Abstract The upper Palaeocene–lower Eocene Umm er Radhuma Formation in the subsurface of Qatar is dominated by subtidal carbonate depositional packages overlain bedded evaporites. In Saudi Arabia and Kuwait, peritidal sequences with intercalated evaporites carbonates have been previously interpreted to dolomitized via downward reflux hypersaline brines. Here, textural, mineralogical geochemical data from three research cores are presented which, contrast, more consistent dolomitization...

Abstract Recrystallization of dolomite can alter textural, mineralogical and geochemical attributes used to infer environmental conditions initial dolomitization. A meta‐analysis the published literature shows that extensive recrystallization is most common in old deeply buried dolomites, but data from Palaeocene–Eocene Umm er Radhuma Formation Qatar show this also happen geologically young carbonates have never been buried. Evidence comes a principal component analysis are integrated with...

ABSTRACT The “dolomite problem” is the product of two distinct observations. First, there are massive amounts ancient marine limestone (CaCO3) deposits that have been replaced by mineral dolomite (MgCa(CO3)2). However, recent (Holocene and Pleistocene) contain relatively minuscule dolomite, although occurrence small quantities observed in many modern settings, from deep to supratidal. Second, low-temperature synthesis laboratory settings has elusive, particularly comparison ease with which...

This review of published literature examines the nature modern carbonate coastal barrier systems, concentrating on islands and their related shoals lagoons in light concepts derived from siliciclastic counterparts. The observations show that subaerial (C-type) barriers are common along transgressing shorelines more abundant than largely subtidal shoals. sediment composition associated contemporaneous marine meteoric cementation do not prevent landward migration during transgression, contrast...

Abstract Anomalously saline waters in Ocean Drilling Program Holes 1127, 1129, 1130, 1131 and 1132, which penetrate southern Australian slope sediments, isotopic analyses of large benthic foraminifera from continental shelf indicate that Pleistocene–Holocene meso‐haline salinity reflux is occurring along the margin. Ongoing dolomite formation observed sediments associated with marine commonly exceeding 50‰ salinity. A well‐flushed zone at top all holes contains pore normal trace element...

Abstract Palygorskite is a fibrous, magnesium‐bearing clay mineral commonly associated with Late Mesozoic and Early Cenozoic dolomites. The presence of palygorskite thought to be indicative warm, alkaline fluids rich in Si, Al Mg. has been interpreted form peritidal diagenetic environments, either as replacement detrital smectite during dissolution–precipitation reaction or solid‐state transformation, direct precipitate from solution. Despite lack evidence, most studies involving these two...

ABSTRACT The timing of dolomitization is difficult to constrain. Many studies suggest that it early, but the rates at which occurs in nature are rarely defined. This study aims pinpoint sedimentary environments using detailed petrography and sedimentological observations from two near-surface research cores lower part Dam Formation (lower Dam) southwestern Qatar. Dam, deposited a shallow-marine–estuarine setting with frequent sea-level fluctuations, presents strong stratigraphic constraints...

Research Article| April 18, 2019 The Geochemistry of Qatar Coastal Waters and its Impact on Carbonate Sediment Chemistry Early Marine Diagenesis John M. Rivers; Rivers 1ExxonMobil Qatar, Science Technology Park, Tech 2, Doha, e-mail: John.m.rivers@exxonmobil.com Search for other works by this author on: GSW Google Scholar Linso Varghese; Varghese Ruqaiya Yousif; Yousif Fiona F. Whitaker; Whitaker 2University Bristol, School Earth Sciences, Office G30, Wills Memorial Building, Queens Road,...

Abstract Barrier islands are important landforms in many coastal systems around the globe. Studies of modern barrier island mostly limited to those siliciclastic realms, where recognized as mobile features that form on transgressive coastlines and migrate landward sea‐level rises. ‘Great Pearl Bank’ along United Arab Emirates coast best‐known carbonate examples. These Holocene islands, however, interpreted be anchored by older deposits immobile. The mid‐Holocene late‐Holocene depositional...

The Khor Al Adaid embayment of southern Qatar represents a unique shallow-water mixed siliciclastic‑carbonate coastal depositional system that developed in hyper-arid climatic setting over the past 6000 years. embayment, which was formed during Flandrian transgression as result flooding across partially fault-controlled incised fluvial drainage, is supplied by quartz-rich sands delivered wind-blown dunes migrating southward surface Qatar. These offshore-migrating eolian-derived sediments are...

