270 research outputs found
The Oligocene Avaj volcanic – plutonic complex of Central Iran: A record of magma evolution and mineral equilibria
No full textThe Avaj Oligocene volcanic – plutonic complex is part of extensive Cenozoic magmatic activity within the Urumieh-Dokhtar magmatic arc of Iran. We use whole rock geochemistry, mineral compositions and crystal size distributions (CSD) in a suite of co-genetic basalt, basaltic andesite and gabbro to determine their petrogenesis. Ca-rich cores in plagioclase (An79-86) overlap empirically modelled compositions, indicating equilibrium crystallization from melts represented by the whole-rock compositions. Clinopyroxene compositions (Mg# 74–80) are compatible with mildly fractionated mantle-derived magmas in an arc setting. Mineral-melt equilibrium is inferred from high Al contents and close correspondence between the measured DiHd and predicted KdFe–Mg (0.23–0.32) in clinopyroxenes, and Kd(Plg/melt)(An–Ab) values of plagioclase cores (0.11–0.15). Clinopyroxene-melt thermometers indicate crystallization at 1119–1173 °C for volcanic and 1099–1134 °C for plutonic rocks. Plagioclase crystal core saturation temperatures range from 1088–1162 °C (volcanic) and 1121–1163 °C (plutonic); these values overlap calculated mineral-melt equilibrium temperatures. Plagioclase CSDs are nearly straight for both volcanic and plutonic samples, with higher nucleation density and steeper slopes for the plutonic samples. Major element variations suggest the Avaj rocks represent co-genetic magmas related by fractional crystallization of the observed mineral phases. We suggest minor crustal assimilation occurred during ascent from a deeper reservoir to a shallower one; CSD data indicate longer magma residence time for plagioclase in the plutonic samples (∼117 years) compared to the residence time of basaltic samples (∼13 years)
Recycled mantle source for porphyry mineralization: U−Pb and Re−Os geochronology, and S–Pb–Cu isotopic constraints from the Urumieh-Dokhtar magmatic arc, central Iran
No full textThe Urumieh-Dokhtar magmatic arc (UDMA) hosts some of the world-class porphyry copper deposits in Iran.
Here, we present high-resolution geochronological and stable isotope data to gain insights into the timing and
source of the metallogeny of Kahang porphyry Cu deposit. Zircon U-Pb data show crystallization age of ca. 15
Ma age for the host porphyry intrusion and Re-Os geochronology yields 14.5 Ma from the molybdenite associated
with the ores. Sulfur isotope values on the sulphide minerals range from - 1.6 ‰ to + 2.1 ‰, indicating a
magmatic source for sulfur. Lead isotopic compositions of the S-bearing minerals are akin to those of the
intrusive rocks, suggesting that the metal was likely sourced from mantle reservoirs. We propose a model for the
UDMA involving slab break-off during the maturity of arc magmatism from the syn- to post-collisional stages of
orogenesis. The δ65Cu data trace a systematic change from the barren to the fertile magmas. We suggest that
partial melting of the sub-continental lithospheric mantle that has previously been refertilized of Cu through time
as the potential source for the formation of ore-bearing magmas
Antimicrobial and antioxidant activities of fermented meat patty with Lactobacillus strains
No full textThe effect of fermentation by Lactobacillus fermentum PTCC 1638, Lactobacillus plantarum subsp. plantarum PTCC 1745 and Lactobacillus sakei subsp. sakei PTCC 1712 on antimicrobial activity against Alternaria alternate PTCC 5224, Aspergillus parasiticus PTCC 5018, Staphylococcus aureus ATCC 25923, Escherichia coli O157 H7 ATCC 35150 and Salmonella Typhimurium ATCC 14028 as well as antioxidant properties (carbonyl assay, peroxide and anisidine value) in a beef patty during 24 h of fermentation and further storage at 4°C for 8 days were investigated. Results indicated that L. plantarum subsp. plantarum had the highest radical scavenging activity (54.3±1.7%) before fermentation. During the fermentation process, DPPH and ABTS activities of the meat patty were improved in comparison to the control. The highest antioxidative value was observed for L. plantarum subsp. plantarum. All of three strains had a strong antimicrobial effect against pathogenic bacteria and fungi. Oxidation products were enhanced in fermented and non-fermented samples. However, the increasing trend of the oxidation process was mitigated in all fermented samples. In particular, the lowest protein and lipid oxidation values were observed in the samples treated by L. plantarum subsp. plantarum. Generally speaking, fermentation improves the antioxidative and antimicrobial effect of meat patty and lengthens its storage period
