56 research outputs found
Tectonic Evolution of the Alborz in Mesozoic and Cenozoic
No full textInternational audienceIn northern Iran the Eo-Cimmerian orogeny resulting from this collision is associated with a regional unconformity and a major change in sedimentation. From Norian to middle Bajocian (Shemshak group), 030° trending extension is indicated by syndepositional normal faults. We assign this extensional tectonics to the rifting phase preceding the oceanic opening of the South Caspian Basin. Dalichai and Lar formations, late-Bajocian to Neocomian in age, conformably cover the Shemshak in central Alborz. They are contemporaneous with the opening of the South Caspian marginal basin. In Alborz, the lower part of the Cretaceous sequence is associated with E-W to WNW-ESE trending normal fault systems associated with magmatism related to an N-S to NNE-SSW trending extension during this period. The Cretaceous-Palaeogene boundary is marked by a major regional unconformity. This unconformity is related to a major inversion of the southern margin of the South Caspian basins. During the early-middle Eocene, southern Alborz is characterized by a rapid subsidence of the Karaj basin. Syndepositional E-W to WNW-ESE trending normal faults are common in the Karaj Formation. They are associated with a well-determined N-S to NNE-SSW extension. We assign the Karaj basin to a back-arc basin related to the NE subduction of the neo-tethyan oceanic lithosphere beneath the southern margin of Eurasia
Tectonic Evolution of the Alborz in Mesozoic and Cenozoic
No full textInternational audienceIn northern Iran the Eo-Cimmerian orogeny resulting from this collision is associated with a regional unconformity and a major change in sedimentation. From Norian to middle Bajocian (Shemshak group), 030° trending extension is indicated by syndepositional normal faults. We assign this extensional tectonics to the rifting phase preceding the oceanic opening of the South Caspian Basin. Dalichai and Lar formations, late-Bajocian to Neocomian in age, conformably cover the Shemshak in central Alborz. They are contemporaneous with the opening of the South Caspian marginal basin. In Alborz, the lower part of the Cretaceous sequence is associated with E-W to WNW-ESE trending normal fault systems associated with magmatism related to an N-S to NNE-SSW trending extension during this period. The Cretaceous-Palaeogene boundary is marked by a major regional unconformity. This unconformity is related to a major inversion of the southern margin of the South Caspian basins. During the early-middle Eocene, southern Alborz is characterized by a rapid subsidence of the Karaj basin. Syndepositional E-W to WNW-ESE trending normal faults are common in the Karaj Formation. They are associated with a well-determined N-S to NNE-SSW extension. We assign the Karaj basin to a back-arc basin related to the NE subduction of the neo-tethyan oceanic lithosphere beneath the southern margin of Eurasia
Inculcate Tehran: Opening a Dialogue of Civilizations in the Shadow of God and the Alborz
No full textThis essay discusses the establishment of Alborz College by American Presbyterian missionaries. Alborz\u27s early years, before its 1940 nationalization by Iran, were shaped by the vision of its first president, Samuel Jordan, a liberal, athletic, pragmatic Christian reformer who led by example, a practitioner of what we now call “social work” and an encourager of female empowerment. Alborz and the Presbyterian mission which gave it birth grew in the context of American social history, including the religious awakening of the early nineteenth century, American doctrines of freedom and universal education, as well as the contradictory impulses of ethnocentricity and ecumenicism. The essay is based on private and governmental archival sources and the experience of the author as a high school student in Tehran.
This history needs to be told.
—Yahya Armajani
All writing is autobiographical.
—Donald Murray
This essay discusses the origins of Alborz College as an effort by private Americans to share with Iran the blessings of their own culture. This they did for decades, cooperating with the Tehran government, without involving Washington. Remarkably, Alborz survived Reza Shah\u27s assault on foreign schools during the 1930s, and it flourished after nationalization as a premier Iranian institution preparing secondary students for modern university studies. It continues as such today
Plio-Quaternary tectonic regime changes in the transition zone between Alborz and Kopeh Dagh mountain ranges (NE Iran)
No full textInternational audienceThis paper is concerned with the changes in the Plio-Quaternary stress states in NE Iran and provides evidence for regional active deformation across a wide transition zone between the Alborz and Kopeh Dagh mountains. The Arabia-Eurasia convergence is involved in the strike-slip faulting along NE-trending left-lateral faults in the eastern Alborz as well as NW-trending right-lateral faults in the western Kopeh Dagh. The inversion result of fault kinematic data (slip-vector measurement of fault plane and focal mechanisms) strongly indicates an active transpressional tectonic regime in the study area. We provide evidence for drastic temporal changes in the stress state during the Plio-Quaternary based on the inversions of fault kinematic data. A regional transpressional tectonic regime with a mean N036 +/- 20 degrees E trending horizontal sigma(1), is representative for the modern stress state. The older state reveals compressional to transpressional tectonic regimes comprising a N135 +/- 20 degrees E trending horizontal sigma(1). The modern transpressional tectonic regime characterized by a regional NE-trending cri is consistent with the inversion of earthquake focal mechanisms that yield a N47 degrees E trending sigma(1) for the present day stress state. The kinematic results are significantly homogeneous and mechanically compatible with the active geological structures, in the way that reverse and strike-slip faulting are coherent with a single sigma(1) direction. (C) 2011 Elsevier B.V. All rights reserved
