Alevtina Petrova's research while affiliated with A.P. Karpinsky Russian Geological Research Institute and other places

Regional anomaly Aldan Shield is dated to ancient greenstone belt of the earth's crust. Belt is characterized by high depth forming sequences. Rocks of the upper and middle part of the section contain ferruginous quartzite. Geomagnetic and density sections allowed to estimate the power density and magnetic crustal heterogeneities. The methodology of constructing the cuts is the spectral-spatial representation of the fields, convertible into the underlying magnetic and density cuts. According to satellite data confirms the presence of regional anomalies within the Aldan shield, at an altitude of 100 km, it is about 100 nT. The presence of the Central Aldan crast-mantle fault depth of 50-80 km defines metallogenic situation of the region. The structure of the Aldan Shield detects rotational structure. Regional magnetic anomalies arc tangent frame Central Aldan region. May suggest that such behavior of anomalies is caused by of the ancient (Pre-Cambrian) fireplace mantle (the nucleus). Studies have shown that lithospheric sources Aldan shield on satellite magnetic anomalies and magnetic anomalies (ΔT) a Russia are located at depths of 30 to 35 and 40 to 70 km. They are confined to vertical zone deconsolidated at depths of about 30 and 40 - 70 km. By magnetic anomalies (ΔT) a Russian in the crust of the Aldan shield a depth of 15 - 17 km and 25 - 30 km depth revealed magnetite zone, the formation of which is due to the processes of regional metamorphism of ancient crust. Studies have shown the limits of the depth distribution of magnetite zones, mosaic developed within the crust of the Aldan shield after repeated activation of the processes of regional metamorphism.Alpha Ridge in the Arctic Ocean is one of the largest igneous provinces in the world. Tectonic history of the Arctic while not significantly deciphered. Deep structure of the Earth's crust are poorly understood Linearly elongated magnetic anomalies Alpha Ridge clearly seen at the height of the satellite. At an altitude of 100 km reach values of 100 - 120 nT, with gravity anomalies in the reduction of Faye in the central part is only 0 - 20 mg, to the periphery of the ridge rising to values of 40-50 mg. The maximum values of the magnetic anomalies are confined to the Alpha Ridge of the span latitudes 84 - 85N.Deep density and magnetic sections along the latitudinal profiles by satellite measurements showed the following. Lithospheric sources of satellite magnetic anomalies Alpha Ridge located at a depth of about 40 km and are confined to vertical zone centered deconsolidated at depths 30 - 40 km. Higher in the section allocated powerful lens decompressed at a depth of 9 - 18 km.

In 2011, work continued on the interpretation of geophysical data in western Bering Sea. Bering Sea oil-and-gas bearing province occupies a single sedimentary megabasin of the Bering Sea, the formation of which is caused by stage of the Alpine geodynamic development cycle of the Pacific mobile belt. At present, the geological-geophysical exploration maturity of the Bering Sea with respect to oil-gasbearing prognosis is at the level of regional study stage. In 2003, an additional study of oil-gas prospective zones of the Kamchatka Shelf of the Bering Sea was carried out. In the course of works, profile seismic studies and airborne gravity-magnetic survey at 1:200,000 scale were made at three territories: Ilpinsky, Olyutorsky I, and Olyutorsky II. Average survey elevation for the whole area is 300 meters. Geological modeling of sedimentary basin systems was made for this area. Geomagnetic sections it possible to compare the location of the magnetic and weakly magnetic structures with seismic and geological boundaries marker and conducting layers of geoelectric sections. This makes it possible to trace the features of placing magnetic differences in the geologic rock section, to identify their stratigraphic association, select the layers flyuidstubborn, adumbrate reservoir heterogeneity and establish the heterogeneity of internal structure oil-gasbearing zones. Age correlation, thickness estimation and formational characteristics of litho-stratigraphic complexes building up sections are carried out. Geomagnetic deep sections transecting main zones of prospective oil-gas accumulation to airborne magnetic data. Distribution of magnetization in the development interval of potentially productive sandy strata at depths from 1 to 5 km is obtained. The most prospective zones of possible oil-gas accumulation are distinguished in the Olyutorsky and Ilpinsky sedimentary basins. At height of 400 km this minimum keeps the form that speaks about stability of a condition of the permeable zones supervising oil-gas-bearing.

