Development of the Salt Spring Wash Basin in a reentrant in the hanging wall of the South Virgin-White Hills detachment fault, Lake Mead domain, northwest Arizona

Author(s):  
Nathan Blythe ◽  
Paul J. Umhoefer ◽  
Ernest M. Duebendorfer ◽  
William C. McIntosh ◽  
Lisa Peters
Author(s):  
Kristian Svennevig ◽  
Peter Alsen ◽  
Pierpaolo Guarnieri ◽  
Jussi Hovikoski ◽  
Bodil Wesenberg Lauridsen ◽  
...  

The geological map sheet of Kilen in 1:100 000 scale covers the south-eastern part of the Carboniferous– Palaeogene Wandel Sea Basin in eastern North Greenland. The map area is dominated by the Flade Isblink ice cap, which separates several minor isolated landmasses. On the semi-nunatak of Kilen, the map is mainly based on oblique photogrammetry and stratigraphical field work while in Erik S. Henius Land, Nordostrundingen and northern Amdrup Land the map is based on field data collected during previous, 1:500 000 scale regional mapping. Twenty-one Palaeozoic–Mesozoic mappable units were identified on Kilen, while the surrounding areas comprise the Late Cretaceous Nakkehoved Formation to the north-east and the Late Carboniferous Foldedal Formation to the south-west. On Kilen, the description of Jurassic–Cretaceous units follows a recently published lithostratigraphy. The Upper Palaeozoic–lowermost Cretaceous strata comprise seven formations and an informal mélange unit. The overlying Lower–Upper Cretaceous succession comprises the Galadriel Fjeld and Sølverbæk Formations, which are subdivided into six and five units, respectively. In addition, the Quaternary Ymer Formation was mapped on south-east Kilen. The Upper Palaeozoic to Mesozoic strata of Kilen are faulted and folded. Several post-Coniacian NNW–SSE-trending normal faults are identified and found to be passively folded by a later N–S compressional event. A prominent subhorizontal fault, the Central Detachment, separates two thrust sheets, the Kilen Thrust Sheet in the footwall and the Hondal Elv Thrust Sheet in the hanging wall. The style of deformation and the structures found on Kilen are caused by compressional tectonics resulting in post-extensional, presumably Early Eocene, folding and thrusting and basin inversion. The structural history of the surrounding areas and their relation to Kilen await further studies.


Author(s):  
Kristian Svennevig ◽  
Peter Alsen ◽  
Pierpaolo Guarnieri ◽  
Jussi Hovikoski ◽  
Bodil Wesenberg Lauridsen ◽  
...  

NOTE: This Map Description was published in a former series of GEUS Bulletin. Please use the original series name when citing this series, for example: Svennevig, K., Alsen, P., Guarnieri, P., Hovikoski, J., Wesenberg Lauridsen, B., Krarup Pedersen, G., Nøhr-Hansen, H., & Sheldon, E. (2018). Descriptive text to the Geological map of Greenland, 1:100 000, Kilen 81 Ø.1 Syd. Geological Survey of Denmark and Greenland Map Series 8, 1-29. https://doi.org/10.34194/geusm.v8.4526 _______________ The geological map sheet of Kilen in 1:100 000 scale covers the south-eastern part of the Carboniferous–Palaeogene Wandel Sea Basin in eastern North Greenland. The map area is dominated by the Flade Isblink ice cap, which separates several minor isolated landmasses. On the semi-nunatak of Kilen, the map is mainly based on oblique photogrammetry and stratigraphical field work while in Erik S. Henius Land, Nordostrundingen and northern Amdrup Land the map is based on field data collected during previous, 1:500 000 scale regional mapping. Twenty-one Palaeozoic–Mesozoic mappable units were identified on Kilen, while the surrounding areas comprise the Late Cretaceous Nakkehoved Formation to the north-east and the Late Carboniferous Foldedal Formation to the south-west. On Kilen, the description of Jurassic–Cretaceous units follows a recently published lithostratigraphy. The Upper Palaeozoic–lowermost Cretaceous strata comprise seven formations and an informal mélange unit. The overlying Lower–Upper Cretaceous succession comprises the Galadriel Fjeld and Sølverbæk Formations, which are subdivided into six and five units, respectively. In addition, the Quaternary Ymer Formation was mapped on south-east Kilen. The Upper Palaeozoic to Mesozoic strata of Kilen are faulted and folded. Several post-Coniacian NNW–SSE-trending normal faults are identified and found to be passively folded by a later N–S compressional event. A prominent subhorizontal fault, the Central Detachment, separates two thrust sheets, the Kilen Thrust Sheet in the footwall and the Hondal Elv Thrust Sheet in the hanging wall. The style of deformation and the structures found on Kilen are caused by compressional tectonics resulting in post-extensional, presumably Early Eocene, folding and thrusting and basin inversion. The structural history of the surrounding areas and their relation to Kilen await further studies.


