scholarly journals Structural geological complications for tunnel construction in the Kostenets’s section of the Maritsa fault zone in Central Bulgaria

2021 ◽  
Vol 82 (3) ◽  
pp. 91-93
Author(s):  
Dian Strahilov ◽  
Ivan Dimitrov
Keyword(s):  
Fault Zone ◽  
Metamorphic Rocks ◽  
Tunnel Construction ◽  
Lateral Forces ◽  
Geological Features ◽  
Design Solutions ◽  
Discontinuity Network

The structural geological features defining the discontinuity network in metamorphic rocks hosting railway tunnels are described. Discussion on the faults, joints, lineation and stresses found from fault population is presented. It is demonstrated that the formation of some brittle joints is related to the ductile stretching lineation. The geotechnical situation for the tunnel construction is complicated and requires reassessment of the design solutions in order to accommodate substantial lateral forces and prevent shear of the tubes.

scholarly journals Dynamic Change Characteristics of Groundwater Affected by Super-Long Tunnel Construction in the Western Mountainous Area of China

2019 ◽  
Vol 11 (8) ◽  
pp. 2329
Author(s):  
Zhiqiang Zhang ◽  
Peng Xu ◽  
Heng Zhang ◽  
Kangjian Zhang
Keyword(s):  
Fault Zone ◽  
Dynamic Change ◽  
Water Inrush ◽  
Water Inflow ◽  
Economic Losses ◽  
Tunnel Construction ◽  
In Situ Observation ◽  
Mountainous Area ◽  
Linear Cavity ◽  
Change Characteristics

The problem of groundwater is very prominent in super-long tunnel construction, which brings serious potential safety hazards and economic losses to the project. The knowledge of dynamic change characteristics of groundwater and prediction of water inflow is the key to ensure rational design and safe construction in super-long tunnel. In this paper, numerical simulation and in situ observation are conducted to investigate dynamic change characteristics of groundwater and the prediction of water inflow based on the Daxiangling tunnel in Sichuan Province of China. The results show that the numerical model established with detailed geological data and validated with field monitoring data can effectively analyze dynamic change characteristics of groundwater, as well as predict water inflow. The initial state of groundwater is steady when the tunnel is unexcavated. Tunnel excavation has a significant influence on the distribution of groundwater. The flow direction of groundwater will change, and the contour lines of groundwater will be intensive at the tunnel face. These changes will be more obvious and dramatic when the tunnel is excavated into the fault zone, which is a signal that the water inrush is more likely to occur in the fault zone because of a lot of joints and fractures. A connected linear cavity is formed with tunnel holing-through and groundwater begins to flow vertically downwards to the tunnel. As far as the prediction of water inflow is concerned, the numerical method can more precisely calculate the value of water inflow with less than 15 percent relative error compared with the groundwater dynamics method.

Protolith ages and deformation mechanism of metamorphic rocks in the Zhangbaling uplift segment of the Tan-Lu Fault Zone

2014 ◽  
Vol 57 (11) ◽  
pp. 2740-2757 ◽  
Author(s):  
Tian Zhao ◽  
Guang Zhu ◽  
ShaoZe Lin ◽  
LeJia Yan ◽  
QinQin Jiang
Keyword(s):  
Fault Zone ◽  
Deformation Mechanism ◽  
Metamorphic Rocks

U–Pb zircon and monazite ages from the Kapuskasing uplift: age constraints on deformation within the Ivanhoe Lake fault zone

1994 ◽  
Vol 31 (7) ◽  
pp. 1096-1103 ◽  
Author(s):  
T. E. Krogh ◽  
D. E. Moser
Keyword(s):  
Fault Zone ◽  
Granulite Facies ◽  
Ductile Deformation ◽  
Metamorphic Rocks ◽  
High Grade ◽  
Granulite Metamorphism ◽  
Superior Craton ◽  
Age Constraints

