Geochemistry and ore formation

14-31

Authors: Kravchenko G.L., Rusakon N.F.

The Archean of Ivanovka metaultrabazite massif in the central Azov area in basin of Kiltichiya river is characterized. Analogical rocks are exposed on the surface as boulders, xenoliths and rock outcrops (up to 100 m) in the middle flow of the Obitochna river. It is suggested that these rocks similar in composition, structural and textural characteristics and origin ar made up the single large (up to 15 km in diameter) Kiltichie-Obitochna ultramafic massif, the rocks from which have deen derived from the same magma chamber. The rocks of this massif are presented by peridotites and olivine pyroxenites preserved as a relict “layers” (from 1 to 28 m) among more older amphibole rocks. The primary composition of these rocks are coincided to lherzolite, ortho- and clinopyroxenites, websterites. By ftot (19,5-22,3%) ratio and increased content of Al2O3, TiO2, CaO and alkalis these rocks belong to ultraferribasites as differentiates of basaltic magma, i.e. they belong to gabbro-peridotite complex. In some parts of metaultrabasites with increasing of rock basicity (M/F to 8,3-10,1) and decreasing ftot (up to 9,010,7%) is observed transition to more deeply hyperbasite formations. The peculiarity of rocks in the Kiltichie-Obitochna massif occurs during imposed regional metamorphizm they had been serpentinized and intensive amphibolized. As a result hornblendites and wide distributed actinolite-tramolite rocks have been formed. The last are presented 1) chlorite-actinoliteanthophyllite and chlorite-actinolite tremolitites and 2) significantly actinolite (without anthophyllite) chlorite-tremolite aktinolitites and properly aktinolitites. Primary magmatic ultrabasites that were formed during introducing porridge-like magma (as protrusion) into host rocks and later they have been undergone progressive and regressive metamorphizm by some times. As a result of these processes they are presented by metaultrabazites. Majority of them are considered as secondary metamorphic rocks. Intensive processes of granitization and Na-metasomatism that had taken place in Neoarchean essentially converted ancient metaultrabazites in diorites, quartz diorites and tonalite of obitochna complex (2.92 Ga) in the central and eastern part of the massif while these metaultrabazites of Shevchenko complex (2.83 Ga) of western part this massif have been converted in plagiogranites and plagiomigmatite.

50-57

Authors: Mytrokhyn O.V., Shumlyanskyy L.V., Vishnevskaya E.A., Omelchenko A.M., Mitrokhina T.V.

The chemical composition of non-metamorphosed basic dykes within the Ingul (ID) and Volyn (VD) domains have been studied with the purpose of clarification of possibility of geochemical classification and correlation of the dyke rocks of the Ukrainian Shield. For this purpose, all available chemical analyzes of the dyke rocks from ID and VD were used, including those published in the literature and original analyses performed on the author’s samples. The initial list of samples included 325 analyses on mayor oxides produced in different years by the «wet» chemistry and XRF methods. The content of volatile components (CVC), determined as a sum of H2O+, CO2, SO2, F , Cl and LOI was used to reject altered rocks, the chemical composition of which could undergo significant modification under influence of the low-temperature hydrothermal-metasomatic processes. It was established previously that in the least altered rocks the CVC does not exceed 2 %, whereas in moderately altered dykes it is 2–4 %, and in intensively altered rocks the CVC varies in the range of 4–18 %. The samples having the CVC in excess of 4 % and dykes that were presumably affected by silicification were excluded from the further consideration. The final set of samples included 40 analyses of the ID dykes and 171 analyses of the VD dykes. To clarify the distribution of microelements we used ICP-MS analyses most of which were carried out by authors. It has been shown that dykes in both domains belong to the tholeiitic and subalkaline petrogenetic series. The similarity of geochemical variations of dyke composition in two spatially separated domains of the Ukrainian Shield evidences about the similarity of processes of magmatic evolution. Revealed peculiarities of the chemical composition can be used as indicators for classification and correlation of dyke formations in the Ukrainian Shield.

70-79

Authors: Ivanov B.N., Stepanyuk L.M., Donskoy N.A., Syomka V.O., Bondarenko S.M., Shevela A.Yu.

The Central Ukraine Uranium Province confines the Vatuntinskoe, Novokonstantinovskoe, Partizanskoe and Aprelskoe ore fields. All features mentioned above can be divided, based on geological features of each, into such types: VatutinskoNovokonstantinovskiy and Partizansko-Aprelskiy. For the first type mentioned the chlorite-epidote and rybekite-egirine albitites, which form ribbon-like layers, are specific. The second one occurs along linear faults. Ore bodies associated with albitites follow direction of the linear structures. They had simple morphology, flattened and lens-shaped ones. The composition of albitites and type of structural ore precipitation conditions of the Vatutinka, Dokuchaevskoe deposit and the bottom layer of the Novokonstantinovka deposit are similar. On deep horizons of the Novokonstantinovka deposit a bottom ore floor (layer) has been discovered. It is related to a column-like body (layer) of albitites of aegirine-carbonate-biotite composition. The structural ore precipitation conditions in the case are not related to linear seams of mylonites and cataclisites, but zones of pre-ore volume cataclasis. The ore bodies related to them have irregular complex shape. Ore fields of the second type have similar peculiarities.

95-100

Authors: Klos V.R., Zhovinsky E.Ya., Kryuchenko N.O., Prikhodko M.V.

The results of the study of the geochemical state of the surface sediments (soils) of the Kiev region contaminated with sewage sludge from the Bortnicheskaya Aeration Station (BSA). Geochemical associations are determined, ecological-geochemical estimates of soils are carried out, geochemical parameters are calculated. According to the total pollution index, it is established that the surface sediments, where the sludges are used as fertilizers, are characterized by an extremely dangerous level of contamination: BSA silt fields (396), flowerbed beds (280), virgin soils (236), agricultural lands (186). This indicates the danger of using silt as an organic fertilizer for growing agricultural products. It is established that in the presence of an organic component in surface sediments, Zn and Cd are transformed into more mobile ones, and Cu and Pb – into less mobile compounds, which must be taken into account when fertilizers are needed.