Maharlou Lake, located in southwest Iran, is an intra-continental sedimentary basin. Its area is about 280 knf with an average water depth of 1.5m during wet seasons. The water level in the lake is controlled by several factors, including runoff from Maharlou catchments, groundwater seepage, and dircet rainfall over the lake and the evaporation rate. Hydrochemistry of the catchments water resources showed mainly chloride and sulfate waters due to the geology of the surrounding areas and its variable lithology. Hydrochemical investigations were carried out over a time period from 1975 to 2002 using previously published analysis, together with newly collected water samples. Two hundred thirty samples were collected during summer 2002 and spring 2005. Results showed distinct changes in the brine type over time; from Mg-S0 4-Cl type reported in 1970 to a recent Na-Mg-Cl-(SO,,) type, which is comparable with Great Salt Lake in the USA. A Change in diluted water composition going from HCO l :::: Ca + Mg to HCO, « Ca + Mg has taken place. That is, the path of brine composition on the Eugster and Hardie flow diagram has "changed from row (1l 2b to the path II, and may finally result in a Ca-Na-Cl or ;":a-S0 4-Cl brine type in the future. In this study, two mixed zones of fresh and saline waters were recognized in the northwest and center of the lake, with the lowest ionic concentrations, located where there is significant river and ground water supply.
This study investigates the depositional environment and sequence stratigraphy of the Asmari Formation (OligoeeneMiocene) in Gaehsaran Area. The formation is carbonate sequence, which is laid down in the southern side edge Neotethys Ocean (Zagros area). The Asmari Formation represents sedimentation on a carbonate ramp. Seven major microfacies and three subfacies are recognized which include: MF-I) planktonic foraminifer wackestone-packstone, MF-2) nummulitic-bioclastic-corallinacean wackestonepackstone, MF-3) bioclastic grainstone. MF-4) ooid-grainstone, MF-5) bioclastic-miliolid-borelisid, MF-6) miliolid-intraclast-bioclast and MF-7) carbonate mudstones (laminated mudstone, fossiliferous mudstone and algal mudstones).This carbonate succession consists offour, thick shallowing-upward sequences. Based on shallowing and deepening trend of depositional facies and changes in the cycle stacking pattern four third-order depositional sequences were identified.With the concern of 7 microfacies kinds, five carbonate sedimentary environments are represented. These environments from basin to land: outer slope to basin and slope sited in outer ramp; shoal and shelf lagoon located between middle ramp-internal ramp; and restricted lagoon and low intertidal too supratidal set up in the internal ramp. The formation indicates a large-scale trend of decreasing accommodation upward.The lower Asmari layers was laid down on open-marine conditions and represented by a laterally equivalent shaley facies, assigned to that generally the Pabdeh formation and communicated prograding side edge to the upward gradient attitudes, while the center to the upper parts of the formation were deposited in lower energy settings with more frequent evidence of exposure and evaporitic conditions, reflecting ramp settings established behind the prograding margin. The top side of the sequence is obviously marked by an erosional surface. which is overlaid by thick tidal flats. The surface erosional shows intense staining and leaching out suggesting diagenetic alteration during the sub-aerial exposure.With petrographic methods five kinds of dolomite arc differentiated in this formation: 1-dolomicrite 2-dolomierosparite 3-sucrosic dolomite 4-cloudy center dolomite and 5-saddle dolomite.
Background, aim, and scope The rapid growth of the world's population over the past few decades has led to a concentration of people, buildings, and infrastructure in urban areas. The tendency of urban areas to develop in sedimentary valleys has increased their vulnerability to earthquakes due to the presence of soft soil and sediment. Several earthquakes have clearly demonstrated that local soil and sediment conditions can have a significant influence on earthquakeinduced ground motion and damage pattern, respectively. Many studies confirm the relationship between site effect and ground motion ). In order to classify the suitability of the soil and subsurface sediment units for urban planning and compare their mechanical behavior with the non-uniform damage observed in the 2003 earthquake, we performed some geotechnical and geophysical analyses of soil and sediment samples collected from different locations in Bam City. Methodology Geophysical and geotechnical properties, such as grain size distribution, sorting, plasticity, Poison's ratio, shear strength, compression index, permeability, and P and S wave velocities in soil and subsurface sediments, were measured. Maps (in GIS environment) and crosssections were prepared for the study area.Results According to our observations, a great number of buildings were damaged in areas of the city where silty and clayey soils dominate, presenting very low permeability, low wave velocity together with high plasticity, and compressibility. In the study area, we recognized eight sediment types. Shear wave propagation velocities allowed for the identification of four seismic layers referred to as the surface layer, second layer, and third layer and seismic bedrock. We found that the damages observed in the Bam area were related to the physical and mechanical properties of the soil and subsurface sediment units. We also found that the soil thickness that was estimated by geophysical surveying shows a direct relationship with damage rate observations. Furthermore, we observed that landslide and qanat collapses have occurred in some areas where sand and silty sand soils and subsurface sediments dominate. DiscussionThe distribution of the damage shows a microzonation that is very serious in some points in the city along
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.