This thesis examines the Late Quaternary palaeoenvironmental history of the palaeovalley system located on the sea bed of the eastern English Channel. The work is based on an analysis of 500 km of high resolution seismic data, 189 boreholes, and an extensive grain size, microfossil and geochemical dataset. Within the study area arc two major palaeovalleys incised into Tertiary bedrock. They are on average 2 to 8 km wide and contain between 20 and 30 m of Late Quaternary sediments. Four Seismic Sequences are identified, separated by two sequence boundaries and one ravinement surface. Using an uplift-corrected eustatic sea level as a relative sea-level history for the study area, it is suggested that the palaeovalleys were cut at the transition from MOIS6 to 5e, and were infilled with transgressional shoreface sediments during the interval between MOIS5e and MOIS4. An upper seismic unit, also comprising marine sediment, developed following the Last Glacial Maximum as an extensive lag deposit. Comparison of this work with other records from the English Channel and other continental shelves demonstrate the pervasive importance of eustalic and tectonic controls in dctennining palaeovalley development. The major palaeovalleys of the English Channel probably originate from MOIS 12, created by the drainage of a large proglacial lake in the North Sea via the Strait of Dover. The palaeovalleys in the PhD study area post-date this initial phase of valley development, and were formed by a major гivег flowing through the region (presumably one or more the Thames, Rhine or Meuse). The results of this PhD demonstrate the high potential of continental shelf records as archives of Late Quaternary land-ocean interaction, as well as the benefits of close liaison between industry and academic stakeholders involved in offshore aggregate and palaeoemironmental exploration.

Fault zones, hosted in fractured carbonate reservoirs, can behave as either high porosity and permeability conduits, favoring the migration of fluids; or, conversely, as low porosity and permeability barriers, retarding fluid flow, due to the presence of fine-grained fault gouges (Agosta and Aydin, 2006, Agosta and Kirschner, 2003). Due to these reasons, fault zones can have great economical importance for the hydrocarbon industry. Furthermore, within fault zones, the cyclic accumulation and sudden release of trapped, high pressure fluids can trigger earthquakes and aftershocks (Miller et al. 2004). In this project, we referred to the classical fault zone architecture models defined by Sibson (1977) and Chester et al. (1993), in which faults are built up of a fault core (where most of the displacement is localised), a damage zone (containing fractured host rocks) and the protolith (the unfractured host rock). Faults, with displacements ranging from cm- to km-scale have been studied within two study areas, Flamborough Head, UK and the Gubbio fault in the Northern Apennines, Italy. Flamborough Head is a peninsula in East Yorkshire, which represents analogues for hydrocarbon rich, fractured North Sea chalk reservoirs; whereas the Gubbio fault is a regional scale, seismically active normal fault, characterized by complex fault zone architectures, cutting through different types of carbonates. At both study areas, field-based, outcrop-scale structural observations were completed in order to explore the internal architecture and infer the fluid transmissibility of the fault zones. Additionally, microscale structural observations were made using representative thin sections, collected from the different fault zone domains of the studied fault zones. Qualitative structural observations were complemented with quantitative analyses to study the variation of fracture and vein density and connectivity patterns across the fault zones, which were later used as a proxy for fluid transmissibility. These analyses included established 1D (transects) and 2D (image analysis) methods and a newly developed workflow for the modelling of fracture networks in 3D, based on LiDAR data. 3D modelling of fracture networks was developed using different fracture height/length aspect ratios. The quantitative comparison of different aspect ratio 3D models with established 1D and 2D results, by using misfit graphs, enabled to validate the different 3D models and to estimate the mean aspect ratio of fractures within the fault zones. Qualitative and quantitative results were integrated in conceptual fault zone architecture and fluid flow models. At Flamborough Head small (cm-scale) and larger (up to 20 m) displacement normal faults were studied in two different types of chalks: one characterized by cm-scale interlayered marl horizons and another one, absent of it. Within the marl-free host rock, in the fault zones of both the small and the large displacement faults, fluid assisted deformation features, such as veins, are often observed. On the contrary, in marl-rich units, fluid assisted deformation features are absent, while fractures filled with intruded marl from the interlayered horizons are common. This suggests that the occurrence of fluid flow in this lithology is primarily controlled by the protolith. 