Geoarabia最新文献

{"title":"Middle East Geologic Time Scale 2015 Ediacaran and Cambrian Periods","authors":"","doi":"10.2113/geoarabia2001511","DOIUrl":"https://doi.org/10.2113/geoarabia2001511","url":null,"abstract":"","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"4-D evolution of anticlines and implications for hydrocarbon exploration within the Zagros Fold-Thrust Belt, Kurdistan Region, Iraq","authors":"Mjahid Zebari, C. Burberry","doi":"10.2113/geoarabia2001161","DOIUrl":"https://doi.org/10.2113/geoarabia2001161","url":null,"abstract":"\u0000 The Zagros Fold-Thrust Belt, extending from southern Iran, through northern Iraq and into Turkey, is characterized by elongate NW-trending anticlines that house large hydrocarbon accumulations. In recent years, the Kurdistan region of northern Iraq has become an area of interest for both structural studies and petroleum exploration-related investigation. Key questions to be answered concern the nature of the anticlines and whether the geometry of any associated thrusts can be predicted from surface geomorphology, as well the 4-D evolution of the area and along-strike continuity of the anticlines. To address these questions, this study combines field data, remote-sensing data concerning the structure and geomorphology of the anticlines, and structural modeling in order to produce robust interpretations of the geometries of the reverse fault structures that core the majority of these anticlines. Results indicate that this methodology can be used to constrain potential thrust configurations at depth and the probable style of fold amplification and lateral propagation. In addition, this study shows that the growth of the anticlines can be considered in 4-D, with consideration given to the interaction of the Zagros-age deformation with the pre-existing basement fabric. We demonstrate that combining both structural and geomorphological methodologies can lead to a better understanding of the geometry and evolution of the trap-forming structures in the Kurdistan region of Iraq and thus is expected to be of interest to the petroleum industry.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micropalaeontology and palaeoenvironments of the Miocene Wadi Waqb carbonate of the northern Saudi Arabian Red Sea","authors":"G. Hughes","doi":"10.2113/geoarabia190459","DOIUrl":"https://doi.org/10.2113/geoarabia190459","url":null,"abstract":"\u0000 The Saudi Arabian Red Sea stratigraphy consists of a variety of lithologies that range from evaporites, deep- and shallow-marine siliciclastics and carbonates, biostratigraphically constrained to range from the Late Cretaceous, Campanian, to Late Pliocene. The succession consists of pre-rift Mesozoic and Palaeogene sediments, and syn-rift and post-rift late Palaeogene and Neogene sediments. Three main episodes of shallow-marine carbonate deposition can be determined, including those of the earliest Early Miocene Musayr Formation of the Tayran Group later Early Miocene Wadi Waqb Member of the Jabal Kibrit Formation and of the Pliocene Badr Formation of the Lisan Group. The Midyan area of the northern Red Sea offers a unique window into the Cretaceous and Miocene succession that is otherwise only present in the deep subsurface. The sediments are of hydrocarbon interest because of the presence of source rocks, siliciclastic and carbonate reservoirs. The Wadi Waqb reservoir is hosted within the Wadi Waqb Member of the Jabal Kibrit Formation, and is of latest Early Miocene to possibly earliest Middle Miocene age. It is considered to have formed a fringing reef complex that formed a steep, fault-influenced margin to a narrow platform, similar to Recent coralgal reefs of the Red Sea.\u0000 The Wadi Waqb Member is exposed on the east and west flanks of the Ifal Plain. The bioclasts are considered to have traveled as a submarine carbonate debris flow 25 km from their presumed source to the east and possibly the west, and consist mostly of rhodoliths, echinoid and coral fragments together with the benthonic larger foraminifera Operculinella venosa, Operculina complanata, Heterostegina depressa and Borelis melo. The planktonic foraminifera include species of Globigerina, Globigerinoides and Praeorbulina; no specimens of the Middle Miocene planktonic foraminiferal genus Orbulina have yet been encountered in the thin sections. The presence of Borelis melo melo, and of B. melo curdica within the region, indicates a latest Early Miocene age. No specimens of the age-equivalent larger benthonic foraminiferal genera Miogypsina or Lepidocyclina have been observed, and this is consistent with evidence from the Wadi Waqb equivalent carbonates elsewhere in the Red Sea and Gulf of Suez.