Gypsum Beds Research Articles

Impact of Soil Amendments and Improved Alkaline Water on the Physico-chemical Characteristics of the Soil, the Distribution of Salt in the Soil, the Growth, and the Yield of Hybrid Cotton Grown in Sodic Soil with Drip Irrigation

The effects of ameliorated alkali water and soil amendments on the soil properties, growth, and yield of hybrid cotton in sodic soil under drip irrigation were investigated in this field experiment at Anbil Dharma lingam Agricultural College and Research Institute, Trichy, using cotton (RCH-20) as a test crop. The main-plot treatments included drip irrigation with gypsum treatment water and drip irrigation with spent wash treatment water; the sub-plot treatments included soil application of gypsum @ 50% GR (5.2 t ha-1) and a one-time soil application of distillery spent wash at 5 lakh liters ha-1. The treatment without amendments under main plot and sub-plots was used as a control. The experiment was designed in a strip-plot design with four replications. The application of additives through irrigation water or soil dramatically lowered the post-harvest soil's pH. Plots applied with wasted wash had the greatest pH reduction (M1S1) 7.81, followed by those applied with gypsum (M2S2) 7.90 and control (M3S3) 8.15. Because there was more soluble salt present in the spent wash treated plots, there was a little rise in EC. Drip irrigation with distillery spent wash (DSW) treated water and drip irrigation with gypsum treated water, respectively, resulted in ESP decreases of (M2S2) 0.97 and (M1S1) 0.61 over control. Similarly, ESP decreased by 2.63 and 1.31 when gypsum and DSW were applied to the soil, respectively, compared to the control. The organic carbon values ranged from (M3S3) 0.47 to (M2S2) 0.92 percent. In general, an increase in organic carbon content was observed in all the treatments that received amendments (Gypsum& DSW) compared to control. Salt distribution pattern conducted in treatment of distillery spent wash @ 5.0 lakh liters ha-1 significantly increased vertical depth of soil pH ranges (7.56,7.68,7.80,8.30) and decreased EC ranges (1.05,1.02,1.00,0.95) followed by horizontal line soil pH ranges (7.54,7.51,7.49,7.50) and EC ranges (1.04,1.02,1.00,1.02) at 120 DAS after application. In the experimental field recorded vertical depth of soil increased pH and decreased electrical conductivity compared to horizontal distances of soil pH and EC. The physico- chemical properties reduced in treatment one time application of DSW @ 5 lakh liters ha-1 recorded the highest physico -chemical properties followed by the treatment receiving irrigation with gypsum bed treated alkali water and lowest was recorded in the untreated alkali water irrigated through drip system in non- amended soil.

Coupling of X-ray fluorescence and Strontium isotopes to track brine influences in continental deposits: study of the Oligocene sediments in the Digne area (SE basin, France)

Deciphering past salt tectonics events is often difficult in orogenic domains. The southwestern Alpine foreland in France presents a long Mesozoic extensive salt tectonics history, inverted during the Cenozoic Alpine orogeny. Syn-orogenic Cenozoic salt-related deformations are rather difficult to identify because of the contemporaneous shortening experienced by the foreland. This study is based on sedimentologic and geochemical approaches (Sr concentration and 87 Sr/ 86 Sr ratio) of the Oligocene non-marine succession of St Geniez (Digne region, France. Oligocene salt influences are highlighted by (1) high strontium concentrations (>1000 ppm) in most of the series, (2) the occurrence of Halophyticgastropods and (3) the deposit of two gypsum beds. 87 Sr/ 86 Sr ratio measured in the limestones and the gypsum beds confirm a Triassic origin for the strontium, originating from the diapir of Sorine, located to the south-west for the first part of the series, and from the Authon Thrust, located to the north, for the upper part. Geochemical values also suggest the occurrence of two Triassic evaporite levels, one already known and attributed to the Carnian-Norian (Late Triassic) and one attributed to the Olenekian-Anisian (Ealy-Middle Triassic). These results support that combined use of field geology and geochemistry can provide information on erased past salt-tectonics.