Nutritional composition and antioxidant activity of vobla roach (Rutilus rutilus caspicus) muscle tissue exposed to heavy metals
No full textThe present study was carried out to study the toxic effects of different sublethal concentrations of cadmium chloride and lead salts [CdCl2 and Pb(NO3)2] on lipid, carbohydrate, protein contents and antioxidant enzymes of vobla-roach (Rutilus rutilus caspicus), a common Caspian fish species, in laboratory bioassays. R. rutilus caspicus was exposed to various sublethal concentrations of CdCl2 and Pb(NO3)2, i.e. 0.75, 1.5 and 2.25 mg L-1 for 24, 48, 72 and 96 hr. Then, the fishes
were sacrificed and muscle was collected for the determination of carbohydrates, lipids, proteins, lipid peroxidation (LPO), catalase (CAT) and superoxide dismutase (SOD) activities. The results showed that the maximum decrease in lipid, carbohydrate and protein contents were observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (55.76%, 46.25% and 48.81%, respectively). Furthermore, antioxidant enzyme activities increased when fishes were exposed to cadmium
and lead. The maximum increase in the lipid peroxidation and superoxide dismutase was recorded at 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (184.47 % and 110.52 %, respectively). According to the results, catalase activity decreased with increasing concentration of heavy metals and exposure duration. The maximum decrease in catalase activity was observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (81.21 %). In general, both heavy metals were
highly toxic in muscle of R. rutilus caspicus, with lead showing higher toxicity then cadmium in terms of nutritional parameters and antioxidant enzyme activity
An integrated approach for characterization of a fractured-rock carbonate aquifer in the Zagros Region of Iran
No full textKarst aquifers typically exhibit a wide range of dissolution effects that include end-members of matrix, fracturedrock, and conduit-dominated types. This study employs an integrated approach involving geological studies, hydrogeological assessments, hydrochemical and isotopic analysis, and dye tracer tests to investigate the Sarvak limestone aquifer (SLA) in the Zagros Region, southwest Iran. Key characteristics of the SLA include numerous stratification boundaries, thin limestone layers with intercalated siliceous and marl impurities, extensive joint and fracture networks, predominant autogenic recharge, and absence of notable point recharge features (e.g., sinkholes, dolines), and the exchange flow with the Bakhtiari River (B-R) has made it a unique aquifer. Numerous pieces of evidence, such as low spatial and temporal changes in groundwater level, insignificant seasonal variations in the hydrochemical and isotopic composition of water samples, and the supersaturation state of groundwater with calcite and dolomite minerals, suggested a slow flow regime in many parts of the SLA. This regime is characterized by low velocity and long residence time of groundwater. The results reveal that despite the high solubility of carbonate rocks, extensive joint networks can limit significant karst development, leading to fluid flow behavior similar to that of fractured-rock aquifers. Therefore, SLA can be considered a fractured rock and karst aquifer. The identified paths with fast flow in the dam area are unremarkable and cannot provide a large portion of the Pelle Khan Spring discharge
Constraints from geochemistry, zircon U-Pb geochronology and Hf-Nd isotopic compositions on the origin of Cenozoic volcanic rocks from central Urumieh-Dokhtar magmatic arc, Iran
No full textConsiderable debate persists regarding the petrogenesis of high-alumina basalts (HAB) which are purported to occur exclusively in subduction zones. Major and trace element, mineral chemistry, whole-rock Sr-Nd-Hf-isotopes and zircon U-Pb age data are reported for the Cenozoic Eshtehard HABs, in order to constrain the nature of mantle beneath the central Urumieh-Dokhtar magmatic arc, and further investigate the mechanism of HABs generation. Eshtehard HABs, chemically akin to those from continental arcs, include basaltic, basaltic andesite, andesitic and dacitic rocks. U-Pb geochronology of zircon yield ages of 47.2 ± 0.6 Ma, 43.9 ± 0.3, and 40.9 ± 0.5 to 39.4 ± 0.9 for basaltic, andesitic and dacitic samples, respectively. Basaltic andesitic dikes intruded into dacitic hosts yield age of ca. 