Northeastern Oman Research Articles

Architecture of the post-obductional Sunub Structure, northeastern Sultanate of Oman: Based on mapping, 3D gravity inversion and shale migration

We examined the structural evolution of the poorly understood Sunub Structure, which is associated with the northern margin of the Saih Hatat Dome and the extensional Frontal Range Fault (northeastern Oman). The Sunub Structure is located at a dextral transtensional segment and on the hanging wall of the NNE-striking Frontal Range Fault. The fault was active during the Campanian(?)/Maastrichtian to early Eocene (Interval I) and mid-/late Eocene to early Miocene (Interval II). Gravitational inversion using 175 stations and mapping shows: (1) The Sunub Structure is possibly >1200–1350 m deep and filled mostly with the >900-m-thick Campanian(?)/Maastrichtian siliciclastic Al-Khod Formation, including shale, and some overlying Paleogene limestones. (2) The bottom of the basin cannot be depicted. (3) The lower part of the structure is a basin (Sunub Sedimentary Basin), bounded by sub-vertical to steep contacts. (4) The upper part of the Sunub Structure is a basin fold displaying a bowl-shape down to ∼300 m below the surface, referred to as the Sunub Bowl. (5) The bowl is cut by radial faults and five ∼E/W-striking transverse faults. The Sunub Structure formed during Interval I as a deep transtensional, syn-depositional basin. Gentle post-depositional tectonics during Interval II and visco-plastic shale movements produced the present-day bowl-shape that is visible at the surface. Gravitational inversion depict possible evidence for shale migration within the Al-Khod Formation. Although no hydrocarbons are present, the Sunub Structure can serve as an analogue for hydrocarbon migration and storage in similar structures.

New constraints on the Neoproterozoic geological evolution of the SE corner of the Arabian Plate (NE Oman)

The Saih Hatat Dome is a tectonic window in northeastern Oman with a NW–SE extent of c. 95 km and an east–west extent of c. 50 km, rimmed by the allochthonous Samail Ophiolite and the tectonically underlying nappes composed of sedimentary rocks from the Neo-Tethyan Hawasina Basin. Rocks within the window were affected by high pressure/low-temperature metamorphism during the latest Cretaceous. Stratigraphically, the Saih Hatat Dome contains a basal, several kilometre thick sequence, made up of low-grade metamorphic volcanosedimentary rocks (Hatat Formation). U–Pb zircon laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) data from a quartzdiorite dyke, intruding the basal part of the Hatat Formation yielded a crystallization age of 845 +2/−4 Ma, whereas zircons from a quartz keratorphyre have ages of 870 ± 5 Ma. Thus, the basal schists of the Hatat Formation are Tonian in age, similar to Tonian felsic volcanic rocks and a granodioritic intrusion in the Huqf area, 300 km to the south. Detrital zircons from the Hatat Formation show an age peak of 837 Ma with some Neoarchean and Paleoproterozoic grains, which have no potential source in the Arabian–Nubian Shield. Based on the new results, we propose that the Hatat Formation signifies a Tonian back-arc basin, contemporaneous with calc-alkaline igneous intrusions in the Jabal Ja'alan region. Similar calc-alkaline intrusions of comparable ages have been identified in the Mirbat area of Dhofar and the Huqf region in central eastern Oman. We interpret these outcrops as components of a cohesive island arc, characterized by calc-alkaline volcanic rocks and volcanosedimentary back-arc sedimentation. Our model situates these regions off the coast of NW India during the Tonian.

Predicting climate change impacts on the distribution of endemic fish Cyprinion muscatense in the Arabian Peninsula.

