![All specimens from the Echinoid Marker Bed, Member c, Natih Formation, late middle Cenomanian of Jebel Madamar. a, Temnocidaris (Stereocidaris) sarracenarum (Fourtau), BMNIt E83119, ×2. b, Tetragramma. variolare (Brongniart), BMNtt E83120, ×2. c-g, tteterodiadema lybica (Agassiz & Desor): c, d, adapical and lateral views of Bb, INH E83121, x l.5; e, f, g, oral, adapical anti lalar~l *,;*,1,~: a f R I ] ~ [ -I ~ R ~ I ? ? . ~ i .5_](https://www.researchgate.net/profile/Mike_Simmons3/publication/222038346/figure/fig2/AS:1061664585682945@1630131970900/All-specimens-from-the-Echinoid-Marker-Bed-Member-c-Natih-Formation-late-middle_Q320.jpg)
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Cenomanian echinoids, larger foraminifera and calcareous algae from the Natih Formation, central Oman Mountains
Abstract and Figures
Within the Natih Formation (late Albian-early Turonian) of the Oman Mountains, there occurs a distinctive, correlatable horizon with an abundant and moderately diverse echinoderm fauna. This horizon occurs within Member c of the Natih Formation and can be assigned a latest middle Cenomanian age based on the associated microfossil assemblage which is dominated by alveolinids and gymnocodiacian algae. The depositional environment of this echinoderm-rich bed was probably back barrier, close to radiolitid rudist biostromes and bioclastic shoals which fringed the upper Natih shelf edge. Nine species of echinoid are described, most of which are new records for the Arabian Peninsula. One new species, Pedinopsis sphaerica, is erected. Coenholectypus larteti dominates the assemblage and occurs together with Stereocidaris sarracenarum, Tetragramma variolare, Heterodiadema lybica, Pedinopsis humei, P. desori, P. sphaerica, Hemiaster syriacus and H. cubicus. The composition of the genus Pedinopsis is critically reviewed and a new subgenus, Sinaiopsis, erected. Many of the species have previously been reported from Egypt, the Sinai Peninsula and Israel.
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... There are numerous records with either no or questionable illustration that could, if proven by new data, further demonstrate the geographic distribution of this species and extend it much more widely. These records (west to east) include; Morocco (Ettachfini, 2006;Piuz & Meister 2013), Iberia, including Spain and Portugal Gräfe, 2005;Caus et al., 2009;Vicedo et al., 2011;Consorti et al., 2016b), southern France (Deloffre & Hamaoui 1979); Kosovo (Consorti & Schlagintweit, 2021b); Libya (Dufaure et al., 1984); Slovenia (Jež et al., 2011); Greece (Decrouez 1976(Decrouez , 1978Tsaila-Monopolis, 1977;Fleury, 1980;Pomoni-Papaaioannou & Zambetakis-Lekkas, 2009); Jordan (Al-Rifaiy et al., 1994;Schulze, 2003 andSchulze et al., 2004), southern Iraq (Bernaus & Masse 2007); and Oman (Smith et al., 1990;Kennedy & Simmons, 1991;Piuz and Meister, 2013). ...
... This follows Saint-Marc (1974a who stated the range was middlelate Cenomanian in Lebanon, a range with which Saint-Marc (1981), Arnaud et al. (1981), and Hamaoui in Schroeder & Neumann (1985) concurred but extending the range into the basal Turonian (sometimes questionably). This has led to a certain degree of circular reasoning in subsequent age assignments of the occurrence of the species, in that its presence has been used to argue for an age no older than middle Cenomanian (e.g., Smith et al., 1990;Palci et al., 2008). In fact, it is possible that in the original records of the species from Israel (Hamaoui, 1961(Hamaoui, , 1965(Hamaoui, , 1966, it occurs in the early Cenomanian. ...
... In addition to the references cited above, P. laurinensis is recorded with confirmed or plausible illustration from the late Cenomanian of Albania/Kosovo (Consorti & Schlagintweit, 2021a); the Dinarides Velić & Vlahović, 1994); and the Turkish Taurides (Bignot & Poisson, 1974;Sari et al., 2009;. Unillustrated records or records with questionable illustrations are from Serbia (Radoičić & Schlagintweit, 2007); Albania (Heba, 2008); Tunisia (Philip et al., 1988;Saïdi et al., 1995;Touir et al., 2017); Syria (Mouty et al., 2003;Ghanem et al., 2012); Israel (Hamaoui, 1966); Dubai (Menegatti, 2004) and Oman (Smith et al., 1990;Piuz & Meister, 2013). It seems likely that P. laurinensis does not occur in Mexico, being replaced by the similar, but endemic form, P. chiapanensis (Aguilera-Franco, 2003). ...