Sulfate isotope composition of Messinian evaporites in the Piedmont basin (Italy)

The Piedmont basin (NW Italy) records a Messinian Salinity Crisis (MSC) succession including a selenite gypsum deposit assigned to the Primary Lower Gypsum (PLG, MSC stage 1). Strontium isotope ratios are in the range of the PLG deposits of the Mediterranean area. Sulfate isotope compositions of vertically oriented selenite gypsum beds, in the lower part of the succession, are similar to those reported in other PLG deposits. However, flattened branching selenite cones in the upper part show higher isotope compositions, mainly in δ34S values, suggesting intense BSR conditions, stronger than reported in other PLG deposits. We interpret this chemical shift during deposition of the upper part of the PLG as the result of increased marine restriction assisted by the marginal position of this basin in the Adriatic Gulf during the Apennine and Alpine uplifts.

Affected of Ameliorated Alkaline Water and Soil Amendments on Exchangeable Cation, Macro and Micronutrients in Sodic Soil under Drip Irrigation

The Field experiment was carried out at Anbil Dharmalingam Agricultural College and Research Institute, Tiruchirappalli using cotton (RCH- 20) as a test crop to examine the effect of ameliorated alkali water and soil amendments on soil properties, growth, and yield of hybrid cotton in sodic soil under drip irrigation. In this experiment, Drip irrigation with gypsum treatment water and drip irrigation with spent wash treatment water were used as main-plots treatments. Soil application of gypsum @ 50 % GR (5.2 t ha-1) and one time soil application of distillery spent wash @ 5 lakh litter ha-1 were imposed as sub-plot treatments. The treatment without amendments both under main plot and sub plots were used as control. The experiment was carried out using a strip-plot design with four replications. The application of additives through irrigation water (or) soil considerably decreased the pH of post-harvest soil. The soil exchangeable Ca and Mg were found significant due to soil application of amendments only and value ranged from 8.51 to 9.35 and 5.03 to 5.20 Cmol (p+) kg -1 respectively. The soil available nutrients N, P and K were found significant, and value range from 167 to 311, 15.4 to 21.5, 158 to 928 kg ha-1 respectively. The application distillery spent wash (DSW) and gypsum slightly increased the micronutrient cations range which from 4.80 to 6.85 mg kg-1 of Fe, 8.60 to 10.43 mg kg-1 of Mn, 0.64 to 0.88 of mg kg-1 of Zn, 1.10 to 1.42 mg kg-1 of Cu. The results of the field experiment revealed that application of amended alkali water and amended soil significantly increased all the growth and yield parameters of cotton. An increase in seed cotton yield of 701 and 544 kg ha-1 was recorded due to the application of gypsum treated water and DSW treated water respectively over control. Similarly, an increase of 773 and 973 kg ha-1 of seed cotton yield was recorded due to soil application of gypsum and DSW respectively over control. While considering the interaction effect, soil application of DSW along with gypsum bed treated water found to be the best for getting higher seed cotton yield (3015 kg ha-1) when compared to other treatment combination.

Seepage Simulation of the Proposed Makhool Dam in North Iraq

This study aims to simulate water seepage and identify areas of weakness in the foundations through the right and left sides of the proposed Makhool dam in northern Iraq, using the finite element method by advanced computer software (SEEP/ W, 2012). The earth fill dam is 3670 m long on the Tigris River. Many attempts were made to ascertain the program results on the supposed earth dam and compare the results with those of other analytical methods to verify the program. The results are comparable, showing that the program is suitable for use in the seepage analysis at the proposed Makhool dam. According to the seepage analysis, the quantity of seepage through the left side of Makhool is acceptable within permissible limits; however, the right side has a lot more than the left side because of the presence of cracks, fractures, and cavitations in the stratigraphic sequence of Fatha formation at great depths in the gypsum beds under the diaphragm. The results indicate the need to lower the diaphragm about 6 m extra in the foundation's zone to a level of 49 m.a.s.l until reaching the low permeability clay bed within the foundations' zone. This action will reduce the amount of seepage and flow velocity and avoid using more grouting during the dam life. The design limits of the piezometric head (total head) were also determined, which are supposed to be read by the monitoring devices when operating the dam at the maximum level of the reservoir and the normal operating levels.

A bio-chronostratigraphic study of the upper Miocene from the northern Caltanissetta Basin, Sicily (core 3AGN2S04). Implications for dating the Messinian Salinity Crisis onset

The late Miocene deposits from core 3AGN2S04, located in the northern Caltanissetta Basin (Sicily), display the pre-Messinian Salinity Crisis (MSC) and the MSC events. The present study describes the entire core in terms of lithology, biostratigraphy and magnetostratigraphy and aims to enlighten the relationship between MSC evaporite cyclicity and astronomical forcing. The lithological and micro−/macro-paleontological descriptions document the MSC record, with Stage 1 (onset and Calcare di Base member), Stage 2 (Messinian Erosional Surface) and part of Stage 3 (Upper Gypsum and Lago Mare). Detailed micro-fossil analyses of the pre-evaporites reveal several biostratigraphic events that permit correlations to the well-dated Mediterranean planktonic foraminiferal biostratigraphic zonation of the late Tortonian and Messinian. An integrated bio-cyclostratigraphic analysis allows bed-to-bed correlations of core 3AGN2S04 with the reference sections of Falconara/Gibliscemi (Sicily) and Sorbas (Spain), but also with various other sections from the Caltanissetta Basin. Our cyclostratigraphic correlations show a stratigraphical gap in the core between the late Tortonian Terravecchia Formation and the pre-evaporitic Messinian Tripoli Formation. This hiatus is probably related to the tectonically active geological setting of the northern Caltanissetta Basin. Finally, we show that the repercussions of the paleoenvironmental evolution towards evaporitic deposition and the MSC onset seem to have been diachronous throughout the various perched basins on Sicily characterized by different paleobathymetries. In particular, the onset of the Calcare di Base took place around 40–100 ka before the deposition of the first gypsum bed of the Primary Lower Gypsum units.

Seismites in Miocene gypsum microbialites: Multiproxy tools for paleoenvironmental reconstruction of saline lakes

This work provides the first evidence of seismites within Miocene gypsum microbialites deposited in inland lakes. Seismites are observed on good quality outcrops in two separated successions of the Madrid and Duero basins (central Spain) that are sited nearby strike-slip faults. The successions consist of sandy gypsum facies interbedded with gypsiferous mudstone and marlstone. The association of microbial induced sedimentary structures (MISS) with mineralogical biosignatures such as intrasediment-grown lenticular gypsum, dolomite with inner biomolds and other biological induced minerals, supports that gypsum beds represent microbialites. Gypsum microbialites are characterized by parallel-lamination, cross-bedding and laminated leveling structures. The rapid mineralization of the microbial mats and biostabilization processes may play a role in the preservation of the depositional structures in sulfates. In addition to MISS, several categories of large-scale soft-sediment deformation structures (SSDSs) reflecting ductile and brittle behavior repeat vertically through the successions. These are classified as load casts, pillows, dish structures, convolute bedding and lamination, plastic intrusions, fluid escape tubes, mud/sand volcanoes, Neptunian dikes and fractures. The deformation structures in crystalline sediments are interpreted to be caused by seismic shocks of magnitude over 5 related with syndepositional fault movements. Micromorphological analysis of gypsum beds reveals distinctive features such as cracked crystals, oriented crystals filling dikes and horizontal microstylolites that also indicate seismic shocks. Comparison between the two basins shows some differences in the type and vertical distribution of structures, and this suggests that earthquakes were less frequent and of higher magnitude in the Madrid Basin. The results confirm that microbial gypsum deposits have both high susceptibility to earthquakes and high potential to preserve a wide range of information of the sedimentary environment, including paleoecology, paleogeochemistry, paleohydrodynamics, and seismogenic behavior of microbial sediments and faults.

The lithostratigraphic Tidwell Member of the Morrison or Summerville Formations (Upper Jurassic)—who, what, where, when?

The Tidwell Member, a lithostratigraphic unit on the Colorado Plateau, has variously been referred to the Upper Jurassic Morrison Formation or the Upper Jurassic Summerville Formation. Its authorship has been ascribed to U.S. Geological Survey geologists Robert B. O'Sullivan or Fred Peterson. Because Peterson and O'Sullivan have different type sections, a resolution to authorship is needed. Both authors meet the minimum requirements for a new stratigraphic unit as given by the 1983 North American Stratigraphic Code under which Peterson and O'Sullivan operated. However, both authors also operated under the more restrictive Stratigraphic Nomenclature in Reports of the U.S. Geological Survey, which makes it clear that O'Sullivan used Tidwell Member informally, whereas Peterson made a formal proposal. Thus, Peterson is the rightful author and the type section is at Shadscale Mesa, Emery County, Utah. To resolve the issue of which formation the Tidwell Member belongs, its strata were examined across the northern Colorado Plateau in context with both the underlying marine Summerville Formation and the overlying terrestrial Salt Wash Member of the Morrison Formation. Meters-thick gypsum beds, one criterion for including the Tidwell Member in the Summerville, was found to be mostly restricted to the west side of the Colorado Plateau. Numerous low-angled anticlines at the top of the Summerville Formation are truncated beneath this gypsum, thus the gypsum beds cannot be part of the Summerville Formation. The unconformity marks the J-5 unconformity. Detailed analysis of the gypsum beds shows a complex origin indicative of smaller playa lakes rather than broad coastal sabkhas. The gypsum beds show an interfingering relationship with the overlying and lateral interbedded thin sandstone-siltstone-mudstone-limestone facies assemblage of the Tidwell Member. This relationship is interpreted as localized gypsum playa lakes that formed at the terminus of prograding fluvial fans from the Elko highlands to the west, with possible lesser contribution from the growing fluvial fan exiting from the Grand Canyon bight near the present-day Arizona-Nevada border. An isopachous map of the Tidwell Member supports this interpretation, and also indicates additional, less significant source areas to the southeast and east of the northern Colorado Plateau. A widespread tabular sandstone at the base of the Tidwell Member lateral to the gypsum facies known as Bed A, is interpreted to have originated mostly as a sand sheet analogous to the Selima Sand Sheet of the eastern Sahara or the sand sheet of the Gran Dieserto in Sonora, Mexico. The source of the sand is from the fluvial fans to the west. Similarities between the lithofacies of the contemporaneous Tidwell and Ralston Creek Members of the Morrison Formation indicates deposition under similar environmental conditions. This supports the inclusion of the Ralston Creek Member in the Morrison Formation as previously suggested, rather than as a separate formation.

Petrographic Record and Conditions of Expansive Hydration of Anhydrite in the Recent Weathering Zone at the Abandoned Dingwall Gypsum Quarry, Nova Scotia, Canada

In the Dingwall gypsum quarry in Nova Scotia, Canada, operating in 1933–1955, the bedrock anhydrite deposits of the Carboniferous Windsor Group have been uncovered from beneath the secondary gypsum beds of the extracted raw material. The anhydrite has been subjected to weathering undergoing hydration (gypsification), transforming into secondary gypsum due to contact with water of meteoric derivation. The ongoing gypsification is associated with a volume increase and deformation of the quarry bottom. The surface layer of the rocks is locally split from the substrate and raised, forming spectacular hydration relief. It shows numerous domes, ridges and tepee structures with empty internal chambers, some of which represent unique hydration caves (swelling caves, Quellungshöhlen). The petrographic structure of the weathering zone has been revealed by macro- and microscopic observations. It was recognized that gypsification commonly starts from a developing network of tiny fractures penetrating massive anhydrite. The gypsification advances from the fractures towards the interior of the anhydrite rocks, which are subdivided into blocks or nodules similar to corestones. Characteristic zones can be recognized at the contact of the anhydrite and the secondary gypsum: (1) massive and/or microporous anhydrite, (2) anhydrite penetrated by tiny gypsum veinlets separating the disturbed crystals and their fragments (commonly along cleavage planes), (3) gypsum with scattered anhydrite relics, and (4) secondary gypsum. The secondary gypsum crystals grow both by replacement and displacement, and also as cement. Displacive growth, evidenced by abundant deformation of the fragmented anhydrite crystals, is the direct cause of the volume increase. Crystallization pressure exerted by gypsum growth is thought to be the main factor generating volume increase and, consequently, also the formation of new fractures allowing water access to “fresh” massive anhydrite and thus accelerating its further hydration. The expansive hydration is taking place within temperature range from 0 to ~30 °C in which the solubility of gypsum is lower than that of anhydrite. In such conditions, dissolving anhydrite yields a solution supersaturated with gypsum and the dissolution of anhydrite is simultaneous with in situ replacive gypsum crystallization. Accompanying displacive growth leads to volume increase in the poorly confined environment of the weathering zone that is susceptible to upward expansion.

Mosul Dam, NW Iraq: Is a Safe Dam??

Mosul Dam is located in the northwestern part of Iraq impounding the Tigris River; about 60 km north of Mosul city. This project is multipurpose project; to provide water for irrigation, flood control and hydropower generation. The dam is 113 m high and 3650 m long including the spillway. The dam is earth fill type with a mud core. The dam was designed to impound 11.11 km3 because it is based and underlain by gypsum beds alternated with limestone and marl. Therefore, it is planned to use continuous grouting to fill the karst caverns. The used quantity exceeded 95000 tons of solid grouting materials since 1986 up to 2014. After all, is the dam safe? The details are given in the current article.

A missing link in the mid‐late Permian record of north‐eastern Pangea: A sedimentological evaluation of the Permian Belfast Harbour Evaporite Formation of County Antrim, Northern Ireland

AbstractAncient salt deposits preserve a record of highly specific environmental, climatic and biological conditions, including past surface water chemistry and water depths, local air temperatures, atmospheric composition and halophilic microorganisms. This paper presents the first sedimentological study of the mid‐Late Permian Belfast Harbour Evaporite Formation of Northern Ireland. This formation is dominated by bedded halite, contains some siliciclastic mudstone and bedded anhydrite, and is cross‐cut by intrusive igneous rocks. The bedded halite lithology contains bottom‐growth chevron and cornet crystals, efflorescent crusts and dissolution pipes, which are evidence of a saline surface brine that underwent periods of evapoconcentration, desiccation and flooding. The mudstone lithology contains dewatering structures, intraclasts and mudcracks, which indicate flooding and desiccation in dry mudflats. Bedded anhydrite was deposited as beds of gypsum cumulate crystals in saline surface waters. The Belfast Harbour Evaporite Formation was formed by saline lakes with associated mudflats, based on sedimentary characteristics and supported by mineralogical, geochemical and stratigraphic context. Diagenetic features reflect dissolution and cementation at the surface and shallow subsurface in the depositional environment and limited late‐stage alterations. Syndepositional dissolution pipes in bedded halite were formed by flooding events. Early halite cement is present in dissolution pipes and mudstones. Gypsum/anhydrite repeatedly dehydrated and rehydrated to form an interlocking crystal mosaic. Later features include fluid migration and the intrusion of mafic rocks. The Belfast Harbour Evaporite Formation was deposited by an ephemeral saline lake and dry mudflat system in an arid climate. This study, when compared to age‐equivalent continental deposits elsewhere, suggests that arid settings with saline lakes existed across much of Pangea during the Permo‐Triassic. The Belfast Harbour Evaporite Formation stratigraphically underlies the extremely low pH saline lakes of the Mercia Mudstone Group, implying that it aids in understanding the formation of Pangean acid brine lakes.

Palaeoenvironmental changes in Eocene Tibetan lake systems traced by geochemistry, sedimentology and palynofacies

• Late Eocene continental climate in Central Asia remains poorly understood. • Tibetan lake deposits preserve records of Eocene palaeoenvironmental changes. • Saline lakes in east-central Tibet existed in a cool and semi-arid desert-steppe. • Late Eocene aridification caused a palaeoenvironmental shift in Central Asia. • Tibetan palaeoclimate was primarily influenced by regional to global drivers. Ancient lake deposits preserve detailed records of Cenozoic environmental changes, providing information on past climate, vegetation, precipitation and lake chemistry. This study focuses on palaeoenvironmental changes recorded in Eocene limnic environments across what is today the modern Tibetan Plateau. We describe a section dated as late Eocene (~38–37 Ma) and integrate these findings within a regional context of similarly-aged Tibetan lake deposits across the plateau. These sedimentary archives of environmental change indicate a period of late Eocene aridification and cooling in the lead-up to the greenhouse-icehouse transition, which remains poorly understood in Central Asia. We show, based on geochemical, sedimentological, and palynofacies analyses, that a large saline lake existed within a semi-arid to arid steppe environment in the Nangqian Basin, east-central Tibet. The saline lake experienced cyclic drying intervals with shifts to a playa lake / mudflat system. Evidence of increased aridity is recorded in the upper part of the section, including a thinning of gypsum beds, decrease in palynomorph abundance, and concurrent increase in wood debris and amorphous organic matter. This is consistent with late Eocene aridity in Asia, drying of the playa lake, and an impoverished desert-steppe vegetation. Grain size data and geochemistry indicate a stable provenance of sedimentary material, suggesting that tectonic activity did not dominate sedimentation in east-central Tibet during deposition of these successions. Rather, palaeoenvironmental changes across the Tibetan region were most probably controlled by global climate oscillations and retreat of the proto-Paratethys Sea during the late Eocene: knowledge that is relevant for ecological interpretations through the Cenozoic, Quaternary and to the present.

L’ichthyofaune messinienne du bassin de Sorbas (Almería, Espagne) et ses rapports avec l’environnement sédimentaire

Fish skeletons were collected at three different levels in the Messinian of the Sorbas basin (Andalusia, South Spain). The richest fossiliferous level is a diatomitic stratum which occurs a few metres below the bottom of the evaporitic sequence. It has mainly yielded many juvenile Myctophids: Myctophum licatae and less abundant Maurolicus muelleri This indicates the occurrence of a rather deep open sea in the vicinity. Additionally, some skeletal remains of Sardina ? crassa were found in a clayey intercalation between two massive beds of gypsum. The occurrence of this marine species is indicative of the persistence of the sea during the evaporitic episode. Finally, as shown by the occurrence of aphanius crassicaudus in the postevaporitic Messinian, a lagoonal environment existed in this basin, as a result of a relative lowering of the sea level. Additionally, another fossiliferous locality yielding the same species is reported near Gafares, in the postevaporitic Messinian of the northern part of the Níjar-Carboneras basin.

Multi-episodic recrystallization and isotopic resetting of early-diagenetic dolomites in near-surface settings

ABSTRACTThe lower Eocene Rus Formation in Qatar reflects carbonate deposition in a semirestricted to fully restricted marine setting on a shallow ramp. Petrographic, mineralogical, and geochemical evidence from three research cores show early diagenesis has extensively altered nearly every petrological attribute of these rocks despite not having been deeply buried. In southern Qatar, the lower Rus (Traina Mbr.) consists of fabric-retentive dolomite intervals that preserve mudstone, wackestone, and packstone textures that are interbedded with depositional gypsum beds. In northern Qatar, the same member is dominated by fabric-destructive planar-e dolomite, and evaporites are absent. In both northern and southern Qatar, the upper Rus (Al Khor Mbr.) is composed of fabric-retentive dolomite intervals as well as limestone intervals rich with Microcodium textures that display evidence of dedolomitization. Geochemical analysis reveals that the limestones have an average δ18Ocal of –10.73‰ VPDB and δ13Ccal of –7.84‰ VPDB, whereas average dolomite δ18Odol is significantly higher (–1.06‰ VPDB) but δ13Cdol values (–3.04‰ VPDB; range –10 to 0‰) overlap with δ13Ccal values. Additionally, δ13Cdol trends toward normal marine values with depth away from the calcite–dolomite contact in all three cores. Petrographic observations demonstrate that dolomite crystals are commonly included in calcite and partially to completely replaced by calcite in these intervals and suggests that dolomite formed before calcite in the Microcodium-bearing intervals. Furthermore, the dolomites are commonly cemented by gypsum in the Traina Mbr. in southern Qatar, suggesting that dolomitization may have also occurred before, or concurrent with, bedded gypsum formation and indicates that dolomitization occurred early. Early dolomites were subsequently replaced by Microcodium-bearing limestones at and immediately below paleo-exposure surfaces, and at greater depths recrystallized in mixed marine–meteoric fluids, producing a negative δ13Cdol signature that trends toward more positive values away from the limestone–dolomite contact. Lastly, the dolomites underwent another phase of recrystallization in either marine-dominated fluids or possibly a well-mixed aquifer setting, resulting in a near-0‰ δ18Odol signature but retaining the negative δ13C signature. These findings thus have implications for reconstructing the diagenetic history of carbonate rocks, as they suggest that early diagenesis of carbonates can be extremely complex, resulting in multiple stages of mineral replacement and isotopic exchange in meteoric and shallow marine fluids before significant burial. Furthermore, this study shows that dolomitization of a limestone does not necessarily prevent additional early diagenesis and multiple recrystallization events. Lastly, it emphasizes the importance of incorporating petrographic observations with geochemical data when interpreting the diagenetic history of carbonate rocks.

Mosul Dam Problem and Stability

Mosul Dam is located on the River Tigris about 60 km northwest Mosul in Iraq. It is the biggest dam where its storage capacity reaches 11.11 billion cubic meters at normal operational level (330 m. above sea level). The dam was constructed on alternating beds of karistified limestone, gypsum and marl. This dam suffered from water seepage under its foundation since its operation in 1986. Grouting operations were implemented since that time to overcome this problem. This seepage is believed to be due to dissolution of gypsum beds under the foundation, which was not carefully considered by the designers. It was recommended by the international board of experts that the water level should be kept at or below 319 m.a.s.l. to minimize damages in case of the failure of the dam. ISIS occupied the dam site on 8 August 2014 and it was seized back from the hands of ISIS on the 16th of the same month. They did plenty of damage despite the short period they occupied the area. After that, the Iraqi Ministry of Water Resources rebuilt the damaged parts and used new grouting and maintenance program. Now, the dam looks very safe at 319 m water level at its reservoir. In addition, the impounding was raised 325 m.a.s.l. for few days and nothing abnormal was noticed.

Dye Test within Mosul Dam Area

Mosul Dam is located on the River Tigris about 60 km north of Mosul city in Iraq. The dam is a multipurpose earth fill dam with a storage capacity of 11.11 million cubic meters, which was in operation since 1986. During the first impounding of its reservoir, seepage of water underneath the foundation of dam was noticed due to the desolation of gypsum beds. This raised concern about the stability of the dam and since then grouting operation were carried out. ISIS occupied the dam 8 - 16 August 2014. Grouting operations stopped and number of equipment and buildings were destroyed during that short period. After the defeat of ISIS, the Iraqi Ministry of Water Resources rebuilt and constructed the destroyed parts within the site and a new maintenance operations program was adopted. New training courses for the staff of Mosul Dam were conducted with Trevi Company and US Army Corps of Engineers. In this paper, the dye test is highlighted to monitor the seepage of groundwater within the dam site. It seems that the dam is stable in its present conditions and water level height.

Badush Dam: Planned And Designed As A Protection Dam, Nw Iraq

Badush Dam is uncompleted combined earthfill and concrete dam, it is located on the Tigris River. The dam is planned and designed to be a protection dam downstream of the already existing Mosul Dam to protect population and infrastructure downstream of Mosul Dam. Thisa is attributed to the safety concerns of Mosul Dam which suffers from severe karstification in its foundation due to the presence of thick gypsum beds. The safety of Mosul Dam is a matter of debate since its construction and commissioning in 1986. The construction of Badush Dam started in 1988 and suspended in 1991, although (30 – 40) % of the dam was already built. The geological setting of Badush Dam is almost similar to that of Mosul Dam. Therefore, the foundation of Badush Dam will suffer from the same problem which is karstification because they are located on gypsum beds which are the same rocks under the foundations of Mosul Dam. The thin inclined clay core and foundation treatment works indicate clearly that Badush Dam is designed to have temporary nature which is to contain the volume of Mosul Dam wave (11 × 11km3) in case of collapse of Mosul Dam and to pass the wave downstream without flooding.

Preliminary investigations of rocks and soil at the lower reach of Al-Shor Wadi for water harvesting

The last four decades weather forecasting data marks the precipitation declination and increase dry years, in addition to the desertification migration on the west and northwestern Mosul city. This led to studying the Al-Shor Wadi area to try to make use of the karstic spring water flow through it and to harvest the rainfall flow water. These need to select the best site to construct a dam taking into consideration the geological and geotechnical characteristics of both dam site and lake behind. The dam site appears to be appropriate relying on the large thickness and frequencies of the marl bed, the restriction of gypsum bed thicknesses and frequencies as well as, of the approximate nill karstification.

Petrography and geochemistry of siliciclastic rocks of the Middle Eocene Gercus Formation, northern Iraq: Implications for provenance and tectonic setting

Red coloured Middle Eocene Gercus Formation is a widely exposed rock unit in northern Iraq, southeastern Turkey, and northwestern Iran. Siliciclastic rocks (mudstones and sandstones) are the predominant rocks of this formation which were studied petrographically and geochemically. The Gercus Formation also contains a few beds of limestone, gypsum, and conglomerate. The sandstones are of two types, red and white, mostly immature litharenites, consisting of lithics (85%), quartz (12%), and feldspars (3%). The rock fragments consist dominantly of angular chert and rounded limestone and smaller amounts of sedimentary, magmatic, volcanic, and metamorphic lithics indicating proximity of their source rocks. The provenance discrimination diagrams of the detrital grain counts in sandstones show recycled and collision orogen sources. Petrographic, heavy minerals and major and immobile trace element (e.g. La, Th, Sc, Zr, Hf, and Ti) discrimination diagrams indicated that the Gercus Formation was originated under a collision tectonic setting above a subduction zone as part of an Oceanic Island Arc (OIA), where its sediments were derived from mixed sources, including recycled sediments of chert‐ and carbonate‐rich formations and igneous‐metamorphic ophiolitic complexes of north to north‐east Iraq and adjacent Iranian and Turkish counterparts. The results also indicated a mixed marine (lacustrine and deltaic) and non‐marine (fluviatile) origin for the Gercus Formation. The red sandstones, white sandstones, and mudstones show minor differences in their major, trace, and rare‐earth element (REE) contents and have generally similar Post Archean Australian Shale (PAAS)‐, Upper Continental Crust (UCC)‐, and CI‐chondrite‐normalized distribution patterns indicating their common origin. The average of elements in the siliciclastic rocks is depleted in the high‐field‐strength elements (HFSE), the large‐ion lithophile elements (LILE), and REE; and enriched in some rock‐forming elements (RFE) and mantle rock‐forming elements (MRFE) (Mg, Ca, Cr, Co, Ni) and depleted in others (Si, Al, Fe, Cu, Zn, Ga) relative to PAAS and UCC; whereas, they are depleted in Fe, Mn, Mg, Co, Ni, Cu, Zn, Ga, Na, and P, and enriched in all other RFE, MRFE, LILE, HFSE, and REE compared to CI‐Chondrite. The REE content of these rocks is very low (23–34 ppm) and their LREEs are enriched six times relative to HREEs. These geochemical characteristics suggest a provenance dominated by basic/ultrabasic rocks. The U/Th, V/Cr ratios and the authigenic U values show an oxic depositional environment for the studied siliciclastic rocks.

Mosul Dam: Is it the Most Dangerous Dam in the World?

Mosul Dam is an earth fill dam, with a storage capacity of 11.11 km3 constructed on highly karstified gypsum beds alternating with marl and limestone. After impounding in 1986, seepage locations were recognized. The dam situation now indicates that it is in a state of extreme relative risk. If it fails, then 6 million people will be affected and 7202 km2 area will be flooded. Grouting operations will elongate the life of the dam but will not solve the problem. Building a protection dam downstream will be the best measures to secure the safety of the downstream area and its’ population.