Using multivariate statistical analyses to evaluate groundwater contamination in the northwestern part of Saudi Arabia   总被引：2，自引：1，他引：1  

Taisser Zumlot  Awni Batayneh  Yousef Nazal  Habes Ghrefat  Saad Mogren  Haider Zaman  Eslam Elawadi  Abdalaziz Laboun  Saleh Qaisy 《Environmental Earth Sciences》2013,70(7):3277-3287

Chemical characteristics of groundwater in the Midyan Basin (northwestern Saudi Arabia) were investigated and evaluated. A total of 72 water samples were collected from existing shallow wells and analyzed for different elements. Two multivariate statistical methods, hierarchical cluster analysis (HCA) and principal components analysis (PCA), were applied to a subgroup of the data set in terms of their usefulness for groundwater classification, and to identify the processes controlling groundwater geochemistry. The subgroup consisted of 46 water samples out of 72 samples and 24 variables included major elements (Ca²⁺, Na⁺, Mg²⁺, K⁺, Cl^?, HCO₃ ^?, NO₃ ^?, SO₄ ^2?), minor and trace element (SiO₂, Al, As, B, Ba, Cd, Cr, F, Fe, Mo, P, Pb, Sb, Sn, Ti, and V). For water samples, four geochemically distinct clusters (i.e., C1, C2, C3 and C4) have been observed by hierarchical cluster analysis. Cr, F and Pb are the dominant ions in cluster C2. Al, As, Cd, Mo, Sb and Ti are the dominant ions in cluster C3, while B, Ca, Cl, HCO₃, K, Mg, Na, SO₄ and V are identified as dominant ions in the cluster C4. In the PCA, a total of five components are extracted form the data set, which explained 73.37 % of the total data variability. Among them the first component reveals strong associations between As, B, Cd, Cr, F, Mo, Pb, Sb and Ti. The second component reveals the associations between Ca, Cl, HCO₃, Mg, Na, SO₄ and V.  相似文献   

Regional tectonic and megadepositional cycles of the Paleozoic of northwestern and central Saudi Arabia     

Abdulaziz Abdullah Laboun 《Arabian Journal of Geosciences》2013,6(4):971-984

The Paleozoic succession of the Greater Arabian basin is severely affected by series of major tectonic and climatic events which have caused major stratigraphic breaks and pronounce facies change. The major tectonic movements have resulted in dividing the succession into pronounced megatectonic and depositional cycles. In more tectonically active areas, the succession is less preserved and boundaries between the cycles are more complicated due to longer periods of erosion by later movements and/or nondeposition. Minor stratigraphic breaks within the megacycles subdivide the cycles into smaller subcycles. Following the stabilization of the Arabian–Nubian shield, the Gondwana shelf went through a gentle uplift and tilt probably related to the Assyniyc tectonic movements and thick siliciclastics of the Saq and Qasim Formations were deposited. During Late Caradocian and following the deposition of the Qasim Formation, the area went through a gentle uplift and tilt probably related to the Taconic tectonic movements. Thick succession of the Qasim and Saq Formations were eroded and deep paleovalleys incised in the two formations and underlying basement. The movements were followed by drop of sea level due to glaciation events. Glacial and periglacial deposits of the Zarqa and/or Sarah Formations filled paleovalleys and rest on older units from Ordovician to Precambrian. The third main event occurred during Late Silurian where the preexisting successions, mainly on paleohighs, were affected by tectonic movements synchronous with the Acadian tectonic phase of the Caledonian tectonic movements. The Early Devonian Tawil Formation unconformably rests on eroded Silurian and Late Ordovician deposits of the Sharawra, Qusayba (Qusaiba), and Sarah Formations in the Qusayba Depression in central Arabia. The forth main event is a regional movement contemporaneous with the Hercynian tectonic movement which has reached its maximum phase in the Late Carboniferous. Earlier successions from Carboniferous to Precambrian were affected and the Permo-Carboniferous Shajra Formation unconformably rests on all underlying Paleozoic rock units toward the central Arabia arch and other paleohighs. The Shajra rests on the Devonian Jawbah (Jubah), Jawf (Jauf) and Tawil formations, the Silurian Sharawra, Qusayba, and Uqlah formations, the Ordovician Zarqa/Sarah, and Qasim formations, the Cambro-Ordovician Saq Formation, and finally rests on Precambrian Basement complex in Central Arabia. The tectonic movements played important role in shaping the structural framework of Arabia. The Paleozoic succession included source, reservoir, and seal rocks. Oil and gas have been discovered in sandstone and limestone reservoirs in these rocks in several oilfields in the basin.  相似文献   

