scholarly journals Analysis of Palaeogene strike-slip tectonics along the southern East Greenland margin (Sødalen area)

1969 ◽  
Vol 23 ◽  
pp. 65-68 ◽  
Author(s):  
Pierpaolo Guarnieri
Keyword(s):  
Structural Data ◽  
Field Work ◽  
Strike Slip ◽  
Normal Faults ◽  
Large Area ◽  
East Greenland ◽  
Tectonic History ◽  
History Of ◽  
Host Rocks ◽  
Greenland Margin

This paper describes structural data collected during field work in southern East Greenland, a region characterised by a complex tectonic history. Here, 3D photogeology based on aerial and oblique photographs using high-resolution photogrammetry of a 150 km2 area in Sødalen in southern East Greenland shows ESE–WNW-trending faults cross-cutting Paleocene rift structures and flexure-related normal faults. The kinematic analysis highlights oblique and left-lateral strike-slip movements along faults oriented 120°. Strike-slip and dip-slip kinematic indicators on the walls of the chilled contacts between alkaline E–W-oriented dykes and the volcanic host rocks suggest that the faults and dykes formed at the same time, or maybe the faults were re-activated at a later stage. Palaeostress analysis, performed by inversion of fault-slip data, shows the presence of three different tectonic events. Coupling the 3D photogeological tool with structural analysis at key localities is a fundamental way to understand better the tectonic history of such a large area.

scholarly journals Surging glaciers in Greenland – a status

1988 ◽  
Vol 140 ◽  
pp. 106-110
Author(s):  
A Weidick
Keyword(s):  
Aerial Photography ◽  
Wide Angle ◽  
Large Area ◽  
East Greenland ◽  
West Greenland ◽  
Geodetic Institute ◽  
Glacier Changes ◽  
History Of ◽  
Glacier Surges

New wide-angle vertical aerial photography covering most of West and East Greenland were flown in the years 1981 and 1985 by Mark Hurd Corp., Minneapolis, Minnesota, for the Geodetic Institute, Copenhagen. The photographs are on a scale of approximately 1:150 000,so that single photographs cover a large area, and are valuable as bench marks for glacier changes. These photographs have been used for updating information on West Greenland glacier changes and the history of West Greenland glacier surges. Those covering East Greenland have been used for location of importantcentres of surging glaciers.

scholarly journals Late Cretaceous to Paleogene post-obduction extension and subsequent Neogene compression in the Oman Mountains

GeoArabia ◽  
2006 ◽  
Vol 11 (4) ◽  
pp. 17-40 ◽  
Author(s):  
Marc Fournier ◽  
Claude Lepvrier ◽  
Philippe Razin ◽  
Laurent Jolivet
Keyword(s):  
Late Cretaceous ◽  
Large Scale ◽  
Early Miocene ◽  
Normal Faults ◽  
Zagros Mountains ◽  
Lower Eocene ◽  
Oman Mountains ◽  
Tectonic History ◽  
History Of ◽  
Arabian Platform

ABSTRACT After the obduction of the Semail ophiolitic nappe onto the Arabian Platform in the Late Cretaceous, north Oman underwent several phases of extension before being affected by compression in the framework of the Arabia-Eurasia convergence. A tectonic survey, based on structural analysis of fault-slip data in the post-nappe units of the Oman Mountains, allowed us to identify major events of the Late Cretaceous and Cenozoic tectonic history of northern Oman. An early ENE-WSW extensional phase is indicated by synsedimentary normal faults in the Upper Cretaceous to lower Eocene formations. This extensional phase, which immediately followed ductile extension and exhumation of high-pressure rocks in the Saih Hatat region of the Oman Mountains, is associated with large-scale normal faulting in the northeast Oman margin and the development of the Abat Basin. A second extensional phase, recorded in lower Oligocene formations and only documented by minor structures, is characterized by NNE (N20°E) and NW (N150°E) oriented extensions. It is interpreted as the far-field effect of the Oligocene-Miocene rifting in the Gulf of Aden. A late E-W to NE-SW directed compressional phase started in the late Oligocene or early Miocene, shortly after the collision in the Zagros Mountains. It is attested by folding, and strike-slip and reverse faulting in the Cenozoic series. The direction of compression changed from ENE-WSW in the Early Miocene to almost N-S in the Pliocene.