Freshwater fishes are facing considerable threats in the Arabian Peninsula which is considered as a highly stressed region in the Middle East. It is predicted that northern Oman is likely to face decreasing rainfall and increasing temperature in coming decades. In this study, we focused on an endemic cyprinid fish Cyprinion muscatense, as a model to investigate impacts of climate change on the mountain fishes inhibiting in this arid region. This species is expected to be strongly affected by climate change because of its limited distribution range in a montane area surrounded by lowlands and sea, limiting the species in shift to other areas. We used an ensemble approach by considering two regressions-based species distribution modeling (SDM) algorithms: generalized linear models (GLM), and generalized additive models (GAM) to model the species habitat suitability and predict the impacts of climate change on the species habitat suitability. Based on the distribution models, the montane area located in northeastern Oman was identified as the most suitable habitat for this species. Our results indicate that, even under the minimum greenhouse gas emissions scenario (RCP 2.6), climate change will produce a high reduction in its potential future habitats. According to the results of percent contribution, elevation and annual minimum temperature were the most important variables in predicting the species suitable habitats. Results also showed that only a small percentage of suitable habitats for the species within boundaries of protected areas. Therefore, the impact of climate change on the species appears particularly alarming. Although our study was restricted to a single cyprinid freshwater species, decreases in potential habitats are likely predicted for other cyprinid fish species restricted to the mountains of this region, suggesting severe consideration is needed for aquatic systems in future conservation planning, especially for endemic freshwater fishes.

Distinct oxygenation modes of the Gulf of Oman over the past 43 000 years – a multi-proxy approach

Abstract. Changing climatic conditions can shape the strength and extent of the oxygen minimum zone (OMZ). The presence and variability of the OMZ in the Arabian Sea is of importance to the latter's ecosystem. The state of oxygenation has, for instance, an impact on the pelagic and benthic faunal community or the nitrogen and carbon cycles. It is important to understand the dynamics of the OMZ and related marine environmental conditions because of their climate feedbacks. In this study, we combined three independent proxies to reconstruct the oxygenation state of the water column and bottom water in the Gulf of Oman for the past 43 kyr approximately. This multi-proxy approach is done for the first time at the northeastern Oman margin located in the Gulf of Oman. We used bulk sedimentary nitrogen isotopes (δ15N) and the alkane ratio (lycopane +n-C35)/n-C31 and benthic foraminiferal faunal analysis to reconstruct the strength of the OMZ in the water column and bottom water oxygenation, respectively. Our results show that the Gulf of Oman experienced strong pronounced OMZ and bottom water deoxygenation during the Holocene. In contrast, during Marine Isotope Stage 2 (MIS 2), including the Last Glacial Maximum (LGM), the Gulf of Oman was very well ventilated, with a highly diverse benthic foraminiferal community. This may have been caused by stronger wind-induced mixing and better ventilation by oxygen-rich water masses. Our results also show moderate oxygenation during MIS 3, with deoxygenation events during most of the warmer Dansgaard–Oeschger (D–O) events. We propose two distinct oxygenation modes for the Gulf of Oman: (1) a stable period of either strongly pronounced water column OMZ and bottom water deoxygenation or well-oxygenated water column and bottom water conditions and (2) an unstable period of oscillating oxygenation states between moderately oxygenated (stadials) and deoxygenated (interstadials, D–O events) conditions. The unstable period may be triggered by an interstadial Atlantic meridional overturning circulation (AMOC) mode, which is required to initiate D–O events.

Uplift Dynamics of the Obducted Northeastern Continental Margin of the Arabian Peninsula, Sultanate of Oman

AbstractEustatic sea level changes and vertical tectonic movements are producing uplifted paleoshorelines. Along subduction zones, uplifted terraces are used to study fault activities and, overall, allow to interpret the tectonic history of plate convergence. Northeastern Oman is experiencing plate convergence following the late Cretaceous obduction of the Semail Ophiolite. Post‐obduction shallow‐marine carbonates have been uplifted to different elevations from 133 to >2,000 m. The present study employs a multidisciplinary approach to elucidate the variability in relief and to introduce a geodynamic model that extends beyond the temporal constraints imposed by the late Quaternary age of the sediments found on the uplifted terraces. Stratigraphic and fault analyses produced a post‐obductional geodynamic model to advance the existing regional models in the framework of the subduction of the Arabian Plate in the Makran Zone. In addition, we rely on imaging geodesy, geomorphology and dating to explain the late Quaternary uplift scenario. Overall, analyses of geomorphology, stratigraphy, and fault patterns reveal spatially heterogeneous post‐late Cretaceous uplift in the region. Compartmentalization by major faults created individual blocks and relief variability. Within the timeframe of marine terrace formation (late Quaternary), we also observed spatially varied displacements. Ground displacements by Interferometric Synthetic Aperture Radar document an ongoing spatial heterogenous uplift at approximately 1.3 mm/a. Finally, temporal variability was evident during the late Quaternary by unusually high late Pleistocene (<40 ka) uplift rates averaging ≥2 mm/a in younger terraces, while for older terraces (>40 ka) the uplift rate is distinctly lower (<1 mm/a).

