Central Zagros Research Articles

Amphibian hotspots in Iran: Effectiveness of current protected area and priorities for conservation planning

The identification of conservation priority areas for amphibians in Iran remains unexplored. Although protected areas play a vital role in biodiversity conservation, 40 percent of amphibians are at risk of extinction. The present study aimed to identify the priority areas for amphibian conservation and assess the effectiveness of the current protected conservation areas. 2192 species occurrence points for 23 amphibians, including 16 species of Anura and 7 species of Caudata, were curated. These occurrence points in addition to bioclimatic, anthropogenic, and geographical variables were used to model the species distribution. Then, the richness and rarity maps of amphibians were determined and hotspots identified based on the top 10 % area of the country with the highest richness and rarity values. Finally, Iran's protected areas were overlaid to evaluate the current coverage of hotspots and identify future conservation priorities. Although approximately 12 % of Iran is currently protected, the present study findings indicate that the current network of protected areas is ineffective for amphibian conservation; over 90 % of hotspots for amphibians lie outside the current national protected area network. The most important hotspots are located in the Caspian Hyrcanian Mixed Forest, the western margin of the North Zagros, and the Central Zagros Mountains Forest-Steppe ecoregions of the country. Among different types of protected areas that overlap with amphibian hotspots, protected areas and wildlife refuges respectively ranked the highest in quantity and size, while national parks ranked the lowest. In the current study, a baseline of top candidate areas for expanding protected areas where habitats can be managed to protect amphibians in Iran was provided. To further improve protected areas' coverage, priority conservation areas in the Zagros Mountains Forest-Steppe hotspots were recommended.

Increasing drought frequency in the central Zagros Mountains of western Iran over the past two centuries

The Zagros region in western Iran has experienced prolonged drought, significantly impacting water resource and forest ecosystems over the past few centuries. Understanding historical prolonged drought is crucial for making precise forecasts of shifts in regional drought in the Zagros region. Due to the lack of comprehensive historical records, the use of proxy records is considered a valuable tool for reconstructing past drought variations. We aimed to construct a tree-ring chronology of Juniper (Juniperus polycarpus) in the central Zagros region to comprehend its growth response to climate variables. We cored 25 J. polycarpus trees from the Keygooran forest reserve in western Iran and developed the tree ring chronology (1802–2022) using dplR. The relationships between tree growth and climate variables of monthly mean temperature, precipitation, PDSI (Palmer Drought Severity Index), and SPEI (Standardized Precipitation Evapotranspiration Index) were examined. The analysis revealed a strong positive correlation between tree growth and SPEI March-September of 1990–2018 on a 48-month timescale with a 2-year lag (r = 0.61, p < 0.05) which was included in the transfer model. Consequently, the SPEI-48 March-September was reconstructed for the period 1802–2022. On this reconstruction, several extremely dry years in 1832, 1867, and 1876 and extremely wet years in 1807, 1814, 1838, 1850, 1907, and 1908 years were identified, some of them aligning with historical records in Iran. Furthermore, there was a relationship between SPEI-48 March-September and teleconnection events suggesting that certain drought occurrences in the area were associated with the El Niño-Southern Oscillation (ENSO). Consequently, this reconstruction can serve as a reliable proxy for large-scale drought variability in the Zagros region of western Iran. Moreover, our research underscores the utility of SPEI in reconstructing the history of semi-arid climate conditions.

Revisiting Neolithic Ali Kosh: New Insights into Settlement Sustainability, Human Mobility, and Subsistence Strategies

ABSTRACT In western Asia, the Zagros foothills played a fundamental role in the formulation of early explanatory hypotheses on the origins of agriculture. The excavations at the emblematic Neolithic site of Ali Kosh, Deh Luran, led to the development of the so-called “marginal zone hypothesis.” However, some chronological inconsistencies remained until a new stratigraphic excavation was carried out in 2017 to revise the findings. According to the new evaluation, Ali Kosh was occupied from ca. 7500–6500 cal b.c. During the Boz Mordeh phase (ca. 7500–7350 b.c.), the inhabitants occupied the site seasonally, but they became increasingly sedentary in the succeeding Ali Kosh phase (ca. 7350–7000 b.c.). In addition to obsidian, they also imported beads of stone and sea shell. Moreover, they increasingly relied on herding sheep and fully domesticated goats. The emergence of Neolithic life in the lowlands was a direct consequence of cultural changes in the central Zagros. It is not yet known whether this was a result of climatic deterioration or population pressure in the highlands.