Paleocene sub-basaltic sediments on Savoia Halvø, East Greenland

2002 ◽  
pp. 111-116 ◽  
Author(s):  
Henrik Nøhr-Hansen ◽  
Stefan Piasecki
Keyword(s):  
Sea Level ◽  
Sedimentary Basins ◽  
Field Work ◽  
Lava Flows ◽  
Rift Basins ◽  
Flood Basalts ◽  
East Greenland ◽  
Sedimentary Deposits ◽  
Early Paleocene ◽  
Greenland Margin

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Nøhr-Hansen, H., & Piasecki, S. (2002). Paleocene sub-basaltic sediments on Savoia Halvø, East Greenland. Geology of Greenland Survey Bulletin, 191, 111-116. https://doi.org/10.34194/ggub.v191.5137 _______________ Field work by the Geological Survey of Denmark and Greenland (GEUS) on Savoia Halvø, central East Greenland in 2001 (see also Larsen et al. 2002, this volume) included a study of sediments underlying the Palaeogene basalts on the south coast of Scoresby Sund (Fig. 1). The importance of this small exposure is based on the fact that it provides one of the few opportunities for establishing a marine biostratigraphic date for the sediments below the basalts. Dinoflagellate cysts from the sediments provide a maximum Early Paleocene age for the onset of the volcanism in central East Greenland. Reports from previous field work have mentioned the sediments (Hassan 1953; Birkenmajer 1972), but no precise age assignment was presented due to the absence of diagnostic fossils. The sub-volcanic sediments of Savoia Halvø represent the youngest preserved marine sedimentary deposits of the Upper Palaeozoic – Cenozoic rift-basins onshore East Greenland. The overlying Palaeogene flood basalts occasionally contain very thin sedimentary beds between the lava flows, but these were deposited above sea level. Neogene uplift of the East Greenland margin brought a definitive end to accumulation in the old sedimentary basins (Watt et al. 1986; Christiansen et al. 1992).

Multidisciplinary analyses for mapping and evaluating kinematics and stress/strain field at active faults and fissures at NE Rift, Mt Etna (Italy)

2021 ◽  
Author(s):  
Susanna Falsaperla ◽  
Alessandro Tibaldi ◽  
Noemi Corti ◽  
Emanuela De Beni ◽  
Fabio L. Bonali ◽  
...  
Keyword(s):  
Active Faults ◽  
Normal Fault ◽  
Structural Data ◽  
Field Work ◽  
Normal Faults ◽  
Extension Rate ◽  
Mt Etna ◽  
Hazardous Zone ◽  
Eruptive Fissures ◽  
Ne Rift

<p>Strategies for disaster risk reduction in volcanic areas are mostly driven by multidisciplinary analyses, which offer effective and complementary information on complex geomorphological and volcano-tectonic environments. For example, quantification of the offset at active faults and fissures is of paramount importance to shed light on the kinematics of zones prone to deformation and/or seismic activity. This provides key information for the assessment of seismic hazard, but also for the identification of conditions that may favor magma uprising and opening of eruptive fissures.</p><p>Here we present the results of a study encompassing detailed geological, structural and seismological observations focusing on part of the NE Rift at Etna volcano (Italy). The area is situated at an elevation ranging between 2700 and 1900 m a.s.l. where harsh meteorological conditions and difficult logistics render classical field work a troublesome issue. In order to bypass these difficulties, high-resolution (2.8 cm) UAV survey has been recently completed. The survey highlights the presence of 250 extension fractures, 20 normal fault segments, and 54 eruptive fissures. The study allows us to quantify the kinematics at extensional fractures and normal faults, obtaining an extension rate of 1.9 cm/yr for the last 406 yr. With a total of 432 structural data collected by UAV along with SfM photogrammetry, this work also demonstrates the suitability of the application of such surveys for the monitoring of hazardous zone.</p>

Extension and transtension associated with strike-slip faults and its relation with aquifer potentials: a case study in Aravalli terrane (North Gujarat), India

2020 ◽  
Author(s):  
Rudra Mohan Pradhan ◽  
Tapas Kumar Biswal
Keyword(s):  
Complex Geometry ◽  
Fractured Rock ◽  
Primary Source ◽  
Structural Data ◽  
Shear Zones ◽  
Structural Features ◽  
Strike Slip ◽  
Normal Faults ◽  
Fold Belt ◽  
North Gujarat

