Facies stacking patterns in a modern arid environment: a case study of the Abu Dhabi sabkha in the vicinity of Al‐Qanatir Island, United Arab Emirates

Strohmenger, Christian J.; Shebl, Hesham; Al‐Mansoori, Abdulla; Al-Mehsin, Khalil; Al-Jeelani, Omar; Al-Hosani, Ismail; Al-Shamry, Ali; Al-Baker, S.

doi:10.1002/9781444392326.ch7

Cited by 18 publications

(42 citation statements)

References 42 publications

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“…2F and H), are present at Site 2 and Site 3, respectively. The radiocarbon age of these buried microbial mats are 880 ± 40 yr bp for Mat 2 and 1680 ± 40 yr bp for Mat 3 (Strohmenger et al. , 2009).…”

Section: Study Areamentioning

confidence: 99%

“…In the study area, mapped and described by Strohmenger et al. (2009), three representative locations referred to as Site 1 (24°8′55·60″ N; 54°6′9·60″ E), Site 2 (24°8′47·60″ N; 54°6′11·50″ E) and Site 3 (24°8′36·00″ N; 54°6′16·10″ E) are defined (Fig.…”

Section: Study Areamentioning

confidence: 99%

“… Idealized stratigraphy along the studied transect across the sabkha. Radiocarbon ages of the buried microbial mats from Strohmenger et al. (2010).…”

Section: Study Areamentioning

confidence: 99%

“…As the previously studied areas of the sabkha are no longer accessible with the recent development of the Abu Dhabi coastline, a new area has been explored which provides the ideal conditions to test the microbial dolomite model. Herein, the results of a geochemical and microscopic investigation of living surface and buried microbial mats along an intertidal to supratidal transect, as described in Strohmenger et al. (2009), are reported.…”

Section: Introductionmentioning

confidence: 99%

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Dolomite formation within microbial mats in the coastal sabkha of Abu Dhabi (United Arab Emirates)

Bontognali¹,

Vásconcelos²,

Warthmann³

et al. 2010

Sedimentology

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Microbial mediation is the only demonstrated mechanism to precipitate dolomite under Earth surface conditions. A link between microbial activity and dolomite formation in the sabkha of Abu Dhabi has, until now, not been evaluated, even though this environment is cited frequently as the type analogue for many ancient evaporitic sequences. Such an evaluation is the purpose of this study, which is based on a geochemical and petrographic investigation of three sites located on the coastal sabkha of Abu Dhabi, along a transect from the intertidal to the supratidal zone. This investigation revealed a close association between microbial mats and dolomite, suggesting that microbes are involved in the mineralization process. Observations using scanning electron microscopy equipped with a cryotransfer system indicate that authigenic dolomite precipitates within the exopolymeric substances constituting the microbial mats. In current models, microbial dolomite precipitation is linked to an active microbial activity that sustains high pH and alkalinity and decreased sulphate concentrations in pore waters. Such models can be applied to the sabkha environment to explain dolomite formation within microbial mats present at the surface of the intertidal zone. By contrast, these models cannot be applied to the supratidal zone, where abundant dolomite is present within buried mats that no longer show signs of intensive microbial activity. As no abiotic mechanism is known to form dolomite at Earth surface conditions, two different hypotheses can reconcile this result. In a first scenario, all of the dolomite present in the supratidal zone formed in the past, when the mats were active at the surface. In a second scenario, dolomite formation continues within the buried and inactive mats. In order to explain dolomite formation in the absence of active microbial metabolisms, a revised microbial model is proposed in which the mineral‐template properties of exopolymeric substances play a crucial role.

