Transition from I‐type to A‐type magmatism in the Sanandaj–Sirjan Zone,NW Iran: an extensional intra‐continental arc

The South Dehgolan pluton, in NW Iran was emplaced into the Sanandaj–Sirjan magmatic–metamorphic zone. This composite intrusion comprises three main groups: (1) monzogabbro–monzodiorite rocks, (2) quartz monzonite–syenite rocks, and (3) a granite suite which crops out in most of the area. The granites generally show high SiO₂ content from 72.1%–77.6 wt.% with diagnostic mineralogy consisting of biotite and amphibole along the boundaries of feldspar–quartz crystals which implies anhydrous primary magma compositions. The granite suite is metaluminous and distinguished by high FeOt/MgO ratios (av. 9.6 wt.%), typical of ferroan compositions with a pronounced A‐type affinity with high Na₂O + K₂O contents, high Ga/Al ratios, enrichment in Zr, Nb, REE, and depletion in Eu. The quartz monzonite–syenites show intermediate SiO₂ levels (59.8%–64.5 wt.%) with metaluminous, magnesian to ferroan characteristics, intermediate Na₂O + K₂O contents, enrichment in Zr, Nb, REE, Ga/Al, and depletion in Eu. The monzogabbro–monzodiorites show overall lower SiO₂ content (48.5%–55.9 wt.%) with metaluminous and calc‐alkaline compositions, relatively lower Na₂O + K₂O contents, low Ga/Al ratios, and FeOt/MgO (av. 1.6 wt.%) ratios, low abundances of Zr, Nb, and lower REE element concentrations relative to the granites and quartz monzonite–syenites. These geochemical differences among the three different rocks suites are likely to indicate different melt origins. We suggest that the South Dehgolan pluton resulted from a change in the geodynamic regime, from compression to extension in the Sanandaj–Sirjan zone during Mesozoic subduction of the Neo‐Tethys oceanic crust beneath the Central Iranian microcontinent. Copyright © 2015 John Wiley & Sons, Ltd.     

Calcareous nannofossils from chalky limestone of upper Abderaz Formation and lower part of Abtalkh Formation in the Kopet-Dogh range NE Iran

For the first time, the calcareous nannofossils of the chalky limestone of upper Abderaz Formation and lower part of Abtalkh Formation have been studied. In this study, 83 nannoplanktonic species of 45 genera were identified and presented. A biostratigraphic study of calcareous nannofossils from this section has allowed the recognition of five calcareous nannofossil biozones of Sissingh (Geol Mijnbouw 56:37–65, 1977) CC17–CC21. On the obtained calcareous nannofossils, the age of this section is Late Santonian/Early Campanian–Early Late Campanian.     

Cosmological dynamics of a quintom field on the warped DGP brane

As a generalization of the Brans-Dicke type scalar-tensor gravity in a braneworld context, we study cosmological phase space of a braneworld model with induced gravity in the presence of a scalar field on the brane. We consider a quintom field minimally or non-minimally coupled to induced gravity on the warped DGP brane and we present a detailed analysis of the critical points, their stability and late-time cosmological viability of the solutions within a phase space approach. In particular, de Sitter solutions, different from the famous self-accelerated branch of the DGP model are found and the phase-space analysis for checking their attractor properties is performed. We analyze also the possibility of crossing of the phantom divide by the effective equation of state parameter of the model. We also focus on the classical stability of the solutions in w–w′ phase plane.     

Spectroscopy of Rindler modified Schwarzschild black hole

We study quasinormal modes (QNMs) of uncharged Grumiller black hole (GBH). This massive BH has a Rindler acceleration a, and hence it is also called Rindler modified Schwarzschild BH. After reducing the radial equation of the massless Klein-Gordon equation to the Zerilli equation, we compute the complex frequencies of the QNMs of the GBH. To this end, an approximation method which considers small perturbations around its horizon is used. Considering the highly damped QNMs in the process proposed by Maggiore, the quantum entropy and area spectra of these BHs are found. Although the QNM frequencies are tuned by the Rindler term, we show in detail that the spacing does not depend on it. Here, the dimensionless constant ? of the area spectrum is found to be double of its Schwarzschild value. The latter result is also discussed.     