What controls structural variations along the Zagros Collision Zone? Insights from geophysical observations and thermo-mechanical modelling

The Zagros Collision Zone is a complex tectonic region formed as a consequence of the collision between Arabia and Eurasia after the subduction of the Neo-Tethys ocean. The NW-SE striking Zagros orogen consists of the following parallel tectonic units (from SW to NE): Zagros Fold and Thrust Belt (ZFTB), Sanandaj–Sirjan Metamorphic Zone (SSZ), and Urumieh–Dokhtar Magmatic Arc (UDMA). In this study, we perform a combined analysis of recent geophysical data, revealing pronounced differences in the crustal and lithospheric structure along the Zagros Mountains. The northwestern sector shows a fairly uniform crustal thickening across the broad symmetric orogen from the ZFTB to the UDMA. In contrast, in the central Zagros, the transition from a relatively narrow zone of high elevations and high-frequency relief in the ZFTB to a smoother surface topography of the SSZ and UDMA occurs with an abrupt increase in Moho depth below the SSZ. The last observation has recently been interpreted as a result of “relamination” process, where the felsic upper crust of the Arabian plate underthrust the mafic crust of the Iranian plate. We present geodynamic numerical models of crustal relamination during continental collision and compute static gravity field of the resulting structures. We show that oblique closure of the Neo-Tethys affects lateral variations in the style and extent of crustal relamination, which control the observed along-strike changes in crustal configuration and orogen altitude. In particular, a narrow and higher orogen (as in the central Zagros) develops in the experiments with a young and wide oceanic plate, whereas an old and narrow subducting plate tends to form a broad and lower topography (as in the northwestern Zagros). This is geometrically consistent with the progressive closure of the Neo-Tethys from NW to SE during the oblique continental collision between Arabia and Eurasia.

The 2013 Mw 6.2 Shonbeh (Kaki) earthquake (Zagros-Iran): seismo-tectonic implications for the Kazerun shear transition zone from high-resolution aftershock and InSAR data analysis

SUMMARY The aim of this study is to investigate the aftershock sequence data recorded by a dense temporary seismological network deployed in the epicentral area of the 2013 April 9 Shonbeh (Kaki) earthquake, located in the south of the Simply Folded Belt of the Zagros (Iran). For a comprehensive understanding, coseismic displacements of the Shonbeh earthquake have been investigated using Interferometric Synthetic Aperture Radar (InSAR) data. The epicentral distribution of high-resolution relocated aftershocks shows NW–SE and N–S trending of seismicity. The aftershocks are confined between ∼3 and ∼14 km depth, which implies that the rupture occurred mostly within the sedimentary cover beside the fault parameters retrieved from InSAR modelling. Projection of precisely located aftershocks on NE-oriented section and InSAR ground displacement data are consistent with both NW-trending NE- and SW-dipping fault segments. We observe a NNW–SSE right-lateral strike-slip motions that accommodate oblique convergence and differential motion between the North and Central Zagros. The spatial pattern and focal mechanisms of aftershocks are consistent with a distributed deformation between NW–SE trending reverse and N–S trending right-lateral strike-slip fault segments in the south of the Kazerun transition zone that accommodates a wide shear zone.

Intraspecific diversity of Meriones persicus (Rodentia; Gerbillinae), the main plague reservoir in Iran, and its connection to enzootic plague in Iran.