A key but challenging task for biostratigraphers is to provide a biozonal/bioevent framework for geological correlation. Species of Larger Benthic Foraminifera (LBF) are important biostratigraphic markers in depositional environments where classical biostratigraphic fossils such as planktonic micro- and macrofossils are rare or absent – e.g., tropical-subtropical shallow water platforms. However, a lack of taxonomic rigour in identifying some LBF species, together with a lack of good age-calibration of their occurrences, has given rise to artificially extended biostratigraphic and paleogeographic ranges for many taxa, diluting their usefulness. In this study, the occurrences of Cenomanian LBF belonging to a “planispiral morphogroup”, both agglutinated and calcareous, have been critically evaluated to determine (i) identity; (ii) stratigraphic range; and (iii) palaeogeographic distribution.
Since the last major review of the group in 1985, a voluminous literature has appeared reporting occurrences and adding new taxa. An extensive review of some 600+ published items on Cenomanian planispiral LBF – mostly published after 1985 – and a critical review of the confidence in species identification and age-calibrations therein, has led us to identify 39 taxa (three in “open” status) which appear to have distinct identity. The vast majority of these records are from Neotethys although some also occur in (or are endemic to) the Caribbean/West Atlantic and the Eastern Pacific.
The quality of the published taxonomic data is variable and many published records based on identity can be discounted or termed “unconfirmed”. Likewise, many records (confirmed or otherwise) are poorly age-calibrated due to lack of corroborating biostratigraphy or chemostratigraphy, or by using circular reasoning.
We summarise and illustrate the main defining characteristics of each taxon and their possible confusion species, including new taxa described since the mid-1980s. We publish new, more confident, age-ranges for these taxa – confirmed by identity and/or age-calibration – and identify where published range data may be unreliable. Paleogeographic distribution maps for each taxon are also provided. Particular stratigraphic issues around the Cenomanian-Turonian boundary are observed due to the difficulty of identifying that boundary, or its preservation, in shallow marine
carbonate settings.
Although most Cenomanian planispiral LBF are somewhat long-ranging, an increase in diversity throughout the middle – late Cenomanian has shown potential for biostratigraphic resolution to at least substage level using this group. Integration of the planispiral taxa with other LBF morphogroups, after similar treatment, will yield even higher biostratigraphic resolution of Cenomanian LBF and provide a sound basis for biozonation (both local and global), correlation, and age calibration.
... Calonge et al. (2002) documented the FO of these spices in the Middle Cenomanian. Praetaberina bingistani has been used as an index spices for the Late Cenomanian in Iran (Reiss et al. 1964;Smith et al. 1990;Fourcade et al. 1997;Afghah et al. 2014;Afghah and Fadaei 2015;Consorti et al. 2015), Italy (Borghi and Pignnati 2006) and Syria (Ghanem et al. 2012). Several taxa and genus (e.g. ...
... Definition: This zone is defined from the FO of Praetaberina bingistani to the upper strata of the Sarvak Formation. Age: Reiss et al. (1964), Smith et al. (1990), Fourcade et al. (1997), Afghah et al. (2014), Afghah and Fadaei (2015) and Consorti et al. (2015) from Iran, Borghi and Pignnati (2006) (2015) and Afghah et al. (2014), from the Late Cenomanian. Recognition of the mentioned taxa in the Interior Fars zone indicate the paleogeographic distribution of these taxa in the shallow water environment of the Late Cenomanian strata in the Zagros basin. ...
In this study, the Sarvak Formation in the Kuh-e Zana stratigraphic section has been investigated in terms of Cenomanian biostratigraphy, microfacies analysis, and depositional environment interpretation. The section is located in the Interior Fars zone in the Zagros Basin. The selected section of the Sarvak Formation consists of 211 m of limestone and overlies the Kazhdumi Formation conformably whereas the upper limit of the Sarvak Formation is not obvious. Based on paleontological data three biozones in the study area were established: (1) Nezzazata simplex interval zone (Early Cenomanian), (2) Chrysalidina gradata interval zone (Middle Cenomanian), (3) Cisalveolina fraasi (fallax) & Cisalveolina lehneri—Praetaberina bingistani assemblage zone (Late Cenomanian). Based on petrographic studies, eleven microfacies were identified as follows: MF1: Oligosteginid bioclast wackestone to packstone, MF2: Bioclastic wackestone–packstone, MF3: Bioclastic peloidal wackestone–packstone, MF4: Rudist floatstone, MF5: Rudist rudstone, MF6: Foraminifera intraclastic grainstone, MF7: Benthic foraminifera rudist debris packstone–grainstone, MF8: Bioclastic grainstone–packstone, MF9: Bioclastic benthic foraminiferal wackestone to packstone, MF10: Bioclastic peloidal packstone, MF11: Algal-foraminiferal wackestone–packstone. Microfacies analysis shows that the Sarvak Formation comprises three paleoenvironments as the outer ramp, middle ramp, and inner ramp (shoal and lagoon).
