27 research outputs found
The Origin and MgCl2–NaCl Variations in an Athalassic Sag Pond: Insights from Chemical and Isotopic Data
No full textThe examination of past and new chemical–isotopic data (2H/1H–18O/16O,11B/10B and87Sr/86Sr ratios) shows the meteoric origin of the Sawa Lake (Muthanna Governorate, Iraq) and its connection with the local aquifers, which feed the lake via the groundwater emerging from its floor through fault systems. The chemical and isotopic evaporation models are traced by geochemical computer codes by using a different composition of some potential inflows to the lake (e.g., the Euphrates River and Dammam aquifer). The main product of the chemical evaporation models is gypsum, as confirmed by the mineralogical examination of the sediment and the surrounding outcrops. A strong18O–2H enrichment is a consequence of the evaporation effect in arid regions; δ18O–Cl models and δ11B = + 23.4‰ exclude the contribution of any seawater-derived fluids. This latter value along with87Sr/86Sr = 0.707989 suggests a mixed origin from the Eocene–Miocene aquifers. The isotope and chemical evaporation paths from the meteorically recharged sources match the lake composition. However, compositional switches from NaCl toward MgCl2occurred in the last decade and are related to post-drought periods, showing that the interaction of the recharging waters with the local soils (Na–Mg exchange and/or the leaching of the top layer salts) have a role in the chemical composition. This demonstrates that the lake is significantly influenced by climatic variations
Chemical and isotope composition of the oilfield brines from Mishrif Formation (southern Iraq): Diagenesis and geothermometry
No full textThis paper focuses on the geochemical composition and isotope geochemistry of brines in the Cenomanian–Turonian carbonate Mishrif reservoir of southern Iraq. Main dissolved constituents, trace elements, δ2H and δ18O, 87Sr/86Sr, mineral saturation indices and thermodynamic calculations were investigated in formation waters from the Mishrif Formation to obtain a better understanding of brine evolution and diagenetic effects over geological time. Previous published δ11B data were also reinterpreted as a geothermometer tool. The results are compared with previous published data for local oilfields and coeval formations in the Arabian Gulf. The Mishrif brine has a marine origin and is diagenetically modified to Ca-excess and Na-deficit. Formation waters are quartz supersaturated and are in equilibrium with chalcedony and calcite-dolomite in the temperatures range of 50–75 °C, which is also confirmed by calcite-water oxygen isotope fractionation and δ11B geothermometer. The potential role of clays in conditioning brine chemistry during diagenetic processes was highlighted by activity diagrams; in particular, their adsorption/exchange effect on sodium could explain the lower temperature obtained by the Na/Li geothermometer (42 ± 6 °C). The δ2H and δ18O values show that oxygen isotope composition of the brines was isotopically more affected by interaction with limestone during diagenesis than seawater evaporation. The main effect is an 18O-enrichment on the brine starting from the SMOW value. Locally, dilution by present-day meteoric water was also detected (Rumaila South), which is shifted towards the local meteoric water line. The strontium isotope ratios range from 0.707713 to 0.707749 and correspond to a marine strontium of late Cenomanian–early Maastrichtian age, except for the Majnoon sample, which shows a more radiogenic value (0.708043). Radiogenic strontium and gypsum and anhydride saturation indices of the Majnoon sample could indicate the contribution of calcium and sulphate from the strontium-rich sulphate minerals of the Cambrian salt domes occurring in the oilfields of southern Iraq. The higher manganese concentration (4 mg/l) and the slightly higher temperature inferred by geothermometers (up to 74 °C) in comparison with present-day could indicate that the Majnoon brine is a hot fluid, probably related to a deeper structure such as the Zagros Foredeep Fault
Impact of North African Sand and Dust Storms on the Middle East Using Iraq as an Example: Causes, Sources, and Mitigation
No full textThis study aims to determine the reasons for the increase in the frequency of sand and dust storms in the Middle East and to identify their sources and mitigate them. A set of climatic data from 60 years (1960–2022) was analyzed. Sand storms in Iraq are a silty sand mature arkose composed of 72.7% sand, 25.1% silt, and 2.19% clay; the clay fraction in dust storms constitutes 70%, with a small amount of silt (20.6%) and sand (9.4%). Dust and sand storms (%) are composed of quartz (49.2, 67.1), feldspar (4.9, 20.9), calcite (38, 5), gypsum (4.8, 0.4), dolomite (0.8, 1.0), and heavy minerals (3.2, 6.6). Increasing temperatures in Iraq, by an average of 2 °C for sixty years, have contributed to an increase in the number of dust storms from 75 to 200 times annually. North African storms affect the Middle East, with a monthly average exceeding 300 g/m3 in peak dust seasons. To reduce the negative impacts on public health, property, and infrastructure, the study suggests solutions to mitigate them, including reducing carbon dioxide gas emissions to prevent the expansion of drought and the afforestation of the desert with plants adapted to drought using advanced techniques and avoiding land overuse
Geochemistry of Termite Hills as a Tool for Geochemical Exploration of Glass Sand in the Iraqi Western Desert
No full textA preliminary assessment of the geochemical factors affecting groundwater and surface water quality around the rural communities in Al-Anbar, Western Desert of Iraq
No full textGeochemistry and mineralogical composition of the airborne particles of sand dunes and dust storms settled in Iraq and their environmental impacts
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Assessment of sulfurous springs in the west of Iraq for balneotherapy, drinking, irrigation and aquaculture purposes
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