Plague, a lethal zoonotic disease, primarily circulates within rodent populations and their fleas. In Iran, the widely distributed jird, Meriones persicus, serves as the principal reservoir for plague, with a belief in the existence of five out of its six recognized subspecies within the country. However, these subspecies are classified into four mitochondrial cytochrome b sub-lineages (IA, IB, IIA, IIB). This discrepancy, combined with the presence of an unnamed sub-lineage in central Iran awaiting taxonomic clarification, has left intraspecific taxonomy unsettled and obscured the true alignment between mtDNA sub-lineages and nominal subspecies. In this study, we investigated the intraspecific variation in the cytb gene across populations sampled throughout Iran, focusing on underexplored regions between the Zagros and Alborz Mountains and central Iran. While our genetic data generally support reported subspecies validity in Iran, we raise questions about M. p. baptistae, emphasizing the need for further data from its type territory in Pakistan. Two main lineages of M. persicus (I and II) exhibit geographical isolation, with limited overlap in the central Zagros Mts., where three subspecies (M. p. ambrosius, M. p. rossicus, and M. p. persicus) coexist. Superimposing infected rodents' geographic coordinates onto updated sub-lineages' distribution revealed a potential association between sub-lineage IA (M. p. rossicus) and all enzootic plague cases from 1946 to 2023. M. persicus rossicus extends into the Caucasus (where plague infections are common), Eastern Turkey, and Iraq. Consequently, interpreting this finding in the context of plague surveillance in Iran and neighboring areas requires caution.

Monitoring of Plant Ecological Units Cover Dynamics in a Semiarid Landscape from Past to Future Using Multi-Layer Perceptron and Markov Chain Model

Anthropogenic activities and natural disturbances cause changes in natural ecosystems, leading to altered Plant Ecological Units (PEUs). Despite a long history of land use and land cover change detection, the creation of change detection maps of PEUs remains problematic, especially in arid and semiarid landscape. This study aimed to determine and describe the changes in PEUs patterns in the past and present, and also predict and monitor future PEUs dynamics using the multi-layer perceptron-Markov chain (MLP-MC) model in a semiarid landscape in Central Zagros, Iran. Analysis of PEUs classification maps formed the basis for the identification of the main drivers in PEUs changes. First, an optimal time-series dataset of Landsat images were selected to derive PEUs classification maps in three periods, each separated by 16 years. Then, PEUs multi-temporal maps classified for period 1 (years 1986–1988) period 2 (years 2002–2004), and period 3 (years 2018–2020) were employed to analyze and predict PEUs dynamics. The dominant transitions were identified, and the transition potential was determined by developing twelve sub-models in the final change prediction process. Transitions were modeled using a Multi-Layer Perceptron (MLP) algorithm. To predict the PEU map for period 3, two PEUs classification maps of period 1 and period 2 were used using the MLP-MC method. The classified map and the predicted map of period 3 were used to evaluate and validate the predicted results. Finally, based on the results, transitions of future PEUs were predicted for the year 2036. The MLP-MC model proved to be a powerful model that can predict future PEUs dynamics that are the result of current human and managerial activities. The findings of this study demonstrate that the impact of anthropogenic processes and management activities will become visible in the natural environment and ecosystem in less than a decade.

Two new species of brush-tailed mouse, genus Calomyscus (Rodentia: Calomyscidae), from the Iranian Plateau

Abstract The monogeneric family Calomyscidae includes the brush-tailed mice, genus Calomyscus, which have a Palearctic distribution ranging from the Hindu Kush Mountains in western Pakistan to the eastern Mediterranean region. Zagros Mountains—stretching from northwest to south of Iran—was assumed for long as the range of a single species, Calomyscus bailwardi; however, recent studies revealed considerable heterogeneities among the geographical populations presumably referring to the persistence of undescribed diversity. One such group from the western Zagros Mountains has recently been recognized as C. behzadi Akbarirad, Dezhman, Aliabadian, Siahsarvie, Shafaeipour, and Mirshamsi, 2021. Using molecular, morphometric, geometric morphometric, and karyotypic data, we examine the divergence of 2 additional groups from western Iran and name these as new species. The first of these species is distributed in the northern Zagros and western Alborz Mountains in northwestern Iran was recovered as the sister species to C. urartensis from the South Caucuses. The second species from a single locality in the central Zagros Mountains was clustered closely with C. grandis from the western Alborz Mountains. Morphologic analyses, karyological features, and genetic distances disentangled these 2 new species from their sister species.