2017 ◽  
Vol 18 (6) ◽  
pp. 2028-2053 ◽  
Author(s):  
D. Bonnemains ◽  
J. Escartín ◽  
C. Mével ◽  
M. Andreani ◽  
A. Verlaguet

2021 ◽  
Author(s):  
Willemijn S.M.T. van Kooten ◽  
Edward R. Sobel ◽  
Cecilia del Papa ◽  
Patricio Payrola ◽  
Alejandro Bande ◽  
...  

<p>The Cretaceous period in NW Argentina is dominated by the formation of the Salta rift basin, an intracontinental rift basin with multiple branches extending from the central Salta-Jujuy High. One of these branches is the ENE-WSW striking Lomas de Olmedo sub-basin, which hosts up to 5 km of syn- and post-rift deposits of the Salta Group, accommodated by substantial throw along SW-NE striking normal faults and subsequent thermal subsidence during the Cretaceous-Paleogene. Early compressive movement in the Eastern Cordillera led to the formation of a foreland basin setting that was further dissected in the Neogene by the uplift of basement-cored ranges. As a consequence, the northwestern part of the Lomas de Olmedo sub-basin was disconnected from the Andean foreland and local depocenters such as the Cianzo basin were formed, whereas the eastern sub-basin area is still part of the Andean foreland. Thus, the majority of the Salta Group to the east is located in the subsurface and has been extensively explored for petroleum, while in northwestern part of the sub-basin, the Salta Group is increasingly deformed and is fully exposed in the km-scale Cianzo syncline of the Hornocal ranges. The SW-NE striking Hornocal fault delimits the Cianzo basin to the south and the Cianzo syncline to the north. During the Cretaceous, it formed the northern margin of the Lomas de Olmedo sub-basin, which is indicated by an increasing thickness of the syn-rift deposits towards the Hornocal fault, as well as a lack of syn-rift deposits on the footwall block. Structural mapping and unpublished apatite fission track (AFT) data show that the Hornocal normal fault was reactivated and inverted during the Miocene. Although structural and sedimentary features of the Cianzo basin infill provide information about the relative timing of fault activity, there is a lack of low-temperature thermochronology. Herein, we aim to constrain the exhumation of the Lomas de Olmedo sub-basin during the Cretaceous rifting phase, as well as the onset and magnitude of fault reactivation in the Miocene. We collected 74 samples for low-temperature thermochronology along two major NW-SE transects in the Cianzo basin and adjacent areas. Of these samples, 59 have been analyzed using apatite and/or zircon (U-Th-Sm)/He thermochronology (AHe, ZHe). Furthermore, 49 samples have been prepared for AFT analysis. The ages are incorporated in thermo-kinematic modelling using Pecube in order to test the robustness of uplift and exhumation scenarios. On the hanging wall block of the N-S striking east-vergent Cianzo thrust north of the Hornocal fault, Jurassic ZHe ages are attributed to pre-Salta Group exhumation. However, associated thrusts to the south show ZHe ages as young as Eocene-Oligocene, which might indicate early post-rift activity along those thrusts. AHe data from the Cianzo syncline show a direct age-elevation relationship with Late Miocene-Pliocene cooling ages, indicating the onset of rapid exhumation along the Hornocal fault in the Miocene. This is consistent with regional data and suggests that pre-existing extensional structures were reactivated during Late Miocene-Pliocene compressive movement within this part of the Central Andes.</p>