In situ U–Pb age determination of apatite from carbonatite and kimberlite in the Batain Basin, eastern Oman

Northeastern Oman is characterized by carbonatite and kimberlite complexes, which are the ideal samples for studying the relationship between carbonatite and kimberlite. However, the ages of the Oman kimberlite and carbonatite complexes are still unknown, which restricts the understanding of the relationship between carbonatite and kimberlite in Oman. In this study, we use in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to analyze the apatite from Oman carbonatite, kimberlite, and spessartite. The U–Pb apatite ages are 141.6 ± 6.0 Ma, 137.4 ± 5.2 Ma, and 141.2 ± 6.2 Ma for carbonatite, spessartite (a kind of calc-alkaline lamprophyre), and kimberlite, respectively. These results suggest that the carbonatite and kimberlite were emplaced contemporaneously, followed by calc-alkaline carbonatite (spessartite) emplaced in the Early Cretaceous. The occurrence of carbonatite, kimberlite, and spessartite magmatism of Oman was contemporaneous with the time of the Gondwana breakup during the opening of the Indian Ocean. It is seen that 140 Ma–130 Ma is one of the strongest global kimberlite abundance peaks of the 250 Ma–50 Ma kimberlite bloom, which corresponds with the period of the Pangea supercontinent breakup. The Oman kimberlites and carbonatites are related to a distal effect of the breakup of the Gondwana portion of the Pangea supercontinent, which provided a cool, volatile-fluxed decompression-related circumstance for the formation.

Lithospheric evolution of eastern Arabia based on surface wave and receiver function analyses

The geodynamic evolution of Eastern Arabia comprises three major events that must have acted on the entire lithosphere below the present-day passive continental margin. Starting with the Pan-African plate assembly during the Late Proterozoic, NNE-oriented structural trends were established which were reactivated during Infracambrian and Ordovician extension. Permian Pangean breakup and rifting created two rift axes to form the present-day geometry of the eastern and northern passive margins of Eastern Arabia. SW-directed obduction of the Semail Ophiolite during the Late Cretaceous was the latest major tectonic event that shapes the present-day geology of northern Oman. Recent anisotropic ambient noise tomography, surface wave analysis of earthquake data and receiver function analysis reveal the present-day lithospheric thickness of ∼100 km, and the previously unknown, highly variable internal structure of the East Arabian continental crust. We integrate all newly available seismological observations into a consistent geodynamic model that describes the evolution of lithospheric thickness and crustal heterogeneity, identifies crustal segmentation and relates inherited structures to lateral variations within the dynamics of ophiolite obduction.A sharp, NNE-striking contrast of ∼10% in shear wave velocity (VS) in the lower crust separates felsic Arabian continental crust in the NW from intermediate lithologies in the NE of Oman. This crustal segmentation is interpreted as being established during the Pan-African orogeny. High VS in the lower crust of northeastern Oman is likely due to Permian mafic intrusions related to the Pangean breakup. Mild crustal thickening below todays high topography is attributed to Late Cretaceous time, where northward continental subduction below the Neo-Tethys led to underthrusting and thickening of the continental crust and ultimately to obduction of the Semail Ophiolite.After post-obduction relaxation, we argue that lithospheric thickness, margin perpendicular fast directions of anisotropy and contemporaneous mid- to late Eocene basanite intrusions are indicative of an overall relaxed state of stress of the lithosphere at that time. In consequence, we propose marginal erosion of the base lithosphere on the passive Arabian plate margin during the Late Eocene as a geodynamic process that facilitated margin-wide emergence of the Oman Mountains. Altogether, the present configuration of the lithosphere in northeastern Arabia preserves imprints from Late Proterozoic Pan-African assemblage, Permian Pangean break-up, Late Cretaceous subduction and ophiolite obduction, and Cenozoic post-obduction evolution.

