No abstract

In this paper, we use satellite images, field observations and aeromagnetic data to describe major tectonic features in the central portion of the Urumieh-Dokhtar Magmatic Arc (UDMA) in Central Iran. Most of the analyzed structures such as horsetail splays, rotated blocks, positive flower structures and sedimentary basins have not been previously recognized. The NW-SE-trending Zefreh Fault is the most important dextral transpressional active lineament in the area. Maps of filtered aeromagnetic anomalies confirmed that the fault also affects the basement. Based on our field observations and cross-cutting relationships, tectonic evolution of the central part of the UDMA is interpreted in terms of two main stages:(1) formation of main thrusts during shortening and exhumation of older rocks in the UDMA after Eocene-Oligocene, and (2) transpressional movements reactivating the main thrust faults to reverse-dextral strike-slip faults during the Pliocene-Quaternary. The present-day deformation of the UDMA is mostly dominated by strike-slip movements. These two stages are interpreted as reflecting a change in convergence vector between Arabian and Eurasian plates.

No abstract

No abstract

Background. Large-scale geological structures, such as lineaments, are of great research interest due to their potential to mark the presence of ore fields.Aim. To determine the relationship between ore deposits, lineaments and large-scale faults in Iran using satellite imagery, digital relief modelling and structural mapping.Materials and methods. In this study, we compiled a map of lineaments in the Iran, which were determined both automatically and manually. A database of the distribution of ore deposits and lineaments was compiled from available maps, publications and reports on ore deposits in Iran. These maps were overlaid to study the relationship between the locations of the lineaments, faults and ore deposits.Results. An analysis of the lineaments revealed on geological maps indicates the presence of four dominant strike directions of large and small lineaments. The developed lineament map shows the main northwest trending longitudinal faults, which are parallel to the main strike of the Zagros orogenic belt; sublatitudinal and submeridional trending oblique faults; northeast trending transverse faults. A “Combined map of lineaments and deposits of copper, lead, zinc and iron in Iran” was compiled by the ArcGis software using maps of lineaments and mineral deposits. The ore deposits identified were analysed to determine the distribution of the distances between each deposit using the counting and cumulative methods the ArcGis software.Conclusions. About 90% and 50% of ore deposits are located at a distance of less than 15 km and 5 km, respectively, from the centre line of the associated lineament. A direct relationship between the density of lineaments and the presence of deposits was observed. The obtained results demonstrate the potential of this method for assessing the prospects of ore fields in hard-to-reach and poorly studied regions.