Structural Geological Data Research Articles

Geodynamic Setting on the Paleo-Asia Continent Eastern Margin in the Paleocene

The isotopic-geochemical and geochronological data obtained allow us to justify the middle Paleocene - early Eocene stage of magmatism within the Sikhote-Alin. The volcano-plutonic complexes of this stage are characterized by distinctive mineralogical and geochemical features of the A-type igneous rocks that differ greatly from the Late Cretaceous I-type igneous rocks, which imply a geodynamic regime other than subduction at the paleo-Asian eastern margin during this period. According to the geological-structural data of the Cretaceous and Paleogene parts of the Shimanto accretionary complex, this magmatic stage coincides with changing of the geodynamic mode of subduction of an oceanic plate by geodynamic mode of transform sliding of the latter along the paleo-Asian continent eastern margin and, again, by geodynamic mode of subduction of an oceanic plate.

Improving the conceptual – Numerical model of Sabalan geothermal system using geological, geophysical and structural information

This paper introduces a computational model based on the structural and petrophysical characteristics of the high-enthalpy geothermal reservoirs. Conceptual model of the Sabalan geothermal field is provided through integrating the various exploring information including the structural data, geological data, geophysical models, well logs and field evidences. Heat source is properly estimated by implementing the Curie depth map. The finite element method, adapted to the complex geometry of the model, is used to solve the governing equations. All-important physical and structural properties of the reservoir including the anisotropic and heterogonous permeability distribution, fluid flow through the faults and specific boundary conditions are considered. Optimization analysis is conducted to calibrate the model parameters. Simulated thermodynamic properties of the reservoir are compared with the wellbore measured data to validate the results.

The Intrusive Phase in the Evolution of a Volcanic Structure and of Au–Ag Low Sulfidation Mineralization: The Nevenrekan Deposit, Magadan Region, Russia

This paper provides information on the structural setting and ore composition of the Nevenrekan deposit. We provide an account of the regional and local factors of mineralization control. The ore bodies are confined to the junction between regional faults and annular ruptures of a circular subsidence. The geochemical zoning of the ore field is disturbed. We show how geochemical associations are distributed in the ore zones of this deposit. The structural geological and geochemical data, as well as results from a comparison among the Au‒Ag low sulfidation (LS) deposits at the Okhotsk–Chukchi, Uda–Murgali, and Central Kamchatka volcanogenic belts, shows that the mineralization occurred in two phases. The first phase involved the generation of epithermal Au–Ag mineralization, while the second, plutogenic, phase produced intrusion-related gold system that is seen as epidotization and silicification of rocks in the ore field, as well as in the metamorphism of volcanogenic mineralization. The presence of the later mineralization phase associated with granitoids is typical of the Nevenrekan deposit as distinguished from the other Au–Ag (LS) deposits in the Evensk ore region, and makes it similar in this respect to the Karamken, Nyavlenga, and Cirotan deposits.

Coulomb stress transfer between parallel faults. The case of Norcia and Mt Vettore normal faults (Italy, 2016 Mw 6.6 earthquake).

We investigated Coulomb stress transfer (CST) between the two normal, parallel nearest-neighbour seismogenic Monte Vettore and Norcia Faults (central Italian Apennines). Soon after the Mount Vettore Fault System earthquake of 30 October 2016 (Mw 6.6), we surveyed surface faulting evidence along both this and the Norcia Fault System, wondering on the mechanism that could have triggered the discontinuos surface ruptures formed along the latter. Really, seismological data show that the Norcia Fault did not release earthquakes during the 2016–2017 central Italy seismic, i.e., did not slip at depth. First, we mapped and defined the coseismic slip vector of the surface coseismic ruptures. Geological-structural data and geological cross-sections have been integrated to identify kinematic constraints and the relationships between the two faults systems. Then, we calculated the Coulomb stress generated by the Monte Vettore Fault System on 30 October. Results show that a positive lobe formed in the uppermost volume of the hanging-wall of the Norcia Fault System. Then, we simulated the Coulomb Stress Transfer in the case of the activation of the Norcia Fault System. From our analyses, it is possible to hypothesize that during a high magnitude seismic event (Mw 6.6–6.9) these two parallel fault systems can interact by transferring Coulomb stress reciprocally, although at different crustal level, and with different implications.

