Zagros Zone Research Articles

Investigating the geochemical behavior and exploration potential of lithium in brines; a case study of Bam salt plug, Zagros Zone, southern Iran

Lithium (Li) is a scarce and technologically important element; the demand for which has recently increased due to its extensive consumption, particularly in manufacturing of Li-ion batteries, renewable energy, and electronics. Li is extracted from brines, pegmatite, and clay minerals; though extraction from brines is economically preferred. More than 200 salt plugs are in the Zagros Mountains which represent potential sources for Li exploration. This preliminary study collected first data on the abundance of Li in the salt plugs in southern Iran, and investigated Li distribution during evaporation of halite-producing brine ponds. The XRD analysis of powdered samples showed that gypsum and halite are the dominant solid phases in the ponds in which Li is concentrated in gypsum, while halite is depleted of Li. ICP-MS and ICP-OES analyses showed that Li in brines is concentrated during the evaporation by factors up to 28 with total contents up to 40 mg kg‒1. The Mg/Li ratio was higher than 70, which makes the brine unsuitable for conventional evaporation extraction techniques which require Mg/Li ratios of less than 6. Considering that 25 mg kg‒1 is a suitable concentration of Li for exploration purposes, the results of this study suggest that with the advancement of extraction techniques, the depletion of presently used high-grade Li reserves, the increasing demand for lithium, the need for extraction from diverse sources, and the exploration of new resources, the salt plug brines have an exploratory potential for Li in the future.

PARURGONINA VALANGINIANA N. SP. FROM THE VALANGINIAN OF SW IRAN (ZAGROS ZONE): THE FIRST CRETACEOUS RECORD OF THE GENUS

The new larger benthic foraminifer Parurgonina valanginiana is described from the Valanginian deposits of the Fahliyan Formation of southwestern Iran (Zagros Zone). It is separated from the uppermost Oxfordian-lowermost Tithonian generotype P. caelinensis (Cuvillier et al.) by a distinct time gap. The Lower Cretaceous specimens exhibit a larger embryonic chamber whereas the internal structural and other biometric data are generally in conformity with the Upper Jurassic morphotypes. Besides the Middle Jurassic P. primaeva Kamoun & Peybernès and the Upper Jurassic P. caelinensis, P. valanginiana sp. nov. represents the third species of the genus described and possibly a Valanginian marker endemic for the Arabian Plate. In the Fahliyan Formation, P. valanginiana sp. nov. occurs in wackestones associated with Pseudocyclammina lituus (Yokoyama). Additional data for the micropalaeontological assemblages (benthic foraminifera, calcareous algae) of the shallow-water carbonates of the Fahliyan Formation are provided. As it is also the case in the United Arab Emirates (Granier, 2008), it is proposed that the Tithonian/Berriasian boundary does not, as generally indicated in the literature, coincide with the boundary of the Hith Formation and the Fahliyan Formation, but instead occurs within the latter. The new finds provide further evidence that the Tithonian/Berriasian boundary did not represent a major rupture or extinction for larger benthic foraminifera. On the contrary, the Berriasian/Valanginian boundary corresponds to a natural discontinuity (both sedimentological and biological) possibly enhanced by a hiatus of the upper Berriasian strata. The foraminiferal diversity remains quite high during early Valanginian times then falls drastically, which suggests that the Berriasian/Valanginian crisis is a double barelled crisis (first base Valanginian, second intra-Valanginian).

Micro-biofacies of the Maastrichtian Tarbur Formation, Neo-Tethys Zagros Basin, Iran, clue to penecontemporaneous faults and environmental hydrodynamics

The main purpose of this research main is to study the role of local faults in the formation of rudist assemblage composition and thickness in the Maastrichtian deposits of the Tarbur Formation in the High Zagros sub-basin. Based on the taphonomic studies and micro-biofacies analysis, three micro-biofacies were identified in the study areas. These micro-biofacies were formed in the shallow marine environments in the study areas. The Tarbur Formation in the Ardal and Murak areas was deposited in a high-energy environment based on the distribution of micro-biofacies. Other areas were formed in low-energy environments. The activities of local faults were an important and effective factor in the formation of rudist association with high thickness and the distribution of hydrodynamic energy in different areas of the carbonate platforms. The thickness of these rudist colonies increased from northwest to southeast in the High Zagros zone.