Reinterpreting Bedouin Shaabook Weaving Techniques and Materials through the Co-Creation of Omani Contemporary Jewellery

The goal of this practice-based research is to create new interpretations of traditional Omani Bedouin crafts to inform the creation of contemporary jewellery. According to observations made during fieldwork with settled Bedouin craftspeople, traditional Bedouin methods for tanning leather (using plant materials such as Galqa and Qarat) and the production of leather thread for weaving are described, as is the use of weaving techniques in the production of Shaabook (headpieces), Hebla (leather belts), and traditional homemade decorative trims (Talli, Siim, and Suffah). A collaborative/co-creation workshop with a group of settled Omani Bedouin in North Eastern Oman served as the basis for this research. Participants in the workshop had a variety of traditional weaving techniques under their belts. Working in teams, the participants wove modular elements that were then combined to form a neckpiece. Using reflective analysis, the issue of hybridity is investigated in order to establish a link between the past and the present in the creation of contemporary Omani jewellery pieces.

Population genetic structure of a major reef-building coral species Acropora downingi in northeastern Arabian Peninsula

Current seawater temperatures around the northeastern Arabian Peninsula resemble future global forecasts as temperatures > 35 °C are commonly observed in summer. To provide a more fundamental aim of understanding the structure of wild populations in extreme environmental conditions, we conducted a population genetic study of a widespread, regional endemic table coral species, Acropora downingi, across the northeastern Arabian Peninsula. A total of 63 samples were collected in the southern Arabian/Persian Gulf (Abu Dhabi and Qatar) and the Sea of Oman (northeastern Oman). Using RAD-seq techniques, we described the population structure of A. downingi across the study area. Pairwise G’st and distance-based analyses using neutral markers displayed two distinct genetic clusters: one represented by Arabian/Persian Gulf individuals, and the other by Sea of Oman individuals. Nevertheless, a model-based method applied to the genetic data suggested a panmictic population encompassing both seas. Hypotheses to explain the distinctiveness of phylogeographic subregions in the northeastern Arabian Peninsula rely on either (1) bottleneck events due to successive mass coral bleaching, (2) recent founder effect, (3) ecological speciation due to the large spatial gradients in physical conditions, or (4) the combination of seascape features, ocean circulation and larval traits. Neutral markers indicated a slightly structured population of A. downingi, which exclude the ecological speciation hypothesis. Future studies across a broader range of organisms are required to furnish evidence for existing hypotheses explaining a population structure observed in the study area. Though this is the most thermally tolerant acroporid species worldwide, A. downingi corals in the Arabian/Persian Gulf have undergone major mortality events over the past three decades. Therefore, the present genetic study has important implications for understanding patterns and processes of differentiation in this group, whose populations may be pushed to extinction as the Arabian/Persian Gulf warms.

Collapse of Holocene mangrove ecosystems along the coastline of Oman

AbstractSedimentological, geochemical, and paleontological investigations of the coastline of northeastern Oman have provided the authors with an in-depth insight into Holocene sea levels and climate conditions. The spatial distribution and species assemblage of mangrove ecosystems are analyzed. These ecosystems are sensitive to changes in sea level and precipitation and thus reflect ecological conditions. The close proximity to archaeological sites allows us to draw conclusions regarding human interaction with the mangrove ecosystems. Our interdisciplinary inquiry reveals that the mangrove ecosystems along the east coast of Oman collapsed ~6000 cal yr BP on a decadal scale. There is no sedimentological evidence for a mid-Holocene sea-level highstand. The ecosystem collapse was not caused by sea-level variation or anthropogenic interferences; rather, it was the consequence of reduced precipitation values related to a southward shift of the Intertropical Convergence Zone. This resulted in a decrease of freshwater input and an increase in soil salinity. Further, the aridification of the area caused increased deflation and silting up of the lagoons.