\u0000 In the east, the Wadi Waqb is represented by discontinuous fringing rhodolith and coral reefs that are welded to steep cliffs of granitic basement. In Wadi Waqb, located in hills that form the western margin to the Ifal Plain, the Wadi Waqb carbonates consist of packstones containing autochthonous planktonic foraminifera and abundant shallow-marine microfossils that are considered to have been derived from the basement-founded rhodolith and coral reefs in the east. The Wadi Waqb reservoir is located beneath the central part of the Ifal Plain, approximately midway down a ramp between the in situ rhodolith-coral reefs and the mixed allochthonous and autochthonous facies at Wadi Waqb. The re","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow burial dolomitization of an Eocene carbonate platform, southeast Zagros Basin, Iran","authors":"A. Zohdi, S. Moallemi, R. Moussavi-Harami, A. Mahboubi, D. Richter, A. Geske, A. Nickandish, A. Immenhauser","doi":"10.2113/geoarabia190417","DOIUrl":"https://doi.org/10.2113/geoarabia190417","url":null,"abstract":"\u0000 Here, a case example of a dolomitized Eocene ramp setting from the southeastern Zagros Basin is documented and discussed in the context of published work. This is of significance as well-documented case examples of Eocene dolomitized inner platforms are comparably rare. The same is true for detailed diagenetic studies from the Zagros Basin in general. Three measured field sections were combined with detailed petrographic and geochemical analyses and four main dolomite types were defined. The most significant dolomite type is present in the form of a volumetrically significant occurrence of meter-thick beds of strata-bound dolostones. These dolomites are characterized by near-stoichiometric composition, fabric-retentive and fabric-destructive textures, subhedral to anhedral in shape and most being in the tens-of-microns range.\u0000 Dolomite δ18O (averaging -2.6‰) values are depleted relative to that expected for precipitation from Eocene seawater (averaging 0‰), while δ13C (averaging -0.1‰) values are within the range of Eocene seawater values (averaging 0.5‰). Dolomite Type II and III 87Sr/86S values from 0.7079 to 0.7086 are somewhat elevated with respect to Eocene seawater (0.7077 and 0.7078). Based on these data, it is suggested that moderately evaporated seawater, via shallow seepage reflux, acted as agent for the initial dolomitization process. Subsequently, early diagenetic dolomites were recrystallized during shallow burial to variable degrees. The absence of volumetrically significant evaporitic deposits indicates that the salinity of porewater during dolomitization was beneath the threshold limit for gypsum precipitation. In addition, ascending saline fluids from deep-seated salt diapirs might have affected dolomitizing fluids.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Open versus closed mesogenetic systems in Cretaceous fluvial and tidal sandstones, Sirt Basin, Libya","authors":"M. Khalifa, M. Gasparrini","doi":"10.2113/geoarabia1904113","DOIUrl":"https://doi.org/10.2113/geoarabia1904113","url":null,"abstract":"\u0000 This study constrains factors controlling the distribution of diagenetic alteration and their impact on reservoir quality of the Cretaceous sandstones from the Al-Bayda Platform, located in the southern Sirt Basin (Libya). These factors include the presence of early cements as well as the influx of hot basinal brines. The studied samples come from two blocks in the Khalifa Field, which are dislocated by a major normal fault. The deep-burial (mesogenetic) alteration includes the partial to pervasive replacement of early (eogenetic) dolomite and calcite cements by ferroan-dolomite, ankerite and siderite, precipitation of grain-coating chlorite, and cementation by quartz overgrowths, barite and anhydrite, particularly in the downthrown block. The association of quartz overgrowths with barite suggests that deep burial was influenced by the influx of hot basinal brines through faults. Conversely, deep-burial alteration in braided fluvial deposits of the Nubian sandstones of the upthrown block include: illitization of eogenetic smectite, quartz cementation and formation of chlorite.