1D quantitative analysis at Flamborough Head showed that, as also predicted by classical fault zone models, vein density progressively increases in the damage zones of faults moving from the protolith towards the fault core. 2D quantitative analysis showed that fracture connectivity remains as low as background values in the outer parts of the damage zones, whereas it increases rapidly in the inner parts. By comparing the fracture density and connectivity patterns measured from different aspect ratio 3D models with results measured from 1D and 2D analyses showed that the most realistic model is the 1/5 fracture aspect ratio one. The Gubbio fault cuts through a carbonatic multilayer containing carbonates with different marl content. In the Marne a Fucoidi formation marl is homogenously distributed, while in the overlying Scaglia Group marl is absent. Within the damage zone, hosted in the Marne a Fucoidi formation, fluid assisted deformation features are rare and are only present in the damage zones of subsidiary faults that entirely cut through the formation, linking the under and overlying marl free carbonates. On the contrary, within the damage zone, hosted in the Scaglia Group, fluid assisted deformation features are common, especially close to the fault core of the Gubbio fault and in the damage zone of subsidiary faults. Similarly to Flamborough Head, this suggests that the occurrence of fluid flow is primarily controlled by the nature of the protolith. As predicted by classical fault zone models, 1D quantitative analysis across the Gubbio fault showed that vein density increases in the damage zone moving from the protolith towards the fault core. Similarly to results from Flamborough Head, 2D quantitative analysis showed that fracture connectivity is low in the outer parts of the damage zones, but increases rapidly within the inner parts, and the comparison of 3D models with 1D and 2D results showed that the most realistic model is the 1/5 aspect ratio one. The conceptual fluid flow models, built for the study areas, highlights: a) the importance of different marl content host rocks controlling the initiation of fluid flow; b) the development of smaller and larger displacement normal faults and the effects of their displacements on fluid transmissibility; c) the effects of fault damage zones, positioned in an overlapping geometry, resulting in the development high and low fracture connectivity subdomains and fracture corridors; d) the differences in the relative variation of fracture/vein density and connectivity throughout the damage zone compared to background values; e) the fluid transmissibility of the different fault rocks, located within different subdomains of the fault core and f) the anisotropy of fluid transmissibility in the fault core.

A new surface attribute was developed during the course of the thesis, which enables fault-related deformation – specifically, the apparent dip of mapped horizons measured in a direction perpendicular to the average strike of a fault array (here termed “fault-normal rotation”, or “FNR”) – to be quantitatively analysed around imaged faults. The new utility can be applied to any 3D surface and was used to analyse centimetre-scale to kilometre-scale fault-arrays, interpreted from laser scan point clouds, digital elevation models, and 3D seismic datasets. In all studied examples, faults are surrounded by volumes of fault-related deformation that have variable widths, and which can consist of faults, fractures and continuous bed rotations (i.e. monoclines). The vertical component of displacement calculated from the areas of fault-related deformation on each horizon act to “fill-in” apparently missing displacements observed in fault throw profiles at fault overlaps. This result shows that complex 3D patterns of fault-related strain commonly develop during the geometrically coherent growth of a single fault-array. However, if the component of continuous deformation was not added to the throw profile, the fault-array could have been misinterpreted as a series of isolated fault segments with coincidental overlaps. The FNR attribute allows the detailed, quantitative analysis of fault linkage geometries. It is shown that overlapping fault tip lines in relay zones can link simultaneously at multiple points, which results in a segmented branch line. Fault linkage in relay zones is shown to control the amount of rotation accommodated by relay ramps on individual horizons, with open relay ramps having accommodated by larger rotations than breached relay ramps in the same relay zone. Displacements are therefore communicated between horizons in order to maintain strain compatibility within the relay zone. This result is used to predict fault linkage in the subsurface, along slip-aligned branch lines, from the along-strike displacement distributions at the earth’s surface. Relay zone aspect ratios (AR; overlap/separation) are documented to follow power-law scaling relationships over nine orders of magnitude with a mean AR of 4.2. Approximately one order of magnitude scatter in both separation and overlap exists at all scales. Up to half of this scatter can be attributed to the spread of measurements recorded from individual relay zones, which relates to the evolution of relay zone geometries as the displacements on the bounding faults increase. Mean relay AR is primarily controlled by the interactions between the stress field, of a nearby fault, and overlapping fault tips, rather than by the host rock lithology. At the Kilve and Lamberton study areas, mean ARs are 8.60 and 8.64 respectively, which are much higher than the global mean, 4.2. Scale-dependent factors, such as mechanical layering and heterogeneities at the fault tips are present at these locations, which modify how faults interact and produce relatively large overlap lengths for a given separation distance. Despite the modification to standard fault interaction models, these high AR relay zones are all geometrically coherent.

