Tectonic Deformation and Volatile Loss in the Formation of Noctis Labyrinthus, Mars

2021 ◽  
Author(s):  
Corbin L. Kling ◽  
Paul K. Byrne ◽  
Rachel M. Atkins ◽  
Karl W. Wegmann
Keyword(s):  
Tectonic Deformation ◽  
Volatile Loss

Structure and tectonic evolution of the South Patagonian fold and thrust belt: Coupling between subduction dynamics, climate and tectonic deformation

2019 ◽  
pp. 675-697
Author(s):  
Matías C. Ghiglione ◽  
Gonzalo Ronda ◽  
Rodrigo J. Suárez ◽  
Inés Aramendía ◽  
Vanesa Barberón ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Tectonic Deformation ◽  
Thrust Belt ◽  
The South ◽  
Fold And Thrust Belt

Evidence of Active Tectonic Deformation in Kishtwar Area, Jammu and Kashmir, Northwest Himalaya, India

2019 ◽  
Vol 93 (3) ◽  
pp. 331-342
Author(s):  
Ahsan ul Haq ◽  
S. K. Pandita ◽  
Yudhbir Singh ◽  
G. M. Bhat ◽  
Shiv Jyoti Pandey ◽  
...  
Keyword(s):  
Tectonic Deformation ◽  
Jammu And Kashmir ◽  
Northwest Himalaya ◽  
Active Tectonic

scholarly journals New seismological data from the Calabrian arc reveal arc-orthogonal extension across the subduction zone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tiziana Sgroi ◽  
Alina Polonia ◽  
Graziella Barberi ◽  
Andrea Billi ◽  
Luca Gasperini
Keyword(s):  
Lateral Displacement ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Velocity Model ◽  
Tectonic Deformation ◽  
Accretionary Wedge ◽  
Tectonic Structures ◽  
Plate Convergence ◽  
Seismogenic Layer ◽  
Regional Tectonic

AbstractThe Calabrian Arc subduction-rollback system along the convergent Africa/Eurasia plate boundary is among the most active geological structures in the Mediterranean Sea. However, its seismogenic behaviour is largely unknown, mostly due to the lack of seismological observations. We studied low-to-moderate magnitude earthquakes recorded by the seismic network onshore, integrated by data from a seafloor observatory (NEMO-SN1), to compute a lithospheric velocity model for the western Ionian Sea, and relocate seismic events along major tectonic structures. Spatial changes in the depth distribution of earthquakes highlight a major lithospheric boundary constituted by the Ionian Fault, which separates two sectors where thickness of the seismogenic layer varies over 40 km. This regional tectonic boundary represents the eastern limit of a domain characterized by thinner lithosphere, arc-orthogonal extension, and transtensional tectonic deformation. Occurrence of a few thrust-type earthquakes in the accretionary wedge may suggest a locked subduction interface in a complex tectonic setting, which involves the interplay between arc-orthogonal extension and plate convergence. We finally note that distribution of earthquakes and associated extensional deformation in the Messina Straits region could be explained by right-lateral displacement along the Ionian Fault. This observation could shed new light on proposed mechanisms for the 1908 Messina earthquake.

scholarly journals Basement Structure and Styles of Active Tectonic Deformation in Central Interior Alaska

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 127
Author(s):  
Nilesh C. Dixit ◽  
Catherine Hanks
Keyword(s):  
Crustal Structure ◽  
Foreland Basin ◽  
Active Regions ◽  
Structural Features ◽  
Tectonic Deformation ◽  
Block Rotation ◽  
High Concentration ◽  
Intraplate Earthquakes ◽  
Interior Alaska ◽  
Nenana Basin