20–18 Ma. εHf(t) values for Eocene zircons display a range variable from −6.4 to +6.5. Miocene zircons have higher εHf(t), ranging between −1.8 and +10.7. The studied rocks are characterized by enrichment in incompatible trace elements and have relatively homogeneous Sr-Nd isotopes. Integrated studies indicate that Eshtehard HABs were derived from the hydrated, dominantly depleted shallow asthenospheric mantle wedge (and possibly also in the lower lithosphere) overlying subducted oceanic lithosphere. Traversing lithospheric mantle and Cadomian crust, and assimilating crustal material while fractionating plagioclase, high-Ca pyroxene, magnetite, and amphibole, the primary melt formed Eshtehard high-alumina, low-Mg# basalts. We hypothesize that ponding of hydrous magma at the base of the crust allowed for further crustal assimilation and fractionation of Ca-pyroxene and magnetite without plagioclase and zircon nucleation; then, ascending magmas through the crust led to crystallization of plagioclase and eventually zircon. We suggest comparatively high water content (rather than high crystallization pressure), up to 4% sediment melt and less than 10% of continental crust materials were involved, as subordinate components, in the petrogenesis of Eshtehard HABs
Hydrogeology of non-salt Gachsaran Formation in Iran: an example from the Zagros Range-Tang sorkh Valley
No full textThe study area of Tang sorkh Aquifer is located on the northern flank of the Derak anticline, a part of the Zagros Mountain Range, in the central-south of Iran. The study area is limited to undifferentiated non-salt Gachsaran Formation (NSGF), mainly composed of alternative layers of marl and marlstone, and gypsum. This paper is focused on the hydrogeological and hydrochemistry characteristics of the NSGF. A detailed geological cross section, perpendicular to the strike of the GF was prepared by detailed field surveying. The thickness of GF is 1,268 m, with 82 alternative units of marl, marlstone, gypsum, sandstone and limestone. The sub-aquifers are limited to four limestone, five gypsum, and one gypsum-halite units. The waters of these sub-aquifers emerge as springs or seepage into the Tang sorkh River (TR). The average discharge of springs emerging from limestone and gypsum units ranges between 0.3–8.4 and 0.5–0.75 l s−1, respectively. The source for sub-aquifers is mainly recharge from precipitation or river water. Marly layers disconnect the hydraulic connection between the sub-aquifers, directing the general flow parallel to the strikes. The lack of sinkholes and caves in the gypsum units is due to the small thickness of sub-aquifers, and consequently, low amounts of recharge water. The springs are classified into four groups based on their lithology, electrical conductivity, type of water, and trend of ion-concentration. The type of water in most of the springs is calcium-sulfate. The electrical conductivity is the main parameter to differentiate the hydrochemistry of the groups. The hydrochemistry of springs depends on the recharge from the TR, and the lithology of sub-aquifers and their adjacent units
Arc magmatism associated with continental convergence in the SE segment of the UDMA, Iran: Insights from zircon geochronology and Hf–Sr–Nd–Fe isotopes
No full textMagmatic suites provide the keys to evaluate the growth and reworking of continental crust. Late Cretaceous to
Pleistocene convergence in the Urumieh–Dokhtar magmatic arc (UDMA) of Iran produced continental-arc
magmatism that traces the transition from subduction to collision. The extent and origin of some magmatic
segments in the SE UDMA remain poorly understood. The Oligocene (31 to 25 Ma) Jiroft plutonic rocks here
investigated encompass the compositional spectrum from gabbro to granodiorite. Zircon εHf(t) (-1.3 to +8.1),
whole rock εNd(t) (+0.8 to +3) and δ56Fe (0.07‰ to 0.16‰) are intermediate between values of depleted mantle
and arc-related magmas, and indicate low degrees of oxidization of metasomatized mantle. Modelling indicates
that the trace element patterns of Jiroft parental melts can be closely replicated by 4% partial melting (i.e., F =
4%) of a mantle source which was metasomatized by 2% of sediment melt. The parental melt fits well with a
model pattern of ~97% batch melt (i.e., 98% DM + 2% sediment at F = 4%) and contaminated with ~3% upper
crustal components. The 31–25 Ma magmas of the SE UDMA formed before the main collision event (< 20 Ma)
between Arabia and Iran, in conjunction with changing tectonic regime from extensional to compressional.
