Advanced interpretation of gravity data for determining the structural framework: case of Fkirine and Djebibina area (transition between central Tunisian Atlas and Sahel domain, North Africa)

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
H. Mouakhar ◽  
H. Gabtni ◽  
A. Bel Kahla
Keyword(s):  
North Africa ◽  
Gravity Data ◽  
Structural Framework ◽  
Tunisian Atlas

Discovery of a new Lower Cretaceous Wealden-type ostracod fauna from the Bouhedma Formation, Central Tunisian Atlas, North Africa

2021 ◽  
pp. 104942
Author(s):  
Manel Chnayna ◽  
Benjamin Sames ◽  
Khaled Trabelsi ◽  
Yassine Houla ◽  
Amine Hanini ◽  
...  
Keyword(s):  
North Africa ◽  
Lower Cretaceous ◽  
Tunisian Atlas

Tectonic framework of the Barra de São João Graben, Campos Basin, Brazil: Insights from gravity data interpretation

2014 ◽  
Vol 2 (4) ◽  
pp. SJ65-SJ74 ◽  
Author(s):  
Leandro B. Adriano ◽  
Paulo T. L. Menezes ◽  
Alan S. Cunha
Keyword(s):  
Gravity Data ◽  
Shear Zones ◽  
Data Interpretation ◽  
Fault System ◽  
Magnetic Data ◽  
Southeastern Brazil ◽  
Rift System ◽  
Seismic Line ◽  
Structural Framework ◽  
Campos Basin

The Barra de São João Graben (BSJG), shallow water Campos Basin, is part of the Cenozoic rift system that runs parallel to the Brazilian continental margin. This system was formed in an event that caused the reactivation of the main Precambrian shear zones of southeastern Brazil in the Paleocene. We proposed a new structural framework of BSJG based on gravity data interpretation. Magnetic data, one available 2D seismic line, and a density well-log of a nearby well were used as constraints to our interpretation. To estimate the top of the basement structure, we separated the gravity effects of deep sources from the shallow basement (residual anomaly). Then, we performed a 2D modeling exercise, in which we kept fixed the basement topography and the density of the sediments, to estimate the density of the basement rocks. Next, we inverted the residual anomaly to recover the depth to the top of the basement. This interpretation strategy allowed the identification of a complex structural framework with three main fault systems: a northeast–southwest-trending normal fault system, a northwest–southeast-trending transfer fault system, and an east–west-trending transfer fault system. These trends divided the graben into several internal highs and lows. Our interpretation was corroborated by the magnetic anomalies. The existence of ultradense and strongly magnetized elongated bodies in the basement was interpreted as ophiolite bodies that were probably obducted by the time of the shutdown of the Proterozoic Adamastor Ocean.

Ostracods from the marginal coastal Lower Cretaceous (Aptian) of the Central Tunisian Atlas (North Africa): Paleoenvironment, biostratigraphy and paleobiogeography

2015 ◽  
Vol 58 (4) ◽  
pp. 309-331 ◽  
Author(s):  
Khaled Trabelsi ◽  
Benjamin Sames ◽  
Amal Salmouna ◽  
Enelise Katia Piovesan ◽  
Soumaya Ben Rouina ◽  
...  
Keyword(s):  
North Africa ◽  
Lower Cretaceous ◽  
Tunisian Atlas

Fault interactions, fault kinematics, and evolution of the structural framework in the Irish Lower Carboniferous

2020 ◽  
Author(s):  
Koen Torremans ◽  
John Conneally ◽  
John Güven ◽  
Robert Doyle ◽  
jiulin Guo ◽  
...  
Keyword(s):  
Base Metal ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Normal Faults ◽  
Integrated Analysis ◽  
Lower Carboniferous ◽  
Fault Systems ◽  
Structural Framework ◽  
Fault Parameters ◽  
Wide Range