A decade of U–Pb dating of zircon and monazite from high-grade metamorphic rocks in the Kapuskasing uplift has identified a series of magmatic and metamorphic events between 2700 and 2585 Ma, and indicates that the onset of regional granulite metamorphism took place at mid-crustal levels of the southern Superior craton ca. 2660 Ma. New U–Pb ages for zircon and monazite have been used to constrain the age of ductile deformation fabrics at two sites in the Ivanhoe Lake fault zone, the structure along which the granulite-facies Kapuskasing structural zone was uplifted. These results suggest that the fault zone was probably active in the late Archean (as young as 2630 Ma) and again at approximately 2500 Ma.

scholarly journals Interactions between the prograding Giant Foresets Formation and a subsiding depocentre: Insights from the Parihaka 3D & ES89 2D seismic surveys

2021 ◽  
Author(s):  
◽  
Aaron Graeme Johnston
Keyword(s):  
Sediment Transport ◽  
Fault Zone ◽  
Large Scale ◽  
Sediment Provenance ◽  
Normal Faulting ◽  
Seismic Section ◽  
Seismic Surveys ◽  
The North ◽  
Geological Features ◽  
Transport Direction

<p>This seismic interpretation project provides new insights into the interaction between the Pliocene-aged Giant Foresets Formation and the faults bounding the Northern Graben. A newly named fault-bounded depocentre within the North Taranaki Graben, the Arawa Sub-Basin, has subsided during the Pliocene, attracting volumes of sediment across the Parihaka Fault within large-scale channels. The study images kilometer-scale channels and explores the interplay between the progradation of the Giant Foresets Formation and normal faulting along the Cape Egmont Fault Zone. A focus is placed on imaging the provenance and depositional facies of sedimentary packages throughout the foresetting sequence of the Giant Foresets Formation.  Mapping of the Waipipian-Nukumaruan-aged foresetting sequence within the offshore northern Taranaki Basin has previously shown the primary sediment transport direction is primarily NNW. This is contradicted by sediment-transport features mapped within the study area showing the sediment transport direction fluctuates between NE and SE. The primary mechanism of sediment redirection is faulting along the Cape Egmont Fault Zone and subsidence within the North Taranaki Graben, an elongate SW-NE graben within the northern Taranaki Basin. Smaller (˜10s m-scale) channels concentrate into much larger (˜100s m- to km-scale) mega-channels that travel E/NE into the subsiding Arawa Sub-Basin. Volcanic intrusions of the Mohakatino Volcanic Formation have also influenced the evolution of the mega-channels in the study area, via uplift and doming of the seafloor which provided a barrier to the transport of sediment.  The Parihaka 3D and ES89 2D seismic surveys are interpreted using the IHS Kingdom software package to create a basic framework of horizons and faults over the Pliocene-Recent interval. Depth grid maps are produced from the grid of horizon picks. Isochore maps are produced which span key intervals between depth grids. A coherency cube of the Parihaka 3D is generated from the 3D seismic volume using OpendTect. Using the framework of faults and horizons within the coherency cube, imaging sediment transport and deposition features in the vicinity of normal faulting is made possible by flattening on a top foresets horizon and horizontally slicing the data at regular intervals. This recreates past conditions by removing the effects of fault-slip and differential compaction. These “time-slices” contain clear images of channels, canyons and fan-deposits allowing sediment provenance and transport direction to be mapped and interpreted. Finally, seismic section images from the Parihaka 3D and ES89 2D seismic surveys are generated along paths intersecting key geological features within the study area.</p>

Deformation history and U–Pb zircon geochronology of the high grade metamorphic rocks within the Klaeng fault zone, eastern Thailand

2013 ◽  
Vol 77 ◽  
pp. 224-233 ◽  
Author(s):  
Pitsanupong Kanjanapayont ◽  
Piyanuch Kieduppatum ◽  
Urs Klötzli ◽  
Eva Klötzli ◽  
Punya Charusiri
Keyword(s):  
Fault Zone ◽  
Metamorphic Rocks ◽  
High Grade ◽  
Zircon Geochronology ◽  
Deformation History

scholarly journals Interactions between the prograding Giant Foresets Formation and a subsiding depocentre: Insights from the Parihaka 3D & ES89 2D seismic surveys