KONTROL STRUKTUR GEOLOGI PADA ALTERASI DAN MINERALISASI DI DAERAH CIBALIUNG, KABUPATEN PANDEGLANG, PROVINSI BANTEN

Cibaliung terletak di dalam Honje Igneous Complex yang merupakan kompleks vulkanik berumur Miosen yang memiliki dua urat kuarsa yang ekonomis untuk ditambang yaitu urat Cikoneng dan urat Cibitung. Keterdapatan urat kuarsa di Cibaliung ini telah ditambang dan diproduksi oleh PT Cibaliung Sumber Daya anak perusahaan PT Aneka Tambang Tbk. Pada proses produksinya urat kuarsa ini telah mencapai batas maksimal produksinya sehingga diperlukan cadangan baru. Metodologi penelitian yang dilakukan antara lain pengamatan struktur geologi dengan analisis kelurusan topografi, circular feature, analisis kelurusan sungai melalui citra Digital Elevation Model, dan pengukuran struktur breksiasi, slickenside, shear fracture dan gash fracture. Hasil interpretasi data lapangan dari 328 lokasi pengamatan dengan 8.114 data struktur geologi menunjukkan bahwa keterdapatan struktur geologi berbanding lurus dengan intensitas alterasi dan mineralisasi. Dari hasil metode analisis struktur dan pergerakan sesar yang dikorelasikan dengan data mineralisasi dan alterasi didapatkan 14 daerah prospek yakni Prospek Cikoneng-Cibitung, Prospek Cibengang, Prospek Rorah Kadal, Prospek Cikeni, Prospek Ramada, Prospek Mastar, Prospek Muara Cikeni, Prospek Cipatat, Prospek Ciburial, Prospek Cikamancing, Prospek Sompok Uara, Prospek Batulawang Utara, Prospek Cikarae-Cingenge, dan Prospek Ciparay. Dari beberapa prospek tersebut direkomendasikan untuk dilakukan ekplorasi lebih lanjut pada enam prospek, yakni Prospek Cibengang, Prospek Ramada, Prospek Cikoneng Barat, Prospek Cikamancing, Prospek Sompok Utara dan Prospek Batulawang Utara.

Digital Field Mapping and Drone-Aided Survey for Structural Geological Data Collection and Seismic Hazard Assessment: Case of the 2016 Central Italy Earthquakes

In this work, a high-resolution survey of the coseismic ground ruptures due to the 2016 Central Italy seismic sequence, performed through a dedicated software installed on a digital device, is strengthened by the analysis of a set of drone-acquired images. We applied this integrated approach to two active sections of the Mt Vettore active fault segment which, in the Castelluccio di Norcia plain (central Italy), were affected by surface faulting after the most energetic events of the sequence: the 24 August, Mw 6.0, Amatrice and 30 October, Mw 6.5, Norcia earthquakes. The main aim is to establish the range in which the results obtained measuring the same structures using different tools vary. An operating procedure, which can be helpful to map extensive sets of coseismic ground ruptures especially where the latter affects wide, poorly accessible, or dangerous areas, is also proposed. We compared datasets collected through different technologies, including faults attitude, dip-angles, coseismic displacements, and slip vectors. After assessing the accuracy of the results, even at centimetric resolutions, we conclude that the structural dataset obtained through remote sensing techniques shows a high degree of reliability.

Remote Sensing Data Integration of Landsat 8 and SRTM for Geomorphological Characteristics Identification in Karst Pringkuku, Pacitan, East Java

Pringkuku is one of the transition areas where the morphology of karst began to develop toward the western part of Gunung Sewu Karst region. The purpose of this research is to identify the landform unit in Pringkuku’s Karst as the result of geomorphological processes recorded by Landsat 8 image and SRTM image. The research was conducted by analyzing and dividing the landform units based on landform parameters such as flow patterns, slope forms, valley forms, and ridge patterns. Structural geology data such as a strike of joints and direct rock sampling are also used as the supporting data. The developing flow patterns are the multi-basinal and rectangular patterns in the western and eastern parts of the area respectively. Inferred from the analysis of joints pattern and stream lineament, the rectangular pattern is in direction NW - SE and NE - SW. The results of this research are two units of karst and structural landform, which are structural limestone hill unit in the eastern part of the area with 68.18% of spreading area of the total extent and conical limestone hill unit in western part of the area with spreading area of 31,82%.