\u0000 This study shows that deep burial of the studied sandstones did not occur in a closed system, but was affected by the influx of hot basinal brines through faults, which formed during basin rifting. This interpretation is supported by the relatively high homogenization temperatures (100–110°C; corrected to 110–125°C) of primary fluid inclusions within quartz overgrowths, which exceed the maximum burial temperatures experienced by the Cretaceous succession, and by the high salinity of these inclusions.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithofacies, diagenesis and reservoir quality of Upper Shu’aiba reservoirs in northwestern Oman","authors":"N. Habsi, M. A. Shukaili, S. Tooqi, S. Ehrenberg, M. Bernecker","doi":"10.2113/geoarabia1904145","DOIUrl":"https://doi.org/10.2113/geoarabia1904145","url":null,"abstract":"\u0000 Core and log data from Lower Cretaceous limestones of the Upper Shu’aiba Member were used to characterize the distribution of lithofacies, clay and porosity within two low-angle clinoforms that form the reservoirs for an oilfield of northwestern Oman. Data from 15 vertical wells, including four with core, and four horizontal well cores were projected into a dip-oriented cross-section derived from a static reservoir model as a basis for visualizing the above variations. Each clinoform consists of a basal “argillaceous zone” and a thicker “reservoir zone” of clean limestone, together reflecting fourth-order cycles of progradation along the margin of the Bab intra-shelf basin. Lithofacies vary in a proximal direction from mudstone and wackestone (mid-ramp) to mud-dominated packstone (slope) to mud-rich floatstone, rudstone and boundstone (ramp crest) and are arranged in a pattern of decreasing water depth and increasing energy both upwards and landward within each clinoform. In contrast, the reservoir zone of a younger clinoform from a nearby oilfield consists of well-sorted grainstone and grain-dominated packstone, illustrating the wide range of depositional conditions that occurred in the ramp-crest facies belt of different units.\u0000 Except within the proximal extent of the younger clinoform, where values are transitional toward reservoir zone values, the argillaceous zones have total porosity mostly < 10% and baseline-normalized gamma-ray (GR) activity > 23 API units, reflecting clay contents of around 10–18%. In contrast, most parts of the reservoir zones have GR of 15–23 API units and porosity of 10–35%. Higher clay content is suggested to be linked with lower porosity through facilitation of both mechanical and chemical compaction, the latter providing a local supply of calcite cement. XRD analyses show that the clays are kaolin, illite/smectite and illite, similar to the clays in the overlying Nahr Umr shale. Most former macropores have been filled by blocky calcite cement in the main oilfield studied, but all lithofacies have similar wide ranges of total porosity of 8% to > 30%.\u0000 The cores were also studied for evidence of diagenesis related to the contact with the overlying Nahr Umr Formation, but profiles of stable-isotope ratios, bulk-rock strontium, petrography and porosity-permeability data show no trends indicative of upward-increasing meteoric diagenesis below this sequence boundary. Meteoric leaching could nevertheless be pervasive throughout the Upper Shu’aiba reservoirs, at least partially accounting for extensive aragonite dissolution and low Sr and δ18O values. Two of the cores show trends of upwards-increasing bulk-rock uranium, manganese and iron, possibly indicative of sea-floor authigenesis. In addition, saddle dolomite near the tops of these cores may reflect late influx of magnesium derived from clay in the Nahr Umr Formation.