2021 ◽  
Author(s):  
◽  
Aaron Graeme Johnston
Keyword(s):  
Sediment Transport ◽  
Fault Zone ◽  
Large Scale ◽  
Sediment Provenance ◽  
Normal Faulting ◽  
Seismic Section ◽  
Seismic Surveys ◽  
The North ◽  
Geological Features ◽  
Transport Direction

<p>This seismic interpretation project provides new insights into the interaction between the Pliocene-aged Giant Foresets Formation and the faults bounding the Northern Graben. A newly named fault-bounded depocentre within the North Taranaki Graben, the Arawa Sub-Basin, has subsided during the Pliocene, attracting volumes of sediment across the Parihaka Fault within large-scale channels. The study images kilometer-scale channels and explores the interplay between the progradation of the Giant Foresets Formation and normal faulting along the Cape Egmont Fault Zone. A focus is placed on imaging the provenance and depositional facies of sedimentary packages throughout the foresetting sequence of the Giant Foresets Formation.  Mapping of the Waipipian-Nukumaruan-aged foresetting sequence within the offshore northern Taranaki Basin has previously shown the primary sediment transport direction is primarily NNW. This is contradicted by sediment-transport features mapped within the study area showing the sediment transport direction fluctuates between NE and SE. The primary mechanism of sediment redirection is faulting along the Cape Egmont Fault Zone and subsidence within the North Taranaki Graben, an elongate SW-NE graben within the northern Taranaki Basin. Smaller (˜10s m-scale) channels concentrate into much larger (˜100s m- to km-scale) mega-channels that travel E/NE into the subsiding Arawa Sub-Basin. Volcanic intrusions of the Mohakatino Volcanic Formation have also influenced the evolution of the mega-channels in the study area, via uplift and doming of the seafloor which provided a barrier to the transport of sediment.  The Parihaka 3D and ES89 2D seismic surveys are interpreted using the IHS Kingdom software package to create a basic framework of horizons and faults over the Pliocene-Recent interval. Depth grid maps are produced from the grid of horizon picks. Isochore maps are produced which span key intervals between depth grids. A coherency cube of the Parihaka 3D is generated from the 3D seismic volume using OpendTect. Using the framework of faults and horizons within the coherency cube, imaging sediment transport and deposition features in the vicinity of normal faulting is made possible by flattening on a top foresets horizon and horizontally slicing the data at regular intervals. This recreates past conditions by removing the effects of fault-slip and differential compaction. These “time-slices” contain clear images of channels, canyons and fan-deposits allowing sediment provenance and transport direction to be mapped and interpreted. Finally, seismic section images from the Parihaka 3D and ES89 2D seismic surveys are generated along paths intersecting key geological features within the study area.</p>

scholarly journals Ultramafic rocks in the North Patagonian Andes: is their emplacement associated with the Neogene tectonics of the Liquiñe–Ofqui Fault Zone?

2017 ◽  
Vol 44 (1) ◽  
pp. 1 ◽  
Author(s):  
Francisco Hervé ◽  
Francisco José Fuentes ◽  
Mauricio Calderón ◽  
Mark Fanning ◽  
Paulo Quezada ◽  
...  
Keyword(s):  
Fault Zone ◽  
Detrital Zircons ◽  
Ultramafic Rocks ◽  
Metamorphic Rocks ◽  
Western Slope ◽  
Low Grade ◽  
Flower Structure ◽  
The North ◽  
Patagonian Andes ◽  
Forearc Region

Serpentinites and fresh or partially serpentinized harzburgite crop out in the western slope of the North Patagonian Andes of continental Chiloé (41°44’-42°12’S). These rocks are spatially associated with low-grade metamorphic rocks containing Cenozoic detrital zircons. The metamorphic rocks, together with Devonian metasediments, have been mapped previously as Late Paleozoic-Triassic metamorfic complex, an age no longer tenable for at least part of the complex. Transpressional tectonic emplacement of the ultramafic body or bodies is thought to have been related to activity on the Liquiñe-Ofqui Fault Zone, following a late Oligocene-Early Miocene extensional phase in the forearc region of the present Andes. This fault zone occurs immediately east of the outcrops of the ultramafic rocks and has been interpreted previously as generating a hemi-flower or flower structure.

Sign in / Sign up

Export Citation Format

Share Document