Academic literature on the topic 'Riedel shears'

Using the analytical approximation method, we calculated stress field parameters for cases with different relative positions of Riedel shears and loads required for shearing. Considering an internal friction angle of 30°, and the distance between adjacent shears exceeding 0.7 of the characteristic shear length, we estimated the Coulomb stress that can lead to fracturing. In the areas between the shears, it is below the shear strength value. This means that if an increase in the external load is lacking, there are no prerequisites for the formation of new fractures that may connect adjacent shears. If the shears are spaced closer to each other (i.e. at distances less than 0.7 of the shear length), the shear strength is exceeded in the areas between them, and new shears can occur there and connect the Riedel shears to each other. Therefore, in observations of a natural system of Riedel shears, it becomes possible to assess whether this system is sufficiently stable in its current status, or, in case of a critical increase in the Coulomb stress in the areas between adjacent shears, the equilibrium can be easily disturbed, and there is a possibility that the main fault forms in the strike-slip zone under study.

This work presents а structural interpretation of a well-known gold deposit from SW Bulgaria. The interpretation is based on the geological map and structural data, collected during the prospecting. The data indicates that а regional sinistral shearing was responsible for a low rank sinistral shear system, which created ore depositional space by the combined action of shear extension and compression. The two mechanisms opened tension gashes, dilated previously formed Riedel faults and buckled the veins and the faults. The buckling happened, when the structures were rotated anticlockwise in the compressional quadrant of the space between the regional shears thus creating buckling structures. Ore shoots have been formed in the extended domains of the main shear and along the dilated previously formed Riedel shears.

The fabric of the ice-thrust argillaceous bedrock from a shear zone was studied in hand specimens, under a polarizing microscope and a scanning electron microscope. The fabric included principal displacement shears, Riedel shears, conjugate sets of particle alignments, cutans, lithorelics, and aggregations which dense cores of randomly oriented groups of clay platelets wrapped by an external layer of oriented clay particles in a turbostatic arrangement. In addition, the bedrock has been disturbed by permafrost, cycles of loading and unloading, and weathering, causing the magnitude of deformation to vary within the ice-thrust shear zone.The fabric of the ice-thrust shear zone is similar to that of shear zones formed by tectonic activity and by laboratory shear tests, suggesting that all these shear zones were formed under conditions of similar kinematic restraint.

Abstract The Mustajärvi gold occurrence lies in the southern part of the Paleoproterozoic Central Lapland Greenstone Belt, in proximity to the first-order transcrustal Venejoki thrust fault system. The gold occurrence is structurally controlled by the second-order Mustajärvi shear zone, which is located at the contact between siliciclastic metasedimentary and mafic to ultramafic metavolcanic rocks. The main mineralization comprises a set of parallel veins and sulfidized rocks that are slightly oblique to the shear zone and are hosted by third-order structures likely representing Riedel R-type shears. The gold-mineralized rock at Mustajärvi is associated with pyrite that is present in 0.15- to 1-m-wide quartz-pyrite-tourmaline veins and in zones of massive pyrite in the host rocks with thicknesses ranging from 1.15 to 2 m. In unweathered rock, hypogene gold is hosted by Au- and Au-Bi-telluride micro-inclusions in pyrite, whereas strong weathering at near surface levels has caused a remobilization of gold, resulting in free gold deposited mainly in the cracks of oxidized pyrite. The geochemistry of both mineralization styles is typical of orogenic gold systems with strong enrichments comprising Au, B, Bi, CO2, Te, and Se; and less consistent anomalous amounts of Ag, As, Sb, and W. Unusual for orogenic gold deposits is the strong enrichment of Ni and Co, which leads to the classification of Mustajärvi as orogenic gold occurrence with atypical metal association.

