Filtering by Subject: Tectonics and Structure

Origin and kinematics of a basin-scale, non-polygonal, layer-bound normal fault system in the Levant Basin, eastern Mediterranean

Amir Joffe, Chris Jackson, Josh Steinberg, et al.

Published: 2022-02-28
Subjects: Geology, Tectonics and Structure

Polygonal, layer-bound normal faults can extend over very large areas (>2,000,000 km2) of sedimentary basins. Best developed in very fine-grained rocks, these faults are thought to form during early burial in response to a range of diagenetic processes, including compaction and water expulsion. Local deviations from this idealised polygonal pattern are common; however, basin-scale, layer-bound [...]

Fault slip-rates and Coulomb stress interactions in the intersection zone of the Hope, Kelly and Alpine Faults, South Island, New Zealand

Jessie L. Vermeer, Mark Quigley, Rob Langridge, et al.

Published: 2022-02-24
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure

The Hope Fault is a major strike-slip plate boundary fault in the Marlborough Fault Zone of New Zealand’s South Island that transfers slip between the Alpine Fault and Hikurangi subduction zone. We use lidar-based geomorphic and fault mapping, and optically stimulated luminescence (OSL; quartz) and infrared stimulated luminescence (IRSL; feldspar) dating of fault-proximal sedimentary deposits to [...]

Along-Dip Segmentation of the Slip Behavior and Rheology of the Copiapó Ridge Subducted in North-Central Chile

Francisco Pasten-Araya, Bertrand Potin, Kellen Azua, et al.

Published: 2022-02-24
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure

We studied the along-dip influence of the Copiapó ridge subduction in the Atacama region, North-Central Chile by building a new seismicity catalog, including similar events and non-volcanic tremors (NVTs). We also obtained a 3-D tomographic model for P- and S-waves velocity (and the implied Vp/Vs ratio). We identify down-dip segmentation involving 4 distinct segments: a locked seismogenic zone [...]

Early evolution of the Adelaide Superbasin

Jarred Cain Lloyd, Alan S. Collins, Morgan L. Blades, et al.

Published: 2022-02-17
Subjects: Earth Sciences, Geochemistry, Geology, Sedimentology, Stratigraphy, Tectonics and Structure

Continental rifts have a significant role in supercontinent breakup, and the development of sedimentary basins. The Australian Adelaide Superbasin is one of the largest and best-preserved rift systems that initiated during the breakup of Rodinia, yet substantial challenges still hinder our understanding of its early evolution and place within the Rodinian supercontinent. In the past decade, our [...]

Macrostratigraphy of the Ediacaran System in North America

Daniel Christian Segessenman, Shanan E Peters

Published: 2022-02-11
Subjects: Earth Sciences, Geochemistry, Geology, Paleontology, Sedimentology, Stratigraphy, Tectonics and Structure

Ediacaran sediments record the termination of Cryogenian ‘Snowball Earth’ glaciations, preserve the first occurrences of macroscopic metazoans, and contain one of the largest known negative δ13C excursions (the Shuram-Wonoka). The rock record for the transition between the Proterozoic and Phanerozoic in North America is also physically distinct, with much of the continent characterized by a wide [...]

S-wave modeling of the Showa-Shinzan lava dome in Usu Volcano, Northern Japan, from seismic observations

Akiko Takeo, Kiwamu Nishida, Hiroshi Aoyama, et al.

Published: 2022-02-09
Subjects: Geophysics and Seismology, Tectonics and Structure, Volcanology

To obtain an internal S-wave velocity structure, we conducted a passive seismic campaign with 21 1-Hz seismometers on and around the Showa-Shinzan lava dome, which emerged during the 1943–1945 eruption of Usu Volcano, Japan. Before the campaign, we calibrated seismometers and found slight phase-response differences between seismometers of less than 1–2 degrees. After the campaign, we extracted [...]

Indian Plate paleogeography, subduction, and horizontal underthrusting below Tibet: paradoxes, controvercies, and opportunities

Douwe J.J. van Hinsbergen

Published: 2022-02-06
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology, Tectonics and Structure, Volcanology

The India-Asia collision zone is the archetype to calibrate geological responses of continent-continent collision, but hosts a paradox: there is no orogen-wide geological record of oceanic subduction after initial collision around 60-55 Ma, yet thousands of kilometers of post-collisional subduction occurred before arrival of unsubductable continental lithosphere that currently horizontally [...]

Trench migration and slab buckling control the formation of the Central Andes

Michaël Pons, Stephan V. Sobolev, Sibiao Liu, et al.

