Summary In accordance with modern trends in the development of the architectural and construction industry worldwide, a transition is being made to the management of building assets using BIM technologies. The principal difference between the information model and the digital one is another approach used in its creation, as well as the attribute content of the model itself. The presented materials contain the experience of creating digital models of the geological structure of roads on the results of GPR surveys and supplementing them with attributive information.
The Proterozoic and Phanerozoic metallogenic and tectonic evolution of the Russian Far East, Alaska, and the Canadian Cordillera is recorded in the cratons, craton margins, and orogenic collages of the Circum-North Pacific mountain belts that separate the North Pacific from the eastern North Asian and western North American Cratons. The collages consist of tectonostratigraphic terranes and contained metallogenic belts, which are composed of fragments of igneous arcs, accretionary-wedge and subduction-zone complexes, passive continental margins, and cratons. The terranes are overlapped by continental-margin-arc and sedimentary-basin assemblages and contained metallogenic belts. The metallogenic and geologic history of terranes, overlap assemblages, cratons, and craton margins has been complicated by postaccretion dismemberment and translation during strike-slip faulting that occurred subparallel to continental margins. Seven processes overlapping in time were responsible for most of metallogenic and geologic complexities of the region (1) In the Early and Middle Proterozoic, marine sedimentary basins developed on major cratons and were the loci for ironstone (Superior Fe) deposits and sediment-hosted Cu deposits that occur along both the North Asia Craton and North American Craton Margin. (2) In the Late Proterozoic, Late Devonian, and Early Carboniferous, major periods of rifting occurred along the ancestral margins of present-day Northeast Asia and northwestern North America. The rifting resulted in fragmentation of each continent, and formation of cratonal and passive continental-margin terranes that eventually migrated and accreted to other sites along the evolving margins of the original or adjacent continents. The rifting also resulted in formation of various massive-sulfide metallogenic belts. (3) From about the late Paleozoic through the mid-Cretaceous, a succession of island arcs and contained igneous-arc-related metallogenic belts and tectonically paired subduction zones formed near continental margins. (4) From about mainly the mid-Cretaceous through the present, a succession of continental-margin igneous arcs (some extending offshore into island arcs) and contained metallogenic belts, and tectonically paired subduction zones formed along the continental margins. (5) From about the Jurassic to the present, oblique convergence and rotations caused orogen-parallel sinistral, and then dextral displacements within the plate margins of the Northeast Asian and North American Cratons. The oblique convergences and rotations resulted in the fragmentation, displacement, and duplication of formerly more continuous arcs, subduction zones, passive continental margins, and contained metallogenic belts. These fragments were subsequently accreted along the margins of the expanding continental margins. (6) From the Early Jurassic through Tertiary, movement of the upper continental plates toward subduction zones resulted in strong plate coupling and accretion of the former island arcs, subduction zones, and contained metallogenic belts to continental margins. In this region, the multiple arc accretions were accompanied and followed by crustal thickening, anatexis, metamorphism, formation of collision-related metallogenic belts, and uplift; this resulted in the substantial growth of the North Asian and North American continents. (7) In the middle and late Cenozoic, oblique to orthogonal convergence of the Pacific Plate with present-day Alaska and Northeast Asia resulted in formation of the present ring of volcanoes and contained metallogenic belts around the Circum-North Pacific. Oblique convergence between the Pacific Plate and Alaska also resulted in major dextral-slip faulting in interior and southern Alaska and along the western part of the Aleutian- Wrangell arc. Associated with dextral-slip faulting was crustal extrusion of terranes from western Alaska into the Bering Sea.
The Proterozoic and Phanerozoic metallogenic and tectonic evolution of the Russian Far East, Alaska, and the Canadian Cordillera is recorded in the cratons, craton margins, and orogenic collages of the Circum-North Pacific mountain belts that separate the North Pacific from the eastern North Asian and western North American Cratons. The collages consist of tectonostratigraphic terfanes and contained metallogenic belts, which are composed of fragments of igneous arcs, accretionary-wedge and subduction-zone complexes, passive continental margins, and cratons. The terranes are overlapped by continental-margin-arc and sedimentary-basin assemblages and contained metallogenic belts. The metallogenic and geologic history of terranes, overlap assemblages, cratons, and craton margins has been complicated by postaccretion dismemberment and translation during strike-slip faulting that occurred subparallel to continental margins. Seven processes overlapping in time were responsible for most of metallogenic and geologic complexities of the region (1) In the Early and Middle Proterozoic, marine sedimentary basins developed on major cratons and were the loci for iron-stone (Superior Fe) deposits and sediment-hosted Cu deposits that occur along both the North Asia Craton and North American Craton Margin. (2) In the Late Proterozoic, Late Devonian, and Early Carboniferous, major periods of rifting occurred along the ancestral margins of present-day Northeast Asia and northwestern North America. The rifting resulted in fragmentation of each continent, and formation of cratonal and passive continental-margin terranes that eventually migrated and accreted to other sites along the evolving margins of the original or adjacent continents. The rifting also resulted in formation of various massive-sulfide metallogenic belts. (3) From about the late Paleozoic through the mid-Cretaceous, a succession of island arcs and contained igneous-arc-related metallogenic belts and tectonically paired subduction zones formed near continental margins. (4) From about mainly the mid-Cretaceous through the present, a succession of continental-margin igneous arcs (some extending offshore into island arcs) and contained metallogenic belts, and tectonically paired subduction zones formed along the continental margins. (5) From about the Jurassic to the present, oblique convergence and rotations caused orogen-parallel sinistral, and then dextral displacements within the plate margins of the Northeast Asian and North American Cratons. The oblique convergences and rotations resulted in the fragmentation, displacement, and duplication of formerly more continuous arcs, subduction zones, passive continental margins, and contained metallogenic belts. These fragments were subsequently accreted along the margins of the expanding continental margins. (6) From the Early Jurassic through Tertiary, movement of the upper continental plates toward subduction zones resulted in strong plate coupling and accretion of the former island arcs, subduction zones, and contained metallogenic belts to continental margins.
