Iranian Journal of Earth Sciences
Volume:2 Issue: 2, Oct 2010

The Nayband strike-slip fault forms the western margin of the micro-continental Lut block in Eastern Iran. Neogene and Quaternary mafic volcanic rocks collected near Tabas, along the northern part of the fault (NNF; 15 Ma), and further to the south, along the middle part of the fault (MNF; 2 Ma), are within-plate sodic-series alkali olivine basalts with high TiO2 and up to >16% normative nepheline. Their high MgO, Ni and Cr contents indicate that they crystallized from relatively primitive magmas. Their low La/Nb and Ba/Nb ratios are similar to oceanic island basalts (OIB) and unlike convergent plate boundary arc basalts (IAB). These alkali olivine basalts show enrichment in LREE relative to HREE and limited variation in Sr, Nd and Pb isotopic values which all plot in the range of OIB. Ce/Pb (>39), Nb/U (44-120) and P2O5/K2O (~0.4) ratios suggest that crustal contamination was not significant for MNF basalts. The data may be interpreted as indicating the participation of upwelling mantle asthenosphere and the deeper continental mantle lithosphere in the generation of these basalts. They formed by generally low, but variable degrees of partial mantle melting, which decreased with time from 15 Ma NNF relative to2 Ma MNF basalts. The small volume of melts that formed the MNF basalts rose to the surface along the deep Nayband strike-slip fault with no interaction with the continental crust. The larger volume of NNF basalts interacted to some degree with the crust and are associated with basaltic andesites and andesites.

Red beds, conglomerates and salt were considered azoic and problematic rocks, but Paleopalynology and Inorganic Geochemistry proved to be useful for placing them in time and space. In the early last century, in Mexican NE region, only three Mesozoic red bed units were differentiated, dated as Late Triassic to Late Jurassic. It was important tratigraphically to place them properly as they were considered to be the basement of the marine petroliferous sequence in some Mexican Gulf of Mexico sub-basins. Palynostratigraphic studies since 1969, and X- ray analyses since 1989 allowed to place, in time and space, the Cahuasas, Huizachal, La Joya, and La Boca red bed units, outcropping at the Huizachal-Peregrina and Huayacocotla anticlinoria and, recently, the Rosario, Conglomerado-Prieto and Cuarcítica-Cualac units at the Tlaxiaco Anticlinorium. For reconstructing the paleogeographic distribution of these red beds, their correlation permitted to place the Liassic units as deposited in a half-graben connected to an Epicontinental Sinemurian Sea. This sea, during the Middle Jurassic, was invaded by the Tethysian waters through the Hispanic Corridor formed across the new Gulf of Mexico, which originated by a hot spot with a triple junction origin.

A case study was carried out to see the impacts of shrimp culture on the surface (pond) and ground water (tube-well) quality in three coastal sub-districts of Bagherhat Sadar, Rampal and Morrelganj of Bangladesh. The people of Rampal (100%), Morrelgonj (87.5%) and Bagherhat (75.5%) expressed that salinity of both surface and ground water increased after shrimp culture, and water becomes more turbid, odorous and less tasty compared to pre-shrimp culture scenario. The ground water pH was foo be slightly acidic (6.07– 6.71) but the surface water was mildly alkaline in nature (7.00–7.46). Ground water was more saline (1893–2673ppm) than surface water (513-2253ppm). Potassium level of surface water was very high (97-242ppm) compared to the ground water (11.73-27.37 ppm). This exceeds the WHO Guideline Value (10ppm) and the Bangladesh Standard for Drinking Water (12ppm). The pollution levels of phosphorous and iron were found to be a little higher but other pollutants like nitrate, boron and zinc were found to be very low in surface and ground water in the shrimp culture area of Bangladesh.

For the first time, on the basis of Spitak earthquake experience (Armenia, December 1988), it was found that an earthquake causes intensive and prolonged radon releases that are quickly dispersed in the open air and that is why they are not usually registered but contrastingly displayed in covered premises (such as dwelling houses, schools, kindergartens) even if they are at a considerable distance from the epicenter of the earthquake. The duration of the release includes the period starting from the first foreshock and ending with the last aftershock, i.e. several months. The radiation intensity and duration of the influence are in direct correlation with the intensity of the earthquake. The area affected by radiation is larger than the territory of Armenia. The scale of this impact on the effected population is twelve times higher than the number of people injured in the Spitak earthquake. Data collation from the 2000–2005 time period indicates that a contrasting increase in indoor radon concentrations in Yerevan (several times excessive vs. the sanitary norm) is predetermined not only by strong earthquakes (M ≥ 4.5), but also by the weak (M <4.5), small-depth (H-5-15km), regional (R ≤ 200 km from Yerevan) earthquakes and earthquake swarms occurring in the territory of Armenia, as well as in Iran and Turkey.