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cambrian stratigraphy of Jordan","authors":"J. Powell, A. Abed, Y. L. Nindre","doi":"10.2113/geoarabia190381","DOIUrl":"https://doi.org/10.2113/geoarabia190381","url":null,"abstract":"\u0000 The lower and middle Cambrian succession (Ram Group) in Jordan is described in lexicon-style format to document an important phase of Earth history following the uplift and erosion of the Arabian-Nubian Shield (Aqaba Complex) during the late Neoproterozoic, and younger, but more localised, intrusive and volcanic/volcaniclastic activity that formed the Araba Complex. The early Cambrian Ram Unconformity (ca. 530 Ma) marks the base of a predominantly fluvial siliciclastic succession derived from rapidly eroding Neoproterozoic (including Ediacaran) basement rocks, but includes a brief, but biostratigraphically significant, sequence of marine siliciclastics and carbonates, the early mid-Cambrian Burj Formation.\u0000 Rapid uplift and erosion of the granitoid basement (Arabian-Nubian Shield or ANS) resulted in a peneplanation of the Aqaba Complex over millions of years duration (latest Neoproterozoic to Cambrian) in the Southern Desert of Jordan. Early Cambrian pebbly sandstones and locally derived conglomerates (Salib Formation) were deposited on an alluvial plain by high velocity-high discharge, northward flowing (NNE to NNW) braided rivers, characterised by trough cross-bedding and erosive tabular sets. Brief, and rare, marine influence is represented, locally, by thin Skolithos-burrowed sandstones.\u0000 A regional sea-level rise in the early mid-Cambrian marks a major marine transgressive-regressive cycle and southward thinning carbonate-siliciclastic wedge (Burj Formation) widely present in the subsurface across the Arabian Platform. During deposition of this transgressive marine sequence the palaeoshoreline was oriented WNW-ESE in southern Jordan. The transgressive phase (TST) is represented by tidal-dominated siltstones and fine-grained sandstones (Tayan Member) containing a diverse Cruziana/Rusophycus ichnofaunal assemblage. The overlying carbonate unit (Numayri Member) represents the highstand (HST) and maximum marine flooding surface (MFS), and comprises a carbonate ramp sequence of shelly wackestone, packstone and grainstone with ooids and oncolites, and a diverse shelly fauna including trilobites, brachiopods and hyolithids. A return to regressive tidal-influenced sandstone and siltstone (along with thin carbonates in central Jordan) (Hanneh Member) represents a regressive wedge (RST) deposited in response to renewed uplift of the ANS. Trilobites, represented by the Kingaspis campbelli and Redlichops faunules, suggest a biostratigraphical age of early mid-Cambrian for the carbonate MFS, which equates approximately to the base of the Cambrian Series 3 (Stage 5). This event probably represents the Cambrian marine flooding surface Cm20 (approximate geochronological age of 509 to 505 Ma). South of Feinan, in the Wadi Araba, the carbonates pass laterally to marine sandstone (Abu Khusheiba Sandstone) with extensive Skolithos burrows and Cruziana/Rusophycus traces. Traced southwards (palaeohinterland) the marine influence diminishes, so that the Burj/Abu","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"885 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neoproterozoic microbialites in outcrops of the Qarn Alam salt dome, central Oman","authors":"M. Mettraux, P. Homewood, S. A. Balushi, M. Erthal, N. Matsuda","doi":"10.2113/geoarabia190317","DOIUrl":"https://doi.org/10.2113/geoarabia190317","url":null,"abstract":"\u0000 Limestones and mixed limestone and dolomite facies from the Neoproterozoic to early Cambrian Ara Group are exposed as blocks and rafts by the surface-piercing Qarn Alam salt dome in central Oman. These limestones and dolomites compose laminite-stromatolite-thrombolite-evaporite shallowing-up successions, and are remarkable in that they contain well-preserved microbial textures and fossils (both calcite and dolomite with very small but significant silicates and other mineral species) as well as pristine syn-depositional to very early diagenetic cements from the first stages of sediment lithification.