ABSTRACT The 17 June 2018 MJMA 6.1 (Mw 5.5) Osaka earthquake exhibits a large non–double‐couple component (∼26%), and its aftershock sequence shows a complicated spatial pattern. To better understand the ruptured faults, we relocate the earthquake sequence using P and S arrival times and waveform cross correlations and calculate the focal mechanisms of all MJMA≥2.5 (Mw≥2.3) earthquakes within three months after the mainshock using P‐wave first‐motion polarities and S/P amplitude ratios. Relocated aftershocks image several faults, the northeast‐striking strike‐slip fault, the north‐northwest‐striking reverse fault, and at least two small northwest‐striking features. P‐wave first motions of the mainshock indicate nearly a pure thrust mechanism. We deduce that the earthquake sequence started from a north‐northwest‐striking reverse fault and propagated to a northeast‐striking strike‐slip fault. The aligned strike‐slip aftershocks occurring in the vicinity of the northeast‐striking strike‐slip fault delineates the growth of several newly formed or reactivated northwest‐striking Riedel shears that are conjugated to the northeast‐striking strike‐slip fault.

The Mw=7.4 Izmit (Kocaeli) earthquake of August 17, 1999 (Turkey) ruptured 100 km at least surface faults on land along the northwestern branch of the North Anatolian Fault Zone (NAFZ). Although the preexisting structures of NAFZ has been divided into segments, showing stepover and pull apart geometry, the earthquake ruptures are generally linear, E-W striking (N80°-100°), right-lateral. In small scale and on the recent sediments they show very typical strike-slip displacements (2 to 5m), pop-ups and pressure ridges (N 40- 70°), Ρ (N80°), R (N100-1100) and R' (~N350°) Riedel shears, extensional cracks (N115°-135°), restraining and releasing bends and small pull apart structures. In the epicentral area (Gölcük-Tepetarla) the seismic ruptures did not follow any known or previously mapped fault, but the morphology and the Digital Elevation Model (DEM) show typical and recognizable paleo-earthquake features. That is elongated valleys, shutter ridges, high angle slopes, scarplets, stream offset; while trenching tectonostratigraphy indicate palaeo sag-ponds (clayly deposits) and palaeo liquefaction (C14 dating-Holocene-historical deposits 200 to 11,000 yr. BP).

AbstractBrittle structures exposed in the ablation area of Pasterzenkees, Austria, were interpreted using aerial photographs and maps covering a period of 100 years. The most common structural features observed in aerial photographs are: (1) normal faults, which are particularly well developed along the lateral margins of the glacier and at the terminus; (2) large-scale tension gashes and Riedel shears that develop along the northeastern lateral margin of the glacier and between ice-flow units; (3) thrust faults, which develop at the terminus and cross-cut the full width of the glacier; and (4) band ogives. Longitudinal and transverse topographic profiles are available for the period covered in this study, and ice-flow velocity data are available from 1927. These data provide a means for interpreting the variations of observed structures in terms of ice-flow velocity. Thrust faults predominantly develop during periods of glacier retreat, when the glacier snout becomes an obstacle. Normal faults typically develop in areas of high glacier surface relief and are interpreted as gravity collapse structures. The orientation of sub-vertical, wide open crevasses along the lateral margin of Pasterzenkees varied. These variations are interpreted as reflecting changes of the flow regime and indicate a transition from simple shearing to transtension during a period of ice-flow deceleration.

Riedel shear zones are geometric fault patterns commonly associated with strike-slip fault systems. The progressive evolution of natural Riedel shear zones within the Navajo Sandstone of southern Utah is interpreted from the spatial evolution of small-scale, incipient Proto-Riedel Zones (PRZs) to better-developed Riedel shear zones using field mapping and three-dimensional digital modeling. PRZs nucleate as a tabular zone of localized shearing marked by en èchelon deformation bands, each of which is no more than a few mm wide and tens of cm long, and oriented at 55° - 85° to the trend of the zone. With increasing strain, deformation bands and sedimentary markers are sheared ductily through granular flow and assume a sigmoidal form. The temporal and spatial evolution of bands comprising a Riedel shear zone suggests that PRZs nucleate as transitional-compactional deformation bands under localized, supra-lithostatic fluid pressure. Subsequent bands develop under modified regional stresses as conjugate shear fractures within the strain- hardened axis of the PRZ. These antithetic driven systems are not compatible with traditional synthetic driven models of Riedel shear zones. Unlike most synthetic driven examples, these antithetic driven systems are not controlled by preexisting "basement" structures, thus their geometries reflect a primary propagation or secondary passive deformation mechanism.