РОЗПОДІЛ РТУТІ У ВУГІЛЬНОМУ ПЛАСТІ C7Н ПОЛЯ ШАХТИ «ПАВЛОГРАДСЬКА»

Purpose. Investigation of regularities of mercury distribution in coal of formation c7n of the Pavlogradska mine field. Methodology. Method of atomic absorption analysis of furrow samples of wells. Processing of geochemical and structural-geological data by methods of mathematical statistics using Excel 2016 and Statistica 6.0. The computer program Surfer was used to build maps/ Results. In article considered the distribution of mercury in the coal seam c7н of the Pavlohradska mine field of the Pavlohrad-Petropavlivka geological and industrial district of Donbas. As a result of the study, a map of isoconcentrates and a map of the regional component of mercury content in the coal of the seam were constructed and analyzed. Correlation coefficients between mercury concentration and formation morphological parameters and coal sulfur were calculated. The regression equations between this element and the ash content of coal are also established, which will allow predicting their concentration in the main working coal seams of the geological-industrial area relative to the values of coal ash content. The nature of sulfur distribution is established and the weighted average concentrations and the main descriptive statistics of this element are calculated. Scientific novelty. Peculiarities and regularities of mercury accumulation in coal of formation c7n are revealed. Practical significance. The constructed maps and established correlations are the factual basis for long-term forecasting of mercury concentrations in extracted raw materials and adjustment of technological schemes of coal beneficiation. Keywords: mercury, mine, coal height, ash content, stratum depth, sulfur content, regression equation, correlation coefficient.

Basic Petrological and Structural Analysis in the Zimbi Gold Area (East Cameroon)

The plutono-metamorphic series of the locality of Zimbi, extends over a narrow strip of 135 km2 on the eastern edge of the gold district of Baden-Colomine in East Cameroon. The work carried out in this locality is based on a cartographic approach (processing of maps and Landsat-7 ETM + images), combined with a geological and mining survey on the ground using conventional tools. On the morphostructural level, we observe NE-SW oriented penetrative lineaments. The trajectories of these are deviated or not in contact with other less dense lineaments, organized in networks of directions N-S, NE-SW, ENE-WSW, E-W, NW-SE. Parallel to the main Cameroon Center Shear (N070E), the ENE-WSW network which induces a significant reversal of foliation on contact, defines a structuring dexter shear zone accompanied by NE-SW and EW satellite shear zones with dexter kinematics and NW-SE and NS of senestrial kinematics. The lithological diversity allows the facies of calc-alkaline granite to predominate. Zimbi's range of structural elements highlights a magmatic fluidity substituted in foliation. The foliation directed NE-SW, of dip (40-90 °) either towards the NW, or towards the SE; carries a linearization of stretch submeridienne. The folding that affects it is induced by two directions of compression perpendicular N-S to NE-SW and E-W to NW-SE, which define the voltage slots favorable to mineral concentrations by circulation of mineralizing fluids. The shear zones and the quartz-feldspathic veins, structures favorable to mineralization such as gold, secondarily affect this complex. These geomorphological, lithological and structural geology data make the plutono-metamorphic procession of Zimbi a privileged area for mining research, in the gold district of Baden-Colomine.

Observing Oblique Slip During Rift Linkage in Northern Afar

AbstractExtensional plate boundaries are segmented by offsets that transfer extension between the ends of adjacent portions of the rift by linkage zones ranging in width from a few tens of kilometers to several hundreds of kilometers. However, the kinematics of linkage zones is poorly constrained as direct observations are difficult to make. Here we combine InSAR, seismicity, and structural geology data from the Afar rift to show that an active linkage zone currently connects the two offset Erta Ale and Tat Ali segments. The overall right‐lateral shear between the segments is accommodated primarily by oblique left‐lateral slip along faults subparallel to the rift segments but an active conjugate fault system with right‐lateral slip is also present. Our results provide the first direct observational evidence that offset rift segments during continental breakup can be linked by a shear zone composed of a conjugate set of oblique slip faults.