PSEUDOCYCLAMMINA SARVAKENSIS SP. NOV. AND PSEUDOTEXTULARIELLA BREVICAMERATA SP. NOV.: FURTHER EVIDENCE FOR THE CENOMANIAN MEGADIVERSITY OF LARGER BENTHIC FORAMINIFERA FROM THE SARVAK FORMATION OF SW IRAN

The carbonate succession of the Cenomanian-Turonian Sarvak Formation SW Iran, Zagros Zone contains a diverse assemblage of (larger) benthic foraminifera, such as alveolinids, orbitolinids and others. Two new taxa are described herein as Pseudocyclammina sarvakensis sp. nov. and Pseudotextulariella brevicamerata sp. nov. They are generally not frequently observed (likely biased through a stratigraphic or facies control) as other most common taxa found in the Sarvak Fm. They are herein reported from the Tang-e Darbast (type-locality of both species) and Shahneshin surface sections, and also from the Arman well-1 subsurface section, Fars area and Abadan Plain, respectively in the parts referred to the middle Cenomanian. The Tang-e Darbast section also represents the type-locality of Iraqia ultima Yazdi-Moghadam & Schlagintweit and Simplorabanitina simplex Consorti, Schlagintweit & Yazdi-Moghadam. Pseudocyclammina sarvakensis and Pseudotextulariella brevicamerata are further elements of the so-called ‘Nezzazata-alveolinid’ assemblage zone.

Serpentinite Rocks of Mawat Ophiolite Complex, Northeastern Iraq, Beetwat Village: 1-Petrography and Diffractometry

The Mawat ophiolite complex is of Cretaceous period as a residue of oceanic crust covers about 200 km2, Northeastern Iraq.. The serpentinite rocks are exposed as a diapir in the northeastern suture Zagros zone of Iraq near Beetwat village, The field study and petrography reveal two types of serpentinite, the shear and massive, with three serpentine varieties. The serpentinite rocks are affected by secondary processes such as diagenesis, metamorphism and hydrothermal alteration in different degrees. Some common Textures in these rocks are pseudomorphic such as mesh or sieve textures, glass hour and bastite texture. Nonpsedomorphic textures appear also in these rocks such as interpenetrating fibrous, interlocking textures. Mineralogically, the massive serpentine minerals are lizardite and chrysotile that affected by recrystalization and replacement of lizardite. The (XRD) analysis explain that the serpentine is composed of lizardite, chrysotile, antigorite, in addition to amphibole minerals (anthophyllite and tremolite), chlorite talc, and opaque minerals as chromite.

Extending the stratigraphic range of Nummulites bormidiensis Tellini in the Neo-Tethys (Zagros basin, SE Iran) through biometry and calcareous nannofossil biostratigraphy

A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22-NP23 (=CNO2-CNO3) Zones.We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 um. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelianwhere classically just N. fichteli is reported so far. The stratigraphic distribution of Nummulites bormidiensisis and related transitional forms is here stretched to the Rupelian (SBZ21 and SBZ22A), encompassing older ages than previously recorded throughout the Neo-Tethys Ocean.

