bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palynological biozonation of the Permian of Oman and Saudi Arabia: progress and challenges
Authors: Stephenson Mike H. , Osterloff Peter L. , Filatoff John 
Published: October 2021

ABSTRACT
Extensive palynological work in sequences in Oman and Saudi Arabia, has allowed a framework of eight biozones for the uppermost Carboniferous to Permian rocks in that region. Five of these are established in the palyniferous uppermost Carboniferous to Lower Permian sequence in Oman, and to some extent these are recognisable in sequences of central and southern Saudi Arabia. OSPZ1 (Oman and Saudi Arabia Palynological Zone 1), associated with the lower parts of the Al Khlata Formation and the Unayzah C member, is probably Stephanian in age. OSPZ2 is Asselian-Sakmarian in age, and is associated with the upper part of the Al Khlata Formation and the Unayzah B member. OSPZ3, which is subdivided into three sub-biozones, is associated with the Lower Gharif member; its age may lie in the range late Sakmarian to Artinskian, based on palynology and brachiopod-based ages for the Haushi Limestone, locally present toward the top of the Lower Gharif member. The composition of assemblages from OSPZ1 to OSPZ3 is similar to that of coeval sequences in other former Gondwana countries and the chronostratigraphical ages assigned to them are partly gained from correlation with faunally-calibrated Western Australian palynological biozones. At the level of OSPZ4, such correlation becomes difficult because significant differences are evident between Western Australian and Arabian assemblages, and because other Gondwana palynological biozonations, with which Arabia has greater affinity, are poorly constrained chronostratigraphically. OSPZ4 and the succeeding two biozones are established in the sporadically palyniferous Middle and Upper Permian sequences of Oman and Saudi Arabia. OSPZ4, though poorly characterised due to low palynological recovery, is probably ‘mid-Artinskian’ to Kungurian in age, and is associated with the Middle Gharif member. OSPZ5, present in southeast Saudi Arabia and Oman appears to be associated with the lower to middle parts of the Upper Gharif member, and is constrained in age, partly by the faunally-dated overlying Oman Khuff carbonates, as being Roadian or earliest Wordian in age. So far the assemblages of the highest biozone, OSPZ6, have been recovered only from the ‘basal Khuff clastics’ of central Saudi Arabia, and are believed to be younger than those of OSPZ5; dating by palynological means is difficult but recent microfaunal studies of the ‘basal Khuff clastics’ suggest a Capitanian age. Further study in appropriate palyniferous sections in other Middle Eastern countries may allow a more complete palynological succession to be established.
Foraminifers and algae from the Khuff Formation (late Middle Permian-Early Triassic) of central Saudi Arabia
Authors: Vachard Daniel , Gaillot Jérémie , Vaslet Denis , Le Nindre Yves-Michel 
Published: October 2021

ABSTRACTAlgae and smaller foraminifers of the eponymous Khuff Formation (Saudi Arabia) principally comprise Permocalculus, biseriamminids, hemigordiids and lagenids. Due to the end-Capitanian crisis (Late/Middle Permian boundary) and the regional palaeoecology, fusulinids are rare and only represented by Nankinella sp. and Eostaffella? sp. Palaeofusulinids are completely lacking. New age data shows that these foraminifers correspond to the complete Lopingian (Late Permian) as indicated by several species of Paradagmarita. The position of the Triassic/Permian Boundary is approximately characterised, but requires more accurate studies. Forty-three taxa were identified, mostly in open nomenclature. One new species is described: Glomospirella? linae n. sp. The foraminiferal assemblage is correlated with several associations in Iran, Turkey, Transcaucasia and south China.
The debate over Hubbert’s Peak: a review
Authors: Al-Husseini Moujahed 
Published: October 2021

