The construction of abnormal geochemical fields accompanying gold mineralization is investigated; criteria of its quantitative estimation are developed. Orderliness estimation methods of geochemical field abnormal structures and intensity of hydrothermal process are offered. Dependence between quantitative parameters of these structures and scales of gold mineralization is established. Estimation possibility of deposits and ore fields erosive section by parameter values of abnormal geochemical fields is shown

Perevertaylo, Т. G.

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Administratively, the investigated area is located inthe Kargasok area of Tomsk district. Tectonically, theGugarinskiy and Cobolinniy sites are dated to structuresof the third order, respectively to Srednesobolinniy andSobolinniy local uplifts complicating the arch part ofthe Soboliniy swell located in a deflection between theParabelskiy and Pudinskiy megaswells – in southernpart of the UstTymskaya cavity. The Sobolinniy structure is revealed and partially detailed by seismicsurveyworks MOV s/p 12/6667 year.The complex of fieldgeophysical researches (standard, induction, radioactive, acoustic logging, cavernometry and microsounding) is used for partition and correlation of the studied deposits. With the purpose ofrock lithologic structure studying the analysis of the core field description is conducted; on wells 181 and 213of the Sobolinniy site (further in the text wells S181,213) the core material with revealing of texturestructural features of rocks is studied in details, and on wells 13,181, 182 of the Gurarinskiy site (further in the text wellsG13, 181, 182) and S181, 213 the lithologicpetrographic analysis of sandy rocks in sections is conducted.Results of investigation are shown in Figs. 1 and 2. Symbols are presented in Fig. 3.Bulletin of the Томsк Pоlytеchnic University. 2007. V. 310. № 220UDC 552.5:550.832:553.982 (571/16)LITHOLOGIC AND ELECTROMETRIC CHARACTERISTIC OF PRODUCTIVE LAYERS OF THE GURARINCKIYSOBOLINNIY DEPOSIT LOWCHALKY ADJOURMENTST.G. PerevertayloTomsk Polytechnic UniversityEmail: ezsovaav@ngf.tomsk.ruBeing based on the fieldgeophysical researches data, the detailed studying of core material and the lithologicpetrographic analysis thedescription of lowchalky deposit rock lithologic composition is resulted, the electrometric characteristic of sandy layers is given, laws oftheir distribution in the area and also change of capacities are specified.Fig. 1. The lithologicgeophysical characteristic of B15–B8 layer of the Sobolinnaya 181 wellExplanation to Figures 1 and 2: Свита – Series № Керна – Core number Пласт – LayerЛитолог. колонка – Litholog. column Глубина, м – Depth, m Структ. текст. особ. –Structure texture featuresSandy stratum B15 was opened by drilling in 14 wells.Its capacity (m) is ranging from 15 up to 35 m. Judgingby character of configuration change of spontaneouspolarization (SP) curve, and based on the study of core,it has clearly defined «regressive» orientation and ispresented by alternation of sandy and aleurite rockswith increase in grain sizes bottomup in the section. Inthe bottom part finegrained light grey layered sandstones prevail with traces of sliding and bioturbationalstructures. Lamination is oblique wavy due to alluviumsof carbonaceousargillomicaceous material. For thetop part of the B15 stratum the negative anomaly of SPcurve corresponding to high values αSP=0,6...0,99 ischaracteristic. In logging diagrams of all wells carbonaceous interlayers are also differentiated. It proves to betrue by the core of well S213 (see Fig. 2) represented bylight grey homogeneous sandstone with calcite cementwith abundance of shell and inclusion of vegetative detEarth science21Fig. 2. The lithologicgeophysical characteristic of B15–B8 stratum of the Sobolinnaya 213 wellritus. Further, nonuniform oblique and horizontallayered interlaminations of sandstones, aleurolites andclays with prints of large shells follow. The top border ofthe layer is fixed clearly enough. Higher rocks are overlapped by clay strata with capacity 5...7 m.The layer B14 is traced through out all the studied area, its m does not exceeded 2 m and characterized by lowvalues αSP=0,3...0,54 which corresponds to aleurolites orfinegrained aleuritelike sandstones. Exception is thewell G181 where according to the core descriptionsandstones are presented by finegrained fraction withalluviums of carbonaceous detritus. Grey, dark grey clays with inclusion of pyrite and charred vegetative organicare deposited higher. Capacity of clay rocks is practically identical to the whole section and makes up 4...7 m.Layers B13 represent strata (m=14...28 m) in structure of which 3 sandy layers B131, Б132 and B133 are allocateddivided by clay interlayers. The layer B133 (m=6...12 m)has a regressive construction, the structure of rockschanges bottom up from clay aleurolite up to sandstonewith values αПС=0,5...0,7 which considerably increasein wells S181 (αSP=0,9) and S177 (αSP=0,95). Themost fully the layer is characterized by the core of thewell S213 and represented by light grey, bluish sandstone, at the beginning of the layer aleuritelike, at theend – mediumgrained brown petrosated. The stronglycemented rock is homogeneous, rarely flatlayereddue to alluviums of charred vegetative detritus. The layer B132 is separated from the underlying by an interlayerof grey homogeneous clays, sections of aleuritelikewith rare inclusions of pyrite and large charred vegetative remains. Capacity of a clay pack gradually increasesin submeridian direction from 1 m (wells G13,G181, G16) up to 4,5 m (area of wells S171, S178,S179). The layer B132 is represented by the core in wellsG13, G181 and S213. In the bottom part of the layermediumgrained (the maximal value αSP=0,79) mainlyhomogeneous browngrey medium and weaklycemented with indicators of hydrocarbons (HC) sandstones are deposited gradually transforming above on asection into grey finegrained stronglycemented sandstones without attributes of HC. The transgressive cycleof sedimentation is reflected in configuration of SP curve. The overlying grey clays with inclusion of the charred vegetative organic with a sharp contact are overlapped by sandy rocks of the layer B132 (S213, see Fig. 2).In argilloaleurite rocks the textures of sedimentation sliding and flowing are stated, and sharp contact tooverlying sandstone is also observed. The layer B131 has avery nonuniform construction; it is difficult to distinguish the same sections based on configuration of SPcurve. Even within the limits of small area of wellsG13, G18 and G181 arrangement in the north of theGurarinskiy site different electrometric characteristicsand also sharp change in strata of the layer from 4 up to10 m are observed. The layer is presented by grey sandstones from finegrained aleuritelike up to finemediumgrained fraction (αSP to 0,76) partially obliquelayered due to alluviums of a carbonaceousclay materialand sometimes with HC attributes. In the Sobolinniy site rocks are carbonatized (S181, S213). Inclusions ofintraformational clay pebble, textures of deposit slidingand flowing are stated, which indicates the washout ofunderlying deposits. Higher on a section the rocks arerepresented by clays grey homogeneous seldom layereddue to interlayers of aleurolites with rare prints charredvegetative detritus. A sharp contact of the layer B122 withsandstone is revealed based on the well S181 core. CaBulletin of the Томsк Pоlytеchnic University. 2007. V. 310. № 222Figure 3. Symbols to figures 1, 2Explanation to Figure 3:First column: Second column: Third column: Forth column:Rocks Intraformational conglomerate Inclusions Traces of vital activityClay Single pellet in rock Calcite Sea digging organismsAleurolites Sharp contact Pyrite Fresh water organismsSandstones Cracks filled with calcite Chlorite Organic remainsCarbonaceous rocks Finegrained sandstones Carbonaceous lenses Plant remainsSandstones with calcitecement Finemediumgrained sandstones Lamination Large charred remainsTextures Mediumgrained sandstones Horizontal Flora imprintsHorizontal Indications of oil saturation Oblique Vegetative detritusOblique Horizontalwavy Shell remainsObliquewavy Phosphatized remainesLenticularpacity of the clay pack makes 1...2 m, increasing up to5,5 m in area of wells G16, G19.Layers B12 consist of two parts, are well stated in a section,the deep negative anomaly of SP curve corresponds to them.The layer B122 is also difficult to be referred to the certain type in orientation of logging curve change. The layer stratachanges over a wide range from 6,6 up to 17,4 m in the Gurarinskiy site and in the Sobolinniy – 7,5...11,2 m. Sandstonewith αSP=0,8...0,99 from light grey up to brown petrosated,homogeneous stronglycemented, partially carbonatizedwith inclusion of large vegetative remains. Layers B122 and B121are separated by 3–5 meter strata consisting of interlaminations of greenishgrey clays, aleurolites and grey finegrainedaleuritelike sandstones. Lamination is horizontal, wavy, lenticular. Textures of deposit sliding and flowing, inclusion ofrounded pebble (intraformational washout) also occur.Rocks with an abundance of shell detritus and charred vegetative organic. Capacity of the layer B121 decreases from5...8 m in the Gurarinskiy site up to 3...4 m in the Sobolinniy.In studied territory It is composed of sandstones mediumand coarsegrained (αSP=0,78...1) light grey or brown petrosated, mediumcemented, homogeneous, partially carbonatized. The layer electrometric model in the majority of sections has the form of «triangle» with horizontal pelmatic andinclined straight line, less often serrated or wavy roofing lines.Layers B11 with gross capacity from 13,5 up to25,6 m, clay intercalation (1,6...5,4 m) are divided intoB112 and B111, represented by alternation of greenishgreyclays, greenishgrey aleurolites and light grey, bluishgray and brownish (with HC attributes) sandstones. Layered rocks with traces of washout and sliding