Abstract The continental margin of southern Australia is a site extensive Quaternary cool-water carbonate sedimentation. Seafloor sediments are mixture Holocene biofragments and late Pleistocene relict stranded particles. Relict sediments, produced during Marine Isotope Stages 3 4, generally preserved as iron-stained intraclasts. Such grains in the Great Australian Bight photozoan character. They include symbiont-bearing benthic foraminifers coralline algal particles, indicate that wide...

Abstract Carbonate rocks can be classified in terms of those properties relating to the pore system lithified sediments, so‐called ‘petrophysical rock types’, or ‘depositional types’ which are categorized based on characteristics directly reflecting their original depositional environment. Whereas petrophysical types typically used identify and distribute bodies within a reservoir with similar flow characteristics, ignore capture sedimentary structures, lithology fossils. Both classification...

Abstract In the ancient rock record, early replacement of metastable marine calcium carbonate deposits by dolomite has long been associated with evidence arid depositional environments. Such associations led to development seepage reflux dolomitization model, whereby magnesium‐rich waters concentrated evaporation descend into underlying sediments, replacing primary aragonite and calcite through rock–water interaction. modern coastal systems Qatar, where concentrate halite saturation, both...

Carbonates and evaporites of Paleogene age form the shallow-aquifer rocks mantling most Qatar, including Paleocene Lower Eocene Umm er Radhuma Formation to Middle Rus Dammam Formations. A core-based study was carried out improve general understanding stratigraphic controls on aquifer matrix properties in Qatar. cumulative total 377 m 10-cm-diameter core recovered from three boreholes central northern drilled depths greater than 120 m. Sedimentological attributes these were investigated...

ABSTRACT The lower Eocene Rus Formation in Qatar reflects carbonate deposition a semirestricted to fully restricted marine setting on 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 (Traina Mbr.) consists fabric-retentive dolomite intervals that preserve mudstone, wackestone, packstone...

Abstract The southern Australian continental margin is an immense cool-water carbonate factory. high-energy open shelf blanketed by heterozoan carbonates of both Holocene and late Pleistocene age. Three distinct grain types have been identified radiocarbon dated. These include (1) relict grains, highly abraded iron-stained intraclasts formed during the intermediate sea-level stands Marine Isotope Stages 3 4, (2) stranded gray buff-colored biofragments marooned rise associated with Stage 2,...

Abstract Carbonate rocks that have suffered early near‐surface dolomitization followed by extended meteoric exposure commonly undergo partial delithification, a process results in the formation of dolomitic silts and sands, herein termed dologrus. Dologrus is interpreted to form as result diffuse dissolution porous permeable dolostones prior burial compaction. Such occurs at crystal–pore‐water interface, causing individual crystals corrode along interfacial boundaries, eventually leading...

Abstract Dolomite textures are widely interpreted to reflect physical, mineralogical, and geochemical conditions of crystal growth. In particular, nonplanar dolomites, which display non-faceted boundaries a low percentage crystals with compromise preserved crystal-face junctions, have long been cited as evidence growth in fluids warmer than theoretical dolomite critical roughening temperature (CRT) ∼ 50–100°C. No direct experimental across this range exists, however, confirm the theory that...

Abstract Sequence stratigraphy is the primary tool used by sedimentologists to predict bed-scale flow properties of both marine carbonate reservoirs (associated with carbon sequestration and hydrocarbon recovery) groundwater aquifer systems. Coastal sequence stratigraphic models have been predicated upon existence parasequences, shallowing-upward successions bounded flooding surfaces. Transgressive deposits in such assumed be mostly absent, whereas regressive are presumed form through...

In 1993–1994, researchers at Oak Ridge National Laboratory collected high‐resolution airborne geophysical data on the Reservation, Ridge, TN. The were in part to address concerns about possible undocumented hazardous waste sites. Interpretation of aeromagnetic was complicated, however, by discovery remote areas numerous small magnetic anomalies natural origin. Magnetic susceptibility measurements core showed that underlying Copper Dolomite non‐magnetic. We attribute presence ferromagnetic...

The Ca Voi Xanh (CVX) gas field is located offshore Vietnam along the eastern margin of southern Song Hong Basin. Reservoir rocks are carbonates Middle Miocene (Langhian and Serravallian) age which developed on an isolated platform (length approximately 100 km, width 15 km) top Triton Horst structural high. Shallow‐water corals large small benthic foraminifera main faunal constituents Langhian carbonates, whereas overlying Serravallian principal reservoir at CVX, dominated by deeper‐water...