Observation of magnetic field using Champ satellite and compilation of digital maps of magnetic anomalies for altitudes 100 km and 400 km opens up new possibilities for a more reliable investigation of regional anomalies observed after airborne- and hydromagnetic surveys. For studying regional anomalies of the Mediterranean Sea basin, observed values of geomagnetic field measured along extended tacks for years 1966-1967 on a non-magnetic schooner "Zarya" and data of geomagnetic measurements obtained by Champ satellite for the altitudes 100 km and 400 km were used as source materials. For parameter estimation of magnetic anomaly field structure, the method of spectral-spatial analysis (SSAN) was used. For comparison with seismic and geological sections, the method of conversion of spectral-spatial representation of geomagnetic field into a deep geomagnetic section was used. Along two near-latitude profiles of a geomagnetic survey crossing the Northern and Southern Mediterranean Sea, deep geomagnetic sections are constructed. They allowed studying lateral and vertical distribution regularities of rock magnetization in the Earth's crust. Survey error, detail sampling, and great profile length allowed studying mantle anomalies 5 km to 800 km long in a depth interval from 1 to 50 km to a precision of 10-15%. This allowed estimating features of the largest heterogeneities in deep structure of the middle and lower crust of the Mediterranean. Comparison of geomagnetic sections with seismic data allowed distinguishing large magnetic heterogeneities corresponding to position of deep seismic boundaries in the Earth's crust. An estimation of velocity, density, and magnetic rock characteristics for the middle and lower Earth's crust of the West Mediterranean and Central Basin is made. A comparison of three regional anomalies distinguished after hydromagnetic survey profiles with magnetic anomalies obtained by Champ satellite for heights 100 km and 400 km is carried out. Intensity of magnetic anomalies at a height of 100 km is more than 10 nT. At the ocean level, intensity of these anomalies amounts to 250-300 nT in the Tyrrhenian Sea area and African-Sicilian threshold and approximately to 200 nT in the Phoenician Sea. In geomagnetic sections, regional anomalies are confined to magnetic heterogeneities in a depth interval from 17 to 25 km; they correspond to seismic discontinuity boundaries inside the basement. Magnetic anomaly at a height of 400 km in the Tyrrhenian Sea area of 2-3 nT intensity is confined to a weakly magnetic horizon at a depth of 30-38 km. At the African-Sicilian threshold, where Moho discontinuity is at a depth of 38-40 km, an anomaly of 3-3.5 nT intensity is confined to a more magnetic heterogeneity located at the same depth of 30-39 km. In the Phoenician Sea, a 1-1.3 nT anomaly is confined to a near-vertical magnetic heterogeneity submerging to a depth of more than 30 km. These results enable to specify geophysical modeling of the Mediterranean lithosphere taking into account lateral and vertical distribution regularities of rock magnetization. Interpretation of magnetometric data from hydromagnetic and satellite measurements in association with seismic materials allowed revealing structural features of the Earth's crust, extended the possibilities for forecast of thermal conditions, composition, and state of deep matter.

The purpose of this paper are showed results of studying of specificity of a deep structure of zones of petrogeneration Northern and the Bering seas on aeromagnetic and satellite magnetometric datas. Research lateral and vertical heterogeneitys an earth's crust of Northern sea is carried out on the basis of the analysis of measurements of satellite Champ at height of 100 km and the digital database created on materials of sea shooting of a geomagnetic field, executed on non-magnetic schooner "Zarya". On sea measurements in Northern sea through large oil fields and gas ( Frigg, Ekofisk, Forties trough, Leman, etc.). Geomagnetic sections for an interval of depths from 1 up to 30 km are constructed. It has allowed to study character of distribution of magnetization of breeds of a cover, horizontal lamination intracore layers of an earth's crust and to allocate in zones petrogeneration synvertical fluidoconduct zones the channels described by alternation of not magnetic and low-magnetic layers. They were showed on geomagnetic sections as permeable zones quasi- laminated structures with the lowered magnetic properties in an interval of depths from 8 up to 28 km. Comparison to a map of the magnetic anomalies measured at height of 100 km by satellite Champ, has shown, that areas of the greatest petrocongestions North Sea рифта at height of 100 km are dated for a zone of gradients and a minimum of northeast displacement of regional anomalies of western and east blocks of Northern sea. It corresponds to representations about an orientation of a fissuring zone and the increased size of a geothermal gradient North Sea rift and is corresponded position allocated on hydromagnetic structures deep fluidoconduct channels. Thus, distribution to water areas of deposits of deposits is emphasized not only low-magnetic areas in a thickness of a sedimentary cover where they are directly located, but also by not magnetic lenses in breeds of the base spreading it in intervals of depths of 8-11 km and 15-18 km. The oil-gas-bearing province of the Bering Sea occupies uniform sedimentary megabasin. On aeromagnetic measurements at height of 300 m are constructed geomagnetic sections in an interval of depths from 0.5 km up to 25 km crossing the basic zones possible petrocongestions with traps structural and of structural - stratigraphic types. Distribution of magnetization in an interval of development of potentially productive sandy layers on depths from 1 up to 5 km is received. The most perspective zones possible petrocongestions are allocated in Ilpinsky, Olutorsky and Olutorsko-Komandorsky sedimentary basins. The deep permeable zone with system of low-magnetic lenses in intervals of depths 8-10, 12, 18-20 km, dated to Pilgin zone possible petrocongestions was most brightly showed. Comparison of ground supervision to the data received by results of measurements from satellite Champ at height of 100 km, shows, that large oil-gas-bearing Vertuhovskaya, Karaginskaya, Pahachiskaya and Pilginskaya zones are dated for a minimum isometric satellite magnetic anomaly. At height of 400 km this minimum keeps the form that speaks about stability of a condition of the permeable zones supervising oil-gas-bearing.