Compilation of the Cenozoic magmatic front (i.e., UDMA) and rear-arc (NE Iran and Alborz–Azerbaijan) data
reveals variable degrees of crustal cannibalization during the flare-up episodes. We find that individual segments
of the UDMA experienced different geodynamics conditions, further documenting the diachronous collision and
correspondingly non-uniform crustal thickening across the UDMA
Microstate Analysis Reflects Maturation of the Preterm Brain
No full textPreterm neonates are at risk of long-term neurodevelopmental impairments due to disruption of natural brain development. Electroencephalography (EEG) analysis can provide insights into brain development of preterm neonates. This study aims to explore the use of microstate (MS) analysis to evaluate global brain dynamics changes during maturation in preterm neonates with normal neurodevelopmental outcome.The dataset included 135 EEGs obtained from 48 neonates at varying postmenstrual ages (26.4 to 47.7 weeks), divided into four age groups. For each recording we extracted a 5-minute epoch during quiet sleep (QS) and during non-quiet sleep (NQS), resulting in eight groups (4 age group x 2 sleep states). We compared MS maps and corresponding (map-specific) MS metrics across groups using group-level maps. Additionally, we investigated individual map metrics.Four group-level MS maps accounted for approximately 70% of the global variance and showed non-random syntax. MS topographies and transitions changed significantly when neonates reached 37 weeks. For both sleep states and all MS maps, MS duration decreased and occurrence increased with age. The same relationships were found using individual maps, showing strong correlations (Pearson coefficients up to 0.74) between individual map metrics and post-menstrual age. Moreover, the Hurst exponent of the individual MS sequence decreased with age.The observed changes in MS metrics with age might reflect the development of the preterm brain, which is characterized by formation of neural networks. Therefore, MS analysis is a promising tool for monitoring preterm neonatal brain maturation, while our study can serve as a valuable reference for investigating EEGs of neonates with abnormal neurodevelopmental outcomes
Phytochemical Compositions and Biological Activities of Essential Oil from Xanthium strumarium L.
No full textThe chemical composition of the essential oil (EO) from fresh cocklebur (Xanthium strumarium L.) leaves was investigated by GC-MS. The antimicrobial activity of the EO was tested against Gram-positive and Gram-negative bacteria and fungi. Scolicidal activity was assayed against Echinococcus granulosus protoscolices. In total, 34 compounds were identified, accounting for 98.96% of the EO. The main compounds in the EO were cis-β-guaiene (34.2%), limonene (20.3%), borneol (11.6%), bornyl acetate (4.5%), β-cubebene (3.8%), sabinene (3.6%), phytol (3.1%), β-selinene (2.8%), camphene (2.2%), α-cubebene (2.4%), β-caryophyllene (1.9%), α-pinene (1.8%) and xanthinin (1.04%). The antibacterial and antifungal screening of the EO showed that all assayed concentrations significantly inhibited the growth of Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger (MIC = 0.5 ± 0.1, 1.3 ± 0.0, 4.8 ± 0.0, 20.5 ± 0.3, 55.2 ± 0.0 and 34.3 ± 0.0 µg/mL, respectively). The scolicidal assay indicated that the EO exhibited a significant activity against E. granulosus protoscolices. To the best of our knowledge, this is the first report on the scolicidal activity of X. strumarium. Because of the emergence of antimicrobial drug resistance, the study of new effective natural chemotherapeutic agents, such as the X. strumarium EO, possibly with low side effects, represents a very promising approach in biomedical research
- …