ABSTRACT
The application of various quantitative techniques and assumptions by different authors to forecast the world’s conventional crude oil production in the 21st Century results in highly inconsistent predictions. The forecasts attempt to pinpoint the peak world oil production year (Hubbert’s Peak), peak production rate, and post-peak decline rate, based on estimates of the ultimate recoverable reserves (EURR). These techniques, pioneered by M.K. Hubbert in the mid-1950s, generally consider economic factors, such as the price of oil, as irrelevant in the long run. Some authors support a Low EURR World Scenario (about 2.0 trillion barrels, of which half has already been produced) and forecast Hubbert’s Peak in this decade. Other authors estimate the EURR at about 3.0 trillion barrels (Median EURR World Scenario), and this estimate is the mean EURR assessment of the United States Geological Survey and similar to assessments by several major oil and gas companies. An EURR of 3.0 trillion barrels implies Hubbert’s Peak will occur in 2020, or so, at a production rate of about 90–100 million barrels/day (compared to 85 million barrels/day in late 2005). A few authors support a High EURR World Scenario (4.0 trillion barrels or more) with Hubbert’s Peak in 2030 at a rate of 120 million barrels/day. Sensitivity analysis for Hubbert’s Curve suggest that Hubbert’s Peak moves by three years for every 200 billion barrels of error in the EURR.
Advances in Arabian stratigraphy: Origin and stratigraphic architecture of glaciogenic sediments in Permian-Carboniferous lower Unayzah sandstones, eastern central Saudi Arabia
Authors: Melvin John , Sprague Ronald A. 
Published: October 2021

ABSTRACT
In the subsurface of eastern central Saudi Arabia, deposition of lower Unayzah sediments commenced in late Carboniferous (late Moscovian = late Westphalian-Stephanian) times during the earliest stages of the late Paleozoic Gondwanan glaciation. The Unayzah C member is the lowermost unit, and comprises quartzose sandstones laid down on an extensive glacio-fluvial outwash braidplain upon the pre-Unayzah unconformity (so-called “Hercynian unconformity”). They were overridden during (probably several) glacial re-advances, when the sediments were thrust over each other during the construction of push moraines ahead of the advancing ice sheets. The upper surface of the Unayzah C member represents the final sub-glacial contact of this longlived series of glacial advances and retreats, and demonstrably represents a significant post-Unayzah C unconformity. Subsequent (early Permian) deposits represent the final glacial retreat phase. They include the Unayzah B member and a new, un-named middle Unayzah member that underlies the Unayzah A member.
The Unayzah B member is dominated by glaciogenic sediments, including highly deformed material attributed to seasonal push moraines (and hence representing minor glacial re-advances); ice-proximal, subaqueous outwash fans (high-energy lacustrine turbidites with associated dropstones, and massive diamictites); and ice-distal, glaciolacustrine deposits including laminites, stratified diamictites, ripple cross-laminated sandstones and mudrocks with associated dropstones. In contrast, the un-named middle Unayzah member is characterized by widespread, fine-grained red-beds, representing low-lying alluvial floodbasin deposits. Embedded within these occur aeolian and fluvial sandstones. A significant drainage event is thus implied between the Unayzah B member and the un-named middle Unayzah member. It is marked by a sharp contact between the two members that represents a regionally correlatable disconformity. The end of lower Unayzah deposition is represented in places by paleosol development, indicating a further disconformable contact, separating the un-named middle Unayzah member from the overlying Unayzah A member. This study significantly extends the record of the advance and retreat of the Gondwanan ice sheets in southern Saudi Arabia, and provides sufficient confidence to propose a degree of stratigraphic correlation with coeval deposits in Oman.
The geology of Khuff outcrop analogues in the Musandam Peninsula, United Arab Emirates and Oman
Authors: Maurer Florian , Martini Rossana , Rettori Roberto , Hillgärtner Heiko , Cirilli Simonetta 
Published: October 2021