Дисертація на здобуття наукового ступеня кандидата геологічних наук за спеціальністю 04.00.16 – «Геологія твердих горючих копалин». Державний ВНЗ «Національний гірничий університет». Міністерство освіти і науки, молоді та спорту України, Дніпропетровськ, 2011 р.
Диссертация на соискание ученой степени кандидата геологических наук по специальности 04.00.16 – «Геология твердых горючих ископаемых». Государственный ВУЗ «Национальный горный университет». Министерство образования и науки, молодежи и спорта Украины, Днепропетровск, 2011 г.
Thesis for Candidate Science Degree (Geology) by speciality 04.00.16 – «Geology of hard fossil fuels». National Mining University. Dniepropetrovsk, 2011.
Робота присвячена вирішенню актуальної науково-практичної проблеми впливу зсувної тектоніки на характер деформацій земної поверхні, які утворені внаслідок підземної розробки кам'яного вугілля. На підставі використання апарату комплексної систематизації, оброблення, аналізу і інтерпретації початкових даних режимних структурно-геологічних й топографо-геодезичних зйомок, методів цифрової геологічної картографії, гірничо-геометричного моделювання, статистичного оброблення та морфометричного й морфоструктурного аналізів стосовно ре- льєфу та осідань земної поверхні у роботі запропоновано нове рішення проблеми прогнозування небезпечних зон локалізації деформаційних аномалій. Встановлено, що деформаційні процеси геологічної природи на територіях видобутку виражені в сучасному рельєфі земної поверхні у вигляді просторово-успадкованих зон деформаційних аномалій генетично пов'язаних з тектонічними порушеннями, утвореними в умовах зсувного поля напружень. Нерівномірний розвиток сучасних деформаційних аномалій земної поверхні обумовлений мозаїчно-блоковою структурою вугленосних відкладів, а морфометричні аномалії сучасного рельєфу та сполучених вертикальних деформацій земної поверхні (осідань), які викликані підземною розробкою кам'яного вугілля, контролюються наявністю в масиві гірських порід синтетичних і антитетичних зколів Ріделя, що утворені в контурі розвитку виявлених регіональних зсувних зон. Вивчено та систематизовано особливості тектонічної порушеності Донецького та Львівсько-Волинського вугільних басейнів. Малоамплітудні розриви, що традиційно інтерпретуються як скиди та насуви, в більшості випадків мають зсувну складову. В Донбасі, у зв'язку з розвитком зсувних зон зафіксовані ліві і праві обертальні рухи тектонічних блоків, в ЛВБ – тільки праві. Результати досліджень використані при оцінюванні гірничо-геологічних умов та прогнозуванні небезпечних зон локалізації деформаційних процесів в межах м. Донецька.
Диссертация посвящена проблемам влияния сдвиговой тектоники на деформации земной поверхности, которые образованны в результате подземной разработки каменного угля. В работе предложено новое решение актуальной научной задачи влияния структурно-кинематических особенностей сдвиговых дислокаций в пределах структурно-тектонических зон Донбасса и ЛВБ на деформации земной поверхности. Использование полученных научных результатов и выводов при оценке горно-геологических условий ведения эксплуатационных работ и прогнозировании зон, связанных с деформациями земной поверхности при добыче угля, имеет важное значение для угольной геологии и для решения прикладных задач. Разработан и применен аппарат комплексной систематизации, обработки, анализа и интерпретации начальных данных режимных структурно-геологических и топографо-геодезических съемок. Изучены особенности тектонической нарушенности Донецкого и Львовско-Волынского угольных бассейнов. Установлено, что малоамплитудные разрывы, традиционно интерпретируемые как сбросы и надвиги, в большинстве случаев имеют сдвиговую составляющую. В Донбассе, в связи с развитием сдвиговых зон, зафиксированы левые и правые вращательные движения тектонических блоков, в ЛВБ – только правые. В результате экспериментальных исследований установлено, что деформационные процессы геологической природы на подработанных территориях выражены в современном рельефе земной поверхности в виде пространственно-унаследованных зон деформационных аномалий, генетически связанных с текто-ническими нарушениями, образованными в условиях сдвигового поля напряжений. Неравномерное развитие современных деформационных аномалий земной поверхности подработанных территорий обусловлено мозаично-блоковой структурой угленосных отложений, а морфометрические аномалии современного рельефа и «рельефа оседаний» земной поверхности, образование которых вызвано подземной разработкой каменного угля, контролируются наличием в массиве горных пород сопряженных «тектонополос» – синтетических и антитетических сколов Риделя и наследуют простирание и угол сопряжения зон малоамплитудных тектонических разрывов, морфологически представленных сдвигами, образованными в контуре развития выявленных региональных сдвиговых зон. Результаты исследований использованы при оценке горно-геологических условий и прогнозировании опасных зон локализации деформационных аномалий в пределах подработанных территорий г. Донецка.
The thesis is devoted to solution of the problem related to the influence of strike-slip faults on the recent deformation processes of the ground surfaces due to mine subsidence. On the basis of detailed systematization and treatment of geological and geodetic leveling data, geometric modeling of structural and mining data, integrated morphostructural and morphometric analysis of subsidence surface topography there has been proposed a new solution of the problem of the delineating deformation anomalies of ground surfaces. The obtained results proved that zones of modern deformation anomalies in the mine subsidence relief due to underground coal mining are spatially correlated with faults within tectonic zones of strike-slip origin. Inhomogeneous development of recent deformation anomalies of the ground surface is caused by mosaic block structure of coal-bearing sediments which bear marks of synthetic and antithetic Riedel shears. Peculiarities for tectonic patterns of the Donets and Lviv-Volyn coal basins have been investigated. Small displacement faults have been traditionally interpreted in the Donbas as normal or reversed faults. However, most of them have strike-slip component of movement. Clockwise and counter-clockwise rotation of block within strike-slip zones is recorded in the Donbas and clockwise rotation – in the Lviv-Volyn basin. Results of the research are implemented in the forecast of ground surface deformation hazards within the limits of closed coal mines in Donetsk.