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

“… Idealized stratigraphy along the studied transect across the sabkha. Radiocarbon ages of the buried microbial mats from Strohmenger et al. (2010).…”

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dolomite formation within microbial mats in the coastal sabkha of Abu Dhabi (United Arab Emirates)

Bontognali¹,

Vásconcelos²,

Warthmann³

et al. 2010

Sedimentology

Self Cite

294

252

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“…The basin has an area of 250,000 km 2 and is shallow and semi‐restricted which, combined with its high latitude and the presence of mountainous plateaus and deserts nearby, make the Gulf's climate the most extreme endured by key carbonate biota, such as reef building corals, anywhere (Purkis & Riegl, , ; Purkis et al ., ; Foster et al ., ). In contrast to carbonate platforms with well‐developed shelf edges that are typical for the Caribbean, the Arabian platform exhibits a gentle bathymetric profile, thereby indicating a shallow‐ramp geometry (Shinn, ; Burchette & Wright, ; Uchupi et al ., ; Kirkham, ), ideal for depositing widespread and laterally continuous facies bodies (Alsharhan & El‐Sammak, ; Purkis et al ., ; Strohmenger et al ., , ; Jameson & Strohmenger, ; Lokier et al ., ; Lokier & Fiorini, ).…”

Section: Study Area and Settingmentioning

confidence: 99%

Complex interplay between depositional and petrophysical environments in Holocene tidal carbonates (Al Ruwais, Qatar)

et al. 2017

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Carbonate rocks can be classified in terms of those properties relating to the pore system of lithified sediments, so‐called ‘petrophysical rock types’, or ‘depositional rock types’ which are categorized based on characteristics directly reflecting their original depositional environment. Whereas petrophysical rock types are typically used to identify and distribute rock bodies within a reservoir with similar flow characteristics, depositional rock types ignore pore types and capture sedimentary structures, lithology and fossils. Both classification systems are extensively used to describe reservoir rocks, but the degree of plurality between them remains poorly understood and is the motivation for this study. To examine the degree of congruency between the two classification schemes, a field assessment was conducted for a 175 km2 area situated offshore Al Ruwais, northern Qatar, encompassing depositional environments spanning supratidal, intertidal, shallow subtidal and open marine conditions. A total of 350 surficial sediment samples were collected along 24 shore‐normal transects. Each sample was assigned a ‘petrophysical rock type’ class based on analysis of sedimentary texture (grain size and sorting). ‘Depositional rock type’ classes, by contrast, were defined with reference to faunal content and, in turn, classes of mineralogy were delimited by weighting this content against the mineralogy of each faunal category. Of course, the samples studied correspond to unconsolidated sediments and not to indurated rocks. However, considering only primary porosity and permeability preservation, it is reasonable to assume that the classified sediments would become petrophysical rock types and depositional rock types when consolidated, following their primary grain size, sorting and grain type distribution. Therefore, the term ‘rock type’ is retained here for ease of terminology but, for clarity, these are sediment samples. The discrete samples were interpolated into continuous surfaces describing the distribution of depositional rock types, petrophysical rock types and mineralogy, and spatial correspondence between those surfaces was statistically evaluated. In order to link these parameters with environment of deposition, their correlation with water depth (as audited from airborne light detection and ranging) and ecological habitat (mapped from DigitalGlobe satellite imagery) was also assessed. The data reveal that spatial distributions of sedimentary faunal, petrographic and mineralogical properties do not show exactly congruent patterns. Other meaningful trends do exist, however. For example, the occurrence of certain depositional rock types is indicative of particular petrophysical rock types, and vice versa. Further, connections between petrophysical rock types and mineralogy are emphasized and offer insight as to how the evolution of matrix porosity might be predicted via diagenetic models tuned to specific sediment textures. Useful relationships are also identified between the occurrence of petrophysical...

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Sabkhas, Saline Mudflats and Pans

Warren

2016

Evaporites

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Facies stacking patterns in a modern arid environment: a case study of the Abu Dhabi sabkha in the vicinity of Al‐Qanatir Island, United Arab Emirates

Cited by 18 publications

References 42 publications

Dolomite formation within microbial mats in the coastal sabkha of Abu Dhabi (United Arab Emirates)

Dolomite formation within microbial mats in the coastal sabkha of Abu Dhabi (United Arab Emirates)

Complex interplay between depositional and petrophysical environments in Holocene tidal carbonates (Al Ruwais, Qatar)

Sabkhas, Saline Mudflats and Pans

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