Eliminating common-mode clutter in data is one of the key aspects of road sensing with GPR. Common-mode interference can occur as a result of multipath propagation of an electromagnetic signal when the reflected signal from the same object arrives at the receiver from different directions and with different delays. Similar phenomena also occur when using antennas raised above the surface due to multiple reflections between the air–surface interface and the antenna. These interferences can significantly distort the data received by the GPR and interfere with the accurate determination of the parameters of the roadway. Therefore, the elimination of common-mode clutter is an important task to improve the quality of the obtained results. In this paper, we consider a method for filtering common-mode clutter in the radar data of the multichannel GPR “Terrazond”, which were obtained by sounding a test section of a highway. The results obtained during filtering can then be used to determine the thickness of the pavement layers using approaches that take into account the signal delay determined by the amplitude jump, for example, the common point method or if the permittivity of each layer is known. The obtained thicknesses of pavement layers are compared with the results obtained during core drilling by the Russian Road Research Institute.
The Natalka lode gold deposit, also known as the Matrosov mine, is located in the Magadan region of northeastern Russia at 61° 39′ N, 147° 50′ E. The deposit was discovered in 1943 and production started in 1945. The mine has produced more than 75 metric tons of gold, with an average grade 4 g/metric ton (mt), and has reserves of about 450 mt. The Natalka deposit occurs along the southwestern flank of the Yana-Kolyma metallogenic belt and is confined to the major, NW-trending Tenka fault. The deposit is hosted by Upper Permian carbonaceous sediments, subjected to greenschist metamorphism. The ore zones occur along a Z-shaped, strike-slip fault zone that extends for about 12 to 13 km. In plan view, the ore zones are about 5 km long and 100 to 200 m wide in the northwest portion, 350 to 400 m wide in the central portion, and 600 m wide in the southeast portion of the deposit. The main ore minerals are arsenopyrite and pyrite, which comprise about 95% of the sulfides, along with subordinate pyrrhotite, Co-Ni sulfarsenides, sphalerite, chalcopyrite, galena, native gold, ilmenite, and rutile. Scheelite, tetrahedrite, bournonite, boulangerite, and stibnite occur locally. The major gangue mineral is quartz, with subordinate carbonates, feldspars, chlorite, sericite, kaolinite, montmorillonite, and barite. The total sulfide content of the ore zones ranges from 1 to 3%, and in places up to 5%. Native gold occurs as large individual grains ranging from 0.1 to 2.0 mm in diameter, or as fine disseminations in arsenopyrite. The average gold fineness is 750 to 790. Fluid inclusion studies reveal homogenization temperatures of 150° to 360° C, with mainly liquid and as much as 5% vapor. Two temperature peaks of 280° to 320° C and 180° to 240° C occur in many samples. The δ34S composition of sulfides in orebodies ranges from −6.3 to −2.4 per mil and approximates that of sedimentary rock-hosted pyrite. The δ34S values of the ore solutions are interpreted as having been close to that of the sulfide minerals. The δ18O composition of ore quartz ranges from 13.9 to 14.1 per mil. The calculated δ18O composition for the ore fluid ranges from 7.1 to 7.3 per mil at 300° C. The δ18O values of oxygen indicate a quite homogeneous fluid of metamorphic origin. The sulfur, arsenic, and gold in the ore deposit were mobilized during metamorphism that included transformation of pyrite to pyrrhotite. The PT conditions for this reaction are estimated at about 400°C and 2.5 kbar, approximately at the biotite isograd. Associated decarbonatization and dehydration reactions produced much of the ore fluid. The interaction of ore-fluid sulfur with Fe-bearing silicate and oxide minerals probably caused deposition of sulfide minerals and gold.
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