This study focuses on the detailed investigation of the brittle/plastic transition in quartz-feldspathic rocks at upper-middle crustal conditions and aims to better understand the role of fluids and temperature during deformation. The Calamita Unit (Elba Island, Italy) is a high metamorphic grade unit (T ~ 650 °C) that has been intruded by a monzogranite body at shallow crustal level (P < 0.2 GPa) and coevally deformed during regional shortening for a limited time span (< 1 Ma). These conditions outline the Calamita Unit as an ideal case study to investigate the brittle/plastic transition at approximately constant pressure (i.e. depth) during temperature decrease, reproducing upper-middle crustal conditions. The Calamita Schists are a metapsammitic complex exposed in the lower part of the Calamita Unit. Pseudosection modelling and Ti-in-biotite thermometry constrain the peak metamorphic assemblage, marked by andalusite + cordierite + biotite + K-feldspar, at upper amphibolite facies conditions (T ~ 600 – 700 °C; P ~ 0.2 GPa), with microstructures suggesting partial melting. The retrograde path is constrained by chlorite geothermometry in the 300 – 500 °C temperature range. Detailed field mapping and structural analysis have revealed at map-scale a pattern of heterogeneous deformation characterized by west-dipping high-strain domains localizing eastward-directed deformation interleaved with relatively low-strain domains. In high-strain domains, mylonitic fabrics are, in turn, overprinted in the brittle regime by non-Andersonian subhorizontal faults associated with Riedel shears networks, formed subparallel to C’ shear bands. Microstructural analysis highlights that temperature decrease and fluid influx controlled the mechanical evolution of the investigated rocks, which are marked by the transition from a high-metamorphic grade foliation to shear bands and mylonites with widespread S-C and S-C’ fabrics, characterized by retrograde, synkinematic white mica and chlorite. Quartz microfabric displays an evolution from fast grain boundary migration, developed close to peak metamorphic conditions, to subgrain rotation and bulging recrystallization, tracking decreasing temperature during deformation. During decreasing temperature, deformation localized in mylonitic quartz ribbons at amphibolite facies conditions (450 °C < T < 600 °C), where recrystallization was accommodated by dislocation creep of quartz under dominant prism slip, causing the development of strong Y-maximum crystallographic preferred orientations (CPO). Secondary rhomb and acute rhomb slip assisted the recrystallization of grains unfavorably oriented for prism slip, with the activation of slip systems whose misorientation axis lies close to the vorticity axis. At greenschist facies conditions (300 °C < T < 450 °C), deformation localized in phyllonitic domains, producing phase mixing of phyllosilicates and tiny quartz grains. Relic, large quartz grains hardened and fractured along synthetic and conjugate shear bands. The propagation of shear bands occurred under fluid-rich conditions and was controlled by cyclic fracturing and precipitation of new quartz and phyllosilicate grains, deposited by circulating fluids. Precipitated new quartz grains developed a CPO parallel to shear bands controlled by the opening of dilatant sites. The nucleation of fine-grained quartz and ‘soft’ phyllosilicates enhanced strain softening and assisted strain partitioning into localized C’ shear bands at the brittle/plastic transition. In the brittle regime (T ~ 300 °C), deformation localized on previously formed C’ shear bands, favorably oriented for reactivation, that acted as ductile precursors for misoriented non-Andersonian faults. Brittle deformation in fault zones was controlled by the cyclical interaction between fracturing, taking advantage of weak crystallographic planes in quartz such as the rhombs, and fluid infiltration, assisting the precipitation of new quartz and phyllosilicate grains, lacking a clear preferred orientation. The data presented in this thesis highlight the role played by fluids during deformation of quartz-feldspathic rocks at the brittle/plastic transition, that efficiently control (1) strain softening of ‘stiff’ domains and (2) strain localization into shear bands that have the potential to act as precursors for non-Andersonian fault zones. The proposed model predicts the development of brittle structures discordantly overprinting ductile fabrics developed in the same kinematic regime, which bears implications for the tectonic evolution of rock volumes (i.e. tectonic units and/or metamorphic complexes) exhumed though the brittle/plastic transition.