Geochemical and isotopic constraints on the role of juvenile crust and magma mixing in the UDMA magmatism,Iran: evidence from mafic microgranular enclaves and cogenetic granitoids in the Zafarghand igneous complex

International Journal of Earth Sciences - The Zafarghand Igneous Complex is composed of granite, granodiorite, diorite, and gabbro that contain many mafic microgranular enclaves. This complex was...     

Magnesium Isotopic Compositions of International Geological Reference Materials

Magnesium isotopic compositions are reported for twenty‐four international geological reference materials including igneous, metamorphic and sedimentary rocks, as well as phlogopite and serpentine minerals. The long‐term reproducibility of Mg isotopic determination, based on 4‐year analyses of olivine and seawater samples, was ≤ 0.07‰ (2s) for δ²⁶Mg and ≤ 0.05‰ (2s) for δ²⁵Mg. Accuracy was tested by analysis of synthetic reference materials down to the quoted long‐term reproducibility. This comprehensive dataset, plus seawater data produced in the same laboratory, serves as a reference for quality assurance and inter‐laboratory comparison of high‐precision Mg isotopic data.     

Time trend analysis of some agroclimatic variables during the last half century over Iran

Theoretical and Applied Climatology - We assessed the trends of precipitation, maximum and minimum temperature (Tmax and Tmin), diurnal temperature range (DTR), water requirement of autumn-planted...     

The daily travel of villagers to the city in a case study of Northern Iran

Rural urban migration can often result in decreased agricultural output in countries with scarce land resources. It also can hasten the socio-economic problems associated with the overcrowded cities of the developing world. As only 10% of Iran is arable it is particularly vulnerable to threats to food security and self-sufficiency. This paper examines the daily flow of villagers to a major city near the vital staple crop producing rural district of Lakan, where out-migration is already occurring. Although most discussions of daily travel to cities is typically relegated to commuting, this paper aims to analyze travel for the purpose of access to a variety of facilities and services that villages in the rural district of Lakan lack including secondary schools, post offices, banks, and even telephones and newspaper stands. The paper emphasizes that daily journeys make permanent moves to the city more likely because of the major inconvenience that results from the scarcity of basic facilities within Lakan villages. Travel to a distant city for staple foods at grocery stores or for access to secondary schools, for example, could intensify future out-migration because the heavy inconvenience of constant travel might eventually outweigh the benefits of maintaining residency in villages. The paper utilizes information about daily travel to Rasht to recommend various government construction projects and initiatives to improve the quality of life for villagers and avert future rural–urban migration and the reduction in staple crop production that might result.     

The accountability imperative for quantifying the uncertainty of emission forecasts: evidence from Mexico

Governmental climate change mitigation targets are typically developed with the aid of forecasts of greenhouse-gas (GHG) emissions. The robustness and credibility of such forecasts depends, among other issues, on the extent to which forecasting approaches can reflect prevailing uncertainties. We apply a transparent and replicable method to quantify the uncertainty associated with projections of gross domestic product growth rates for Mexico, a key driver of GHG emissions in the country. We use those projections to produce probabilistic forecasts of GHG emissions for Mexico. We contrast our probabilistic forecasts with Mexico’s governmental deterministic forecasts. We show that, because they fail to reflect such key uncertainty, deterministic forecasts are ill-suited for use in target-setting processes. We argue that (i) guidelines should be agreed upon, to ensure that governmental forecasts meet certain minimum transparency and quality standards, and (ii) governments should be held accountable for the appropriateness of the forecasting approach applied to prepare governmental forecasts, especially when those forecasts are used to derive climate change mitigation targets.

POLICY INSIGHTS

• No minimum transparency and quality standards exist to guide the development of GHG emission scenario forecasts, not even when these forecasts are used to set national climate change mitigation targets.

• No accountability mechanisms appear to be in place at the national level to ensure that national governments rely on scientifically sound processes to develop GHG emission scenarios.

• Using probabilistic forecasts to underpin emission reduction targets represents a scientifically sound option for reflecting in the target the uncertainty to which those forecasts are subject, thus increasing the validity of the target.

• Setting up minimum transparency and quality standards, and holding governments accountable for their choice of forecasting methods could lead to more robust emission reduction targets nationally and, by extension, internationally.