIN SS
- Журнал: GEOKHIMIYA
- Номер: 12
- Год издания: 1993
- Первая страница: 1683
- Последняя страница: 1696
- Аннотация: Potassium feldspar from ovoids of Vyborg rapakivi granite massif quenched on the step of orthoclase-microcline transition was held at 250, 350, 475, 500-degrees-C and P(H2O) = 10(8) Pa during several months. Run products were scanned by X-ray diffractometer in the range 34-37-degrees 2theta (Co(Kalpha) radiation). At first, the profile of difractogram was examined and compared with one for initial sample by a special computer program. Then integral X-ray spectrum was resolved to monoclinic and triclinic components and a ratio I(131)mon/I(131 + 131)tric [I - intensity (area) of peakl] was determined. The ratio of intensities decreased from 2.7 (initial sample) to 1.4-2.2 (run products) in experiments at temperatures below 425-degrees-C. The intensity of a broad orthoclase peak decreased in samples from runs at 475 and 500-degrees-C, while a narrow sanidine peak appeared. Sanidine peak was weak in samples from 475-degrees-C runs and strong in run products at 500-degrees-C. The ratio of intensities decreased in one month duration experiments and then increased in two month duration experiments above 475-degrees-C. These results are interpreted as follows: a) orthoclase (with 2t1 > 0.75) is unstable phase of K-feldspars: b) low-sanidine --> microcline transition occurs between 425-475-degrees-C.
- Добавил в систему: Русаков Вячеслав Серафимович