Abstract The Kalgoorlie gold camp in the Yilgarn craton of Western Australia comprises the supergiant Golden Mile and the smaller Mt. Charlotte, Mt. Percy, and Hidden Secret deposits. Since the camp’s discovery in 1893, ~1,950 metric tons (t) of Au have been produced from a total estimated endowment of ~2,300 t. The camp is located within Neoarchean rocks of the Kalgoorlie terrane, within the Eastern Goldfields superterrane of the eastern Yilgarn craton. Gold mineralization is distributed along an 8- × 2-km, NNW-trending corridor, which corresponds to the Boulder Lefroy-Golden Mile fault system. The host stratigraphic sequence, dated at ca. 2710 to 2660 Ma, comprises lower ultramafic and mafic lava flow rocks, and upper felsic to intermediate volcaniclastic, epiclastic, and lava flow rocks intruded by highly differentiated dolerite sills such as the ca. 2685 Ma Golden Mile Dolerite. Multiple sets of NNW-trending, steeply dipping porphyry dikes intruded this sequence from ca. 2675 to 2640 Ma. From ca. 2685 to 2640 Ma, rocks of the Kalgoorlie gold camp were subjected to multiple deformation increments and metamorphism. Early D1 deformation from ca. 2685 to 2675 Ma generated the Golden Mile fault and F1 folds. Prolonged sinistral transpression from ca. 2675 to 2655 Ma produced overprinting, NNW-trending sets of D2-D3 folds and faults. The last deformation stage (D4; &lt; ca. 2650 Ma) is recorded by N- to NNE-trending, dextral faults which offset earlier structures. The main mineralization type in the Golden Mile comprises Fimiston lodes: steeply dipping, WNW- to NNW-striking, gold- and telluride-bearing carbonate-quartz veins with banded, colloform, and crustiform textures surrounded by sericite-carbonate-quartz-pyrite-telluride alteration zones. These lodes were emplaced during the earlier stages of regional sinistral transpression (D2) as Riedel shear-type structures. During a later stage of regional sinistral transpression (D3), exceptionally high grade Oroya-type mineralization developed as shallowly plunging ore shoots with “Green Leader” quartz-sericite-carbonate-pyrite-telluride alteration typified by vanadium-bearing muscovite. In the Hidden Secret orebody, ~3 km north-northwest of the Golden Mile, lode mineralization is a silver-rich variety characterized by increased abundance of hessite and petzite and decreased abundance of calaverite. At the adjacent Mt. Charlotte deposit, the gold-, silver-, and telluride-bearing lodes become subordinate to the Mt. Charlotte-type stockwork veins. The stockwork veins occur as planar, 2- to 50-cm thick, auriferous quartz-carbonate-sulfide veins that define steeply NW- to SE-dipping and shallowly N-dipping sets broadly coeval with D4 deformation. Despite extensive research, there is no consensus on critical features of ore formation in the camp. Models suggest either (1) distinct periods of mineralization over a protracted, ca. 2.68 to 2.64 Ga orogenic history; or (2) broadly synchronous formation of the different types of mineralization at ca. 2.64 Ga. The nature of fluids, metal sources, and mineralizing processes remain debated, with both metamorphic and magmatic models proposed. There is strong evidence for multiple gold mineralization events over the course of the ca. 2.68 to 2.64 orogenic window, differing in genesis and contributions from either magmatic or metamorphic ore-forming processes. However, reconciling these models with field relationships and available geochemical and geochronological constraints remains difficult and is the subject of ongoing research.