... The outcrops represent an excellent location for the age calibration of the mid-Cretaceous sequences (Fig. 4), whose correlation to other successions on the Arabian Plate is shown in Fig. 2. Much of the Natih succession is rich in shallow-marine benthic foraminifera (e.g. Simmons and Hart, 1987;Smith et al., 1990;Kennedy and Simmons, 1991;Piuz et al., 2014;Vicedo and Piuz, 2017;Piuz and Vicedo, 2020) and rudists (Philip et al., 1995). More open-marine sediments are also present, especially in those parts of the succession which were deposited in intrashelf basinal conditions (van Buchem et al., 2002Droste, 2010), and contain ammonites and planktonic foraminifera (e.g. ...
In order to facilitate the search for new play concepts and exploration opportunities, a sequence stratigraphic synthesis of the Cenomanian-Turonian interval of the Arabia Plate has been compiled. The synthesis is based on published datasets which have been analysed within a temporal framework constrained by biostratigraphy and isotope stratigraphy. The high stratigraphic resolution allows the palaeogeography of the study area to be mapped within 3rd order depositional sequences, and the relative influence of eustasy and tectonics on basin development to be evaluated. This significantly improves the prediction of stratigraphic architecture and depositional morphology at the scale of the entire tectonic plate.
Conceptual models informed by outcrop and subsurface observations have been applied to characterize the development of intrashelf basins in depositional settings that are either isolated from siliciclastics (symmetrical intrashelf basin model) or influenced by siliciclastics (asymmetrical intrashelf basin model). The application of a sequence stratigraphic model across regional well log transects facilitates an understanding of stratigraphic architecture and acts as an important control for the generation of a new suite of gross depositional environment (GDE) maps. These characterise palaeogeography at previously unprecedented resolution and scale during periods of high relative sea-level (maximum flooding surface and highstand systems tract) and low relative sea-level (lowstand systems tract). These maps are complemented by sequence isopachs which reveal changes in accommodation through time and space.
This approach helps characterize the preserved distribution and stratigraphic configuration of petroleum systems elements. In the Shilaif (UAE) and Natih (Oman) intrashelf basins, condensed, organic-rich carbonate source rocks were deposited in restricted, anoxic conditions. These basins resulted from differential aggradation of the carbonate platform during the transgressive systems tract. Grainy, rudist debris-rich carbonate reservoir rocks developed along the margins of the intrashelf basins during highstand progradation. Claystones in the overlying sequence may form intraformational seals and were deposited during retrogradation of the shoreline associated with sea-level rise.
By contrast in the Najaf intrashelf basin (Iraq), there is a significant siliciclastic component sourced from the Arabian Shield. This influx resulted in a mixed carbonate-siliciclastic ramp depositional system on the proximal, western margin of the basin, and an apparent absence of organic-rich intervals within the central basin succession. Grainy carbonate reservoir rocks are restricted to the eastern margin and are charged by older source rocks within the underlying stratigraphy.
The GDE maps record the configuration of these petroleum systems elements within the Cenomanian-Turonian interval and forms the basis for play screening. The Cenomanian-Turonian interval is punctuated by the major mid-Turonian unconformity which is a major tectonostratigraphic boundary of considerable geological and economic significance. In the southern and eastern part of the Arabian Plate, this unconformity has a differential erosion profile that facilitates a subcrop play with exploration potential. Identifying subtle stratigraphic traps is challenging, but by combining GDE facies with the mapped preservation limit for each sequence, it is possible to identify areas where rudist-rich reservoir facies with potential karst enhancement are overlain by a regional claystone seal, high-grading areas with subcrop trap potential.