Ductile deformation of overpressured, fine-grained, argillaceous sediments (“mobile shale”) is commonly invoked to explain the deformation style at the base of thin-skinned, gravitational detachment systems. The usage of “mobile shale” arose as a consequence of poor imaging on seismic reflection data, where low-resolution seismic intervals appeared ductile on a seismic scale (a thickening and thinning of the seismic interval). Acquisition of high-quality seismic reflection data from the Niger Delta provides an opportunity to investigate the internal structures within a basal detachment succession that is commonly referred to as the “mobile shale.” Deformation within the basal detachment succession in down-dip compressional settings is characterised by brittle deformation. Thickening of the basal detachment succession occurs through contractional duplexes and stacked imbricates that have formed within the cores of detachment folds. In up-dip extensional settings, the formation of stacked master detachment faults and detachments, which splay off the pre-existing master detachment fault, incorporates structures that formed in the hanging wall of older, structurally lower detachment faults into the basal detachment succession. Plastic deformation that involves a complete loss of shear strength within the deforming sediment probably does occur. Such processes are invoked to explain the lateral redistribution of strata leading to the formation of a “shale weld” in down-dip compressional settings. The recognition of fault-related folding within detachment fold cores and the deformation imaged beneath a major listric fault system highlights the fact that end-member structural models do not always adequately capture the structural complexity at the base of gravitational detachment systems. Despite the overpressured signature of basal detachment successions composed of argillaceous sediments, overpressure is not synonymous with a wide-spread ductile deformation style. Therefore, the term “mobile shale” – although widely used – inaccurately represents the styles and types of the deformational processes that occur within basal detachment successions composed of overpressured, argillaceous sediments.

1-, 2- and 3-dimensional fracture network characteristics of the mainland Lewisian Gneiss Complex (LGC) have been used assess if the LGC is a suitable onshore analogue for the fracture networks within the offshore Clair basement. Faults that cut the Clair basement rocks are becoming increasingly recognised as important structural conduits that connect (oil & gas bearing) sedimentary packages across the main basement structure. The basement of the Clair field is poorly understood, with limited seismic and well datasets; so using an onshore fracture analogue, of the mainland LGC, will hopefully improve the understanding of the Clair basement fracture systems. To determine the suitability of the mainland LGC as an analogue for the Clair basement four main research questions are asked in this thesis: What is the offshore Clair basement? What are the geological characteristics and attributes of the fracture networks in the mainland LGC? What are the dominant controls on these fracture network characteristics? How can the mainland Lewisian be used as an analogue for the Clair basement? Onshore datasets (outcrop, terrestrial laser scans & NEXTMap® DEM) exhibit prominent NE-SW and/or NW-SE fault and fracture trends. The Clair basement seismic dataset exhibits comparable NE-SW & NW-SE trending faults, but the basement core samples exhibit a strongly aligned NNE-SSW fracture trend that is not so clearly represented in the onshore datasets. Fracture spacing distributions from the mainland LGC have strong power-law relationships over at least three orders of magnitude. Power-law relationships are also present from Clair basement datasets but the lack of large datasets means that these relationships are considered fairly weak. Qualitative and Quantitative onshore and offshore analyses suggest that the mainland LGC is a suitable analogue for the Clair basement to some degree, but that their relationship is not a simple one. The results presented in this thesis do not provide a unique solution for the Clair basement fracture networks. Instead the onshore data provide model types that can be used in sensitivity models to ultimately assess which onshore dataset provides the best geological and statistical analogue for the Clair basement.