The natural fractured basement reservoirs become an obsessive target in Jabung Block. Currently, there are two wells drilled in the block that targeting fractured basement reservoir. They are the NEB Base-1 well that located in western part of the NEB Field and the NEB Base-2 well which located 7 kilometers away to the East of NEB Base-1 well. The first well was technically success, however NEB Base-2 well shows no indication of hydrocarbon influx during the test. Interestingly, the fractures development in both wells shows almost the same condition of fractures orientation, dip-magnitude and fractures intensity. Furthermore, each fracture in both wells can be correlated into several zones, as they indicate similar fracture set orientation at each zone. These findings create a big question, why the similar fractures characters show a very different test result? This study is intended to have that question answered with the idea to focus on the following two workflows: the first is to re-evaluate the previous works starting from re-picking the seismic fault in detail. The second is to analyze the relationship between geomechanical forward modelling result with the structural evolution in Jabung Block through sandbox modelling. The geomechanical forward modelling in the NEB Field imply the critical stress stated that was predominantly located in the western part or within the NEB Base-1 area., This result is strongly correlate with the new basement fault map which shows an intensive faulting in the western area, and is characterized by couples of synthetic-antithetic Riedel shear as a result of the strike-slip faulting. In addition, the sandbox modelling shows a major oblique-slip fault movement was observed within the western area. Therefore, it can be concluded that the intensive strike slip fault plays an important role to enhance the connectivity between fault and fracture to the hydrocarbon storage as shown in the result of NEB Base-1 well. This idea could be used as a guidance to explore another fractured basement prospect within the block.

For the design of mixing and agitation facilities in process engineering it is of central importance to appraise the correct viscosity of fluids. This can be a challenging task when non-Newtonian and/or non-homogeneous fluids need to be processed. Since it is not always possible to analyze them in the classical ways, an propeller viscosimeter approach on the basis of the Rieger-Novak-Method is used. In recent years the Lattice Boltzmann Methods (LBM) are established as an alternative approach to classical computational fluid mechanics methods. The utilization of Cartesian grids avoids the need to discretize with boundary conform meshes. This makes the LBM suitable for complex geometries like a propeller in this case. Numerical simulations were carried out using a 3D in-house Lattice Boltzmann code called SAM-Lattice with our latest extension to non-Newtonian flow. We use a truncated form of the power-law approximation to accommodate the varying flow properties in non-Newtonian simulations, where the effective viscosity is a function of the shear rate. SAM-Lattice comprises the LBM solver and a highly automated grid generator for arbitrarily complex geometries. The code is capable of multi-domain grid refinement as well as multi reference frames and rotational boundaries. The post processing is done using an extension of the open source visualization tool Paraview. We compare results of experiments and LBM simulations for the Newtonian case (Glucose) to validate our Lattice Boltzmann solver. A study of the non-Newtonian, shear thinning case (Xanthan) is conducted to validate the generalized Newtonian model. The propeller viscosimeter is currently under development as a standalone solution for viscosity measurement. For calibration purposes the Metzner-Otto-constant of the propeller device has to be determined. While the constant is valid for the laminar region the numerical results for the agitator characteristics are presented. Different levels of grid refinement are tested to assure independence of the lattice resolutions.