... The Late Albian to Turonian Natih Formation belongs to the Wasia Group (e.g., Forbes et al., 2010) and is part of the Hajar Supergroup (Simmons and Hart, 1987;Smith et al., 1990;Philip et al., 1995;van Buchem et al., 2002;Droste and van Steenwinkel, 2004;Grélaud et al., 2006Grélaud et al., , 2010Homewood et al., 2008;Adams et al., 2011;Wohlwend et al., 2016;Scharf et al., 2021b, their fold-out Fig. A2). It is subdivided into seven members from "A" (top) to "G" (base) (Hughes Clark, 1988;Droste and van Steenwinkel, 2004;Forbes et al., 2010). ...
Two forebulge successions exist in the Oman Mountains at the platform-foreland basin transition between the Late Albian to Turonian Natih Formation and the foreland basin shales of the Late Cretaceous Muti Formation. Forebulge creation is suggested by limestone microfacies analyses and analyses of ferruginous crusts and oolites, showing rapid changes in bathymetry and relative sedimentation rate. Each succession displays basal shallow subtidal limestone, passing upward directly to ferruginous crusts and then to Fe-rich oolites deposited in shallower and agitated water. Each succession is topped by clayey layers. Microfacies and lithological evolution of the two successions are alike, suggesting repetitively similar depositional and tectonic conditions. As both sequences occur at the same site, lateral forebulge migration possibly did not occur, suggesting an overall stationary vertical and stepwise forebulge development. The compositional evolution of the ferruginous crusts was complex and includes postdepositional diagenetic effects of the rocks. Both ferruginous crusts once consisted of iron sulfides, implying at least slightly reducing conditions during their formation, associated with water-deepening events. Both oolite levels contain chlorite, hematite, quartz, calcite and apatite. They also contain fragments of chlorite and hematite as nuclei, suggesting that these fragments derived from preexisting ferruginous crusts. Iron oxyhydroxides and clinochlore within the oolites reflects bathymetric changes to more oxidizing aqueous conditions, associated with water-shallowing events. Fe-rich anoxic to sub-oxic sea water of the marine foreland basin was the source for the crusts and oolites which coincided with a high rate of global Cretaceous ocean crust production and related hydrothermalism as well as the regional proximity of an active spreading axis. Fe was probably stabilized in ocean water as organic Fe complexes and Fe colloids.
Three Upper Cretaceous sections (Boukais sections from the Guir Basin; Gour Louazouaza section from the Tademait Hamada and Gour Belhouillet section from the Tinrhert Hamada) were measured, and their respective echinoid content was studied. Fifteen echinoid species referred to ten genera, are identified and taxonomically described from the upper Cenomanian strata belonging to the Neolobites bioevent. Among the studied echinoids, Pedinopsis (P.) hemisphaerica Abdelhamid, 2014 is recorded for the first time from outside Egypt. The palaeobiogeographic distribution of this fauna is discussed and indicates strong Tethyan affinity.
The Sarvak Formation is a carbonate interval (as part of the Bangestan Group) deposited during the Cretaceous (late Albian-late Turonian), which hosts considerable hydrocarbon reserves. We logged five surface sections west of the Zagros Basin to depict the depositional environment and sequence stratigraphy of the Sarvak Formation. The formation comprises five 3rd order depositional sequences, including six facies belts deposited on a carbonate platform. The lower part of the formation comprises two depositional sequences (late Albian -early Cenomanian) deposited on a ramp. In contrast, the rest of the formation (Cenomanian to early Turonian), composed of three depositional sequences, was deposited on a rimmed shelf. The shift from ramp to the shelf was presumably due to changes in the tectonic regime of the Arabian Plate from passive to active margin, and in part due to the obduction of the Neotethys’ ocean crust during the late Middle Cretaceous, accompanied by the development of shoal complex and rudistic reefs. This resulted in the development of some isolated carbonate platforms bordered by intrashelf basins, particularly in the Lurestan Zone. Active basement faults caused the exhumation of the platform and the development of unconformity on the Cenomanian-Turonian boundary. The five depositional sequences we studied were mainly controlled by eustatic change(s) during Albian, mid-Cenomanian to Turonian.