2001 ◽  
Vol 138 (3) ◽  
pp. 253-276 ◽  
Author(s):  
JEAN-CLAUDE VANNAY ◽  
BERNHARD GRASEMANN

Two paradoxical geological features of the Himalaya are the syn-convergence extension and the inverted metamorphic isograds observed in the crystalline core zone of this orogen. This High Himalayan Crystalline Sequence corresponds to an up to 40 km thick sequence of amphibolite to granulite facies gneiss, bounded by the Main Central Thrust at the base, and by the extensional faults of the South Tibetan Detachment System at the top. Geochronological and structural data demonstrate that coeval movements along both the Main Central Thrust and South Tibetan Detachment System during Early to Middle Miocene times were related to a tectonically controlled exhumation of these high-grade metamorphic rocks. The High Himalayan Crystalline Sequence systematically shows an inverted metamorphic zonation, generally characterized by a gradual superposition of garnet, staurolite, kyanite, sillimanite + muscovite and sillimanite + K-feldspar isograds, from the base to the top of the unit. Recent kinematic flow analyses of these metamorphic rocks demonstrate the coexistence of both simple shear and pure shear during the ductile deformation. The simple shear component of such a general non-coaxial flow could explain a rotation of isograds, eventually resulting in an inversion. The pure shear component of the flow implies a thinning of the metamorphic sequence that must be balanced by a perpendicular stretching of the unit parallel to its boundaries. Inasmuch as seismic data show that both the Main Central Thrust and South Tibetan Detachment System converge at depth, a thinning of the wedge-shaped High Himalayan Crystalline Sequence should induce a ductile extrusion of these high-grade rocks toward the surface. Rapid extension at the top of the sequence could thus be the consequence of a general shear extrusion of this unit relative to its hanging wall. Moreover, this extensional movement should decrease with depth to become zero where the boundaries of the unit meet, accounting for the paradoxical convergence of the South Tibetan Detachment System toward the Main Central Thrust. Furthermore, a general flow combining simple shear and pure shear can reconcile inverted isograds with the lack of inverted pressure field gradient across the High Himalayan Crystalline Sequence, despite an intense non-coaxial deformation. In good agreement with the seismic, kinematic and P–T–t constraints on the Himalayan tectono-thermal evolution, general shear extrusion provides a consistent model accounting for both inverted isograds and rapid extension in a compressional orogenic setting.


1995 ◽  
Vol 132 (5) ◽  
pp. 599-609 ◽  
Author(s):  
G. S. Kimbell ◽  
P. Stone

AbstractThe Iapetus Suture (Solway) line coincides with a magnetic low, which lies between magnetic highs over southwestern Scotland and the Lake District-Isle of Man region. Although topography on deep magnetic basement can account for these long wavelength geophysical variations, an explanation which involves lateral basement magnetization contrasts is preferred on the basis of (a) correlations between inferred magnetization boundaries and major structures delineated from other evidence, and (b) the apparent westward continuation of the Solway low through Ireland and Newfoundland across areas with very different subsidence histories but similar position with respect to the collision of Laurentia and Avalonia. In the preferred model, relatively magnetic continental crust beneath the Southern Uplands and Lake District terranes is separated by a zone of less magnetic crust interpreted as sedimentary rock of Avalonian affinity carried to deeper structural levels within the Iapetus Suture Zone. The magnetic unit beneath the Southern Uplands is bounded to the south by the northward-dipping Iapetus Suture and to the north by a structure which may have been reactivated in late Caledonian times to produce the Moniaive Shear Zone in the overlying rocks; this unit may represent the ‘missing’ arc terrane inferred from provenance studies. Alternatively, the two magnetic basement domains may have originally been part of the same terrane, with that portion beneath the Southern Uplands rifting from the Avalonian continent during its northwards drift and being subsequently trapped in the hanging wall of the Iapetus Suture. The southern margin of the Lake District domain appears as a discontinuity in the magnetic anomaly pattern, with long wavelength anomalies to the south having a southeast ‘Tornquist’ trend.


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