A revised model for Neogene Zagros foreland sedimentation in the Lurestan arc based on new geochemical data

AbstractThe Zagros foreland basin is an important sedimentary archive for the tectonic and paleoclimatic evolution of the Zagros Mountains and the entire Neotethyan Arabia–Iran collision zone. By combining new geochemical high‐resolution whole rock XRF data with clay mineralogy and soluble salt geochemistry we propose an evolution of the sedimentary environment in the Lurestan arc from the Serravallian to the early Pleistocene, closing a gap in understanding the complex exhumation history of the central Zagros mountain belt. An increase in ultramafic sedimentary input indicates a shift from provenance 1 to provenance 2 by ophiolite exhumation at ca.10 Ma in the Imbricated Zagros north of the Lurestan arc. Our data further indicates that the sedimentary environment of parts of the Lahbari Mb within the Lurestan arc represents a piedmont deposition of fine‐grained alluvial fans and siltstones with aeolian contribution deposited under hyper‐arid climate conditions. These represent provenance shift 3 and were likely sourced from evaporites of the underlying Gachsaran Fm and fluvial deposits of the Lower Aghajari Mb (provenance 1 and provenance 2), uplifted by the Mountain Front Flexure at around 5.6 Ma. Combining XRF whole rock data with clay mineral data refines formation conditions of the clay minerals in the foreland basin such as palygorskite, which is revealed to be authigenic in origin in the Lower Aghajari Mb. as a function of varying Mg‐content due to variations of erosion of the ultramafic and mafic rocks in the Imbricate Zagros belt. Palygorskite in the Lahbari Member is likely both inherited from the Neogene Gachsaran evaporites as well as of authigenic origin.

Abiotic factors impact on oak forest decline in Lorestan Province, Western Iran

The Zagros oak forests in Iran are facing a concerning decline due to prolonged and severe drought conditions over several decades, compounded by the simultaneous impact of temperature on oak populations. This study in oak woodlands of central Zagros forests in Lorestan province analyzed abiotic factors such as climate properties, topographic features, land use, and soil properties from 1958 to 2022. We found that higher elevation areas with steeper slopes and diverse topography show significant potential for enhancing oak tree resilience in the face of climate change. Additionally, traditional land use practices like livestock keeping and dryland farming contribute to a widespread decline in oak populations. Preserving forest biodiversity and ensuring ecological sustainability requires immediate attention. Implementing effective land-use management strategies, such as protecting and regulating human-forest interaction, and considering meteorological factors to address this issue is crucial. Collaborative efforts from stakeholders, policymakers, and local communities are essential to oppose destructive suburban sprawl and other developments. Sustainable forestry practices should be implemented to improve the living standards of local communities that rely on forests and traditional livestock keeping, offer forestry-related jobs, and ensure social security. Such efforts are necessary to promote conservation awareness and sustainable practices, safeguarding this unique and vital ecosystem for future generations.

High-resolution, multi-proxy reconstruction of central Zagros paleoclimate and paleoenvironment from the Late Pleistocene to the Holocene

Proxy-based paleoclimate reconstructions in the central Zagros region suggest the occurrence of several climatic events during the Last Glacial Maximum (LGM) to Holocene. The central Zagros region is situated in a unique transition zone between mid-latitude temperate climate in the north and sub-tropical arid climate in the south and was affected in different climatic periods by the strengthening and weakening of the Indian monsoons, the inter tropical convergence belt, the westerlies and the low-pressure systems of the Mediterranean and the Atlantic Ocean. Our results suggest that a transition occurred from dry and dusty conditions during the LGM to a relatively wetter period with higher carbon accumulation rates in the Early Holocene (11600 cal yr BP). Between 30000 and 19000 cal yr BP, cold and dry climatic conditions with the dominance of Amaranthaceae and semi-desert steppe prevailed in the region. High values of magnetic susceptibility, decrease in organic matter, and increase in allogenic elements indicate the presence of cold and dry climate in the region during the LGM. The Holocene was characterized by relatively less dry and dusty conditions, which is consistent with orbital changes in insolation that affected much of the northern hemisphere. Numerous episodes of high aeolian input spanning a few decades to millennia are prevalent during the Holocene. Dry events identified in the area occurred at 10200, 9200, 8200, 5200, 4200, 3200, 2200, and 1600 cal yr BP. Also Younger Dryas, occurred in the region 12300-11600 years ago, and it was cold and dry period with a decrease amount of pollen and increase in dust.