A New Fast and Low-Cost Photogrammetry Method for the Engineering Characterization of Rock Slopes

Digital photogrammetry (DP) represents one of the most used survey techniques in engineering geology. The availability of new high-resolution digital cameras and photogrammetry software has led to a step-change increase in the quality of engineering and structural geological data that can be collected. In particular, the introduction of the structure from motion methodology has led to a significant increase in the routine uses of photogrammetry in geological and engineering geological practice, making this method of survey easier and more attractive. Using structure from motion methods, the creation of photogrammetric 3D models is now easier and faster, however the use of ground control points to scale/geo-reference the models are still required. This often leads to the necessity of using total stations or Global Positioning System (GPS) for the acquisition of ground control points. Although the integrated use of digital photogrammetry and total station/GPS is now common practice, it is clear that this may not always be practical or economically convenient due to the increase in cost of the survey. To address these issues, this research proposes a new method of utilizing photogrammetry for the creation of georeferenced and scaled 3D models not requiring the use of total stations and GPS. The method is based on the use of an object of known geometry located on the outcrop during the survey. Targets located on such objects are used as ground control points and their coordinates are calculated using a simple geological compass and trigonometric formula or CAD 3D software. We present three different levels of survey using (i) a calibrated digital camera, (ii) a non-calibrated digital camera and (iii) two commercial smartphones. The data obtained using the proposed approach and the three levels of survey methods have been validated against a laser scanning (LS) point cloud. Through this validation we highlight the advantages and limitations of the proposed method, suggesting potential applications in engineering geology.

Evaluation of Geological Risks of Commercial Development of Complex Structured Coal Deposits

The main risk in the commercial development of complex located coal deposits is a geological risk, which is assessed by the results of coal resources classification at sufficient confidence. In conditions of complex located coal deposits, the main factor which determines categories of coal Reserves is the confidence of geological structural data, a reliable estimation of which is provided only with the use of quantitative methods. The use of conventional geostatistical and geometrical approaches to the reserves categorization in this kind of deposits is impossible. The confidence of complex located coal deposits is proposed to be quantitatively evaluated by the similarity degree of seams position on the adjacent exploration lines. This similarity is estimated with a special similarity coefficient varying from 0 to 1, determined based on curves correlation, which is adapted to the problem-solving method, in the complex plane. The obtained results provide the quality increase of the geological materials confidence evaluation and can be used to solve issues of the geological risk evaluation of the development of complex located coal deposits, during commercial or state expertise of geological information.

Automated Classification Analysis of Geological Structures Based on Images Data and Deep Learning Model

It is meaningful to study the geological structures exposed on the Earth’s surface, which is paramount to engineering design and construction. In this research, we used 2206 images with 12 labels to identify geological structures based on the Inception-v3 model. Grayscale and color images were adopted in the model. A convolutional neural network (CNN) model was also built in this research. Meanwhile, K nearest neighbors (KNN), artificial neural network (ANN) and extreme gradient boosting (XGBoost) were applied in geological structures classification based on features extracted by the Open Source Computer Vision Library (OpenCV). Finally, the performances of the five methods were compared and the results indicated that KNN, ANN, and XGBoost had a poor performance, with the accuracy of less than 40.0%. CNN was overfitting. The model trained using transfer learning had a significant effect on a small dataset of geological structure images; and the top-1 and top-3 accuracy of the model reached 83.3% and 90.0%, respectively. This shows that texture is the key feature in this research. Transfer learning based on a deep learning model can extract features of small geological structure data effectively, and it is robust in geological structure image classification.

Inversion of Structural Geology Data for Fold Geometry

AbstractRecent developments in structural modeling techniques have dramatically increased the capability to incorporate fold‐related data into the modeling workflow. However, these techniques are lacking a mathematical framework for properly addressing structural uncertainties. Previous studies investigating structural uncertainties have focused on the sensitivity of the interpolator to perturbing the input data. These approaches do not incorporate conceptual uncertainty about the geological structures and interpolation process to the overall uncertainty estimate. In this work, we frame structural modeling as an inverse problem and use a Bayesian framework to reconcile structural parameters and data uncertainties. Bayesian inference is applied for determining the posterior probability distribution of fold parameters given a set of structural observations and prior distributions based on general geological knowledge and regional observations. This approach allows for an inversion of structural geology data, where each realization can differ in the structural description of the fold geometries, instead of finding only a single best fit solution. We show that analyzing the variability between the resulting models highlights uncertainties associated with the geometry of regional structures. These areas can be used to target where additional data would be most beneficial for improving the model quality and efficiently reducing structural uncertainty.