are frequently broken with pebble of carbonaceous compositioninclusion with an abundance of shells remains in variousconditions, vegetative remains with bioturbational textures. Lamination is lenticular, wavy, faltering. Pathes ofdigging worms and very small burrows of ground animalsare observed. Conglomeratelike rocks occur. In general,the intensively indent SP curve is characteristic for layersB11. The layer B112 on a greater part of the Sobolinniy site, east and southwest of the Gurarinskiy site has a clearly defined sandstone regressive orientation with αПС inthe top part up to 0,72. On greater part of the Gurarinskiy site and in the area wells S214, S177, S179, S171location the layer section has a ternary constructionwhere more sanded ones are the bottom and top layers.The layer B111 is mainly composed of two intercalationsandstones with capacity from 2...6 m and 1...3 m separated by clay interlayer up to 3 m thick. In general, for layers B11 the intensively indent SP curve is characteristic.The layer B10 is distributed throughout the territory.Distinctive features of the layer are: small capacity –2...5 m and deep negative SP anomaly with αSP from 0,8up to 1. Exception is made with wells S178 and S180where αSP makes 0,71 and 0,72. The electrometric modelof the layer in the majority of wells represents «triangle»with inclined pelmatic and roofing lines, sometimescomplicated by small serration. In the base of the layer lieargilloaleurite rocks light grey and greenishgrey, withchaotic lumpy textures, with an abundance of remainsand prints of different size shells, charred vegetative detritus. There are traces of ground animal vital activity.Brown sandstone petrosated, from finemediumgrainedup to coarsegrained, mediumcemented, homogeneous.On greater part of the Gurarinskiy site sandstones ofthe layer B10 are blocked by thick strata (up to 10 m), composed of multicoloured brown and green clays. Moving ina submeridian direction, beginning from the well G28and practically throughout the territory of the Sobolinniysite (except for wells S171, s178, S183) there is an interlayer represented by alternation of agrilloaleurite greenishgrey layered rocks, brownishbrown clays and greenishgrey aleuritelike sandstones (except for finegrainedsandstones in wells S175 and S211 where αSP increasesup to 0,59), sometimes with HC attributes. Presence ofwashout traces and infringement of layers, partially slidingand conglomeratelike textures, pebble of carbonaceouscomposition inclusion, an abundance of carbonaceousmaterial, plant remains of various conditions, paths ofworms are defined. Occurrence in the section of multicolored and greencolored sandyargillaceous deposits indicates the change of sedimentation conditions (freshenedshallow pool). Brown color is caused by congestions ofiron hydroxide which was carried over from the continentand deposited near the coastal line [1].The layer B9 has a nonuniform construction and unsteady m – from 3 up to 10,5 m. In its structure from 1 up to 4sandy intercalations of different thickness are present havingin most cases shallow negative anomaly with αSP up to 0,6.The layer B8 in the Gurarinskiy site is not virtually possible to compare to those in the Sobolinniy. On the territory of the former it is represented by alternating intercalations of sandstones, aleurolites and clays, m of which varies from 1 up to 4 m and the gross thickness of the layer makes 6,0...15,0 m. In the Sobolinniy site m of the layer increases up to 13...23 m due to sanding of the section, especially noticeable in the southern part (wells S171, S178and S181). Values of αSP make 0,7...1 almost in all wells.Thus, in distribution of layers B9 and B8 the clearly defined regularities are not observed, they sharply differ fromunderlying layers; have a nonuniform construction,sharp changes of structure and capacity which is characteristic for continental or transitive type of sedimentation.This conclusion proves also to be true by L.J. Trushkova’s[2] research which marks that in the field of lagoon andcontinental deposit development sandy layers are lithologically unstable, differentialeed in sections conditionallyand not traced even within the limits of separate prospecting areas. Position of their bottom border is usually defined by underlying clay caps and roofs, as a rule, are indistinct and cannot be done unequivocally.Earth science23REFERENCES1. Gurova T.I., Kazarinov V.P. Lithology and paleogeography of theWesternSiberian lowland in connection with oilgas bearing ability.– Moscow: Gostoptechizdat, 1962. – 370 p.2. Trushkova L.Ja. Basic regularities of productive layers and caps distribution in Neocomian of the ObIrtishskoe interfluve // Lithology and Paleogeography Questions of Siberia: Works of SNIIGGandMS. – 1970. – Issue 106. – P. 4–12.Received on 01.11.2006

Lithologic and electrometric characteristic of productive layers of the gurarinckiy-sobolinniy deposit low-chalky adjourments

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