Published: 2022-02-03
Subjects: Geophysics and Seismology, Other Earth Sciences, Tectonics and Structure

The formation of the Central Andes dates back to ~50 Ma, but its most pronounced phase, including the growth of the Altiplano-Puna Plateau and pulsatile tectonic shortening phases, occurred within the last 25 Ma. The reason for this evolution remains unexplained. Using geodynamic numerical modeling we infer that the primary cause of the pulses of tectonic shortening and growth of Central Andes is [...]

Quaternary E-W extension uplifts Kythira Island and segments the Hellenic Arc

Gino de Gelder, David Fernández-Blanco, Nazik Ögretmen, et al.

Published: 2022-01-25
Subjects: Geology, Geomorphology, Paleontology, Sedimentology, Stratigraphy, Tectonics and Structure

Several crustal and lithospheric mechanisms lead to deformation and vertical motion of the upper plate during subduction, but their relative contribution is often enigmatic. The Hellenic Forearc has been uplifting since Plio-Quaternary times, yet the spatiotemporal characteristics and sources of this uplift are poorly resolved. The remarkable geology and geomorphology of Kythira Island, in the [...]

Phanerozoic sedimentary cover history of the Hudson Platform: a heuristic modeling perspective

Kalin T. McDannell, Paul B. O'Sullivan, Kerry Gallagher, et al.

Published: 2022-01-19
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure

Understanding the long-term erosion and burial history of cratons is challenging due to the incompleteness of the rock record. Low-temperature thermochronology has been applied to provide constraints on these histories and apatite fission-track dating has been one of the preferred methods for the past four decades. Thermochronological data are often inverted for a thermal history along with [...]

Resolving the location of small intracontinental earthquakes using Open Access seismic and geodetic data: lessons from the 18 January 2017 mb 4.3 Tenere, Niger, earthquake

Timothy J Craig, Steven J. Gibbons

Published: 2022-01-14
Subjects: Geophysics and Seismology, Tectonics and Structure

A low-magnitude earthquake was recorded on January 18, 2017, in the T\'{e}n\'{e}r\'{e} desert in Niger. This intraplate region is exceptionally sparsely covered with seismic stations and the closest open seismic station, G.TAM in Algeria at a distance of approximately 600 km, was unusually and unfortunately not operational at the time of the event. Body-wave magnitude estimates range from $m_b [...]

Variations in Earth's 1D viscosity structure in different tectonic regimes

Anthony Osei Tutu, Christopher Harig

Published: 2022-01-14
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Earth’s long-wavelength geoid provides insights into the thermal, structural, and compositional evolution of the mantle. Historically, most estimates of mantle viscosity using the long-wavelength geoid have considered radial variations with depth in a symmetric Earth. Global estimates of this kind suggest an increase in viscosity from the upper mantle to lower mantle of roughly 2 -- 3 orders of [...]

Structural traps and seals for expanding CO2 storage in the northern Horda Platform, North Sea

Johnathon Lee Osmond, Mark Joseph Mulrooney, Nora Holden, et al.

Published: 2021-12-24
Subjects: Geology, Geophysics and Seismology, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Stratigraphy, Tectonics and Structure

The maturation of geological CCS along the Norwegian Continental Shelf is ongoing in the Norwegian North Sea, however, more storage sites are needed to reach climate mitigation goals by 2050. In order to augment the Aurora site and expand CO2 storage in the northern Horda Platform, regional traps and seals must be assessed to better understand the area’s potential. Here, we leverage wellbore and [...]

Imaging evolution of Cascadia slow-slip event using high-rate GPS

Yuji Itoh, Yosuke Aoki, Junichi Fukuda

Published: 2021-12-24
Subjects: Earth Sciences, Geophysics and Seismology, Tectonics and Structure

The slip history of short-term slow slip event (SSE) is typically inferred from daily Global Positioning System (GPS) data, which, however, cannot image the sub-daily processes, leaving the underlying mechanisms of SSEs elusive. To address the temporal resolution issue, we attempted to employ the kinematic subdaily GPS analysis, which has never been applied to SSE studies because its [...]

A snapshot of the earliest stages of normal fault development

Ahmed Alghuraybi, Rebecca E. Bell, Chris Jackson

Published: 2021-12-22
Subjects: Earth Sciences, Geology, Tectonics and Structure

Despite decades of study, models for the growth of normal faults lack a temporal framework within which to understand how these structures accumulate displacement and lengthen through time. Here, we use borehole and high-quality 3D seismic reflection data from offshore Norway to quantify the lateral (0.2-1.8 mmyr-1) and vertical (0.004-0.02 mmyr-1) propagation rates (averaged over 12-44 Myr) for [...]


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