Fault domain boundaries are characteristic features of segmented rift systems and have been recreated in analogue models. Two end member conceptual models of fault domain boundaries currently exist. 1) Accommodation zones, which are broad regions of overlapping normal faults and which trend oblique to the rift axis. 2) Transfer zones, which are discrete sub-vertical fault systems that directly link en-echelon normal fault domains. These structures are commonly believed to segment natural rift systems on a variety of scales and impact directly upon the stratigraphic and magmatic evolution of a basin. The NE Atlantic Margin is a volcanic passive margin which has undergone a series of rift events culminating with continental breakup in the Early Cenozoic. From potential field, seismic reflection, seismic refraction and ocean bottom seismometer datasets, a series of rift-oblique lineaments (loosely referred to as ‘transfer zones’) have been identified which are commonly inferred to compartmentalise and laterally offset structural highs and depocentres developed within the Mesozoic – Cenozoic rift basins. A range of hypotheses are proposed to explain the origin of these lineaments, including fault domain boundaries, basin-wide strike-slip faults and other, non-tectonic origins. Using well-calibrated 2D and 3D seismic data, this study critically assesses the structural, stratigraphic and magmatic evidence for the rift-oblique lineaments in the Faroe-Shetland Basin and Vøring Basin, both located upon the NE Atlantic Margin. Results from the Faroe-Shetland Basin show structures previously attributed to basin-wide strike-slip deformation can be more simply explained as igneous intrusions, hydrothermal vent complexes, gas chimneys and/or faults that transfer extensional strain between en-echelon rift segments (i.e. fault domain boundaries). There is little evidence to suggest that activity along a series of discrete, basin-wide lineaments controlled Paleocene sedimentation in the basin. In the northern Vøring Basin, a previously identified fault domain boundary (the Rym Accommodation Zone) is analysed to understand if, and how strain is transferred between two adjacent fault domains. The results of this study highlight major differences between the offset rift segments in view of the style of rifting, timing, the loci of faulting, the relative uplift and subsidence histories as well as the impact of variations in the deep crustal structure. Analyses reveal that strain is not fully transferred across the fault domain boundary, with significant variation in beta factors calculated for each rift segment. The structural style within the Rym Accommodation Zone is complex, with the rotation of normal fault orientations, major relay ramp formation and rift perpendicular normal oblique faulting observed, elements that are not present in most existing conceptual models of accommodation zones. The results also imply that transfer zones may be an integral part of a larger accommodation zone rather than an opposite end member as previously believed. In the final aspect of the study, a second rift-oblique lineament is analysed in the northern Vøring Basin: the Gleipne Lineament. Results highlight the close structural relationship between the Gleipne Lineament and underlying basement structure, with the lineament acting as a conduit for sediment to enter the Vøring Basin during phases of rifting. Under periods of minimal upper crustal deformation, the lineament exerted a lesser control upon basinal sedimentation. The Rym Accommodation Zone in contrast did not source sediment into the Vøring Basin, instead, it compartmentalised the basin during rifting which increased the complexity of the predicted basin fill. Increased Late Paleocene intrusive and extrusive igneous deposits are observed along the strike of both lineaments but are not directly linked to active tectonic deformation. In conclusion, rift-oblique lineaments are unlikely to be basin-wide features and each appears to be unique in its structural style and geological origin. In turn, this means that different lineaments are likely to have different impacts upon the stratigraphical and magmatic development of a basin. Previous inferences that basin-wide lineaments have controlled sediment entry and transport within rift basins on the NE Atlantic Margin need to be substantiated on a case-by-case basis. The results of this study are further considered and discussed to predict the nature of rift-segmenting structures in the sub-basalt region of the Faroe-Shetland Basin, which is poorly resolved by current 2D and 3D seismic imaging.