A Bayesian luminescence chronology for the Bawa Yawan Rock Shelter at the Central Zagros Mountains (Western Iran)

Bawa Yawan Rock Shelter is one of the critical Palaeolithic sites discovered recently in the Central Zagros in Western Iran. The site exhibits a rich assemblage from the Middle Palaeolithic (Zagros Mousterian) to the Epipalaeolithic, and it discloses one Neanderthal canine tooth. The site stands out as one of the handfuls of Palaeolithic sites in the Central Zagros that contain human remains. Therefore, establishing a reliable chronology revealing the temporal period in which Neanderthals inhabited the region plays a significant role in our understanding of the human past in the region. We employed luminescence dating in combination with Bayesian modelling to improve the precision of the estimated ages. Our results indicate that the Middle Palaeolithic assemblages unearthed from geological layers GH3 to GH5 in the site fall in the [58–80] ka time frame (68% credible interval). More importantly, the Bayesian age for the layer containing the Neanderthal remains exhibited [65–71] ka (68%). This age contradicts the previous 14C-based chronology. We argue that it is likely that the 14C dates underestimate the timing of the Middle Palaeolithic industries at Bawa Yawan.Furthermore, our study reveals the first luminescence age for the Epipalaeolithic in the Central Zagros, which is dated to [13–15] ka (68%).

Taxonomy and pathogenicity of fungi associated with oak decline in northern and central Zagros forests of Iran with emphasis on coelomycetous species.

Oak decline is a complex disorder that seriously threatens the survival of Zagros forests. In an extensive study on taxonomy and pathology of fungi associated with oak decline in the central and northern part of Zagros forests, 462 fungal isolates were obtained from oak trees showing canker, gummosis, dieback, defoliation, and partial or total death symptoms. Based on inter-simple sequence repeat (ISSR) fingerprinting patterns, morphological characteristics, and sequences of ribosomal DNA (28S rDNA and ITS) and protein coding loci (acl1, act1, caM, tef-1α, rpb1, rpb2, and tub2), 24 fungal species corresponding to 19 genera were characterized. Forty percent of the isolates were placed in eight coelomycetous species from seven genera, namely, Alloeutypa, Botryosphaeria, Cytospora, Didymella, Gnomoniopsis, Kalmusia, and Neoscytalidium. Of these, four species are new to science, which are introduced here as taxonomic novelties: Alloeutypa iranensis sp. nov., Cytospora hedjaroudei sp. nov., Cytospora zagrosensis sp. nov., and Gnomoniopsis quercicola sp. nov. According to pathogenicity trials on leaves and stems of 2-year-old Persian oak (Quercus brantii) seedlings, Alternaria spp. (A. alternata, A. atra, and A. contlous), Chaetomium globosum, and Parachaetomium perlucidum were recognized as nonpathogenic. All coelomycetous species were determined as pathogenic in both pathogenicity trials on leaves and seedling stems, of which Gnomoniopsis quercicola sp. nov., Botryosphaeria dothidea, and Neoscytalidium dimidiatum were recognized as the most virulent species followed by Biscogniauxia rosacearum.

A POSSIBLE PARTHIAN-ERA ANAHITA SANCTUARY AT RABANA IN THE KURDISTAN REGION OF IRAQ

Rabana-Merquly was a major regional centre of the Parthian era in the central Zagros highlands. This article explores the hypothesis that the Rabana intramural settlement was in part a ‘sanctuary’ devoted to the ancient Persian water goddess Anahita, based upon extensive architectural augmentations around an ephemeral waterfall, combined with the nearby construction of a probable fire altar. Two jar burials excavated in 2022 inside an adjacent building show this complex also functioned as a mausoleum. Carbon-14 dating of these cremation deposits supports occupation of the site during the second to first centuries B.C. Twin rock reliefs at the entrances to Rabana-Merquly indicate that the fortress was likely associated with the ruling dynasty of Adiabene, a vassal kingdom of the Parthian (or Arsacid) Empire in north-east Mesopotamia. A further link to Natounissarokerta/Natounia on the Kapros is suggested by the iconography of that city's coinage, which features an obverse image of a goddess, potentially a hybrid representation of Anahita-Tyche.