Iraqia ultima sp. nov. (Orbitolinidae) from a new succession encompassing the Cenomanian-Turonian boundary in SW Iran (Sarvak Formation, Zagros Zone)

Iraqia ultima sp. nov. (Orbitolinidae) from a new succession encompassing the Cenomanian-Turonian boundary in SW Iran (Sarvak Formation, Zagros Zone)

Systematic Paleontology of Bartonian Larger Benthic Foraminifera from Shahrekord Region in High Zagros, Iran

The Jahrum Formation is characterized by abundant benthic Foraminifera in carbonate beds, partly marly and dolomitic limestones in the Kuh-e-Soukhteh (Shahrekord region). This formation covers a huge stretch of the Zagros Zone which is a part of the central Tethyian realm during the Paleogene time. Bio-stratigraphic analysis of the larger benthic Foraminifera distinguishes one assemblage zone assigned to the late middle Eocene (Bartonian). This new biostratigraphic range is represented by the index fossil Rhabdorites malatyaensis (Sirel) and is correlated with calcareous rocks in the Shiraz area (south Iran), Dhofar section (Oman), and Socotra Island (Yemen). The Jahrum Formation is dominated by rich miliolids-agglutinated Foraminifera with rare small rotaliids and without Nummulites Lamarck and Alveolina d'Orbigny indicating that the formation was deposited in a shallow water environment (nearshore lagoonal zone) with low energy.

Tarburiconus simplex gen. et sp. nov. (Orbitolinidae) from the upper Maastrichtian Tarbur Formation of SW Iran

A new larger benthic foraminifera of the family Orbitolinidae Martin is described as Tarburiconus simplex gen. et sp. nov. from the upper Maastrichtian Tarbur Formation of southwest Iran (Zagros Zone). Differences of Tarburiconus gen. nov. to the Paleocene Fallotella Mangin and the Lower-Upper Cretaceous Paracoskinolina Moullade are discussed. Tarburiconus gen. nov. represents further evidence for an upper Maastrichtian diversification of larger benthic foraminifera, e.g. agglutinated conical taxa, before their extinction at the K-Pg boundary. Tarburiconus gen. nov. is another genus of the Orbitolinidae known only from the Upper Cretaceous Global Community Maturation Cycle (between CT and K-Pg boundaries).

Stratigraphic architecture and depositional–diagenetic evolution of Oligocene–Miocene carbonate–evaporite platform in the southern margin of the Neo-Tethys Ocean, Lurestan zone of Zagros, Iran

The Oligocene–Miocene (OM) depositional sequences (Asmari Formation) are marked by remarkable changes in thickness, lithology, depositional facies characteristics, and diagenesis history throughout the Zagros area, as the southern margin of the Neo-Tethys Ocean. An integrated sedimentological, geochemical and sequence stratigraphic analysis of these sequences is presented in two surface and subsurface sections located in the Lurestan zone. Macroscopic (field-scale) descriptions and microscopic petrographic studies represent 12 microfacies deposited on a ramp-like carbonate platform. Complex diagenesis history of the Asmari Formation encompasses hypersaline, marine, and meteoric, to shallow- and deep burial realms. Cathodoluminescence microscopy and stable isotopic (carbon and oxygen) compositions of whole-rock, micrite, and carbonate cements of different generations are used for the precise interpretation of depositional–diagenetic processes. Regional stratigraphic architecture of these strata is defined by the correlation of studied sections throughout the Zagros area, in a sequence stratigraphic framework. Development of restricted lagoons or salterns with deposition of evaporites, and hypersaline diagenetic overprints point to a completely different depositional-diagenetic evolution. The Oligocene–Miocene transition (OMT) event is correlated with global records. A 3 to 4 ‰ increase in δ18O is considered as the signature of a cooling event at the OM boundary. Variable geochemical features of the OM sequences in the Zagros area can be due to the tectonic activities and changes of paleoenvironmental conditions. Results of this study provide new insights about the Oligocene–Miocene depositional systems in the Zagros area and, in a larger scale, on the southern margin of the Neo-Tethys Ocean.