The Nam Con Son Basin is one of several Tertiary rift basins located on the continental shelf, offshore Indochina. It has received relatively little attention until recently and remains a poorly understood sedimentary basin. The discovery and production of significant volumes of hydrocarbons from within fault-bounded structural highs has spurred a drive to better understand the basin structure. Previous interpretations of regional 2-dimensional seismic data suggested a complex structure, with E-W trending Eocene-Oligocene faults, overprinted by a rhomboidal pattern of mainly N-S and NE- SW trending Miocene faults and the possible involvement of compressional and/or strike-slip tectonics. The driving mechanism for extension on the continental shelf is not fully understood, but the Cenozoic structural evolution was undoubtedly influenced by a heterogeneous crust cut by a number of pre-existing Palaeozoic and Mesozoic structures. Crucially, the western extent of South China Sea rifting in the region may have been controlled by the -N-S trending edge of the Indochina craton, a major rheological boundary that likely underlies the Nam Con Son Basin. In addition to its economic importance, the proximity of the basin to the tip of the South China Sea, the possible involvement of wrench tectonics and the potential influence of pre-existing fabrics, makes it an ideal target for academic study. A 3-dimensional seismic dataset from the centre of the Basin has been used to build a fault/horizon model of the Early-Middle Miocene syn-rift sequence. The faults have a wide range of orientations and, in all cases, the hanging wall is down-thrown consistent with apparent normal offsets; there is no evidence for strike-slip or reverse faulting. By accurately modelling the fault surfaces and the fault/horizon intersections, the dip, strike, dip-azimuth and offset of 225 faults have been calculated and used to quantitatively analyse the fault sample. The timing of fault activity has been constrained for each fault and shows that all the faults are broadly contemporary but that the number of active faults increased through time. This is partly attributed to continuing subsidence on graben bounding faults" which focussed faulting and extension within the graben. There is no correlation between fault strike and fault age and the faults show no significant rotation about vertical axes with progressive deformation. The range of fault orientations likely reflects the conflicting influences of the -NW-SE regional extension direction and the dominant -N-S trending basement fabric. A systematic variation in maximum dip-slip fault offset (defined as the distance between the footwall and hangingwall cutoffs measured parallel to the fault surface) with fault strike has revealed an 'ideal' fault orientation, which can be used to infer the direction of maximum horizontal extension. The relationship between this extension direction, the dominant pre-existing basement fabric and the regional displacement direction is consistent with a model of moderately extension-dominated dextral transtension for the Nam Con Son Basin synchronous with the opening of the South China Sea. At a local scale, the influence of the underlying Eocene-Oligocene structures has produced offset depocentres, along strike fault polarity flips, and complex accommodation zones.

The results of a detailed investigation into the relationships between folds, faults and joints in the Orielton anticline are presented. The study continues the early structural work of Dixon (1921) and the stress analysis of the area made by Anderson (1951). The Orielton anticline is a compound and faulted Armorican fold largely affecting Upper Palaeozoic rooks. The structural pattern of the anticline developed during two major deformation phases: the first essentially corresponding to a period of folding and thrusting, the second to a period of wrench faulting. Within each phase, which is divisible, faulting occurred before jointing with joint sets not necessarily lying parallel to equivalent faults. The attitudes of both faults and joints depend on fold geometries. Faults are oriented relative to fold axial planes and axes, whilst joint attitudes are largely controlled by bedding dip and the plunge of the bedding - fracture cleavage intersection. It is tentatively suggested that the dependence of fracture attitudes upon fold geometries is due to the operation of residual stress systems. The dihedral angle between complementary shear planes has been investigated and shown to be consistently low, usually less than 50º. Regional tension joints appear to be absent. Joint orientations in collapsed blocks of Carboniferous Limestone enclosed in Triassio breccias show that all phases of the deformation belong to the Armorican orogeny.