\u0000 The facies are described at scales ranging from outcrop (1–100 m) to the SEM (μm-scale). Outcrop-scale sedimentology and high-resolution stratigraphy are described in detail, and petrographic and geochemical analyses are recorded. The depositional environment is interpreted to have been shallow marine subtidal to intertidal and hypersaline supratidal, with low-energy tidal flats and channels, lagoons or salinas, and continental sabkhas.\u0000 Both calcitic and dolomitic phases show microbial fossils and structures with fabrics of mineralised extra-cellular polymeric substances (EPS). The occurrence of syn-sedimentary primary dolomitic matrix in thrombolites is interpreted to result from the degradation of a thicker microbial mat, during or after growth, which provided the right micro-environmental conditions for the precipitation of dolomite. A caliche crust and sabkha evaporites (the white band) cap the laminite-thrombolite succession and together with karst breccias, fracture fills and neptunian dykes, record an emersion at the top of each of the depositional units.\u0000 Stable isotopes of carbon and oxygen of the microbialite to evaporite facies show close values for δ13C (+2‰ to +4‰) but a broader range of δ18O (+0.5‰ to -5‰). These values, and their spread recorded within sets of laminae, indicate little to no diagenetic resetting and therefore should be close to original equilibrium values for seawater and early diagenetic fluids. Later diagenetic cements in fractures show entirely different values with δ13C in the range of -2‰ to -6‰, and δ18O from -7.5‰ to -11‰.\u0000 Whereas dolomite shows no post-depositional diagenetic modification and records preservation of finely detailed EPS mineralisation, the calcite of clumps of clots and mesoclots shows neomorphism with reorganisation into crudely fascicular-optic crystals that cut across primary sediment and early diagenetic cement fabrics.\u0000 Preservation of both sedimentary facies and the fossil record is remarkable for these ca. 540 million year old rocks and indicates that diagenesis had little effect on the microbialites at Qarn Alam.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Midyan Peninsula, northern Red Sea, Saudi Arabia: Seismic imaging and regional interpretation","authors":"R. Tubbs, H. G. Fouda, A. Afifi, N. Raterman, G. Hughes, Y. Fadolalkarem","doi":"10.2113/geoarabia1903165","DOIUrl":"https://doi.org/10.2113/geoarabia1903165","url":null,"abstract":"\u0000 The Midyan Peninsula of northwest Saudi Arabia offers an exceptional opportunity to observe a complex interplay of rifting, salt tectonics, and strike-slip faulting. Recently onshore 3-D, transition zone 2-D, and offshore 2-D seismic data have been acquired in the area. In addition, ongoing fieldwork and an active drilling program have provided new insights into the geologic history of the region. The initial stages of continental rifting began during the Early Oligocene (ca. 33 Ma) and often utilized pre-existing basement fault trends. The early syn-rift sedimentary record is typified by formation of deep half-grabens filled with thick wedges of primarily continental sediments, with lesser amounts of evaporitic and marine deposits.\u0000 Seismic data show a distinct break in deposition occurred ca. 21 Ma characterized by a persistent angular unconformity near the basin-bounding fault, before a shift to marine and offshore deposits of the Lower Miocene Burqan Formation. Post-Burqan a second angular unconformity termed the mid-clysmic event is evident away from the basin edge. This surface exhibits significant relief created by re-activation of older EW-trending faults and lower Maqna Group sediments display substantial thickening across these faults. Overall, the Maqna section transitions from normal marine sedimentation to more restricted basin conditions before being succeeded by the thick-layered evaporite sequence of the Mansiyah Formation.\u0000 Approximately 15–12 Ma active strike-slip faults appeared in the Red Sea and shifted the extension from rift normal to highly oblique directed at N15°–20°E, parallel to the Gulf of Aqaba. During this transition the composition of the rift-fill changed as well from basin-wide precipitates to thick siliciclastic wedges of the Ghawwas Formation. Seismic images of the Ghawwas show abrupt thickness changes and stratal geometries that date deposition as coincident with both the growth of Mansiyah Formation diapirs and the movement of a large detachment at the base of the Mansiyah.