Tsunami and storm sediments in Oman: Characterizing extreme wave deposits using terrestrial laser scanning

Accurate determination of geometric parameters is key to a holistic understanding of storm and tsunami deposits and for modeling wave magnitudes responsible for the displacement of large boulders. We present a new approach in acquiring high-resolution geometric data on coastal boulder deposits related to extreme wave events. The reconstruction of boulder movements along coastlines contributes to a better understanding of storm and tsunami dynamics. Critical parameters for both determining their origin of the event, and providing more accurate modeling parameters, include boulder size, shape, weight, age and lithology. We used terrestrial laser scanning (TLS) on two sites with 327 boulders along the Oman coastline in order to prove the method’s validity. TLS results in very accurate and detailed three dimensional reconstructions of the boulders and can be used to reconstruct the origin of the boulders based on shape and texture. The method also provides refined size, volume and mass estimates for the boulders. According to the results at least 3 large-scale inundation events were recorded on the northeastern Oman coastline during the late Holocene. Dating results on displaced beach rock boulders suggest severe events around 7540 ± 120 cal yr. BP, 1175 ± 115 cal yr. BP and 265 ± 155 cal yr. BP, which each left a clear and distinctive coastal boulder ridge. The largest displaced boulder has a length of 7.36 m, a calculated mass of 120.5 t, and experienced a vertical uplift of 1.3 m during an inundation event. The results suggest a tsunamigenic origin of the coastal boulder trains, and highlight a potential of strong tsunami events along the Omani coastline.

Tectonic observations in the northern Saih Hatat, Sultanate of Oman

The Saih Hatat region, in northeastern Oman, is characterized by a large tectonic window, tectonically overlain during the upper Cretaceous by nappes composed of sedimentary rocks from the Mesozoic Hawasina ocean and the Samail ophiolite. In this window, the autochthonous sedimentary cover of the eastern Arabian Platform from the Late Neoproterozoic to the Cenomanian is well exposed. The oldest of these strata, the Hatat schists, were deformed into a NE-facing fold nappe during the upper Cretaceous. Within the overturned and thrusted lower limb of that fold nappe, we identified three small windows exposing stratigraphically younger Hiyam carbonates and Ordovician sandstone. The structural inventory of the windows and the surrounding area indicates three major tectonic phases. The first deformation led to NNE-SSW trending fold structures which probably formed simultaneously with the major fold nappe of the Hatat schists, followed by the extreme attenuation and thrusting of the lower limb of the fold nappe. The second phase was a gentle folding of the thrust with N-S oriented fold axes and third deformation phase that formed WNW-ESE oriented open folds. The windows are situated in the intersection of anticline axes of these two superposed fold generations and represent a mini basin-and-dome structure with an extension of just 1 km × 1 km.

ASSESSMENT OF OPTIMUM VALUE FOR DIP ANGLE AND LOCKING RATE PARAMETERS IN MAKRAN SUBDUCTION ZONE

Abstract. Makran subduction zone is one of the convergent areas that have been studied by spatial geodesy. Makran zone is located in the South Eastern of Iran and South of Pakistan forming the part of Eurasian-Arabian plate's border where oceanic crust in the Arabian plate (or in Oman Sea) subducts under the Eurasian plate ( Farhoudi and Karig, 1977). Due to lack of historical and modern tools in the area, a sampling of sparse measurements of the permanent GPS stations and temporary stations (campaign) has been conducted in the past decade. Makran subduction zone from different perspectives has unusual behaviour: For example, the Eastern and Western parts of the region have very different seismicity and also dip angle of subducted plate is in about 2 to 8 degrees that this value due to the dip angle in other subduction zone is very low. In this study, we want to find the best possible value for parameters that differs Makran subduction zone from other subduction zones. Rigid block modelling method was used to determine these parameters. From the velocity vectors calculated from GPS observations in this area, block model is formed. These observations are obtained from GPS stations that a number of them are located in South Eastern Iran and South Western Pakistan and a station located in North Eastern Oman. According to previous studies in which the locking depth of Makran subduction zone is 38km (Frohling, 2016), in the preparation of this model, parameter value of at least 38 km is considered. With this function, the amount of 2 degree value is the best value for dip angle but for the locking rate there is not any specified amount. Because the proposed model is not sensitive to this parameter. So we can not expect big earthquakes in West of Makran or a low seismicity activity in there but the proposed model definitely shows the Makran subduction layer is locked.