The NE Atlantic margin plays host to numerous basins, developed in phases from the Devono-Carboniferous through to the Cenozoic, which record the build up to plate separation and formation of the North Atlantic Ocean. Existing models for this invoke broadly NW-SE extension within the basins, which are segmented by regional-scale NW-SE trending strike-slip lineaments, which are commonly termed ‘transfer zones’. However, there is a general paucity of information concerning the true kinematics of the so-called transfer zones. In this study, the Palaeogene and later structural evolution of the NE Atlantic margin is investigated using abundant field data collected on the Faroe Islands, and systematic observations that characterise the related deformation structures developed in the Faroe Islands Basalt Group (FIBG). Structures in the Faroe Islands provide evidence for a 6-stage tectonic evolution, here split into 3 broad phases: (1a) E-W to NE-SW extension, accommodated by dip-slip N-S and NW-SE trending faults. Continued NE-SW extension (1b) was then accommodated by the emplacement of a regionally significant NW-SE- and NNE-SSW-oriented dyke swarm. Event 1 affects the majority of the FIBG stratigraphy, resulting in thickness variations, most notably across the Judd, Brynhild and Westray (‘transfer’) fault-zones. Continued magmatism and anticlockwise rotation of the extension vector led to (2a) the emplacement of ENE-WSW and ESE-WNW conjugate dykes, followed by intrusion of the large, saucer-shaped sills on the islands. Their intrusion heralded the onset of N-S crustal extension and was followed by (2b) crustal extrusion involving both E-W shortening and further N-S extension facilitated primarily by slip on ENE-WSW (dextral) and ESE-WNW (sinistral) conjugate strike-slip faults, interlinked with minor NE and SW dipping thrust faults. During the final stages of this event (2c), the regional extension vector rotated into a NW-SE orientation that was accommodated predominantly by slip along NE-SW oriented dextral-oblique-slip faults. Event 2 began towards the end of magmatism associated with the FIBG, and most likely continued through to the onset of oceanic-spreading on the Aegir ridge (ca. 55 Ma). Finally, (3) Event 1 and 2 structures were reactivated as extension and extensional-hybrid features, characterised best by the entrainment of clastic material along fault planes. Relative timings of Event 3 structures suggest they formed during a period of compression and uplift following the formation of a through-going mid-ocean ridge system (i.e. on the Reykjanes, Kolbeinsey and Mohns ridges). The progressive anticlockwise rotation of the extension vector identified here is broadly consistent with the most recent NE Atlantic continental break-up reconstructions. Importantly, this model does not require basin-scale transfer zones during the Palaeogene, suggesting instead that these NW-SE faults formed as normal faults during a pre-cursor margin-parallel extension episode (Event 1) prior to the onset of oceanic spreading in the Faroe-Iceland sector. This study emphasises the importance of carrying out detailed field studies in addition to the more usual regional-scale modelling studies, in order to validate and add further detail to basin kinematic histories. Mineralised syn- to post-magmatic fault sets display a recurring zeolite-calcite-zeolite trend in mineralisation products, which precipitate during successive phases of fault development during each individual event. Fault style and damage zone width appear to be related to the stage of fault development, with early fault/vein meshes linking to form through-going structures with associated damage zones. Dykes and sills are found to form their own fractures, rather than exploiting pre-existing sets. Dyke propagation appears to be buoyancy-driven, with magmatic pressure overcoming the minimum compressive stress. Sills, however, most likely seeded at an interface in the stratigraphy between a weak, more ductile material (i.e. a sedimentary horizon), and a rigid material (i.e. basalt lavas) above. Following this initial development, sill growth and propagation would likely be controlled by viscous dissipation, leading to the complex ramp and flat architecture, with rapid intrusion resulting in upward ramping of the sill. The alternation from fault events, to dyke events and back again corresponds to a switch from faulting with mineralisation along extensional hybrid veins, to magmatic intrusions into extension fractures followed by extensional hybrids (conjugates), and back to extensional and shear hybrid faults (again as conjugates). This alternation reflects variations in the differential regional stress, as well as the magmatic evolution of the margin, and most likely relates to the migration of lithospheric thinning northwestwards across the area, towards the eventual axis of break-up. We find that, in particular, faults in basalts are in many ways comparable to faults formed at shallow crustal depths in carbonate rocks and crystalline basement, most likely reflecting the similarities in their mechanical properties under near-surface pressures and temperatures. The nature and style of the post-magmatic fault infills provides compelling evidence to suggest that subterranean cavities associated with faults were persistent open features within the FIBG. Structures equivalent to these late, clastic-filled faults of the Faroes may occur in other parts of the NE Atlantic margin, particularly along the axes of gentle regional-scale folds that are widely developed in the region. The late fault displacements observed are all well below seismic resolution, and such structures may be more widespread across the region than previously anticipated. Importantly, the probable unsealed nature of the clastic infills makes them potential fluid-migration pathways, both up- and across-faults within the Cenozoic volcanic sequences of the NE Atlantic region.