The Mikkes basin is located at the north center of Morocco. It comprises three different zones which represent diversified geologies which shelter a phreatic and confined aquifer in the Sais basin and a shallow aquifer in the Tabular Middle Atlas. The springs in the Sais phreatic aquifer have suffered a maximum depletion. The springs with a deep or mixed origin are known as low flow variation springs. Actually, the variations of the fall of spring’s flows could be linked to a different hydro-geological context of these springs.

Climate change and its possible impacts on the environment and socio-economic systems now constitute the most important environmental problem facing mankind in the 21st century. Climate change will increase poverty and hardship, endanger food security, destabilize economies, decrease food and water and create social insecurity in many countries and undermine our goals for achieving sustainable development. An in-depth analysis was carried out on the nature and characteristics of climatic changes and the roles of renewable energy and energy efficiency in combating the threat of climate change especially in relation to mitigation measures. Energy policy is therefore becoming an increasingly important tool for medium and long term planning to mitigate GHG emissions and to adapt to climate change especially in the developing countries. This paper highlights the fact that research efforts for the rest of the 21st century be directed towards harnessing renewable energies like the solar, wind and geothermal energies to replace the present day burning of fossil fuel energy for lighting, heating, cooling, manufacturing, cooking, transport, entertainment, etc. This will help to reduce the emission of green house gases (GHGs) and ozone depletion and in the long run the global warming effect.

The Bikilal layered gabbro-complex is composed of zones/layers of olivine/ pyroxene gabbro and hornblende gabbro. Within the hornblende gabbro, repeated lens-like thin and elongated bodies of hornblendite are found intimately associated with massive and disseminated ilmenite-magnetite bodies, in places with apatite. Petrological examination of the hornblende gabbro shows 50-55% hornblende, 40-45% plagioclase, 5-7% opaque minerals/ilmenite + magnetite/, and 5-15% apatite and that of hornblendite shows 75% hornblende, 10-15% apatite, 10-15% ilmenite and rare sulphides, and traces of Uranium. Regardless of the type of lithological units, two main zones of phosphate mineralization, the upper and lower zones, were identified and delineated entirely based on phosphate (P2O5) assay values of chip, channel and, core samples,The strike length of the upper zone is 1600m. There are two main layers of phosphate mineralization in the upper zone; the average thickness of each layer is 30m and 40m respectively. The strike length of the lower zone is 3000m having a thickness of 60m ─ 200m. The mineable reserve of Soji-Bikilal phosphate deposit is estimated to be 181 million tons, at a grade of 3.5% P2O5. Preliminary beneficiation trial reveals commercial grade concentrate, at which the overall weight recovery, is in the range of 3-5%. The Radioactivity of Uranium has not been determined and hence re-evaluation of the phosphate rock for Uranium content should be carried out. Similar Gabbro intrusions occur in Western Ethiopia and in East Africa which should be assessed for phosphate potential to develop the fertilizer potential of the East Africa Region.

A brief account of the representative and workable industrial minerals namely magnesite, talc and barite in Lesser Himalaya, is presented here emphasizing their genesis. Deposits of magnesite and talc are found associated with Neoproterozoic, plateform type, shelf-slope limestone-dolomite host rocks from inner Lesser Himalayan sequences. Field, textural, geochemical signatures and fluid inclusions trapped in dolomite and magnesite reveal within basin processes, in an increased burial- diagenetic environment responsible for formation of magnesite replacing dolomite. Talc is formed at the expense of magnesite and silica, and with limited dolomite involvement at transition conditions from diagenetic to metamorphism. Barite deposit is hosted within Neoproterozoic Nagthat quartzite rocks of outer Lesser Himalaya, wherein its textures, fluid inclusion, sulfur and strontium isotopic studies helped in genetic understanding.

Soil conservation and control of erosion is a basic problem in all countries. The goal of this research is to estimate erosion and sediment yield in Ekbatan Dam drainage basin by Erosion Potential Method (EPM), using Geographic Information System (GIS). The basin is located in Hamedan Province, west of Iran, in a cold and semi- arid region, with an average annual rainfall of 334mm. The study area is about 218 km2 and is divided into 8 sub- basins. Sub- basins 1 and 6 are the largest (49.14 km2), and smallest (9.92km2), respectively. Elevation ranges between 1960 to 3580 m. The litho-units include schist, granite, hornfels, limestone, sandstone, (Pre- Jurassic to Neogene in age), conglomerate, and recent alluvium. Most sediment in the basin is generated from erosion of schist. The main factors in the EPM (slope average percent, erosion, rock and soil erosion and land- use) were evaluated using GIS software. Data layers used in this study were created from topographic, homorain, homotemp, geology, lithology maps, landsat TM digital images, and field observations. According to calculated results, the coefficient of erosion and sediment yield (z) for this basin fall into moderate and heavy erosion classes. For avoiding soil erosion in this basin, therefore, soil conservation operations should be performed.