ABSTRACT
A revision of the stratigraphy of late Palaeozoic and early Mesozoic carbonates (Bih Formation) in the Musandam Mountains near Ras Al Khaimah, United Arab Emirates (UAE), clarifies the presence of deposits that are age-equivalent to the Late Permian and Early Triassic Khuff Formation. Biostratigraphic markers including benthic foraminifera and calcareous algae indicate a Permian age for the stratigraphically oldest outcrops ranging from late Wuchiapingian to late Changhsingian (K4 and K3 reservoir units in the subsurface). A Late Induan – Early Olenekian (Early Triassic) age is documented for the stratigraphically youngest outcrops. Sedimentological features, stacking patterns and microfacies of the Permian outcrops show strong affinity to the KS3 and KS2 Khuff sequences, dominated by high-energy bioclastic pack- and grainstone. The depositional environment of the Bih Formation is further characterised by a palynological evaluation of claystones and by XRD analysis of clay minerals. Spectral gamma-ray data from the outcrop, which indicate Uranium depletion following the extinction of Permian foraminifera, help to pinpoint the position of the Permian – Triassic boundary and to correlate the measured section with the subsurface. Some stratigraphic intervals in outcrop are affected by strong secondary dolomitisation and do not reflect the same diagenetic patterns as their subsurface counterparts. Patterns of secondary dolomitisation, however, indicate the flow of formation water and thus mimic pore-fluid flow in the subsurface reservoirs. The depositional facies show clear resemblances to the reservoir facies, and the studied outcrops most likely represent the best analogue to the Khuff reservoirs in the UAE and in the North Dome/South Pars field area, offshore Qatar and Iran.
Opening of the Neo-Tethys Ocean and the Pangea B to Pangea A transformation during the Permian
Authors: Muttoni Giovanni , Gaetani Maurizio , Kent Dennis V. , Sciunnach Dario , Angiolini Lucia , Berra Fabrizio , Garzanti Eduardo , Mattei Massimo , Zanchi Andrea 
Published: October 2021

ABSTRACTWe studied the stratigraphy, composition, and paleomagnetic properties of lateritic weathering profiles of Permian age from northern Iran and western Karakoram, Pakistan. A limited set of samples deemed representative yielded stable low-inclination paleomagnetic components carried essentially by hematite of chemical origin isolated in massive, fine-grained, and homogeneous ferricrete facies. These laterites originated at equatorial paleolatitudes characterized by intense weathering processes under warm and humid climatic conditions. Paleomagnetic estimates of paleolatitude from Iran, Karakoram, and north Tibet from this study and the literature, albeit sparse, provide testable constraints on the motion of the Cimmerian terranes as the result of the opening of the Neo-Tethys Ocean along the eastern margin of Gondwana during the Permian. We confirm and help refine previous suggestions that the Cimmerian terranes migrated from southern Gondwanan paleolatitudes in the Early Permian to subequatorial paleolatitudes by the Middle Permian – Early Triassic. As a novel conclusion, we find that timing, rates, and geometry of Cimmerian tectonics are broadly compatible with the transformation of Pangea from an Irvingian B to a Wegenerian A-type configuration with Neo-Tethyan opening taking place contemporaneously essentially in the Permian.
Decastroia razini n. gen. n. sp. – A new alveolinacean (foraminifera) from the Cenomanian of Socotra Island (Yemen)
Authors: Vicedo Vicent , Serra-Kiel Josep 
Published: October 2021

ABSTRACT
The architecture of a new alveolinacean, Decastroia razini, from the Cenomanian shallow-water sediments of Socotra Island is described. The shape of the new genus is globular to slightly elongated. The internal structure is characterised by septula and floors that individualise two rows of superposed tubular chamberlets, an upper row of large, cortical chamberlets and a lower row of small, medullar ones. The chamberlets of the same chamber are communicated by preseptal passage.
Nukhul Formation in Wadi Baba, southwest Sinai Peninsula, Egypt
Authors: Hewaidy Abdel Galil A. , Farouk Sherif , Ayyad Haitham M. 
Published: October 2021