<p>Fault systems in the Irish Lower Carboniferous are important in relation to its subsurface groundwater, geothermal and mineral resources. For example, major base metal deposits in the world-class Irish Orefield occur in association with normal faults. Despite their economic importance, however, the fault networks and structural framework at depth are still poorly constrained. The Irish Carboniferous Basin is an excellent area to study the extensional fault systems and evolution of rift basins, given the relatively low amounts of later compressional deformation and metamorphism, and because high-quality subsurface datasets exist from several decades of mineral exploration. Our work aimed at developing a coherent structural framework for the Lower Carboniferous in Ireland, to unravel the geometries and kinematics of faulting in a carbonate-dominated rift basin that developed on top of a strong pre-existing structural template in the underlying basement rocks.</p><p>We have defined the geometry of key fault systems in the rift across a wide range of scales, using three-dimensional integrated analysis of large datasets. These datasets include public and proprietary onshore 2D reflection seismic, mapping, drillhole, micro-palaeontological, aeromagnetic, electromagnetic, and ground gravity data. Our work has revealed the nature of segmentation patterns and interactions of normal faults, including synthetic and conjugate relay zones. Quantification of fault parameters, kinematic analysis and kinematic restoration have allowed us to gain insights into the distribution of extension during rifting in time and space, using growth sequences and facies changes on faults. The analysis of this structural framework in relation to several mineral deposits, and in combination with lithofacies distribution and the development of bathymetry during basin formation, allows us to better understand current and past fluid flow pathways, especially in relation to base metal mineralising events.</p>

Charophyte biostratigraphy of the non-marine Lower Cretaceous in the Central Tunisian Atlas (North Africa): Palaeobiogeographic implications

2016 ◽  
Vol 67 ◽  
pp. 66-83 ◽  
Author(s):  
Khaled Trabelsi ◽  
Mohamed Soussi ◽  
Jamel Touir ◽  
Yessin Houla ◽  
Chedly Abbes ◽  
...  
Keyword(s):  
North Africa ◽  
Lower Cretaceous ◽  
Tunisian Atlas

scholarly journals Integrating geological mapping and geophysical analyses in Southern Espinhaço Range, eastern edge of the São Francisco Craton, Brazil

2021 ◽  
Vol 39 (1) ◽  
Author(s):  
William Medina Leite Féres ◽  
Pedro Ângelo Almeida Abreu ◽  
Wilbor Poletti
Keyword(s):  
Gamma Ray ◽  
Gravity Data ◽  
Geological Mapping ◽  
Gamma Ray Spectrometry ◽  
Narrow Strip ◽  
Espinhaço Range ◽  
Structural Framework ◽  
Regional Tectonic ◽  
History Of ◽  
General Geometry