Aeromagnetic and ground gravity data for the Canadian Superior Province, filtered to extract long wavelength components and converted to pseudo-gravity, highlight deep, N-S trending regional-scale, rectilinear faults and margins to discrete, competent mafic or felsic granulite blocks (i.e. at high angles to most regional mapped structures and sub-province boundaries) with little to no surface expression that are spatially associated with lode ('orogenic') Au and Ni-Cu-PGE-Cr occurrences. Statistical and machine learning analysis of the Red Lake-Stormy Lake region in the W Superior Province confirms visual inspection for a greater correlation between Au deposits and these deep N-S structures than with mapped surface to upper crustal, generally E-W trending, faults and shear zones. Porphyry Au, Ni, Mo and U-Th showings are also located above these deep transverse faults. Several well defined concentric circular to elliptical structures identified in the Oxford Stull and Island Lake domains along the S boundary of the N Superior proto-craton, intersected by N- to NNW striking extensional fractures and/or faults that transect the W Superior Province, again with little to no direct surface or upper crustal expression, are spatially associated with magmatic Ni-Cu-PGE-Cr and related mineralization and Au occurrences. The McFaulds Lake greenstone belt, aka. 'Ring of Fire', constitutes only a small, crescent-shaped belt within one of these concentric features above which 2736-2733 Ma mafic-ultramafic intrusions bodies were intruded. The Big Trout Lake igneous complex that hosts Cr-Pt-Pd-Rh mineralization west of the Ring of Fire lies within a smaller concentrically ringed feature at depth and, near the Ontario-Manitoba border, the Lingman Lake Au deposit, numerous Au occurrences and minor Ni showings, are similarly located on concentric structures. Preliminary magnetotelluric (MT) interpretations suggest that these concentric structures appear to also have an expression in the subcontinental lithospheric mantle (SCLM) and that lithospheric mantle resistivity features trend N-S as well as E-W. With diameters between ca. 90 km to 185 km, elliptical structures are similar in size and internal geometry to coronae on Venus which geomorphological, radar, and gravity interpretations suggest formed above mantle upwellings. Emplacement of mafic-ultramafic bodies hosting Ni-Cr-PGE mineralization along these ringlike structures at their intersection with coeval deep transverse, ca. N-S faults (viz. phi structures), along with their location along the margin to the N Superior proto-craton, are consistent with secondary mantle upwellings portrayed in numerical models of a mantle plume beneath a craton with a deep lithospheric keel within a regional N-S compressional regime. Early, regional ca. N-S faults in the W Superior were reactivated as dilatational antithetic (secondary Riedel/R') sinistral shears during dextral transpression and as extensional fractures and/or normal faults during N-S shortening. The Kapuskasing structural zone or uplift likely represents Proterozoic reactivation of a similar deep transverse structure. Preservation of discrete faults in the deep crust beneath zones of distributed Neoarchean dextral transcurrent to transpressional shear zones in the present-day upper crust suggests a 'millefeuille' lithospheric strength profile, with competent SCLM, mid- to deep, and upper crustal layers. Mechanically strong deep crustal felsic and mafic granulite layers are attributed to dehydration and melt extraction. Intra-crustal decoupling along a ductile décollement in the W Superior led to the preservation of early-formed deep structures that acted as conduits for magma transport into the overlying crust and focussed hydrothermal fluid flow during regional deformation. Increase in the thickness of semi-brittle layers in the lower crust during regional metamorphism would result in an increase in fracturing and faulting in the lower crust, facilitating hydrothermal and carbonic fluid flow in pathways linking SCLM to the upper crust, a factor explaining the late timing for most orogenic Au. Results provide an important new dataset for regional prospectively mapping, especially with machine learning, and exploration targeting for Au and Ni-Cr-Cu-PGE mineralization. Results also furnish evidence for parautochthonous development of the S Superior Province during plume-related rifting and cannot be explained by conventional subduction and arc-accretion models.