ABSTRACTThe Nukhul Formation is the oldest syn-rift rock unit in the Gulf of Suez rift system in Egypt. The age of the formation is inadequately resolved by biostratigraphy and it is generally assigned to the Lower Miocene by stratigraphic position. For this study a surface section was measured and sampled at Wadi Baba, located in the southwestern Sinai Peninsula. It yielded 17 planktonic foraminiferal species and 17 foraminiferal benthonic species. The planktonic foraminiferal assemblage was used to divide the formation into two planktonic foraminiferal zones: (1) Globigerina ciperoensis Zone (O6) of Late Oligocene Chattian age; and (2) Globigerinoides primordius Zone (M1) of Early Miocene Aquitanian age. The two zones coincide with depositional sequences: (1) Chattian Lower Nukhul Sequence, with its upper boundary coinciding with the Chattian/Aquitanian (Oligocene/Miocene) boundary; and (2) Aquitanian Upper Nukhul Sequence, with its upper sequence boundary coinciding with the Aquitanian/Burdigalian boundary.
Ediacaran–Cambrian Sirab Formation of the Al Huqf region, Sultanate of Oman
Authors: Nicholas Christopher J. , Gold Sophia E.P. 
Published: October 2021

ABSTRACT
The Ediacaran–Cambrian Ara Group of the South Oman Salt Basin in the Sultanate of Oman is one of the world’s oldest petroleum systems and holds some of the most important hydrocarbon reserves in the country. However, the Ara Group salt and isolated carbonate platforms, or ‘stringers’, are known only from the subsurface and deformed fragments brought to the surface in salt-piercing domes. Thus, determining Ara source and reservoir facies architecture at high resolution is a particular problem. Here we present the results of field surveying in the Haushi-Huqf region over a number of years specifically to investigate the possibility of Ara Group equivalents being exposed in outcrop. Defined here, for the first time, is the new Sirab Formation, which we incorporate into the top of the Neoproterozoic–Cambrian Huqf Supergroup. In general, it conformably overlies the Buah Formation. However, at some localities on what were probably fault-bounded palaeo-topographic highs, the Sirab Formation rests unconformably on eroded Buah Formation or directly on the even older Shuram Formation. The Sirab Formation is overlain with marked angular unconformity by the siliciclastics of the Haima Supergroup. As such, the Sirab Formation occupies the same lithostratigraphic position as the Ara Group subsurface. We subdivide the formation into three principal members; the lower Ramayli Member, middle Shital Member and upper Aswad Member. A fourth, the Salutiyyat Member, can be recognised where the Sirab Formation lies on eroded Nafun Group palaeo-topographic highs and is probably the chrono-stratigraphic lateral equivalent at least in part of the upper Ramayli Member. The Ramayli and Shital members contain evaporite units, including halite beds, and fault- or eustatically-controlled cyclical peritidal carbonates indicating that the Al Huqf area was a shallow trough or graben during this period within a regional structural high. The middle and upper members contain significant microbial build-ups including thrombolite framestone reefs, which are the principal reservoir subsurface in the Ara ‘stringers’, and rare crinkly laminites which are the presumed source rock at depth. Whilst the precise age dates for the formation and chronostratigraphy of each member still need to be resolved, it is clear that the Sirab Formation includes exposures of litho- and bio-facies present in the Ara Group and thus could provide useful surface analogues for the petroleum geology of the South Oman Salt Basin and Central Oman High in the future.
Impact of diagenesis on the spatial and temporal distribution of reservoir quality in the Jurassic Arab D and C members, offshore Abu Dhabi oilfield, United Arab Emirates
Authors: Morad Sadoon , Al-Aasm Ihsan S. , Nader Fadi H. , Ceriani Andrea , Gasparrini Marta , Mansurbeg Howri 
Published: October 2021