Uranium and rare earth elements in the phosphate deposits of the Pabdeh Formation, Zagros Zone, Iran: concentrations and geochemical patterns comparison

Uranium and rare earth elements in the phosphate deposits of the Pabdeh Formation, Zagros Zone, Iran: concentrations and geochemical patterns comparison

New data on some type-species of Maastrichtian-Paleocene Dasycladales (green algae) from Iran Part III. Rostroporella Segonzac 1971

Rostroporella oviformis Segonzac represents the type species of the monospecific genus Rostroporella described from the Thanetian of France (type locality). Well preserved material of this large-sized dasycladale from the Paleocene of Iran (central and east Iran, and Zagros Zone, SW Iran), allows a better characterization of the algal thallus, e.g.,shape of the thallus, reproductive structures and the ranges of biometric parameters. The thallus is thought to be moniliformwith ovoid articles. The reproduction with comparably large, elongated gametophores disposed laterally above the first order laterals refers to the goniosporate type. The suprageneric position of Rostroporella, previously placed within the family Polyphysaceae (formerly Acetabulariaceae), is discussed and transferred into the family Bornetellaceae.

Fractured reservoir distribution characterization using folding mechanism analysis and patterns recognition in the Tabnak hydrocarbon reservoir anticline

Naturally, fractured reservoirs play a considerable part in the study, production, and development of hydrocarbon fields because most hydrocarbon reservoirs in the Zagros Basin are naturally fractured. Production from those reservoirs is usually affected by the presence of a system of connected fractures. In this study, the Tabnak hydrocarbon field on the fold–thrust belt at the Zagros zone in the Persian plate has been analyzed by the facies models, folding mechanism analysis to identify fracture reservoir patterns. The results show a flexural fold with similarity in the folding mechanism and some open fracture potential made by limestone, shale, clay, and anhydrite in the study area's facies models. Consequently, the stress pattern and type of fracture issue on the fold's upper and lower layers will be similar. On the Tabnak anticline reservoir using image processing techniques in MATLAB R2019 software and kriging geostatistical methods, fracture surface patterns as a block model extended to the depth. Using the model results, fractures’ orientation distribution in adjacent wells 11, 14, and 15 is appropriate. The results also have similarities with the facies models, folding mechanism assessment, well test, and mud loss data analysis. These results can affect the development plans’ primary approach by drilling horizontal and sleep wells and hydrocarbon reservoir management strategies.

Cenomanian “orbitoliniform” foraminifera—State of the art and description of Ebrahimiella dercourti (Decrouez and Moullade, 1974) gen. et comb. nov. (family Coskinolinidae) from the Sarvak Formation (SW Iran, Zagros Zone)

From surface and subsurface sections of the middle Cenomanian Sarvak Formation of SW Iran (Zagros Zone), specimens of “Valdanchella” dercourti Decrouez and Moullade were recovered. With the occurrence of a pseudo-keriothecal wall structure, a large subapical embryo and the lack of horizontal partitions, this taxon can be assigned neither to the late Berriasian–Valanginian Valdanchella Canerot and Moullade nor to any other known genus. Therefore, the genus Ebrahimiella is established with the new combination E. dercourti (Decrouez and Moullade) and assigned to the family Coskinolinidae. Orbitoliniform larger benthic foraminifera evidenced a distinct radiation, in Cenomanian shallow-water carbonates of the former southern Neotethyan margin, especially the Arabian Plate, including also endemic forms. Whereas the lower (p.p. middle?) Cenomanian exhibits the dominance of Orbitolininae (genera Orbitolina, Mesorbitolina, Conicorbitolina), the middle Cenomanian documents the appearance of new taxa of the Dictyoconinae (e.g. Persiconus sarvaki Yazdi-Moghadam and Schlagintweit). An updated inventory of Cenomanian orbitoliniform taxa with stratigraphic ranges is provided.

Methodology Specific Features of Underground Water Thermomonitoring at the Bucher-1 NPP Site in the Islamic Republic of Iran

The article presents some of the possibilities of thermometry when monitoring groundwater at the Bushehr-1 NPP. Possible sources of local anomalies of the temperature field recorded in the wells are considered. It is shown that temperature measurements allow, incl. to determine the important features of the operation of the monitoring system wells, their design characteristics, the integrity of the casing strings and the power sources of the aquifers. And in the conditions of the Bushehr-1 NPP site, which is known to be in a complex seismotectonic environment, temperature monitoring is of particular additional importance. Monitoring temperature measurements in wells provide more information about changes in the hydrogeodynamic field before tectonic events compared to traditional measurements of the liquid column level. For this reason, temperature monitoring at the Bushehr NPP site should become a part of specialized seismic monitoring aimed at the safe operation of the NPP in difficult seismotectonic conditions in the Zagros zone and the adjacent part of the Iranian coast of the Persian Gulf.