\u0000 Roughly five million years ago, organized seafloor spreading began in the southern Red Sea and strike-slip motion intensified as deformation began to focus along the Dead Sea/Aqaba strike-slip fault system. Adjacent to Midyan, a pull-apart basin in the Gulf of Aqaba has opened over 26 km perpendicular to the strike-slip system resulting in significant footwall uplift. The positive interference of the Aqaba/Dead Sea and Red Sea footwall uplifts has uniquely exposed the full syn-rift stratigraphic section from basement to Upper Miocene at Midyan, making the area an ideal locality for field studies. Presence of the complete Miocene section on the Aqaba shoulder uplift clearly indicates the uplift occurred after the Miocene. Salt-filled pull-apart basins in the same orientation as the Gulf of Aqaba are also observed on 3-D seismic data in the Ifal Basin.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68187241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proposed correlation of Oman’s Abu Mahara Supergroup and Saudi Arabia’s Jibalah Group","authors":"M. Al-Husseini","doi":"10.2113/geoarabia190217","DOIUrl":"https://doi.org/10.2113/geoarabia190217","url":null,"abstract":"\u0000 The Ediacaran–Cambrian Middle East Geologic Time Scale is extensively revised in the 2014 version (Enclosure). It suggests the top of the Abu Mahara Group glacial diamictites in Oman represent the termination of the late Cryogenian Marinoan Glaciation at 635 Ma. The overlying Ediacaran Nafun Group of Oman is shown between 635 and 547 Ma based on geochronologic data, and divided into: (1) the Lower Nafun Supersequence (635–582 Ma) consisting of the Hadash Formation (cap carbonate), the Masirah Bay Formation (clastics) and the Khufai Formation (carbonates); and (2) the Upper Nafun Supersequence (582–547 Ma) consisting of the Shuram Formation (clastics and carbonates) and the Buah Formation (carbonates). The Nafun Group lies below the Ediacaran– lower Cambrian Ara Group (evaporites and carbonates), which contains the Ediacaran/Cambrian Boundary currently dated at 541 Ma.\u0000 The Sub-Shuram Unconformity, which corresponds to the global Shuram δ13C Negative Excursion, separates the Nafun supersequences. Its age was estimated by assuming the thicknesses of the Nafun formations are proportional to time in the Masirah-1 Well, where the Nafun Group attains its greatest-known thickness of 2,308 m in Oman. This assumption coincidently estimated the unconformity at 582 Ma, the same age as the Ediacaran Gaskiers (Varanger or Varingian) Glaciation. The new calibration was used to correlate the Nafun formations to the rock-time units of the Jibalah Group in several isolated basins along the Najd Fault System in the Arabian Shield, using recently published geochronologic data and δ13C measurements, as follows.\u0000 The younger part of the Lower Nafun Supersequence (635–582 Ma) is here correlated to the Lower Jibalah Supersequence (605 ± 5 to 582 Ma), represented by the Umm al-Aisah Formation in the Jifn Basin, located along the Halaban-Zarghat Fault Zone of the Najd Fault System. The Umm al-Aisah Formation consists of volcanics and clastics that give way to the Umm al-Aisah Limestone. The Upper Nafun Supersequence (582–547 Ma) is here correlated to the Upper Jibalah Supersequence, which unconformably overlies the Umm al-Aisah Limestone, with its basal unit being the Gaskiers-coeval Jifn Polymictic Conglomerate (≥ 200 m thick). In the Bir Sija Basin, located along the Rika Fault Zone of the Najd Fault System, the likely Gaskiers-coeval polymictic conglomerate (150 m thick) is overlain by a 20 m-thick limestone unit, the Bir Sija Limestone, possibly a cap carbonate. The Upper Jibalah Supersequence continues with clastics overlain by the Muraykhah Formation (carbonates) or mixed clastics-carbonates of its equivalent formations. In several outcrops the Upper Jibalah Supersequence is overlain by the lower Cambrian Siq Sandstone Formation (≤ 525 ± 5 Ma) implying the Sub-Siq Unconformity represents a hiatus between 547 and 525 ± 5 Ma. The Jifn Formation in the Jifn Basin, however, may represent continuous deposition between 582 Ma and 525 ± 5 Ma.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}