The Sarvak Formation is a carbonate sequence of the Late Albian-Early Turonian age in Zagros Basin in Iran. In this investigation, the Sarvak Formation at the Pyun Anticline section (Izeh Zone) has been studied. It consists of limestone of 797m thick which overlies the Kazhdumi Formation conformably and underlies the Gurpi Formation unconformably at Pyun Anticline. A very rich fossil association (85 genera and 132species) characterizes the Pyun section. Based on the stratigraphic distribution of diagnosed foraminifers, five biozones are established:1-Muricohedbergella- Globigerinelloides sp. assemblage zone (Late Albian) 2-Praealveolina iberica- Chrysalidina gradata interval zone (Early Cenomanian) 3-Chrysalidina gradata- Cisalveolina fraasi (fallax) and C. lehneri interval zone (Middle Cenomanian)4-C. fraasi (fallax) and C. lehneri - Praetaberina bingistani assemlage zone (Late Cenomanian) 5-Nezzazatinella picardi- Mangashtia- Dicyclina assemblage zone (Early Turonian). Based on the petrographic and sedimentology analyses, some 13 carbonate microfacies were identified. The investigated microfacies confirm ramp-type paleoenvironment. These microfacies from distal to proximal environments consist of: MF1:Planktonic foraminifera wackestone–packstone, MF2:Oligostegina planktonic foraminifera wackestone to packstone, MF3:Planktonic-benthic foraminifers sponge spicules wackestone-packstone, MF4:Rudist floatstone, MF5:Rudist rudstone, MF6:Bioclast intraclast grainstone, MF7:Peloid intraclast grainstone, MF8:Benthic foraminifers rudist grainstone-packstone, MF9:Peloid bioclast grainstone-packstone, MF10:Bioclast (benthic foraminifers) wackestone-packstone, MF11:Peloid bioclast packstone, MF12:Dacycladacea benthic foraminifera packstone-wackestone, MF13:Miliolids wackestone-packstone.
The Sarvak Formation is a carbonate sequence of the Late Albian‐Early Turonian age in Zagros Basin in Iran. In this investigation, the Sarvak Formation at the Pyun Anticline section (Izeh Zone) has been studied. It consists of limestone of 797m thick which overlies the Kazhdumi Formation conformably and underlies the Gurpi Formation unconformably at Pyun Anticline. A very rich fossil association (85 genera and 132species) characterizes the Pyun section. Based on the stratigraphic distribution of diagnosed foraminifers, five biozones are established:1‐Muricohedbergella‐ Globigerinelloides sp. assemblage zone (Late Albian) 2‐Praealveolina iberica‐ Chrysalidina gradata interval zone (Early Cenomanian) 3‐Chrysalidina gradata‐ Cisalveolina fraasi (fallax) and C. lehneri interval zone (Middle Cenomanian)4‐C. fraasi (fallax) and C. lehneri ‐ Praetaberina bingistani assemlage zone (Late Cenomanian) 5‐Nezzazatinella picardi‐ Mangashtia‐ Dicyclina assemblage zone (Early Turonian). Based on the petrographic and sedimentology analyses, some 13 carbonate microfacies were identified. The investigated microfacies confirm ramp‐type paleoenvironment. These microfacies from distal to proximal environments consist of: MF1:Planktonic foraminifera wackestone–packstone, MF2:Oligostegina planktonic foraminifera wackestone to packstone, MF3:Planktonic‐benthic foraminifers sponge spicules wackestone‐packstone, MF4:Rudist floatstone, MF5:Rudist rudstone, MF6:Bioclast intraclast grainstone, MF7:Peloid intraclast grainstone, MF8:Benthic foraminifers rudist grainstone‐packstone, MF9:Peloid bioclast grainstone‐packstone, MF10:Bioclast (benthic foraminifers) wackestone‐packstone, MF11:Peloid bioclast packstone, MF12:Dacycladacea benthic foraminifera packstone‐wackestone, MF13:Miliolids wackestone‐packstone.
Reservoir facies in Fahud field and throughout northwestern Oman are in shallow-shelf carbonates of the middle Cretaceous Mishrif and Mauddud Formations. Interparticle porosity formed in the Mishrif as sand aprons of lithoclast and skeletal grainstones surrounding fault-block islands, and less commonly in the Mauddud as biostromes of rudist packstones. Moldic porosity after fine rudist debris is more common than interparticle porosity and occurs in thicker stratigraphic units, interpreted to have formed locally in meteoric-water lenses associated with islands, and regionally during subaerial exposure associated with sea level lows.
A discussion is presented of the Cretaceous formations involved in Fahud field. Along the Trucial Coast, as in northwestern Oman, it is not difficult to date the time of formation of the foredeep. This article provides a stratigraphic correlation chart for the Cretaceous along the Arabian side of the Arabian Gulf. The terminology presented on this correlation chart reflects oil-industry usage in the area, including correlations published by Owen and Nasr, Loutfi and Jaber, Arabian American Oil Company, Beydoun and Dunnington, and Hassan et al.