Large areas of the European shelf seas (North, Norwegian, Greenland, Barents, Pechora, Kara) were regions, where under the influence of deep mantle masses activation of magmatic and tectonic processes, which impacted the formation of morphostructures and sea bottom topography, composition and thickness of marine sedimentary strata, ore genesis took place. According to modern conception, in the Mesozoic and Cenozoic, lithosphere plates of the West Arctic Region were a part of the Laurasian Continent and overlaid the Iceland mantle plume. Plume volcanism leaves a peculiar trace on the surface of lithosphere plates formed during their passing over plume hotspots. The age of magmatic formations along the plume trace regularly changes from the oldest Late Permian - Early Triassic in the south Kara and Pechora seas; then the Late Jurassic - Early Cretaceous in the Barents Sea, north of Novaya Zemlya, Frantz Josef Land (FJL),), Spitsbergen; the Paleogene in the Southeast and West Greenland, and, finally the Miocene - present day in Iceland and Spitsbergen. It was interesting to analyze the morphostructural features of magnetic anomalies after airborne magnetic and satellite data due to plume magmatism show in the Barents-Kara Region. An investigation of magnetic anomaly field structure of the Barents Sea water area along seismic lines and extended profiles crossing known deposits was carried out. Geomagnetic and density sections to a depth of 40 km were constructed; this allowed the estimation of deep structure heterogeneity of the Barents Sea water area. Within the Barents Sea water area, permeable areas with lenticular-laminated structure of the upper and lower Earth's crust containing feebly magnetic areals with reduced rock density within the depth interval of 8-12 km and 15-20 km are revealed. They are usually combined with increased subhorizontal stratification of medium with extended seismic boundaries and represented by rheologically weakened zones. Main cause of such zones formation is, most likely, their increased fluid saturation. Such deep lamination may be caused by plume age dynamics and non-uniform warming and subsequent cooling of different pracontinent parts associated with it. Morphology analysis of multiscale magnetic anomalies - near-surface (altitude 100-300 m) and satellite at a height of 100 km (Champ) indirectly confirms plume volcanism show in the Barents-Kara Region. A multirank periodicity in the Iceland plume activity is traced in sequence of extended alternating satellite anomalies of northwest strike with an intensity of ±10-20 nT. Extended negative anomalies framing a positive anomaly may be caused by deep heating of asthenospheric rocks. Heat flows (HF) formed during magmatism impulses caused pyrolytic transformations of organic matter of sedimentary strata and development of oil- and gas-formation areas. Presence of a thick sedimentary cover on platform plates in the Kara and Barents seas during the Mesozoic plume magmatism contributed to formation of numerous bedded intrusions, sills; plateaus appeared, volcanoes of central type and volcanogenic-sedimentary island formed in the areas where magma reached the surface. Middle- and Late Paleozoic destruction of the Barents - Kara Plate did not totally destroy the Proterozoic continental crust during plume magmatism; it caused its thinning and downwarping. Thermal relaxation after this tectonic event caused a rather quick fixation of quasistationary background HF values characteristic for other Paleozoic structures as well. Average value of deep heat flow in the Barents Sea amounts to 54 MW/m2 Zones of local temperature and heat flow elevation formed in a stationary field in conditions of structural-geological and thermophysical heterogeneities. A common tendency of confinedness of large hydrocarbon deposits to the areas with increased thermal potential is revealed in the shelf of West Arctic seas.