OIB signatures in basin-related lithosphere-derived alkaline basalts from the Batain basin (Oman) — Constraints from 40Ar/39Ar ages and Nd–Sr–Pb–Hf isotopes

Tertiary rift-related intraplate basanites from the Batain basin of northeastern Oman have low SiO2 (<45.6wt.%), high MgO (>9.73wt.%) and moderate to high Cr and Ni contents (Cr >261ppm, Ni >181ppm), representing near primary magmas that have undergone fractionation of mainly olivine and magnetite. Rare earth element systematics and p-T estimates suggest that the alkaline rocks are generated by different degrees of partial melting (4–13%) of a spinel-peridotite lithospheric mantle containing residual amphibole. The alkaline rocks show restricted variations of 87Sr/86Sr and 143Nd/144Nd ranging from 0.70340 to 0.70405 and 0.51275 to 0.51284, respectively. Variations in Pb isotopes (206Pb/204Pb: 18.59–18.82, 207Pb/204Pb: 15.54–15.56, 208Pb/204Pb: 38.65–38.98) of the alkaline rocks fall in the range of most OIB. Trace element constraints together with Sr–Nd–Pb isotope composition indicate that assimilation through crustal material did not affect the lavas. Instead, trace element variations can be explained by melting of a lithospheric mantle source that was metasomatized by an OIB-type magma that was accumulated at the base of the lithosphere sometimes in the past. Although only an area of less than 1000km2 was sampled, magmatic activity lasted for about 5.5Ma with a virtually continuous activity from 40.7±0.7 to 35.3±0.6Ma. During this period magma composition was nearly constant, i.e. the degree of melting and the nature of the tapped source did not change significantly over time.

3D geometry and kinematic evolution of the Wadi Mayh sheath fold, Oman, using detailed mapping from high-resolution photography

The Wadi Mayh sheath fold in north-eastern Oman is one of the largest and best-exposed sheath folds known, and presents a unique opportunity to better understand this somewhat enigmatic style of deformation. We undertook high-resolution photographic surveying along Wadi Mayh to document the sheath fold in 61 georeferenced panoramic photomerges. Here we present ten such images that provide a structural interpretation of the sheath fold and surrounding structure. We resolve this structure in a simplified three-dimensional model and in two orthogonal cross sections, and propose a kinematic evolution to explain the geometry. The Wadi Mayh sheath fold is the most prominent example within what we suggest is a composite sequence of sheath folds, which is itself enclosed within a SSW-closing recumbent syncline at the base of the major Saih Hatat nappe. Sheath folding is accommodated within Permian Saiq Formation limestones showing carpholite assemblages (6–8 kbar; 275–375 °C). A major discontinuity separates this sequence from enveloping older rock units. The sequence formed during progressive top-to-north, ductile shearing as the overlying nappe migrated northwards with respect to the underthrusting Hulw unit. This process occurred during SSW-directed exhumation of partially subducted continental crust in NE Oman, approximately 15 Ma after obduction of the Oman ophiolite initiated.

Petrology of Late Jurassic allochthonous ultramafic lamprophyres within the Batain Nappes, Northeastern Oman