The Carajás Terrane in the Amazon Craton hosts Precambrian Cu-Au deposits with resources larger than 100 million tonnes of ore (e.g. Igarapé Bahia-Alemão, Cristalino, Sossego, 118 and Salobo). This thesis examines at a local scale, structural aspects of the Sossego and Sequeirinho deposits, located in the Archaean granite-gneiss basement of the Canaã dos Carajás region, the boundary between the Carajás and Rio Maria Granite Greenstone Terranes. The study focuses on the understanding of the processes, controls and styles of two regionally representative Archaean IOCG examples and also investigates the tectonic framework and structural evolution of the Canaã dos Carajás region. Primary data comprises traditional methods of field mapping and structural analysis, microscopic investigation, combined with modern digital mapping, lineament and particles size analysis. The principal aims of the study include: (1) identification of crustal scale regional lineaments and their relationship with mineral deposits; (2) a new tectonic framework and structural model for the Canaã dos Carajás region; and (3) description and interpretation of the structural framework of the Sossego and Sequeirinho mines. The most prominent crustal scale lineaments in the Carajás Terrane comprise early WNW-ESE sets that configure the regional structural trend and mark the basement-cover assemblage contact, and relatively late NE-SW lineaments. Higher lineament frequencies and density were observed in the cover assemblage domain and coincide with numerous lineament intersections. Mineral occurrences and deposits are clustered and spatially associated with domains of higher lineaments density and areas where major lineaments intersect. Then, there is a spatial relationship between major lineaments and the occurrence of mineral deposits. The Canaã dos Carajás region comprises Archaean TTG gneisses, lens shaped amphibolite bodies, 2.7 Ga. syn-tectonic alkali granitoids and 1.88 Ga. isotropic granites. These rocks display widespread heterogeneous, anastomosing WNW-ESE and NE-SW foliation sets, related steeply dipping ductile shear zones associated with steep-to-moderately plunging mineral lineations. The nature and geometry of the ductile fabrics are compatible with a bulk pure-shear dominated transpression with partitioning of strain intensity with shortening and extensional directions oriented at approximately near horizontal (~020° Az) and near vertical respectively. Microstructures in quartz and feldspar indicate deformation at metamorphic conditions compatible with middle to upper amphibolite facies (~650-700°C), overprinted by deformation at middle to upper greenschist facies conditions (~400-500°C). The Canaã dos Carajás region represents part of an original granite-greenstone terrane that has undergone substantial reworking during a late sinistral transpressional deformation. The reworking took place at c.a. 2.7 Ga, coeval with syn-tectonic sub-alkaline magmatism. The basement comprises intensely deformed rocks uplifted from the lower-to-middle crust, deformed under high amphibolite facies conditions and later affected by localised deformation at greenschist facies conditions. The structural framework of the Sossego and Sequeirinho deposits comprises regional WNW-ESE structures (foliations and shear zones) offset by NE-SW sinistral faults. Sequeirinho is hosted along a NE-SW sinistral fault, associated with a positive magnetic anomaly. It comprises an “S” shaped tabular orebody whose tips are hosted by sub-vertical WNW-ESE sheared and foliated granitoids and schists. These are linked by a NE-SW sinistral fault zone containing mineralized breccias. Sossego comprises a sub-circular, vertical, pipe-like orebody with a central breccia body surrounded by a stockwork array of sulphide veins, faults and shear zones. Tensile and shear veins show single or composite mineral fillings consistent with episodic vein opening, with a progressive change in hydrothermal fluid composition during time. The Sossego breccias show high clast angularity, characteristic of immature explosion breccias, whilst the Sequeirinho breccias display rounded fragments with low angularity, typical of mature breccias whose particle fragmentation was dominated by wear and attrition during subsequent slip along a fault zone. Microstructures in quartz and feldspar indicate that the deformation at Sossego and Sequeirinho initially took place under low-to-middle (300-400°C) and middle-to-upper (400-500°C) greenschist facies, respectively. Latter overprinted by brittle-ductile structures and veins containing lower-temperature minerals formed between 170-250°C. The rocks in the area of the mines record deformational processes that initially took place under the viscous regime (>15km), represented by mylonites and ultramylonites. Progressive exhumation, possibly synchronous with regional transpressional thickening led to conditions compatible with the frictional-viscous transition with intense fluid activity, with mineralization.