Identifying Intraplate Mechanism by B-Value Calculations in the South of Java Island

Java is the most populous island in Indonesia with 50 million people live there. This island geologically formed at the Eurasia plate margin by the subduction of the Australian oceanic crust. At the south part of Java, beside the occurrence of 2-plate convergence earthquake (interplate), there are also the activities of the intraplate earthquake. Research for distinguish this 2 different earthquake type is necessary for estimating the behavior of the earthquake that may occur. The aim of this research is to map the b-value in the south of Java using earthquake data from 1963 until 2008. The research area are divided into clusters based on the epicenter mapping results with magnitude more than 4 and three different depth (0-30 km, 30-60 km, 60-100 km). This location clustering indicate group of earthquakes occurred by the same structure or mechanism. On some cluster in the south of Java, b-value obtained are between 0.8 and 1.25. This range of b-value indicates the region was intraplate earthquake zone, with 0.72-1.2 b-value range is the indication of intraplate earthquake zone. The final validation is to determine the mechanism of a segment done by correlating the epicenter and b-value plot with the available structural geology data. Based on this research, we discover that the earthquakes occur in Java not only the interplate earthquake, the intraplate earthquake also occurred here. By identifying the mechanism of a segment in the south of Java, earthquake characterization that may occur can be done for developing the accurate earthquake disaster mitigation system.

An apatite U–Pb thermal history map for the northern Gawler Craton, South Australia

Apatite U–Pb thermochronology was applied to granitoid basement samples across the northern Gawler Craton to unravel the Proterozoic, post-orogenic, cooling history and to examine the role of major fault zones during cooling. Our observations indicate that cooling following the ∼2500 Ma Sleaford Orogeny and ∼1700 Ma Kimban Orogeny is restricted to the Christie and Wilgena Domains of the central northern Gawler Craton. The northern Gawler Craton mainly records post-Hiltaba Event (∼1590 Ma) U–Pb cooling ages. Cooling following the ∼1560 Ma Kararan Orogeny is preserved within the Coober Pedy Ridge, Nawa Domain and along major shear zones within the south-western Fowler Domain. The Nawa Domain samples preserve U–Pb cooling ages that are >150 Ma younger than the samples within the Coober Pedy Ridge and Fowler Domain, indicating that later (∼1300 Ma) fault movement within the Nawa Domain facilitated cooling of these samples, caused by arc collision in the Madura Province of eastern Western Australia. When compared to 40Ar/39Ar from muscovite, biotite and hornblende, our new apatite U–Pb ages correlate well, particularly in regions of higher data density. Our data also preserve a progressive younging of U–Pb ages from the nucleus of the craton to the periphery with a stark contrast in U–Pb ages across major structures such as the Karari Shear Zone and the Southern Overthrust, which indicates the timing of reactivation of these major crustal structures. Although this interpolation was based solely on thermochronological data and did not take into account structural or other geological data, these maps are consistent with the structural architecture of the Gawler Craton and reveal the thermal footprint of known tectonic and magmatic events in the Gawler Craton.

Deciphering the Late Cretaceous‐Cenozoic Structural Evolution of the North Peruvian Forearc System

AbstractThe link between plate tectonics and the evolution of active margins is still an ongoing task to challenge since the acceptance of plate tectonic paradigm. This paper aims at deciphering the structural architecture and uplift history of the North Peruvian forearc system to better understand the evolution and the mechanics that govern the Late Cretaceous‐Cenozoic building of this active margin. In this study, we report surface structural geology data, interpretation of seismic reflection profiles, apatite fission track data, and the construction of two offshore‐onshore crustal‐scale balanced cross sections. The structure of the North Peruvian forearc system is dominated by an accretionary style with northwestward propagation of thrust‐related structural highs involving continental/oceanic basement rocks and off‐scrapped sediments. The thrust systems bound thick thrust‐top forearc depocenters mainly deformed by crustal normal to strike‐slip faults and thin‐skinned gravitational instabilities. The sequential restoration of the margin calibrated with apatite fission track data suggests a correlation between uplift, shortening, and plate convergence velocity during Late Cretaceous and Miocene. Pliocene‐Quaternary shortening and uplift of the coastal zone is rather related to the subduction of asperities during convergence rate decrease. The development of crustal normal to strike‐slip faulting and subsidence zones might be the consequence of slab flexure, local basal erosion along subduction fault, and/or oblique subduction associated with sediment loading control. We conclude that the evolution of the North Peruvian forearc system was controlled by subduction dynamics, strong sediment accumulation, and recent ridge subduction, and it recorded the orogenic loading evolution of the Andes over the Cenozoic.