<p>Fractured rock aquifers are one of the most difficult aquifers to characterize due to complex geometry and fracture network. In Aravalli terranes of North Gujarat, communities depend on basement rock aquifers as the primary source of water supply. The hydrogeology of these aquifers is poorly understood and the drinking/irrigation wells are frequently placed in this area with little appreciation of the fracture systems. Increasing water demand puts stress to explore groundwater from less reliable sources of basement rocks and hence, makes it vital to identify potential hydrogeological zones. Lineament studies are commonly used for targeting groundwater bearing zones in hard rock terrane and very often ignore the other important structural settings viz. extension, transtension etc. For the present study, structural data pertaining faults and fractures have been mapped through fieldwork and Electrical resistivity imaging (ERT) technique. The key objective of the study is to correlate the structural features (extensional and transtensional settings) with geophysical profiles and to find out potential hydrogeological zones from where water can be explored economically. The study area comes under the Ambaji basin of Aravalli-Delhi fold belt which is a Proterozoic fold belt running 700-800 km in NE-SW direction and situated in NW India. The Aravalli-Delhi fold belt had undergone multiple phases of deformation. In this area, three major sets of fractures are present and are oriented largely in WNW-ESE, NE-SW, and NW-SE direction. The WNW-ESE fracture is dextral in nature which has interpreted from the displacement of fold limbs. Further, these are right lateral en-echelon normal faults where NE-SW extension has been taken place. There is another set of fracture i.e. NW-SE which is due to stretching of strike-slip fault. The ductile shear zones in the area are also parallel to the NW-SE fracture set. The shear zones are opened-up due to extension and formed potential aquifers. ERT has been carried out along and across the fractures to understand the subsurface fracture geometry. The ERT shows deep sited fractures and low resistivity values at the cross-section of WNW-ESE faults with the shear zone. This concludes a strong correlation between different structural settings with potential aquifers which could be used for pumping as well as artificial recharge sites for long term sustainability.</p><p><strong>Keywords-</strong> Aravalli terrane, Aquifer, Extension, Fracture, ERT</p>

Change of stress magnitudes during the polyphase tectonic history of the Cretaceous Gyeongsang basin, southeast Korea

2013 ◽  
Vol 184 (4-5) ◽  
pp. 467-484 ◽  
Author(s):  
Pom-yong Choi ◽  
Jacques Angelier ◽  
Jean-Paul Cadet ◽  
Jae-Ha Hwang ◽  
Choon Sunwoo
Keyword(s):  
Principal Stress ◽  
Maximum Principal Stress ◽  
Strike Slip ◽  
Rock Mechanic ◽  
Shear Stresses ◽  
Tectonic History ◽  
Tectonic Events ◽  
Gyeongsang Basin ◽  
Relative Chronology ◽  
History Of

Abstract In order to evaluate the change of stress magnitudes in the Gyeongsang basin during its tectonic history, we analyzed multiple faulting episodes in the Barremian-Aptian Hasandong Formation at the Yusu site. As elsewhere in southeast Korea, the recorded sequence consists of a succession of more than fourteen faulting episodes, and the relative chronology shows that a strike-slip faulting episode usually coexisted with a coaxial extensional episode. Likewise, seven couples of synchronous coaxial episodes recognised in the Gyeongsang basin are assigned to seven tectonic events (T_1 to T_7 events). The friction line (in the sense of Byerlee) allows us to determine the ratios between principal stress magnitudes as well as the origin of the dimensionless Mohr diagram. This line can be deduced from tension fractures on fault planes affected by friction and from the lower limit of scattered distribution of the normal stresses vs. shear stresses of faults. Dimensionless failure envelopes drawn for coaxial strike-slip and extensional episodes are adjusted to the experimental Mohr failure envelope derived from rock mechanic tests to determine the complete stress tensors. The maximum principal stress magnitudes of strike-slip episodes show a transition from 169 MPa in the Barremian-Coniacian T_1 Event through 263 MPa and 246 MPa in the T_2 and T_4 events, respectively to 235 MPa in the Quaternary T_7 Event; additional horizontal extension (ΔσT) have changed from −6 MPa in the T_1 Event through −8 MPa in the T_2 Event to −17 MPa in the T_7 Event. Because the studied site is currently exposed, the determined overburden (1.9 km) for the T_7 Event seems to be important, indicating the presumable occurrence of this event during the early Quaternary rather than at the present day.