DICTYOCONELLA HENSON, 1948, UPPER CRETACEOUS LARGER BENTHIC FORAMINIFERA: A TAXONOMIC REVISION WITH THE ESTABLISHMENT OF GUSICELLA GEN. NOV. (TYPE-SPECIES DICTYOCONELLA MINIMA HENSON)

In his monograph on Mesozoic-Cenozoic Larger Benthic Foraminifera from the area of Middle East and south-western Asia, Henson (1948) erected the genus Dictyconella for more or less "compressed-conical" dictyoconids including D. complanata (type-species) and D. minima. Both are however, structurally completely different, e.g. aligned (in the latter) versus alternating structural elements (in the former), and cannot either belong to the same genus or the same subfamily (Dictyoconinae versus Dictyorbitolininae). Therefore, the new genus Gusicella is erected with the type-species Dictyoconella minima, resulting in the new combination Gusicella minima. Gusicella represents the only taxon of the Dictyorbitolininae in the Upper Cretaceous Global Community Maturation Cycle of Larger Benthic Foraminifera (here: conical agglutinated). Due to the revision, Dictyoconella is described as a monospecific genus and an assumed Maastrichtian newcomer which, like Gusicella, became extinct shortly afterwards, namely at the K-Pg boundary mass-extinction event. Both taxa appear to be restricted to the former Arabian Plate of the southern Neotethyan margin. The new data provided are based on material from the Maastrichtian Tarbur Formation of southwestern Iran (Zagros Zone).

Moho depth variations and Vp/Vs ratio in the Zagros (Iran) from teleseismic converted waves

Variation of Moho depth and Vp/Vs ratio beneath the Zagros using 3 years of teleseismic recording at twenty permanent broadband seismic stations of the Iranian Seismological Center (IRSC) where are scattered all over Zagros is presented in this paper. The results of this study are the first receiver function study for the Moho depth beneath these stations on this new dataset. We determine receiver functions by the time domain iterative deconvolution method and Moho depth and Vp/Vs ratio using a modified Zhu and Kanamori method. Our results indicate that the Moho depth beneath the Zagros Mountain Range varies from ~ 30–35 km in western Zagros near the Arabian platform, up to ~ 45 km beneath Central Zagros. In the main Zagros zone, our results indicate a uniform pattern for the Moho depth. The Moho depth reaches ~ 50–54 km beneath stations near Sanandaj-Sirjan Zone (SSZ), indicating a considerable increase of Moho depth from the west toward the east of Zagros. The depth of Moho in the southeast of Zagros is less than other parts of Zagros. We found deepening of the Moho depths beneath stations near the SSZ which can be due to the overthrusting of the crust of Zagros by the crust of central Iran along the MZT. The average Vp/Vs ratio in Zagros is 1.8.

The Van Microplate: A New Microcontinent at the Junction of Iran, Turkey, and Armenia