Central Interior Alaska is one of the most seismically active regions in North America, exhibiting a high concentration of intraplate earthquakes approximately 700 km away from the southern Alaska subduction zone. Seismological evidence suggests that intraplate seismicity in the region is not uniformly distributed, but concentrated in several discrete seismic zones, including the Nenana basin and the adjacent Tanana basin. Although the location and magnitude of the seismic activity in both basins are well defined by a network of seismic stations in the region, the tectonic controls on these intraplate earthquakes and the heterogeneous nature of Alaska’s continental interior remain poorly understood. We investigated the crustal structure of the Nenana and Tanana basins using available seismic reflection, aeromagnetic and gravity anomaly data, supplemented by geophysical well logs and outcrop data. We developed nine new two-dimensional forward models to delineate internal geometries and the crustal structure of Alaska’s interior. The results of our study demonstrates a strong crustal heterogeneity beneath both basins. The Tanana basin is a relatively shallow (up to 2 km) asymmetrical foreland basin with its southern, deeper side controlled by the northern foothills of the Central Alaska Range. Northeast-trending left lateral strike-slip faults within the Tanana basin are interpreted as a zone of clockwise crustal block rotation. The Nenana basin has a fundamentally different geometry. It is a deep (up to 8 km), narrow transtensional pull-apart basin that is deforming along the left-lateral Minto Fault. This study identifies two distinct modes of current tectonic deformation in Central Interior Alaska and provides a basis for modeling the interplay between intraplate stress fields and major structural features that potentially influence the generation of intraplate earthquakes in the region.

scholarly journals Fault reactivation and strain partitioning across the brittle-ductile transition

Geology ◽  
2019 ◽  
Vol 47 (12) ◽  
pp. 1127-1130 ◽  
Author(s):  
Gabriel G. Meyer ◽  
Nicolas Brantut ◽  
Thomas M. Mitchell ◽  
Philip G. Meredith
Keyword(s):  
Fault Slip ◽  
Fault Reactivation ◽  
Ductile Deformation ◽  
Tectonic Deformation ◽  
Gradual Change ◽  
Bulk Rock ◽  
Total Deformation ◽  
Bulk Strain ◽  
Brittle Ductile Transition ◽  
Ductile Flow

Abstract The so-called “brittle-ductile transition” is thought to be the strongest part of the lithosphere, and defines the lower limit of the seismogenic zone. It is characterized not only by a transition from localized to distributed (ductile) deformation, but also by a gradual change in microscale deformation mechanism, from microcracking to crystal plasticity. These two transitions can occur separately under different conditions. The threshold conditions bounding the transitions are expected to control how deformation is partitioned between localized fault slip and bulk ductile deformation. Here, we report results from triaxial deformation experiments on pre-faulted cores of Carrara marble over a range of confining pressures, and determine the relative partitioning of the total deformation between bulk strain and on-fault slip. We find that the transition initiates when fault strength (σf) exceeds the yield stress (σy) of the bulk rock, and terminates when it exceeds its ductile flow stress (σflow). In this domain, yield in the bulk rock occurs first, and fault slip is reactivated as a result of bulk strain hardening. The contribution of fault slip to the total deformation is proportional to the ratio (σf − σy)/(σflow − σy). We propose an updated crustal strength profile extending the localized-ductile transition toward shallower regions where the strength of the crust would be limited by fault friction, but significant proportions of tectonic deformation could be accommodated simultaneously by distributed ductile flow.

Granitoid complexes and the Archean tectonic record in the southern part of northwestern Ontario

1979 ◽  
Vol 16 (10) ◽  
pp. 1965-1977 ◽  
Author(s):  
W. M. Schwerdtner ◽  
D. Stone ◽  
K. Osadetz ◽  
J. Morgan ◽  
G. M. Stott
Keyword(s):  
Large Scale ◽  
Vertical Motion ◽  
Strike Slip ◽  
Horizontal Motion ◽  
Tectonic Deformation ◽  
Northwestern Ontario ◽  
Greenstone Belts ◽  
Second Period ◽  
Transcurrent Faults ◽  
Regional Compression

Two principal, possibly overlapping, periods of tectonic deformation can be distinguished in the Archean of northwestern Ontario, a period of dominantly vertical-motion tectonics and a period of dominantly horizontal-motion tectonics. Gigantic diapirs of foliated to gneissic tonalite–granodiorite developed during the first period and appear to be responsible for the gross structure of, and the major folds within, the metavolcanic–metasedimentary masses ("greenstone belts"). These diapirs are most likely due to mechanical remobilization of early tabular batholiths which originally intruded the oldest supracrustal rocks presently exposed. Later massive to foliated, dioritic to granitic plutons that vary from concordant, crescentic plutons to partly discordant plutons of various shapes and sizes were emplaced into the diapirs.The second period of tectonic deformation is characterized by large-scale dextral shearing and the development of major transcurrent faults under northwesterly regional compression. The strike-slip motions of this period outlasted the late plutonism, and led to the development of mylonitic zones which cut all Archean granitoid plutons.

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