40Ar/39Ar dating of Quaternary lavas in northwest Iran: constraints on the landscape evolution and incision rates of the Turkish-Iranian plateau
No full textWe report five new <sup>40</sup>Ar/<sup>39</sup>Ar ages for basaltic lavas in the Maku region of northwest Iran, between ca. 1.87 and 0.40 Ma, which help constrain the tectonic and landscape evolution of this part of the Turkish–Iranian plateau. Flows originated from the composite volcanoes Ararat (Agri Dagi), Tendürek and Yigit Dagi, in eastern Turkey (Anatolia). These volcanoes are within the Turkish–Iranian plateau, which is a consequence of the Arabia–Eurasia collision, but has a poorly constrained evolution and surface uplift history. Current plateau elevations are typically 1.5–2 km, and relief between non-volcanic summits and basins is typically on the scale of ∼1 km. Samples are from flows that passed along pre-existing river valleys. Gorges were cut by re-established rivers after the eruptions, but the great majority of the local relief (∼95 per cent) lies above the sampled flows and so most likely pre-dates the volcanism. Gorge depths and lava ages allow local Quaternary fluvial incision rates to be calculated, which are ∼0.01 to 0.05 mm yr−1. These rates imply slow surface uplift of this part of the Turkish–Iranian plateau during the Quaternary. We therefore constrain the generation of the great majority of relief in the study area to be pre-Quaternary, and caused by the tectonic construction of the plateau, rather than a subcrustal origin related to the Quaternary magmatism
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Shemiran Dialect Group
No full textA blurry region in the dialectology of Iran is the central Alborz, an extensive area bounded by the Caspian littoral in the north and the plain of Tehran in the south. While some linguistic data on the northern valleys of central Alborz (namely those of the Kojur and Nur river valleys) that clearly defines them as varieties of Māzandarāni has been available for some time, the data on the Jājrud valley, immediately north of Tehran across the Towchāl range, and on Shemirān, now within the municipal boundaries of the capital, have only been published recently. This development has persuaded this author to undertake an extensive study of these districts, resulting in the present paper (among others), which attempts to cover Shemirān, the southernmost district of central Alborz
The relationship between information and communications technology (ICT) and organizational learning in Department of Youth and Sports of Alborz Province
No full textOrganizational learning is a complex process which refers to growth and development of new knowledge and possesses a potential force for behavior change and there are multiple factors which can affect this variable. The aim of the present research is to study the relationship between Information and Communications Technology and organizational learning in department of Youth and Sports of Alborz Province and for this purpose 171 of the managers, deputies and experts of this department have been selected with the use of simple random sampling method and have responded to the organizational learning questionnaire of Neefe (2001) and the author-made questionnaire of Information and Communications Technology. The validity of the questionnaire was confirmed by the experts and professor in this field and their reliability was tested by using Cronbach’s alpha test which is equal to 0.89 and 0.82 for the questionnaires of organizational learning and Information and Communications Technology, respectively. Finally, the gathered data from these questionnaires were analyzed by using LISREL software in terms of the analyzed measurement model. The results indicate that there is a significant and positive relationship between Information and Communications Technology and the dimensions of organizational learning, except for systematic thinking dimension
A bioclimatic characterization of high elevation habitats in the Alborz mountains of Iran
No full textThe Alborz mountains in N-Iran at 36° N rise from the Caspian Sea to 5671 m a.s.l., with warm-temperate, winter-deciduous forests in the lower montane belt in northern slopes, and vast treeless terrain at higher elevation. A lack of rainfall (ca. 550 mm at high elevations) cannot explain the absence of trees. Hence, it is an open question, which parts of these mountains belong to the alpine belt. Here we use bioclimatic data to estimate the position of the potential climatic treeline, and thus, define bioclimatologically, what is alpine and what is not. We employed the same miniature data loggers and protocol that had been applied in a Europe-wide assessment of alpine climates and a global survey of treeline temperatures. The data suggest a potential treeline position at ca. 3300 m a.s.l., that is ca. 900 m above the upper edge of the current oak forest, or 450 m above its highest outposts. The alpine terrain above the climatic treeline position shows a temperature regime comparable to sites in the European Alps. At the upper limit of angiosperm life, at 4850 m a.s.l., the growing season lasted 63 days with a seasonal mean root zone temperature of 4.5 °C. We conclude that (1) the absence of trees below 2850 m a.s.l. is clearly due to millennia of land use. The absence of trees between 2850 and 3300 m a.s.l. is either due to the absence of suitable tree taxa, or the only potential regional taxon for those elevations, Juniperus excelsa, had been eradicated by land use as well. (2) These continental mountains provide thermal life conditions in the alpine belt similar to other temperate mountains. (3) Topography and snow melt regimes play a significant role for the structure of the alpine vegetation mosaics.© The Author(s) 201
Statistic and genetic investigation of faults in North Tehran tectonic wedge (South Central Alborz)
No full textTectonic evolution and Late Triassic- Middle Eocene extension in central Alborz, Iran.
No full textInternational audienc
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