In northwestern Iran, magmatic activity occurred during three main intervals: The Cretaceous, Eocene, and Miocene-Quaternary. The first two phases of magmatic activity are more consistent with arc-type magmatism on an active continental margin; whereas the last phase, which has calc-alkaline and alkaline affinities, shows more similarity to postcollisional magmatism. Magmatic belts are mostly situated in the northern and eastern parts of the Oshnavieh–Salmas–Khoy ophiolite belt (OSK-Ophiolite) in northwestern Iran. The OSK-Ophiolite is known as the Neotethys, an ocean remnant in northwestern Iran, and extends to eastern Turkey and surrounds the Van area. This configuration shows that the Van microplate and surrounding ocean have played an important role in the evolution of magmatic activity in northwestern Iran, eastern Turkey, and the Caucasus since the Cretaceous. The Van microplate is situated among the Arabian plate to the south, northwestern Iran to the east, and Armenia to the north. The subduction of the northern branch of the Neotethys oceanic lithosphere beneath southern Eurasia has been critical in flare-up magmatism in the southern Caucasus since the Late Cretaceous. Considering the Van area as a new microplate makes understanding the geodynamic evolution of this area easier than in the many tectonic models that have been suggested before. When regarding the Van microplate, the main suture zone, which is known as the Bitlis–Zagros zone, should be changed to the Zagros–Khoy–Sevan–Akera suture zone, which extends to the eastern and northern Van microplate and western Iran.

Morphological changes of the large foraminiferal genus Loftusia during the Maastrichtian and its palaeogeographical inferences from the Zagros and Neotethys basins

This study examines the morphological changes of the Loftusia genus from the Zagros Belt of southern Iran using quantitative data. Eight Tarbur Formation outcrops were investigated in the High Zagros and the Lurestan sub zones. The observed Loftusia species are of mid Maastrichtian age in the High Zagros and the mid to late Maastrichtian age in the Lurestan and Murak areas, and they are often observed in deposits of the lagoon environments with high nutrient conditions. Two (Tang-e Shabi Khoon area) and four (Murak area) cycles were recognized based on the morphological parameter changes of Loftusia species. The correlation of the number of cycles of Loftusia species between the Zagros basin and the different areas of the Neotethys basin indicates that Loftusia species sizes change in time. The obtained data shows that the number of the sedimentary cycles (alternating shale and limestone layers) in the High Zagros zone is more different than the Lurestan zone. The High Zagros zone comprises rich terrigenous shale with higher nutrient flux in comparision to the Lurestan zone and other areas of the Neotethys basins. The number of cycles decreased from the southeast toward the northwest of the Neotethys basin. It is thought changes in Loftusia species in the Zagros basin are related to nutrient input during the Maastrichtian age and were independent of evolutionary trends.The genus Loftusia disappeared in the High Zagros zone at the end of the late Maastrichtian. The subsidence of the basin is associated with the Dena and High Zagros Faults. Due to the activities of those faults, the Tabur Formation was not deposited in the High Zagros zone areas. The genus Loftusia appeared in the southeast region of the Arabian plate during the early Maastrichtian, and migrated to the northwest of the Neotethys during the Maastrichtian.

Schroedericonus n. gen. (type-species Dictyoconus turriculus Hottinger and Drobne, 1980), Paleocene larger benthic foraminifera (Orbitolinidae)

Abundant specimens of the orbitolinid Dictyoconus turriculus Hottinger and Drobne from Thanetian shallow-water carbonates of the Zagros Zone, SW Iran, allow new taxonomic insights. With a high conico-cylindrical test, lacking a prominent eccentric initial spire and the occurrence of a distinct zone of only primary beams between the marginal zone (with subepidermal network) and central zone, this species always stood out from a morphological perspective among the other species of the genus Dictyoconus Blanckenhorn. However, its generic status was never challenged. The aligned arrangement of the main radial partitions and also of the pillars to a large extent, rules out a possible inclusion of this species in a rigorous classification framework within the genus Dictyoconus Blanckenhorn and therefore, the subfamily Dictyoconinae Moullade because its members display an alternating pattern of the respective structural elements. In addition, intercalary elements also occur and account for the partly irregular pattern, a pattern similar with that of Dictyorbitolina Cherchi and Schroeder. The new genus Schroedericonus is introduced with the new combination Schroedericonus turriculus (Hottinger and Drobne) and assigned to the Dictyorbitolininae Schroeder. As a consequence of this taxonomic review, there are no other species of Dictyoconus in the Paleocene. The distributional pattern of Dictyoconus (upper Cretaceous and Eocene) can be considered as a classical example of iterative evolution.