Iris pseudomeda (Iridaceae), a new species of Iris section Oncocyclus from Iran

Iris pseudomeda is described and illustrated as a new species of Iris section Oncocyclus from Kurdistan province in northwestern Iran. It occurs among subalpine flora of Zagros mountain range, on stony calcareous hillsides and the brink of grassland fields. A complete morphological description, conservation status, botanical illustrations, notes on habitat and distribution range are presented for the new species. Furthermore, taxonomic relationships of I. pseudomeda with other members of this rhizomatous bearded section, particularly I. meda, are also discussed.

Regional 3-D lithosphere structure of the northern half of Iran by local earthquake tomography

SUMMARY The 3-D P-wave velocity structure of the northern half of Iran crust has been determined from the local earthquake tomography using a high-quality data set of semi-automatically re-picked arrival times. The quality and quantity of these re-picked phase data allow the 3-D imaging of large parts of the northern half of Iran lithosphere between 0 and 60 km depth. Our new P-wave tomography model represents a major improvement over existing models in terms of reliability, resolution and consistency. First-order anomalies such as the crustal roots of the Zagros and Alborz Mountains are clearly resolved. In addition, several shallow smaller-scale features like the Central Iran sedimentary basin and volcanic and igneous rocks are visible in the tomographic image. Our results show deep Moho depressions beneath the Central Alborz and Zagros mountain ranges that are part of the Arabia–Iranian–Eurasia continental collision zone and locally this Moho topography agrees very well with existing models of other studies. The observed P-wave velocity structure suggests that compared to the Sanandaj-Sirjan and Zagros mountain ranges there is a minor crustal thickening beneath the Alborz mountain range and Kopeh Dagh region.

Structural relief across the NW segment of the Zagros Mountain Front Flexure in the Kurdistan Region of Iraq: implications for basement thrusting

<p>Within the NW segment of the Zagros belt in the Kurdistan Region of Iraq, the Zagros Mountain Front Flexure separates the High Folded Zone from the Foothill Zone and forms a pronounced topographic and structural step. Due to the lack of outcrops and subsurface data, balanced and kinematic valid geometrical interpretations for the subsurface deformation associated with this step are not well constrained yet. To solve this, we estimated the structural relief across seven regional transects crossing the Mountain Front Flexure and we constrained the geometry of deformation from deformed-state and forward-modeled balanced cross-sections. The calculated structural relief for six out of seven transects ranges from 2 to 3 km. By using forward modeling, we show that predominantly thick-skinned deformation is needed to explain this amount of relief across the Mountain Front Flexure. Our best-fitting result suggests c. 6.5 km of displacement along a basement thrust fault that dips c. 25° at the top of the basement and that is shallowing downwards. About 4.2 km of this displacement on the basement fault were accommodated up-section by thrust-related and detachment folding of the Triassic and younger units within two prominent anticlines. About 2.3 km of displacement was transferred to the Foothill Zone, forming detachment folds above the Triassic detachment level. Inclined river terraces on the flank of anticlines within the Foothill Zone indicate ongoing displacement on this basement fault. The amount of shortening within the low topographic part of the belt from the deformation front to the limit of seismogenic thrusting within the Imbricated Zone, implies that the Late Miocene to Quaternary shortening rates there were much lower than the present-day geodetically derived convergence rates for this part of belt. These results shed new light on the geometry of the Zagros and its structural evolution.</p>

Structural Evolution of Lorestan salient in North Zagros Mountain Belt, Iran

<p>Zagros foreland basin is the most important oil-gas foreland basin in the world. At least 60 oil and gas fields have been found. Therefore, research in this area will enrich the petroleum geological information of the foreland basin as an important basis for oil and gas exploration. First, we conduct 2D restoration of Lorestan salient in North Zagros Mountain Belt with 2DMove to test the rationality of the equilibrium profile and understand the structural evolution of the Lorestan salient. Base on the 2D restoration, faults evolved in the ways of in-sequence and out-of-sequence, many faults have breached the cover layer from basement then produced anticline, in the earlier stage of deformation. Anaran anticline and Kabir Kuh anticline caused by the thrusts that displacement along the thrust are 5769 m and 11496 m, respectively. The Vardalan, Dareh Baneh and Naft Anticline also produced by the basement thrust later, this result suggest that surface topography and anticline are highly associated with basement thrust. Second, using the Move2017-Surface to establish the 3D structural model to observe the lateral variation of the strata, some strata have lateral variation, the Mishan formation is absent in the NW but gradually appear to the SE and the Triassic carbonates thickness decreases from almost 1000 m in the southwest to 200 m in the northeast. This reduction in thickness may associated with late Triassic normal faulting and erosion. Third, we project the earthquake on the cross section to understanding the relation between earthquake distribution and tectonic patterns. Based on the analysis of seismicity and geological profiles, earthquake focal mechanisms are mostly reverse faulting with NW–SE strikes and the distribution is over whole horizontal Zagros belt but concentrated in depth of 5~16 km. In addition, larger magnitude earthquakes mainly distribute in southwest Lorestan, it implies that it is the main regime of active tectonics.</p>