Did glaciers exist during Pleistocene in the Midyan region, northwest corner of the Arabian Peninsula?     

Abdulaziz Abdullah Laboun 《Arabian Journal of Geosciences》2012,5(6):1333-1339

Spectacular erratic boulders, polymictic conglomerates, and sedimentary structures are discovered in many localities at the Midyan Peninsula, east of the Gulf of Aqaba. These deposits are discontinuous, and they unconformably overlie older lithological units of Proterozoic, Cretaceous, Paleogene, and Neogene ages. The erratic boulders are composed of basement rocks, sandstone, and limestone. Some of the boulders exceed 2?m (6?ft) in diameter. The boulders are sub-rounded to rounded, striated, polished, grooved, and faceted. The polymictics are composed of heterogeneous coarse clastics (ranging from boulders to conglomeratic sandstones) of various rock types and fill incised paleovalleys. The sedimentary structures include polished, faceted, and striated boulders, pavements, U-shaped valleys, slumps, and fan-shaped structures. These deposits are herein informally named the Midyan Formation. A Pleistocene age is assigned to the formation based on its stratigraphic position. The polymictic conglomerates are interpreted as glaciogenic tillite, and the erratic boulders and sedimentary structures are considered to have been deposited by glacial erosion, deposition, and possibly tectonics. This interpretation raises the question; did glaciers exist during Pleistocene in the Midyan region? If this interpretation is valid, then recognition of Pleistocene glaciation in Arabia fills a blank spot in the global map of the ??Ice Age??. Pleistocene glacial features were reported in Yemen and regions in north Iraq.  相似文献   

Geochemical assessment of groundwater contamination with special emphasizes on fluoride,a case study from Midyan Basin,northwestern Saudi Arabia   总被引：1，自引：0，他引：1  

Habes Ghrefat  Yousef Nazzal  Awni Batayneh  Taisser Zumlot  Haider Zaman  Eslam Elawadi  Abdulaziz Laboun  Saad Mogren  Saleh Qaisy 《Environmental Earth Sciences》2014,71(4):1495-1505

Water samples for chemical analyses were collected in January 2012. A total of 72 samples of groundwater were collected from 72 boreholes in the Midyan Basin, northwestern Saudi Arabia. Samples were collected in polyethylene bottles and preserved and the used analytical techniques were in accordance with the standard methods from American public health association. Geochemical analyses of the groundwater samples from Midyan Basin reveal the concentration of fluoride (F) between 0.98 and 2.1 mg/l. Other parameters, e.g, pH, EC, TDS, HCO₃, SO₄, NO₃, Cl, K, Na, Mg, and Ca have been found in a variable proportion. Among them, the concentration of EC, HCO₃, K, Na and Mg is higher than the permissible limits. According to thermodynamical considerations, most of the analysed samples are graded under-saturated with respect to calcite and fluoride, while saturation has been observed in some samples. The under-saturation could probably be attributed to low concentration of calcite and fluoride in the studied wells. Fluoride concentration shows weak positive correlation with EC, TDS, Na, Cl, and SO₄. Factors controlling the concentration of fluoride (F) in the studied samples are the area climate, water chemistry and the presence of accessory minerals in the rocks through which groundwater is circulating, besides the anthropogenic activities in the area.  相似文献