ABSTRACTLate Jurassic ultramafic lamprophyre (UML) sills and dikes occur as 3 km-long intrusions within the allochthonous Whara Formation of the Batain nappes, eastern Oman. The sills and dikes comprise macrocrystic phlogopite and spinel-bearing aillikite and damtjernite. Aillikite is a light grey, massive fine-grained tuffaceous rock with euhedral laths of mica, while damtjernite is a dark grey, medium- to coarse-grained rock with abundant pelletal lapilli and globular segregationary textures. Both lithologies are composed of calcite, phlogopite, apatite, magnetite, spinel, diopside, and richterite. Orthoclase occurs only within damtjernite. The rocks are strongly silica undersaturated (17.6–33.7 wt.% SiO2), with low MgO (4.7–10.2 wt. %) and high Al2O3 (3.5–8.6 wt.%). The aillikites are distinguished from the damtjernites by their lower SiO2, Al2O3, and Na2O abundances, and their higher MgO, CaO, and P2O5 contents. The rare earth element (REE) patterns of both rock types are similar and show strong light REE (LREE) enrichment. Both are enriched in Ba, Th, U, Nb, and Ta, with normalized concentrations of up to 1000 times those of primitive mantle. Relative depletions are apparent for high REE (HREE), K, Rb, Pb, Sr, P, Zr, and Hf. The rocks have initial 87Sr/86Sr ratios of 0.70435–0.70646, whereas initial 143Nd/144Nd ratios vary between 0 · 512603 and 0 · 512716 (εNdi 2.6–3.2). Pb isotopic ratios are more varied among the aillikites and damtjernites: 208Pb/204Pbi = 38.97–39.39 and 207Pb/204Pbi = 15.35–15.58, 206Pb/204Pbi = 18.08–18.96. The abundance of phlogopite, apatite, and rutile and enrichment in LREEs, Ba, Th, U, Nb, and Ta in the Sal UMLs suggest metasomatic enrichment of these rocks following a low degree of partial melting of a depleted source region. Ar–Ar age dating of phlogopite macrocrysts from the aillikites and damtjernites (154 and162 Ma, respectively) correlates with large-scale tectonic events recorded in the proto-Indian Ocean at 140–160 Ma.

Interpretation the Origin and Tectonic Setting of Coastal Sediments in the Northeastern of Oman Sea

This study investigates geochemistary of major and trace elements of sandstones and mudstones in the Chabahar area located of northeastern Oman Sea. In this study, 52 samples were taken from 5 sections included of Tiss, Ramin, Lipar, Gorankash and Garindar estuary. Then have been done grain size and chemical analysis using XRF and ICP AES methods in geological survey of Iran. Comparison of major elements values with the average amounts of upper continental crust indicate due to sedimentation processes or the lack of source rocks contain sodium plagioclase, the amount of Na2O and Fe2O3 in continental crust is highly depleted. Plotted geochemical data of major elements from Late Miocene-Pleistocene, age 10 mudstone and sandstone samples in east coasts of Chabahar in Makran zone, on siliciclastic rocks classification diagrams, showed that the sandstones are genus wackstone, Mudstones and shale. Values range the chemical index of alteration (CIA) and plagioclase index of alteration (PIA) respectively is from 40 to 60 and 40 to 64. However, most samples have values less than 50, suggesting a low to moderate degree of alteration (weathering) and arid to semi-arid climate during deposition in the source area. Major elements geochemistry is not useful for interpreting the tectonic setting. Discrimination plots based on assotiated trace elements, such as Ti, Zr, La, Sc and Th, show that most data located in the active continental margin field and tectonic setting have developed in active continental margin (ACM). Finally, geochemical data and using from sediments silisiclastic discriminate diagrams on the major elements in these rocks shows that the quartzose sedimentary provenance.

A modelling implementation of climate change on biodegradation of Low-Density Polyethylene (LDPE) by Aspergillus niger in soil

Aim: To model the areas becoming and remaining highly suitable for Aspergillus niger growth over the next ninety years by future climate alteration, in relation to the species’ potential enhancement of Low Density Polyethylene (LDPE) biodegradation in soil.Location: Global scaleMethods: Projections of A. niger growth suitability for 2030, 2050, 2070 and 2100 were made using the A2 emissions scenario together with two Global Climate Models (GCMs): the CSIRO-Mk3.0 (CS) model and the MIROC-H (MR) model through CLIMEX software. Subsequently the outputs of the two GCMs were overlaid to extract common areas in each period of time, providing higher certainty concerning areas which will become highly suitable to A. niger in the future. Afterwards, GIS software was employed to extract sustainable regions for this species growth from present time up to 2100.Results: Central and eastern Argentina, Uruguay, southern Brazil, eastern United States, southern France, northern Spain, central and southern Italy, southern Hungary, eastern Albania, south western Russia, central and eastern China, eastern Australia, south east of South Africa, central Zambia, Rwanda, Burundi, central Kenya, central Ethiopia and north eastern Oman will be highly suitable for A. niger growth from present time up to 2100.Main conclusions: Accurately evaluating the impact of landfilling on land use and predicting future climate are vital components for effective long-term planning of waste management. From a social and economic perspective, utilization of our mapped projections to detect suitable regions for establishing landfills in areas highly sustainable for microorganisms like A. niger growth will allow a significant cost reduction and improve the performance of biodegradation of LDPE over a long period of time, through making use of natural climatic and environmental factors.