ABSTRACT. The São Francisco Craton is one of the fundamental pieces on the evolutionary history of the Gondwana supercontinent. At its southeast edge, the Southern Espinhaço Range (SER) is built mainly by Paleo- and Mesoproterozoic units of the Espinhaço Supergroup. At its western domain, one of its major components, the Conselheiro Mata Group, occurs as a relatively narrow strip, being composed by a succession of formations related to coastal and shallow marine environments. Aiming to present and discuss an integrated research, detailed fieldwork was carried out, gamma-ray spectrometry data were reprocessed, and ground gravity data were acquired. This integration allows clarifying the regional crustal structure and the general geometry of the Espinhaço basin. The defined gamma-ray spectrometry domains fit well to the lithological types and structural framework of the stratigraphic units. Bouguer residual anomaly highlights an amplitude of 27 mGal, ranging from -12 to 15 mGal, outlining a gravity compartmentation defined by a central negative anomaly (CNA) surrounded by positive anomalies, which is approximately in conformity with the regional tectonic segments. The CNA conforms to the main axis of SER, indicating the residual metasedimentary coverage of the Espinhaço basin. Its center, positioned above the Lamarão anticline, houses the nucleus of the precursor basin of Conselheiro Mata Group.Keywords: gravimetry; Espinhaço Supergroup; Conselheiro Mata Group.Integrando mapeamento geológico e análises geofísicas na Serra do Espinhaço Meridional, borda leste do Cráton São Francisco, BrasilRESUMO. O Cráton São Francisco é uma das peças fundamentais da história evolutiva do Supercontinente Gondwana. Em sua borda sudeste, a Serra do Espinhaço Meridional é formada, principalmente, por unidades Paleo- a Mesoproterozoicas do Supergrupo Espinhaço. Um de seus principais componentes, o Grupo Conselheiro Mata, ocorre como uma faixa relativamente estreita no domínio ocidental da serra, sendo composto por uma sucessão de formações relacionadas a ambientes marinhos rasos e costeiros. Com o objetivo de apresentar e discutir uma pesquisa integrada, foram realizados trabalho de campo detalhado, processamento de dados gamaespectrométricos e aquisição de dados gravimétricos terrestres. Tal integração permite esclarecer a estrutura crustal regional e a geometria geral da bacia Espinhaço. Os domínios gamaespectrométricos definidos ajustam-se bem às litologias e ao arcabouço estrutural das unidades estratigráficas. Anomalias Bouguer residuais demonstram uma amplitude de 27 mGal, variando entre -12 a 15 mGal, concordando aproximadamente com os segmentos tectônicos regionais e esboçando uma compartimentação gravimétrica definida por uma anomalia negativa central (CNA), cercada por anomalias positivas. A CNA concorda com o eixo principal da Serra do Espinhaço Meridional, definindo a cobertura metassedimentar residual da bacia Espinhaço. Seu centro, posicionado sobre o anticlinal do Lamarão, abriga o núcleo da bacia precursora do Grupo Conselheiro Mata.Palavras-chave: gravimetria; Supergrupo Espinhaço; Grupo Conselheiro Mata.

scholarly journals Geophysical Data Processing for the Delineation of Tectonic Lineaments in South Cameroon

2019 ◽  
Vol 8 (2) ◽  
pp. 1
Author(s):  
Quentin Marc Anaba Fotze ◽  
Charles Antoine Basseka ◽  
Anatole Eugene Djieto Lordon ◽  
Albert Eyike Yomba ◽  
Yves Shandini ◽  
...  
Keyword(s):  
Gravity Data ◽  
Bouguer Anomaly ◽  
Structural Features ◽  
Horizontal Gradient ◽  
Tectonic Event ◽  
Structural Framework ◽  
Pan African ◽  
Eburnean Orogeny ◽  
Tilt Derivative ◽  
Total Horizontal Derivative

The processing of aeromagnetic and gravity data of the Northern part of Congo Craton (South Cameroon region), between latitudes 2°30’-3°30’ N and longitudes 12°-13° E, permitted the determination of the structural features ccurring within the Precambrian basement (Ntem Complex) southwards and the Pan-African belt (Yaounde Group) northwards. The maxima of the Horizontal Gradient within the study area, were obtained using the Blakely and Simpson method (1986). Those maxima were used to trace the magnetic lineaments of the study area. Furthermore, the Total Horizontal derivative of the Tilt derivative applied on the residual grid of Bouguer anomaly guaranteed the enhancement of linear structures which were automatically extracted using the CET Grid Analysis algorithm. The superimposition of both magnetic and gravity lineaments allowed us to display the structural framework of the area, whose major trending directions are E-W, ENE-WSW, and NE-SW. These major lineament directions are likely to be linked to one or more than a single tectonic event such as the ENE-WSW/NE-SW trends, considered as the subduction direction of the Congo craton beneath the Pan-African belt. These trends may be linked to the Eburnean orogeny and are also said to be connected to the Central African Shear Zone (CASZ). The geophysical lineaments identified in the study are defined as potential targets along which mineralization may have been formed, considering the economic potential of the area.

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