The deep structure of the Zagros mountain system according to Taylor approximation seismic tomography data

The seismic tomographic model obtained by the Taylor approximation method provides new constraints on the Earth’s crust and mantle structure beneath the Zagros mountain system at depths of 50—850 km. Based on structural geology and seismic tomography data, we divide the Zagros into Northwestern (Kirkuk, Lurestan, and Dezful regions) and Central (Kazerun and Fars regions) parts. The Central Zagros was formed due to subduction-collision tectonics, and the Northwestern Zagros was formed due to a collision-shear (transpression) tectonic process. Based on the 3D P-velocity model of the Zagros and its surrounding mantle, a high-velocity distal southeastern part of the Arabian Plate was established, subducting under the Central Zagros and the Iranian Plate, following the subduction of the Neotethys. This slab covers an area of 23—32°NL — 49—58°EL, i.e., the Bay of Bengal, the Central Zagros, and the southern part of the Iranian Plate. The maximum horizontal extent of the submerging part of the Arabian slab is 800—1100 km, and the maximum submersion depth is 450—500 km. A number of projections on the horizontal plane of the lines of intersection of the surface of the subducting Arabian Plate with horizontal sections of 50, 100, 200, 300, and 400 km were constructed. We obtained the direction of plate plunging, which in different areas varies from northern to northeastern 30—45°. In the Northwestern Zagros, according to the model, traces of subduction do not appear; however, right-lateral strike-slip deformations along the Main Recent Fault are visible and continue now in the crust. The difference in the types of deformation of the Northwestern and Central Zagros is most likely due to the features of the outlines of the eastern edge of the Arabian Plate and the complex nature of its movements. Analysis of earthquake mechanisms in 1977—2001 shows that the movement of the Arabian Plate could have occurred with frequent alternation in the S-N and N-E directions due to the alternation of spreading processes in the Gulf of Aden and the southeastern part of the Red Sea.

Investigating early agriculture, plant use and culinary practices at Neolithic Jarmo (Iraqi Kurdistan)

The site of Jarmo in Iraqi Kurdistan has yielded key archaeological evidence which supports its interpretation as a large PPNB village. As such, it is the perfect candidate for the study of early agriculture, plant uses, food preparation and cooking practices. In order to explore these, new excavations and intensive sampling and flotation for the recovery of archaeobotanical remains were carried out in 2012 and 2014. This study presents the results from the analysis of the newly recovered archaeobotanical assemblage from Jarmo which has provided invaluable information about early crop agriculture and plant use. Furthermore, the in-depth study of recovered remains of archaeological food by high-resolution microscopy has shed light on culinary traditions and dietary choices during the Neolithic in the Central Zagros Area.

Determining the distribution factors of an endangered large carnivore: A case study of the brown bear Ursus arctos population in the Central Zagros Mountains, Southwest Iran

Determining the distribution factors of an endangered large carnivore: A case study of the brown bear Ursus arctos population in the Central Zagros Mountains, Southwest Iran

PRE‐, SYN‐ AND POST‐TECTONIC DIAGENETIC EVOLUTION OF A CARBONATE RESERVOIR: A CASE STUDY OF THE LOWER CRETACEOUS FAHLIYAN FORMATION IN THE DEZFUL EMBAYMENT, ZAGROS FOLDBELT, SW IRAN

