ПРЕЦИЗИОННЫЙ (ICP-MS, LA-ICP-MS) АНАЛИЗ СОСТАВА ГОРНЫХ ПОРОД И МИНЕРАЛОВ: МЕТОДИКА И ОЦЕНКА ТОЧНОСТИ РЕЗУЛЬТАТОВ НА ПРИМЕРЕ РАННЕДОКЕМБРИЙСКИХ МАФИТОВЫХ КОМПЛЕКСОВ

This paper presents an integrated major and trace element data and crystal size distribution analysis for zoned clinopyroxene phenocrysts hosted in variolitic and massive picrobasalts of the Suisaari Formation, Karelian Craton, Eastern Fennoscandian Shield. Clinopyroxenes in variolitic and massive lavas occur as unzoned, reverse, and normally zoned crystal. Oscillatory-zoned clinopyroxenes are only observed in variolitic lavas. The obtained data were examined in order to evaluate the contribution of magmatic processes such as magma mixing, contamination and fractional crystallization to the formation of various zoning patterns of clinopyroxene phenocrysts. Clinopyroxene phenocrysts in both variolitic and massive lavas originate from similar primary melts from a single magmatic source. The obtained data on composition and texture of clinopyroxene phenocrysts together with the crystal size distribution (CSD) analysis suggest that crystallization of the massive lavas mainly involves fractionation in a closed magmatic system, whereas the crystallization of the variolitic lavas is determined by processes in an open magmatic system. The results provide novel information on the evolution of Paleoproterozoic magmatic systems in the Karelian Craton.

To reduce the use of commercial conventional inorganic fertilizers, the possibility of using pulp and paper industry wastes in agriculture as an alternative source of nutrients is recently under study and discussion. This work aimed to evaluate the effect of sodium lignosulfonate application to soil on photosynthetic leaf nutrient (N, P, K, Ca, Mg, Fe, Mn, and Na) and water use efficiency. A pot culture experiment was conducted with cucumber seedlings, using five lignosulfonate concentrations (0, 1, 2.5, 5, and 10 vol. %) in sandy soil under sufficient or low nutrient availability for plants. The impact of nutrient availability on the plants’ physiological traits was stronger than the lignosulfonate impact. Under sufficient nutrient availability, the lignosulfonate application resulted in decreased photosynthetic N, P, K, Ca, Mg, Fe, and Na use efficiency. Cucumber growth and development, and photosynthetic nutrient, water, and light use efficiency were significantly reduced with a nutrient deficiency. The sodium lignosulfonate application was not successful in eliminating the negative effects of nutrient deficit on cucumber seedlings.

The present study provides the first detailed investigation of black agates occurring in volcanic rocks of the Zaonega Formation within the Onega Basin (Karelian Craton, Fennoscandian Shield). Three characteristic texture types of black agates were identified: monocentric concentrically zoning agates, polycentric spherulitic agates, and moss agates. The silica matrix of black agates is only composed of length-fast and zebraic chalcedony, micro- and macro-crystalline quartz, and quartzine. In addition to silica minerals, calcite, chlorite, feldspar, sulphides, and carbonaceous matter were also recognised. The black colour of agates is related to the presence of disseminated carbonaceous matter (CM) with a bulk content of less than 1 wt.%. Raman spectroscopy revealed that CM from black agates might be attributed to poorly ordered CM. The metamorphic temperature for CM from moss and spherulitic agates was determined to be close to 330 °C, whereas CM from concentrically zoning agates is characterised by a lower temperature, 264 °C. The potential source of CM in moss and spherulitic agates is associated with the hydrothermal fluids enriched in CM incorporated from underlaying carbon-bearing shungite rocks. The concentrically zoning agates contained heterogeneous CM originated both from the inter-pillow matrix and/or hydrothermal fluids.