HR: 0800h
AN: V51A-0336    [Abstracts]
TI: Electron probe microanalysis for high pressure minerals investigation
AU: * Lavrentiev, Y G
EM: micropro@uiggm.nsc.ru
AF: Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russian Federation
AU: Sobolev, N V
EM: sobolev@uiggm.nsc.ru
AF: Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russian Federation
AU: Korolyuk, V N
AF: Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russian Federation
AU: Usova, L V
AF: Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russian Federation
AB: In the early 1968 in Siberian Branch of the Academy of Sciences of USSR, Novosibirsk, electron probe microanalyzer MS-46 was installed and started to operate for high pressure minerals EPMA investigation. In collaboration with Geophysical Laboratory of Carnegie Institution (Drs. F.R. Boyd, F. Schairer) a set of standards for silicates analysis was developed. Technique for quantitative analysis was developed (Lavrentiev et al., 1974, Zavodsk. Lab., v. 40, p. 657-661) and applied for the first in the USSR analyses of pyropes, associated with Siberian diamonds both as inclusions and xenoliths of diamondiferous peridotites (Sobolev et al., 1969, Dokl. Akad. Nauk SSSR, v. 188, p. 1141-1143; v. 189, p. 162-165). As a result of that research, unique Cr-rich subcalcic pyropes with high knorringite content were found in diamond-bearing kimberlites only and new mineralogical criteria for diamond exploration were developed (Sobolev 1971, Geol. Geofiz., v. 12, p. 70-80) which are still in use worldwide. Further development of electron probe instruments (JXA-5A, Camebax Micro, JXA-8100) and computers, as well as development of analysis technique led to creation of large analytical database. In another field of EPMA – determination of small concentrations of elements – for the first time importance of 0.01-0.3% Na₂O admixtures in garnets (Sobolev, Lavrentiev, 1971, Contrib. Min. Petr., v. 31, p. 1-12) and K₂O in clinopyroxenes (Sobolev et al., 1970, Dokl. Akad. Nauk SSSR, v. 192, p. 1349-1352) were demonstrated. Since then, determination of sodium content in EPMA of garnets and potassium in pyroxenes became a routine technique. Last generation analyzer (JXA-8100) provided record results down to 6 ppm in detection limit of Ni in pyropes (Lavrentiev et al., Rus. Geol. Geophys., 2006, v. 47, p. 1090-1093). As a result, application of EPMA for single mineral geothermometry (currently based mainly on PIXE method) becomes possible.
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1065 Major and trace element geochemistry
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting