Recent Evaporites From the Abu Dhabi Coastal Flats

Butler, Godfrey P.; Harris, P. M.; Kendall, Christopher G. St. C.

doi:10.2110/cor.82.01.0033

Cited by 72 publications

(56 citation statements)

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“…Due to similar reasons it is possible that the assumed salinity ( NaCl = 6.1) is not representative for the A1, which was succeeded by a carbonate system, dominated by fluids of marine composition. We propose the following processes as a potential alternative Ca source for the pervasive dedolomitization of the Zechstein-2-Carbonates: (i) Gypsum mush compaction (ii) Pressure solution of gypsum and/or anhydrite At surface, gypsum can accumulate as a highly porous mush with reported porosities ranging between 30% and 67% [57,58] and Ca pore fluid saturations being as high as 0.035 moles/liter [57]. During the early stages of compaction these fluids could be expelled into the Ca2 carbonates, thereby introducing fluids rich in Ca into the system [59].…”

Section: Case Study: Zechstein-2-carbonatesmentioning

confidence: 99%

Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

2018

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The Zechstein-2-Carbonates represent one of the most prolific hydrocarbon systems of Central Europe. Carbonate reservoir quality is primarily controlled by mineralogy, with dolomite representing moderate-to-good porosities and calcite commonly representing low porosities. Current models suggest that this calcite is the result of a basin-wide phase of dedolomitization. The calcium (Ca) source for the dedolomites is thought to be derived from the fluids liberated during gypsum-to-anhydrite conversion. We present an easy-to-use and generally applicable template to estimate the dedolomitization potential of these fluids. Depending on reaction stoichiometry, salinity, and temperature, we estimate that between 2.8 * 10 −3 m 3 and 6.2 * 10 −3 m 3 of calcite may replace dolomite for each m 3 of anhydrite created. Within the constraints dictated by the environment of the late Permian Zechstein basin, we estimate that about 5 * 10 −3 m 3 of dedolomite is created for each m 3 of anhydrite. Mass balance constraints indicate that fluids derived from gypsum-to-anhydrite conversion account for less than 1% of the observed dedolomite in most of the studied industry wells from northern Germany.

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Section: Case Study: Zechstein-2-carbonatesmentioning

confidence: 99%

Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

2018

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“…In the lower supratidal zone, below the microbial film and above the intertidal microbial mat, sandy sediments made of millimetric gypsum crystals occur. This is the so-called "gypsum mush" of Butler et al (1983). As observed by these authors, this gypsum sand can be divided in two distinct parts on the basis of the substrate in which it grows.…”

Section: Supratidal Sedimentsmentioning

confidence: 96%

“…Evans et al, 1964Kendall & Skipwith, 1968b, 1969bButler, 1969;Kinsman & Park, 1976;Patterson & Kinsman, 1977;McKenzie et al, 1980;Butler et al, 1983;Hadley et al, 1998), but few of these were concerned with organic matter distribution, and prior to Kenig et al (1990), they mostly focused on microbial mats (e.g. Kendall & Skipwith, 1968a).…”

Section: Introductionmentioning

confidence: 99%

Distribution of organic matter in the transgressive and regressive Holocene sabkha sediments of Abu Dhabi, United Arab Emirates

Kenig

2010

Quaternary Carbonate and Evaporite Sedimentary Facies and Their Ancient Analogues

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Two navigation channels dredged in the 1980s across the hypersaline coastal plain of Abu Dhabi (UAE) offered a unique opportunity to study the distribution of organic matter in transgressive and regressive, subtidal, intertidal and supratidal sediments that accumulated during the Holocene. In modern Abu Dhabi lagoons, intertidal microbial mats and Avicennia marina mangals (mangroves), as well as subtidal seagrass fields dominated by Halodule uninervis, provide significant amounts of organic matter to modern sediments. Each of these primary producers is associated to a distinct sedimentary facies and biocoenosis recognizable in Holocene sediments. The distribution of these biocoenoses obeys a number of rules deriving from the ability of each of the primary producers to adapt to salinity changes in response to lagoon closure, rate of sealevel change, and associated rate of displacement of the intertidal zone, as well as changing progradation and aggradation rates. The subtidal seagrass biocoenosis is mostly part of the transgressive sequence, as the salinity in the Abu Dhabi lagoon was lower prior to barrier island development. In the transgressive sequence, Avicennia marina mangal palaeosols are sparse and formed only where the slope of the substrate was steep enough to allow minimal lateral displacement of the mangal community during transgression. The thin intertidal transgressive sequence is mostly characterized by burrowed microbial mat.The regressive sequence is dominated by the microbial mat biocoenosis in areas of fast progradation of the sabkha (> 1 m yr À1 ) as this community is well adapted to the hypersaline conditions of the intertidal zone. A regressive A. marina mangal palaeosol was observed only where progradation rates were between 0.35-0.75 m yr À1 . The mangal community in Abu Dhabi lagoons is stressed by salinity and fast progradation rates. This contrasts with the dominance of mangal soils in humid tropical environments, where highly productive mangals produce thick and organic matter-rich soils irrespective of the rate of sea-level change and rates of progradation.

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“…The presence of these minerals suggests an average temperature of higher than 22 C and a seasonal temperature of more than 35 C [9]. High rate evaporation in supratidal subenvironment causes gypsum crystals to develop, which in turn absorb calcium, thereby resulting in microcrystalline dolomicrite [17] [18]. Microfacies A3 hosts microcrystalline dolomite or dolomicrite, which are characterized as type-1 dolomite.…”

Section: Investigating the Facies And Depositional Environment Of Hermentioning

confidence: 99%

Facies Analysis and Depositional Environment of Upper Permian Rocks in Darin Section, East-Central Iran

Emraninasab¹,

Adabi²,

Majidifard³

et al. 2017

OJG

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Deposits of Permian rocks in Kalmard Block are recognized with Khan Group, showing various characteristics in different outcrops. This group is made up of three informal formations, namely Chili, Sartakht and Hermez. Upper Permian deposits (Hermez Formation) are composed chiefly of lateritic and carbonate rocks. This formation is composed of 65.5 m lateritic soils, lateritic sandstone, limestone, dolomite and dolomitic limestone in the Darin section. This formation unconformably overlies middle Permian siliciclastic and evaporite deposits (Sartakht Formation), where as it is depicted underlying an erosional unconformity above lateritic deposits of lower Triassic (Sorkh Shale Formation). According to lithologic and microscopic investigations, the deposits of Hermez Formation can be divided into 1 siliciclastic petrofacies and 14 carbonate microfacies. Field observations, along with microscopic examinations, have resulted in identifying tidal flat, lagoon, shoal and open marine environments in the rocks of the studied formation. Vertical changes of microfacies and depth variation curve point to the high thickness of the microfacies of lagoon, tidal flat and shoal environments and low thickness of open marine microfacies. Hermez Formation rocks in Darin section are deposited in a low-angle homoclinal ramp, mostly in the inner ramp, located in the southern Paleo-Tethys Ocean.

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Recent Evaporites From the Abu Dhabi Coastal Flats

Cited by 72 publications

References 0 publications

Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

Distribution of organic matter in the transgressive and regressive Holocene sabkha sediments of Abu Dhabi, United Arab Emirates

Facies Analysis and Depositional Environment of Upper Permian Rocks in Darin Section, East-Central Iran

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