scholarly journals Reactivation of Fault Systems by Compartmentalized Hydrothermal Fluids in the Southern Andes Revealed by Magnetotelluric and Seismic Data

Tectonics ◽  
2020 ◽  
Vol 39 (12) ◽  
Author(s):  
R. K. Pearce ◽  
A. Sánchez de la Muela ◽  
M. Moorkamp ◽  
J. O. S. Hammond ◽  
T. M. Mitchell ◽  
...  
2019 ◽  
Author(s):  
R. K. Pearce ◽  
Almudena Sánchez de la Muela ◽  
Max Moorkamp ◽  
J. O. S. Hammond ◽  
Thomas M. Mitchell ◽  
...  

2020 ◽  
Author(s):  
Quang Nguyen ◽  
Michal Malinowski ◽  
Piotr Krzywiec ◽  
Christian Huebscher

<p>Geological structure and tectonics of the Phanerozoic sedimentary cover within the transition zone between the Precambrian and Paleozoic platform in the Polish sector of the Baltic Sea was imaged using new 2D high-resolution multi-channel seismic reflection data. The new seismic data were acquired in 2016 during the course of RV Maria S. Merian expedition MSM52 within the framework of the BALTEC project. Eight profiles (with the total length of ca. 850km) covered the tectonics blocks located within the Polish Exclusive Economic Zone, stretching from the East European Craton (EEC) to the Paleozoic platform across the Teisseyre-Torquist Zone (TTZ).</p><p>Our in-house seismic processing workflow focused on removing multiples contaminating this shallow-water data, both water bottom and interbed related. Various demultiple techniques such as SRME, TAU-P domain deconvolution, high resolution parabolic Radon demultiple and SWDM (Shallow water demultiple) have been tested. Combination of all those techniques at different stages of the processing with some modifications based on a particular seismic profile proved to be the most effective. Consequently, multiples obscuring seismic sections were efficiently reduced. Data were processed up to Kirchhoff pre-stack time migration.</p><p>The longest seismic profile (line BGR16-212, ca. 240 km long) crosses almost perpendicularly majority of Precambrian and Paleozoic fault systems bordering the tectonic blocks of the EEC basement, so fault systems could be easily interpreted. EEC Precambrian basement is characterized by a regional flexure towards the TTZ. Cambrian-Ordovician exhibits similar geometry and is characterized by a relatively constant thickness related to deposition on the Tornquist Ocean passive margin. Thick Silurian succession is characterized by a regional divergent pattern caused by deposition within the Caledonian foredeep basin. Structural pattern within the W part of the study area is much more complex as this area underwent Late Paleozoic extension/transtension, Variscan inversion, Permo-Mesozoic subsidence and Late Cretaceous inversion.</p><p>This study was funded by the Polish National Science Centre grant no UMO-2017/27/B/ST10/02316.</p>


2019 ◽  
Vol 70 (6) ◽  
pp. 483-493
Author(s):  
Svetlana Kováčiková ◽  
Igor Logvinov ◽  
Viktor Tarasov

Abstract We present results of a study of the peculiarities of the seismicity and electrical conductivity distribution beneath the Ukrainian Eastern Carpathians. Based on the analysis of seismic data for the years 1999–2016, specific zones of concentration of earthquake sources related to the principal fault systems and their intersections have been distinguished. This paper covers two zones, one linked to the contact of the Outer Carpathians and the Carpathian Foredeep and another one linked to the fault system transverse to the Carpathians strike. Both belts of earthquake sources concentration correlate well with the geoelectric models of the studied area obtained as a result of 2D and quasi-3D inversion. Most of the seismic events occur at the intersection of the mentioned seismic zones, at shallower depths, than the main conductive structures appear, concentrated at their marginal parts. The interrelation of both phenomena suggests their common explanation by processes occurring in active fault systems: fracturing, shear deformation, migration of highly mineralized fluids, high porous pressure, accumulation and release of tectonic stress.