Uplift rates of marine terraces as a constraint on fault-propagation fold kinematics: Examples from the Hawkswood and Kate anticlines, North Canterbury, New Zealand

Marine terraces on growing fault-propagation folds provide valuable insight into the relationship between fold kinematics and uplift rates, providing a means to distinguish among otherwise non-unique kinematic model solutions. Here, we investigate this relationship at two locations in North Canterbury, New Zealand: the Kate anticline and Haumuri Bluff, at the northern end of the Hawkswood anticline. At both locations, we calculate uplift rates of previously dated marine terraces, using DGPS surveys to estimate terrace inner edge elevations. We then use Markov chain Monte Carlo methods to fit fault-propagation fold kinematic models to structural geologic data, and we incorporate marine terrace uplift into the models as an additional constraint. At Haumuri Bluff, we find that marine terraces, when restored to originally horizontal surfaces, can help to eliminate certain trishear models that would fit the geologic data alone. At Kate anticline, we compare uplift rates at different structural positions and find that the spatial pattern of uplift rates is more consistent with trishear than with a parallel-fault propagation fold kink-band model. Finally, we use our model results to compute new estimates for fault slip rates (~1–2m/ka at Kate anticline and 1–4m/ka at Haumuri Bluff) and ages of the folds (~1Ma), which are consistent with previous estimates for the onset of folding in this region. These results are consistent with previous work on the age of onset of folding in this region, provide revised estimates of fault slip rates necessary to understand the seismic hazard posed by these faults, and demonstrate the value of incorporating marine terraces in inverse fold kinematic models as a means to distinguish among non-unique solutions.

Uncertainty estimation for a geological model of the Sandstone greenstone belt, Western Australia – insights from integrated geological and geophysical inversion in a Bayesian inference framework

Abstract The spatial relationship between different rock types and relevant structural features is an important aspect in the characterization of ore-forming systems. Our knowledge about this geological architecture is often captured in 3D structural geological models. Multiple methods exist to generate these models, but one important problem remains: structural models often contain significant uncertainties. In recent years, several approaches have been developed to consider uncertainties in geological prior parameters that are used to create these models through the use of stochastic simulation methods. However, a disadvantage of these methods is that there is no guarantee that each simulated model is geologically reasonable – and that it forms a valid representation in the light of additional data (e.g. geophysical measurements). We address these shortcomings here with an approach for the integration of structural geological and geophysical data into a framework that explicitly considers model uncertainties. We combine existing implicit structural modelling methods with novel developments in probabilistic programming in a Bayesian framework. In an application of these concepts to a gold-bearing greenstone belt in Western Australia, we show that we are able to significantly reduce uncertainties in the final model by additional data integration. Although the final question always remains whether a predicted model suite is a suitable representation of accuracy or not, we conclude that our application of a Bayesian framework provides a novel quantitative approach to addressing uncertainty and optimization of model parameters.

Two-stage terrane assembly in Western Gondwana: Insights from structural geology and geophysical data of central Borborema Province, NE Brazil

Combined geophysical and structural data from the Transversal Subprovince of the Borborema Province (NE Brazil) highlight the internal structure of, and interrelationships between, the constituent terranes. Radiometric and magnetic maps show distinctive signatures for the Archean-Paleoproterozoic Alto Moxotó and Meso-to Neoproterozoic Alto Pajeú and Pernambuco-Alagoas terranes. Mapped radiometric and first and second order magnetic lineaments, associated with Euler deconvolution, enable correlation between geophysical data and major structures. In addition to early related deformation of the Alto Moxotó Terrane, combined analysis of late transposition foliations, lineations and kinematic criteria reveal a complex structural evolution marked by two distinct assembly stages. The first phase is characterized by thrust tectonics with top-to-the-south vergence, resulting in the juxtaposition of the allochtonous Alto Pajeú Terrane with the structurally underlying Alto Moxotó Terrane. The terrane boundary is delineated by the Serra de Jabitacá Shear Zone, which is associated with low dipping collisional granitic sheets and ca. 1.0 Ga mafic-ultramafic rocks interpreted as obtudcted ophiolite remnants. Later strike-slip movements strongly folded and obliterated thrust-related markers, and the continental scale E-W Pernambuco Lineament is interpreted as the result of lateral assembly between the composite Alto Pajeú-Alto Moxotó terranes and the Pernambuco-Alagoas Terrane during the metamorphic peak of the Brasiliano orogeny. Evolution of the Borborema Province reflects accretionary processes during the assembly of Western Gondwana.