Preprints
Filtering by Subject: Tectonics and Structure
Evaluating the relationship between the area and latitude of large igneous provinces and Earth’s long-term climate state
Published: 2019-06-12
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
One of the hypothesized effects of large igneous provinces (LIPs) is planetary cooling on million-year timescales associated with enhanced silicate weathering of the freshly-emplaced basalt. This study combines reconstructions of the original surface extent and emplacement ages of LIPs, a paleogeographic model, and a parameterization of LIP erosion to estimate LIP area in all latitudinal bands [...]
Lower crustal earthquakes in the East African Rift System: Insights from frictional properties of rock samples from the Malawi rift
Published: 2019-06-06
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Earthquakes in the southern part of the East African Rift System (EARS) occur at depths up to 45 km in the lower crust, unusually deep for an extensional regime. Typically, earthquakes in continental crust nucleate at temperatures less than 350°C, the temperature at which crystal plastic creep in quartz becomes efficient, corresponding to a depth of ~15 km with an average continental geothermal [...]
Creep on seismogenic faults: Insights from analogue earthquake experiments
Published: 2019-05-30
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Tectonic faults display a range of slip behaviors including continuous and episodic slip covering rates of more than 10 orders of magnitude (m/s). The physical control of such kinematic observations remains ambiguous. To gain insight into the slip behavior of brittle faults we performed laboratory stick-slip experiments using a rock analogue, granular material. We realized conditions under which [...]
Slab Rollback Orogeny model for the evolution of the Central Alps: Seismo-Thermo-Mechanical test
Published: 2019-05-30
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Forces associated with subduction of cold and dense oceanic plates control the motions and deformations of convergent margins. However, how these forces sustain mountain building processes — especially after slab breakoff — is still poorly known. Here we investigate this conundrum by performing 2-D, visco-elasto-plastic, seismo-thermo-mechanical numerical modeling, which simulates both tectonic [...]
Gondwana accretion tectonics and implications for the geodynamic evolution of eastern Arabia: first structural evidence of the existence of the Cadomian Orogen in Oman (Jabal Akhdar Dome, Central Oman Mountains)
Published: 2019-05-30
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The present work describes two early Cambrian folding events within Cryogenian to earliest Cambrian rocks of the western Jabal Akhdar Dome (Central Oman Mountains). This sequence is truncated at an angular unconformity and topped by Permo-Mesozoic sedimentary shelf strata. The Permo-Mesozoic is brittlely deformed and largely unfolded. This differs in style and intensity of deformation with the [...]
Shallow slow slip events along the Nankai Trough detected by the GNSS-A
Published: 2019-05-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Various slow earthquakes (SEQs), including tremors, very-low-frequency events, and slow slip events (SSEs), occur along megathrust zones. In a shallow plate boundary region, although many SEQs have been observed along pan-Pacific subduction zones, SSEs with a duration on the order of a year or with a large slip have not yet been detected due to difficulty in offshore observation. We try to [...]
Extension at the coast of the Makran subduction zone (Iran)
Published: 2019-05-15
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
In the Makran subduction zone, earthquake focal mechanisms and geodetic data indicate that the deforming prism currently experiences N-S compression. However, paleostress inversions performed on normal faults observed along the coast reveal local stress components consistent with N-S extension. Previously proposed mechanisms such as gravitational collapse are not in line with N-S compression and [...]
Pre-existing intra-basement shear zones influence growth and geometry of non-colinear normal faults, western Utsira High–Heimdal Terrace, North Sea
Published: 2019-05-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Pre-existing intra-basement shear zones can induce mechanical and rheological heterogeneities that may influence rifting and the overall geometry of rift-related normal faults. However, the extent to which physical and kinematic interaction between pre-existing shear zones and younger rift faults control the growth of normal faults is less-well understood. Using 3D reflection seismic data from [...]
Dating and morpho-stratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)
Published: 2019-05-04
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
The western part of the Makran subduction zone (Iran) is currently experiencing active surface uplift, as attested by the presence of emerged marine terraces along the coast. To better understand the uplift recorded by these terraces, we investigated seven localities along the Iranian Makran and we performed radiocarbon, 230Th/U and optically stimulated luminescence (OSL) dating of the layers of [...]
Characterising strong force networks produced during granular shear using percolation methods: Revealing the bridge between local grain scale processes and macroscopic sliding
Published: 2019-04-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure
Faults, landslides and subglacial till often contain accumulations of granular debris. Their macroscopic motion is at least to some extent determined by the processes operating in this sheared granular material. A valid question in these environments is how the local behaviour at the individual granular contacts actually sums up to influence macroscopic sliding. Laboratory experiments and [...]
Comment on “Long-term strain oscillations related to the hydrogeological interaction between aquifers in intra-mountain basins: A case study from Apennines chain (Italy)” by Devoti, Riguzzi, Cinti and Ventura
Published: 2019-03-29
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
The paper by Devoti et al. (2018) analyses the GPS time series from seventeen stations located inside and in the neighboring of the L’Aquila intermountain basin. The authors suggest that the observed movements are due to regional hydrological processes likely associated with multi-annual climatic variations. The analysis performed by Devoti et al. (2018) contains an issue in the GPS-InSar [...]
The competition for salt and kinematic interactions between minibasins during density-driven subsidence: observations from numerical models
Published: 2019-03-21
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Stratal geometries of salt-floored minibasins provide a record of the interplay between minibasin subsidence and sedimentation. Minibasin subsidence and resulting stratal geometries are frequently interpreted by considering the minibasins in isolation and implicitly assuming that internal geometries are the result of purely vertical halokinetic processes. However, minibasins rarely form in [...]
Temporally constant Quaternary uplift rates and their relationship with extensional upper-plate faults in south Crete (Greece), constrained with 36Cl exposure dating.
Published: 2019-03-21
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Preserved sets of marine terraces and palaeoshorelines above subduction zones provide an opportunity to explore the long-term deformation that occurs as a result of upper-plate extension. We investigate uplifted palaeoshorelines along the South Central Crete Fault and over its western tip, located above the Hellenic Subduction Zone, in order to derive uplift rates and examine the role that known [...]
Segmentation of rifts through structural inheritance: Creation of the Davis Strait
Published: 2019-03-19
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Mesozoic-Cenozoic rifting between Greenland and North America created the Labrador Sea and Baffin Bay, while leaving preserved continental lithosphere in the Davis Strait which lies between them. Inherited crustal structures from a Palaeoproterozoic collision have been hypothesized to account for the tectonic features of this rift system. However, the role of mantle lithosphere heterogeneities in [...]
Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S
Published: 2019-03-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The Andes are the modern active example of a Cordilleran-type orogen, with mountain-building and crustal thickening within the upper plate of a subduction zone. Despite numerous studies of this emblematic mountain range, several primary traits of this orogeny remain unresolved or poorly documented. The onset of uplift and deformation of the Frontal Cordillera basement culmination of the Southern [...]