The specific features of gold ore provinces of the south of Siberia in a magnetic field at ground height and heights of flight of satellite Champ. T.Litvinova -All-Russian Geological Research Institute (VSEGEI) A. Petrova - St. Petersburg, SPbF IZMIRAN, Russian Academy of Sciences, St. Petersburg For allocation of specific features known gold ore objects (Olimpiadninskoje, Suchoi Log, etc.) is executed the morphological analysis of the magnetic field received on materials of aeromagnetic data and satellite measurements at heights of 100 and 400 km. On the ground data on a map of magnetic anomalies of Russia of scale 1:2 500000 of 50 km on the extended structures crossing known gold ore deposits and promising ore units have been constructed geomagnetic and densitys sections up to depth. On geomagnetic and densitys sections to known large gold ore to deposits are dated deep synvertical the permeable zones described by a synlenticular -layered structure. Extended horizons of not magnetic formations are located on depths about 10, 12, 15-18, 30 and 40 km. On deep densitys sections reference sites ¬ the Suchoi Log, Olimpiadninskoje and Vodorazdelnoje ¬ is characterized by zones of inversion of density. Areas of the loosened breeds are dated to synvertical to deep zones of hydrothermal and fluid study of breeds inside which the loosened lenses in intervals of depths from 2 up to 5 km are formed, 8-13 km, 18-20 and 25-30 km of 35-40 km within the limits of the bottom bark. The analysis of a magnetic field has shown, that gold mineralization in researched region is dated for zones of long-living regional explosive infringements, to permeable terrigenous to thicknesses of depressions, to adjournment depression structures in units of crossing of tectonofluid zones of diagonal orientation. Terrigenous adjournment depression structures are shown on a geomagnetic section as the powerful deflections filled with low-magnetic thicknesses. These deflections are dated to synvertical to deep zones of low-magnetic breeds, probably, reflecting influence of the high-temperature tectonofluid processes occuring on the big depths (up to 30 - 35 km), and explosive infringements shown through systems. It testifies to presence of a long-living deep zone of differentiation of substance when inside the base lenses of the loosened breeds are formed, and more dense breeds mapping in near-surface formations. It was represented interesting to track as the laws allocated on the ground aeromagnetic data are reflected in satellite anomalies. The analysis has shown, that gold ore areas Barguzino - Vitim evgeosynclinal zones gravitate to a local minimum of a magnetic field of satellite Champ at height of 100 km. Zones of minima at height of 100 km coincide with position of permeable blocks of the earth's crust allocated on extended structures, executed by results of ground shooting. The considered zones of minima at height of 400 km practically do not change the morphology. Local steady minima in area Barguzino - Vitim zones on maps of satellite Champ can be connected with heattd-up long-living fluidized the channels providing gold ore and rare-metal a mineralization of the region.

The study of magnetic anomaly field structure of the Barents Sea water area along seismic and extended profiles intersecting known fields is carried out. Geomagnetic and density sections down to 40 km depth are constructed. This allowed the estimation of heterogeneities of the Barents Sea water area deep structure. The analysis of geomagnetic and density sections along extended profiles showed the confinedness of oil-and-gas bearing provinces to deep permeable zones characterized by reduced magnetic and density features. Based on the analysis of permeable zones, regional diagnostic features similar to those obtained earlier in oil-and-gas bearing provinces in other regions, for example, in Timan-Pechora, Volga-Urals and Siberian, as well as in the Northern and Norwegian seas water areas, are revealed. The analysis of magnetic and gravity fields over the region area allowed the delineation of weakened zones as intersection areas of weakly magnetic areals with reduced density. Within the Barents Sea water area, permeable areas with lenticular-laminated structure of the upper and lower Earth's crust containing weakly magnetic areals with reduced rock density within the depth range of 8-12 and 15-20 km are revealed. Such ratio of magnetic and density heterogeneities in the Earth's crust is characteristic for zones with proved oil-and-gas content in the European part of the Atlantic Ocean water area. North Kildin field on 1 AR profile is confined to a trough with thick weakly magnetic stratum discontinuously traced to a depth of 6-10 km. At a depth of approximately 15 km, a lens of weakly magnetic and porous formations is observed. Ludlov field in the North Barents trough is confined to a zone of weakly magnetic rocks with reduced density traced to a depth of 8-9 km. Deeper, at Н=15 km, a lenticular areal of weakly magnetic formations with reduced density is observed. The profile transecting the Stockman field shows that it is located in the central part of a permeable zone. Ledovoe field is in the northern margin of the same zone. SPAN calculations of magnetic and gravity fields in areal option allowed obtaining the distribution of permeable weakly magnetic zones in the Barents Sea water area. The most significant ones are confined to Franz-Victoria trough, Severnaya depression, Malygin saddle, Bjarmeland syneclise, Murmansk-Kurentsovo monocline, Southern Lunin trough and depression, Northern Stockman depression, and Southern Barents syneclise.