Neotectonics of the Caucasus and Kura valley, Azerbaijan

Analysis of remote sensing, gravity, earthquake, horizontal and vertical motion data in the broader Azerbaijan region, located between the colliding Arabia and Eurasian Platform, indicates the overall dextral transpression. The region undergoes deformation by NW-SE striking transpressional strike-slip faults, pure strike-slip faults and thrusts. It is also deformed by N-S to NE-SW striking sinistral strike-slip faults. The study area is located to the NE of the main indentation point. The direction of indentation is roughly parallel to the NW-SE trending symmetry axis of the fanning horizontal motion vectors, to the NNW-SSE trending axis of the fanning 1-stress trajectories and to the fastest slowdown direction of horizontal motions in front of the advancing Arabia, which are all roughly parallel to the Arabian motion vector. The broader Azerbaijan region is situated in the eastern side of these fan-shaped patterns. It is characterized by 1 trends progressively changing from NNW-SSE to NE-SW and by the seismoactive zone thickness increasing SE-ward underneath the Kura Valley from 40 to almost 70 km. Its eastern portion, typical by its small-block mosaic structure, contains some unusual local stress regimes. It is argued that they are related to the addition of the regional tectonic stress, highly perturbed along numerous local strike-slip faults, to local stresses generated by interactions of local rotating blocks. This eastern portion is most prone to block rotations, being most distant from the main indentation point and being affected by the least transpressive strike-slip faulting

Rift structure and sediment infill of hyperextended continental crust: insights from 3D seismic and well data (Xisha Trough, South China Sea)

Three‐dimensional seismic and well data from the deepwater Xisha Trough are used to investigate the rift structure and sediment infill of a region formed adjacently to the initial oceanic ridge of the South China Sea (SCS). The high‐quality data permitted a detailed analysis of features such as: (1) detachment faults soling out at the Moho, (2) rotated and thinned continental blocks covered by thick sediment, and (3) changes in the location of basin depocenters resulting from detachment faulting. During the continental rifting phase (Eocene to earliest Oligocene), faulting was broadly distributed in Xisha Trough and resulted in the generation of isolated grabens/half‐grabens filled by proximal sediment sources. During continental breakup in the Northwest Ocean Sector of SCS (Oligocene), extension became restricted to a narrow region where highly tilted continental blocks and thin crust were formed. Sediment was, at that time, fed to distal depocenters, which are presently bounded by listric faults rooted in a basal detachment. Later in a second stage (early Miocene), synchronously with continental breakup in the Southwest Ocean Sector of the SCS, the study area was blanketed by thick sediment. During the two continental breakup events, the hyperextended Xisha Trough was affected by closely spaced, small‐scale faults rather than large basement‐related structures. Our study highlights the effect of continental breakup as a way to broaden sediment influx from multiple sources into deepwater basins. As a corollary, this work recognizes two distinct breakup sequences in the Xisha Trough, and concludes on their geodynamic significance to the SCS

Data for: Active and Passive: Two Ways Party Systems Influence Electoral Outcomes

Parties can not only actively adjust the electoral rules to reach more favourable outcomes, as is recognized in political science, but they also passively create an environment that systematically influences electoral competition. This so far neglected link is theorized and successfully tested on two out of three contextual factors related to party systems: (a) choice set size (i.e. number of options provided to voters), (b) degree of ideological polarization, and (c) the presence of a populist subject. The research utilizes established datasets (i.e. Constituency-Level Elections Archive, Party System Polarization Index, Chapel Hill Expert Survey, The Manifestos Project Database, and registries of populist parties from other studies) and via OLS regression analysis concludes that the choice set size and presence of a populist subject are attributes with passive influence over electoral systems. Thus, they must be reflected when outcomes of electoral systems are estimated or compared across various contexts

Thick-skin orogen–foreland interactions and their controlling factors, Northern Andes of Colombia

<p>The study draws from reflection seismic, <em>in-situ</em> stress and low-temperature geochronology data on the Eastern Cordillera–Llanos foreland basin system of Colombia, which is an example of the retro-wedge of the orogen with an advancing subduction zone. The system was obliquely converging during deposition of the Lower Oligocene–Lower Miocene Carbonera to recent Guayabo formations, recording it by the northeastward depocentre shift in the proximal Llanos Basin. While the southern portion of the foreland did not flex and undergo flexural normal faulting after Carbonera deposition, the northern portion did. The earthquake data indicate that the northern Eastern Cordillera undergoes strengthening by internal deformation, while the southern segment is already strong enough to undergo significant displacements dominantly along its bounding fault systems. Furthermore, the southern segment initiated detachment of the first thick-skin blocks from the proximal Llanos Basin. Such co-existence of different convergence maturity stages along the orogen strike allows unravelling of its development starting with internal deformation and foreland flexure, followed by mountain building and large-scale boundary fault displacements, to the large-scale foreland deformation. The onset of new foreland accretion seems to be controlled by the resistance of the foreland plate to flexing, given that the orogenic engine continues to drive convergence. </p