2020 ◽  
Author(s):  
Pamela Richetti ◽  
Renata da Silva Schmitt ◽  
Bruno César Araújo ◽  
Maria Filipa da Gama ◽  
Marta Teixeira da Costa Soares

<p>The structural inheritance of the basement plays an important role controlling rift formation and evolution. Here we investigate tectonic and rheological inheritance on brittle reactivation of the Precambrian basement and shear zones in the formation and evolution of the Cretaceous Araripe Basin. The basin is a part of the Northeast Brazilian Rift System, associated with the junction of the Southern and Equatorial branches of the Atlantic Rift. Its basement is part of Neoproterozoic Transversal Zone (Borborema Province), a crustal scale transpressional duplex system, related to the Brasiliano escape tectonic events. </p><p>We present here a synthesis of field observations from the Araripe Basin and its adjacent basement, combined with topographic, aeromagnetic and seismic data to propose a general overview on the tectonic framework and evaluate how it influenced the basin initiation and evolution. Our integrated analysis shows that there are three main structural trends for the basin and its surroundings: NE-SW, E-W and NW-SE. The NE-SW and E-W trends are the most expressive sets of lineaments in the topographic and aeromagnetic data, directly related to the basement framework. Integration of seismic data and filtered aeromagnetic maps confirms that NE-SW and E-W trends represent oblique fault systems.</p><p>Archean, Paleoproterozoic, Mesoproterozoic and Neoproterozoic terranes are arranged side by side in NE-SW mega sigmoid, bounded by the E-W Pernambuco (to the south) and Patos (to the north) dextral shear zones. The Araripe basin units are distributed mostly in two sub-basins, Cariri and Feira Nova, separated by a structural high, controlled by NE-SW and ESE-WNW faults. Analyzing these terranes and their link to the distribution of the depocenters and structures, we find that the NE trending Archean terrane coincides partially with the Feira Nova NE-SW single graben. On the eastern portion of the basin, the graben system is much wider and controlled by NE-SW and ESE-WNW trending fault systems. This wide graben overlies a Neoproterozoic basement terrane constituted by a supracrustal unit (Cachoeirinha Group) of phyllites, metasandstones, metavolcanics with low to medium metamorphic grade.</p><p>This evidence corroborates with the hypothesis that the rheology of the upper crust might be partially influenced by distinct lithotectonic terranes. The older Archean block sustained the narrow sub-basin, indicating a more localizing behavior, while the younger Neoproterozoic terrane, controlled a less localizing graben system with a wider sub-basin in the eastern Araripe basin.</p><p> </p><p>The authors gratefully acknowledge support from Shell Brasil Petroleo Ltda. and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation (Technical Cooperation #20.219-2).</p>


2015 ◽  
Vol 2015 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Matthew Kovacevic ◽  
Jane Cunneen ◽  
Chris Elders

2013 ◽  
Vol 734-737 ◽  
pp. 458-462
Author(s):  
Ya Chun Wang ◽  
Xiang Li ◽  
Rong Zhao ◽  
Xue Qiu ◽  
Zong Bao Liu

The seismic data interpretation shows that faults in Pubei Oilfield developed in the form of the lower, middle and upper fault systems, vertically corresponding to the tectonic evolution stages of Songliao Basin which are rifting, depression and inversion stages; in the plane the faults in Pubei Oilfield appear dense characteristics to be belts, especially in Fuyang oil layer, but not clear and sparse in Putaohua oil layer; faults dense belts in Fuyang oil layer from five orientations combine alternately, cutting Fuyang oil layer into the grid feature, but the faults distribution of Putaohua oil layer is related with the fault blocks division of the Pubei Oilfield. Generally, 8 fault belts separate the Pubei Oilfield into seven fault blocks.


2017 ◽  
Vol 39 (6) ◽  
pp. 106-121
Author(s):  
A. O. Verpahovskaya ◽  
V. N. Pilipenko ◽  
Е. V. Pylypenko

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