Lower Cretaceous carbonates of the Fahliyan Formation form prolific reservoir rocks at oilfields in the Dezful Embayment, central Zagros fold‐thrust belt, SW Iran. The carbonates have undergone significant diagenetic alteration in phases which can in general be linked to the pre‐, syn‐ and post‐tectonic evolution of the fold‐thrust belt. This paper investigates the impact of diagenetic processes on the reservoir quality of the carbonates using integrated petrographic, geochemical and sedimentological analyses of subsurface and outcrop samples of the formation. Diagenetic alterations include:(i) pre‐tectonic eogenesis in the marine and shallow‐burial realm, which resulted in micritization of allochems and cementation by equant and isopachous calcite rims and framboidal pyrite together with limited dolomitization and dissolution of metastable bioclasts. The isotopic compositions of micrite and early calcite cement depart from postulated values of Lower Cretaceous marine carbonates, signifying early stabilization of precursor metastable carbonate minerals and the possible effects of the incursion of meteoric waters and/or increasing burial temperatures;(ii) mesogenesis during the subsequent syn‐tectonic phase, which included Late Cretaceous ophiolite obduction at the northern margin of the Arabian Plate and the later Zagros orogeny in the Miocene‐Pliocene. Diagenetic modifications included the emplacement of hydrocarbons, the development of stylolites and fractures, and the precipitation of saddle dolomite, replacive rhombic dolomite, discrete pyrite, microcrystalline quartz, kaolin and anhydrite. The average stable isotope compositions of saddle dolomite (δ18O: ‐6.9 ‰ ± .9 and δ13C 0.5 ‰ ± 1.6, respectively) also reflects the influence of high temprature basinal fluids;and (iii) “late” (telogenetic, post‐tectonic) uplift‐related modification starting in the Pliocene, when the incursion of meteoric waters resulted in the formation of vugs, the calcitization of dolomite, and cementation by fracture‐filling blocky calcite. The negative δ18O and δ13C stable isotope values (average: ‐5.5 ‰ ± 1.5; and ‐3.6 ‰ ± 5.9, respectively) of late blocky calcite cement suggest the incursion of meteoric water into the system.This study demonstrates that diagenetic processes in carbonates in the Fahliyan Formation, which exerted a significant control on the distribution of secondary porosity, can be related to the tectonic evolution of the central Zagros fold‐thrust belt. Thus, constraining the diagenetic history of carbonate successions within the context of their wider tectonic evolution is important for the prediction of the spatial and temporal distribution of reservoir quality.

Anisotropic gradients in Iran: Quasi-Love waves illuminate the deep structure and deformation style of the Zagros, Alborz, and Kopet Dagh

We investigate the presence of the quasi-Love wave (qL) at 51 seismic stations of a temporary seismic network across the western Arabia-Eurasia collision zone. We quantify the intensity of the qL observations from the April 12, 2014 Solomon Islands earthquake by calculating the peak-to-peak amplitude ratios of the qL and Love waves, and compare them with predicted qL intensities from previous shear-wave splitting results. We determine the polarity, timing, and period-dependence of the qL observations within the period range of 50–100 s. Our analysis reveals that the qL observations at stations in the Zagros and Alborz mountain belts exhibit opposite characteristics. In contrast to the Alborz stations, the intensity of qL observations at the Zagros stations exhibits relatively negligible dependence on the period, while their receiver-scatterer distances are considerably period-dependent. We approximately locate the anisotropic gradients that generate the qL waves. Our results suggest that a lithospheric gap is responsible for the shallow and abrupt variation in the belt-parallel trend of fast-axis orientations in the westernmost part of the Zagros. Additionally, the period/depth dependence of the anisotropic gradients along the boundary between the central Zagros and central Iran provides insight into the variation in the downward dip of the Arabian lithosphere. The anisotropic gradient located to the north of the Doruneh fault in eastern Iran indicates its role as a major shear zone and lithospheric boundary. Finally, we observe that the spatial distribution of the anisotropic gradient in northeastern Iran matches the higher strain-rate areas in the Kopet Dagh Mountains, suggesting coupling between the lithospheric mantle and crust in that region.

Structural relationship between subsurface oil fields in the North Dezful Embayment: Qaleh Nar, Lower and Upper Balarud Anticlines (central Zagros, Iran)

How subsurface anticlines (oil fields) link structurally with faults is of great relevance in the exploration and development of oil fields. In this context, we investigate the geometric relation between lower Balarud (LBR), upper Balarud (UBR) and Qaleh Nar (QN) subsurface anticlines that are the main oil fields in the Northern Dezful Embayment, central Zagros. The Asmari (As) and the Bangestan (Bng) reservoirs are studied geophysically using seismic profiles, well data and underground contour maps (UGC). Interpretation of 3500 m deep seismic profiles indicates the geometry of the studied subsurface anticlines differs vertically and horizontally to a significant proportion. The interpreted structures much resemble As and Bng horizons in each anticline. The UBR got overturned on the LBR due to thrusting possibly in the Late Miocene. The LBR, like a rabbit-ear structure, is situated at the northern edge of the QN. The lower and upper Chenareh and LBR and UBR resemble structurally and are separated mutually by a steep (strike-slip) fault. The fault separates the LBR and UBR from the QN. Interaction of different factors: change in overburden pressure, rate of deformation and uplift in the different parts of the subsurface anticlines moved and accumulated Gachsaran Formation&#x0D; towards both limbs of the anticlines.