ABSTRACTThis study is based on petrographic examination (optical, scanning electron microscope, cathodo-luminescence, backscattered electron imaging, and fluorescence) of 1,350 thin sections as well as isotopic compositions of carbonates (172 carbon and oxygen and 118 strontium isotopes), microprobe analyses, and fluid inclusion microthermometry of cored Jurassic Arab D and C members from 16 wells in a field from offshore Abu Dhabi, United Arab Emirates. The formation was deposited in a ramp with barrier islands and distal slope setting. Petrographic, stable isotopic and fluid-inclusion analyses have unraveled the impact of diagenesis on reservoir quality of Arab D and C within the framework of depositional facies, sequence stratigraphy, and burial history. Diagenetic processes include cementation by grain rim cement and syntaxial calcite overgrowths, formation of moldic porosity by dissolution of allochems, dolomitization and dolomite cementation, cementation by gypsum and anhydrite, and stylolitization. Partial eogenetic calcite and dolomite cementation has prevented porosity loss in grainstones during burial diagenesis. Dolomitization and sulphate cementation of peritidal mud are suggested to have occurred in an evaporative sabkha setting, whereas dolomitization of subtidal packstones and grainstones was driven by seepage reflux of lagoon brines formed during major falls in relative sea level. Recrystallization of dolomite occurred by hot saline waters (Th 85–100°C; and salinity 14–18 wt% NaCl). Anhydrite and gypsum cements (Th 95–105°C; fluid salinity 16–20 wt% NaCl), were subjected to extensive dissolution, presumably caused by thermal sulfate reduction followed by a major phase of oil emplacement. The last cement recorded was a second phase of anhydrite and gypsum (Th 95–120°C; 16–22 wt% NaCl), which fills fractures associated with faults.
Imaging subtle faults using azimuthal coherence attribute: A case study from Central Saudi Arabia
Authors: Alqahtani Faisal , Al-Shuhail Abdullatif A. 
Published: October 2021

ABSTRACT
The coherence attribute is an edge detection method that is widely used for interpreting faults on 3-D seismic time slices. The traditional coherence attribute is calculated on migrated volumes using traces from all available azimuths. It has recently been shown that calculating coherence along specific azimuths can enhance the detection of faults running perpendicular to those azimuths. In this study, we applied azimuthal coherence attribute analysis on a 3-D seismic data set from a gas field in Central Saudi Arabia. We generated four migrated 3-D data volumes sorted by azimuth in addition to a conventional full-azimuth volume. We then calculated the coherence attribute for all volumes and compared each azimuthal coherence volume to the conventional full-azimuth coherence volume. The azimuthal coherence results exhibited an improved definition for faults whose strikes are perpendicular to the sorting azimuth. More specifically, systems of NW-trending discontinuities were imaged more clearly in the NE-SW oriented coherence volume than it was in the full-azimuth coherence volume. The reason for this enhancement is the fact that seismic waves tend to avoid passing through the fault when they propagate parallel to the fault strike therefore missing the effects of the fault while they must pass through the fault when propagating perpendicular to the fault strike which results in better illumination of the fault.
Middle Permian (Guadalupian) fusulinid taxonomy and biostratigraphy of the mid-latitude Dalan Basin, Zagros, Iran and their applications in paleoclimate dynamics and paleogeography
Authors: Davydov Vladimir I. , Sakineh Arefifard 
Published: October 2021

ABSTRACTThe Middle–Upper Permian (Guadalupian–Lopingian) Dalan Basin was part of a very large carbonate ramp/platform along the passive margin of the Arabian Plate, located at mid-latitude Neo-Tethys Ocean. As shown in the modern world the mid-latitudes are areas where climatic fluctuations and velocity of climate change are most significant. Consequently, the most significant variations in foraminiferal diversity occur at higher latitudes as already noted for the Middle Permian (Guadalupian) foraminifers’ record. The fusulinids as a large, warm-water foraminifera were quite sensitive to water temperature. The optimal water temperature for recent warm-water benthic foraminifera with living symbionts, and consequently for fusulinids, is 20–30°C, while the lower limit is 14–16°C. Three climatically-determined assemblages were distinguished in Zagros and the surrounding areas. The first assemblage is characteristic of temperate, cool-water environments and contains smaller foraminifera with no symbionts, which possess resistance to such environments. Fusulinid staffellids, schubertellids, Chusenella, Eopolydiexodina and Monodiexodina can be found in the warmer water environments in a second climatic assemblage, transitional from temperate- to warm-water state. The third assemblage is characterized by the presence of verbeekinids in warm-water conditions in Zagros and appeared where surface-water temperature exceeded approximately 25°C. The proposed model of climate fluctuations and paleogeography in the Neo-Tethys is based on analyses of temporal and spatial distribution of fusulinids. Also, a temperate cool-water Monodiexodina is recorded in this area for the first time. Three new species of fusulinids are described.