scholarly journals Fault Zone Evolution and Development of a Structural and Hydrological Barrier: The Quartz Breccia in the Kiggavik Area (Nunavut, Canada) and Its Control on Uranium Mineralization

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 319 ◽  
Author(s):  
Alexis Grare ◽  
Olivier Lacombe ◽  
Julien Mercadier ◽  
Antonio Benedicto ◽  
Marie Guilcher ◽  
...  
Keyword(s):  
Early Stage ◽  
Field Work ◽  
Uranium Mineralization ◽  
Isotopic Signatures ◽  
Thelon Basin ◽  
Tectonic History ◽  
Evolution And Development ◽  
Major Fault ◽  
History Of ◽  
Oxygen Isotopic

In the Kiggavik area (Nunavut, Canada), major fault zones along, or close to, where uranium deposits are found are often associated with occurrence of thick quartz breccia (QB) bodies. These bodies formed in an early stage (~1750 Ma) of the long-lasting tectonic history of the Archean basement, and of the Proterozoic Thelon basin. The main characteristics of the QB are addressed in this study; through field work, macro and microscopic observations, cathodoluminescence microscopy, trace elements, and oxygen isotopic signatures of the quartz forming the QB. Faults formed earlier during syn- to post-orogenic rifting (1850–1750 Ma) were subsequently reactivated, and underwent cycles of cataclasis, pervasive silicification, hydraulic brecciation, and quartz recrystallization. This was synchronous with the circulation of meteoric fluids mixing with Si-rich magmatic-derived fluids at depth, and were coeval with the emplacement of the Kivalliq igneous suite at 1750 Ma. These processes led to the emplacement of up to 30 m thick QB, which behaved as a mechanically strong, transverse hydraulic barrier that localized later fracturing, and compartmentalized/channelized vertical flow of uranium-bearing fluids after the deposition of the Thelon Basin (post 1750 Ma). The development and locations of QB control the location of uranium mineralization in the Kiggavik area.

scholarly journals The Neogene–Recent Hatay Graben, South Central Turkey: graben formation in a setting of oblique extension (transtension) related to post-collisional tectonic escape

2008 ◽  
Vol 145 (6) ◽  
pp. 800-821 ◽  
Author(s):  
SARAH J. BOULTON ◽  
ALASTAIR H. F. ROBERTSON
Keyword(s):  
Large Scale ◽  
Upper Cretaceous ◽  
Structural Data ◽  
Strike Slip ◽  
Stress Axis ◽  
Normal Faults ◽  
Small Scale ◽  
South Central ◽  
Collision Zone ◽  
Tectonic Escape

AbstractStructural data and a regional tectonic interpretation are given for the NE–SW-trending Hatay Graben, southern Turkey, within the collision zone of the African (Arabian) and Eurasian (Anatolian) plates. Regional GPS and seismicity data are used to shed light on the recent tectonic development of the Hatay Graben. Faults within Upper Cretaceous to Quaternary sediments are categorized as of first-, second- and third-order type, depending on their scale, location and character. Normal, oblique and strike-slip faults predominate throughout the area.The flanks of the graben are dominated by normal faults, mainly striking parallel to the graben, that is, 045–225°. In contrast, the graben axis exhibits strike-slip faults, trending 100–200°, together with normal faults striking 040–060° and 150–190° (a subset strikes 110–130°). Similarly orientated normal faults occur throughout Upper Cretaceous to Pliocene sediments, whereas strike-slip faults are mostly within Pliocene sediments near the graben axis. Stress inversion of slickenline data from mostly Pliocene sediments at ten suitable locations (all near the graben axis) show that σ3 directions (minimum stress axis ≈ extension direction) are uniform in the northeast of the graben but orientated at a high angle to the graben margins. More variable σ3 directions in the southwest may reflect local block rotations. During Miocene times, the Arabian and Anatolian plates collided, forming a foreland basin associated with flexurally controlled normal faulting. During the Late Miocene there was a transition from extension to transtension (oblique extension). The neotectonic Hatay Graben formed during the Plio-Quaternary in a transtensional setting. In the light of modern and ancient comparisons, it is suggested that contemporaneous strain was compartmentalized into large-scale normal faults on the graben margins and mainly small-scale strike-slip faults near the graben axis. Overall, the graben reflects Plio-Quaternary westward tectonic escape from a collision zone towards the east to a pre- or syn-collisional zone to the west in the Mediterranean Sea.

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