Late Cretaceous Sub-Marine Fan System in Batain Mélange Zone, the Fayah Formation in Northeastern Oman

The Batain coast along the northeastern margin of Oman between Ra’s Al-Hadd and Ra’s Jibsch, is comprised of Permian to Late Cretaceous complex stratigraphy in a tectonically deformed area recording Permian rifting to late Cretaceous Tethys closure events. These rocks are thrust over Mesozoic and older autochthonous sedimentary cover in the form of a major nappe structure known as the Batain Nappe. The uppermost part of the Batain nappe is comprised of isolated outcrops of early Maastrichtian siliciclastic Fayah Formation dominated by gravity flow deposits. The Fayah Formation in the Jabal Fayah area is over four hundred meters thick and comprised of five distinct facies associations; namely, i) coarsening-up sandstone, ii) conglomerate, iii) debris- flow, iv) turbidite, and v) inter-bedded sandstone and shale lithofacies. These lithofacies associations are repeated many times in the section. The sandstone lithofacies association exhibits a coarsening-upward trend making sequences tens of meters thick in various parts of the formation. Waterscape structures are common along with occasional sandstone dykes and convolute bedding, reflecting fluidized conditions of deposition. The conglomerate lithofacies association is comprised of a series of interbedded coarsening-upward pebble to gravel size conglomerates containing chert, limestone, granite and volcanic clasts ranging a few mm to cm in diameter. Occasionally these are interbedded with sandstone lithofacies. The conglomerate lithofacies was deposited by a high-energy channelized flow in a sub-aqueous setting. The debris-flow lithofacies association is a matrix supported chaotic mixture of clay and boulders of granite, limestone and volcanic rocks, some of which are meter-sized in diameter, and possibly derived from the nearby basement rocks such as the Jabal Ja’alan basement rocks. It constitutes the most dominant part of the formation. These sediments were deposited along a slope setting, possibly as olistostrome formed due to submarine slumping and sliding. The turbidite lithofacies association is comprised of monotonous grayish-green to brown coloured clays tens of meters thick interbedded with thin, clean, well-sorted sandstone. The Interbedded sandstone and shale lithofacies association is comprised of a half to one meter thick cross-bedded, burrowed arkosic sandstone and plane laminated shale. The sandstone constitutes about 25% of the association with ripple lamination in the upper part of the unit indicating a fining-upward trend. Dewatering structures are common. This association constitutes the upper 100m of the formation. These sediments were deposited in shallow water conditions by channelized flows. Based on the lithofacies associations described above, especially the dominance of debris-flow units and turbidites, the greater part of the Fayah Formation are interpreted as having been deposited under a sub-marine fan setting. Only the upper part of the formation was deposited in a shallow water setting before the onset of overlying carbonate deposits. The sub-marine fan system was active during the last stages of the Tethys Ocean closure at the time of onset of the Batain nappe.

New species of Stenodactylus (Squamata: Gekkonidae) from the Sharqiyah Sands in northeastern Oman.

A new species of gecko of the genus Stenodactylus (Squamata: Gekkonidae) is described from the dune desert of Al Sharqiyah Sands in northeastern Oman. Stenodactylus sharqiyahensis sp. nov. is characterized morphologically by its small size, snout shape, webbing between fingers not very extended, relatively short limbs, and scalation. It is genetically distinct in the mitochondrial DNA and the nuclear MC1R gene from Stenodactylus arabicus to which it has previously been referred. The new species seems to have a restricted distribution confined to the Sharqiyah Sands, which remain isolated from other sand deserts in Arabia. In addition, the data presented herein confirm new locality records for Stenodactylus arabicus in the easternmost limit of its distribution range in western central Oman.