scholarly journals Devonian Jauf Formation, Saudi Arabia: Orbital Second-order Depositional Sequence 28

GeoArabia ◽  
2006 ◽  
Vol 11 (2) ◽  
pp. 53-70 ◽  
Author(s):  
Moujahed Al-Husseini ◽  
Robley K. Matthews

ABSTRACT The Devonian Jauf Formation (Huj Group) froms part of a regional transgressive-regressive depositional sequence that extends more than 1,500 km across the Arabian Platform from the Al Jawf outcrops in northwest Saudi Arabia, to the subsurface of eastern Saudi Arabia and Oman (Misfar Group). The formation ranges in thickness from 200–335 m in eastern Saudi Arabia to about 300–330 m in northwest Saudi Arabia. It disconformably (?unconformably) overlies the continental to shallow-marine Tawil Formation, and is unconformably overlain by the continental Jubah Formation. The Jauf Formation consists of five members that are apparently conformable; from base-up: Sha’iba Shale, Qasr Limestone, Subbat Shale, Hammamiyat Limestone and Murayr. In the Al-Qalibah reference section, it is divided into 21 informal units. The Early Devonian Emsian Hammamiyat Member represents the main marine flooding event; it consists of Hammamiyat units 1–6 each characterized by a clastic section that is capped by limestone. The Jauf Formation is interpreted as an orbital second-order depositional sequence (denoted DS2 28), which is bounded by two second-order sequence boundaries: SB2 28 = Jauf/Tawil (c. 407.6 Ma) and SB2 27 = Jubah/Jauf (c. 393.0 Ma). The Jauf Formation appears to consist of six third-order depositional sequences (DS3 28.1 to 28.6) that were deposited in the Early Devonian, ?Pragian and Emsian stages The Hammamiyat Member (DS3 28.4) is interpreted to consist of six fourth-order orbital cycles (DS4 28.4.1 to 28.4.6) each deposited in 0.405 million years.

GeoArabia ◽  
2005 ◽  
Vol 10 (2) ◽  
pp. 189-192 ◽  
Author(s):  
Moujahed Al-Husseini ◽  
Robley K. Matthews

The recent publication of GTS 2004 (Gradstein et al., 2004) provides an opportunity to recalibrate in time the late Carboniferous, Permian and Early Traissic Arabian Stratigraphy (GeoArabia Special Publication 3, Edited by Al-Husseini, 2004) as represented by the rock units in subsurface Interior Oman (Osterloff et al., 2004a, b) and the Haushi-Huqf Uplift region (Angiolini et al., 2004) (Figure). Additionally, sequence stratigraphic models of orbital forcing (Matthews and Frohlich, 2002; Immenhauser and Matthews, 2004) provide new insights in regards to the time calibration of depositional sequences: the “Rosetta Stone” approach. The Rosetta Stone approach predicts that the period of a third-order depositional sequence is 2.430 ± 0.405 my (denoted DS3 and here adjusted to increase the fourth-order ‘geological tuning fork’ from 0.404 to 0.405 my based on Laskar et al., 2004). The present calibration is also tied to the orbital-forcing model developed by R.K. Matthews (in Al-Husseini and Matthews, 2005; this issue of GeoArabia) that predicts that a second-order depositional sequence (denoted DS2) consists of six DS3s that were deposited in a period of about 14.58 my (6 x 2.430 my); the DS2 being bounded by two regional second-order sequence boundaries (SB2) corresponding to sea-level maximum regression surfaces.


1993 ◽  
Vol 30 (2) ◽  
pp. 301-320 ◽  
Author(s):  
A. F. Embry

Transgressive–regressive (T–R) sequence analysis has been applied to the Jurassic succession of the Sverdrup Basin with sequence boundaries drawn at subaerial unconformities or the correlative transgressive surfaces. A hierarchal system of sequence order that reflects the different nature of the boundaries has been formulated on the basis of boundary characteristics. Second- through fifth-order sequences have been recognized in the Jurassic succession, which itself is part of a first-order sequence of mid-Permian – Early Cretaceous age.The Jurassic strata occur within four second-order sequences. The boundaries of these sequences are characterized by widespread subaerial unconformities across which major changes in depositional and subsidence regimes occur. These boundaries are earliest Rhaetian, earliest Pliensbachian, earliest Bajocian, earliest Oxfordian, and Hauterivian in age.Each second-order sequence is divisible into a number of third-order sequences bounded mainly by basin-wide transgressive surfaces with subaerial unconformities present on the basin margins. The ages of the 10 Jurassic third-order sequences are Rhaetian – Hettangian, Sinemurian, Pliensbachian – Toarcian, late Toarcian – Aalenian, Bajocian, Bathonian, Callovian, Oxfordian – early Kimmeridgian, late Kimmeridgian – early Tithonian, and late Tithonian. The third-order sequences commonly contain three to six fourth-order sequences. These sequences are bound entirely by transgressive surfaces that can be correlated only over a portion of the basin.A good correlation between the second- and third-order transgressive events of the Sverdrup Basin and proposed global events is observed. This worldwide occurrence suggests that the events in part reflect eustatic sea-level changes. The characteristics of the second- and third-order boundaries also indicate that each had a tectonic influence that resulted in a rapid relative sea-level fall (uplift) followed by a rapid rise (subsidence). Given the apparent combination of tectonic and eustatic influence on the generation of the second- and third-order sequence boundaries, they are interpreted to reflect significant plate-tectonic reorganizations that affected the intraplate stress regimes of the oceanic (eustatic) and continental (tectonic) portions of each lithospheric plate.


2019 ◽  
Vol 23 (10) ◽  
pp. 1855-1860
Author(s):  
F.O. Amiewalan ◽  
E.O. Bamigboye

: Biostratigraphic study of Well DX has yielded Cretaceous miospores and dinoflagellates cysts which heightened the recognition of sequence boundaries (SB), Maximum Flooding Surfaces (MFS) and associated Systems Tracts. Five maximum flooding surfaces between 95.6 Ma and 89.0 Ma, four sequence boundaries between 96.4 Ma and 93.0 Ma and threedepositional sequences were identified with varying average thicknesses of sediments interpreted from the gamma ray log and biostratigraphic data. The threedepositional sequences interpreted are -depositional sequence I (96.4 Ma - 95.4 Ma) (8240 ft. - 8120 ft.), depositional sequence II (95.4 Ma - 94.0 Ma) (8120 ft. - 7850 ft.) and depositionalsequence III (94.0 Ma - 93.0 Ma) (7850 ft. - 7550 ft.). All the depositional sequences fall within the third order cycle. The age of the well was attempted based on the presence of some selected marker fossils - Ephedripites spp., Classopollis spp., Spiniferites spp., Cyclonephelium distinctum, Cyclonephelium vannophorum, Subtilisphaera spp., Eucomiidites spp., Triorites africaensis, Odontochitina costata and Droseridites senonicus recovered from the studied intervals and was dated Albian - Santonian. The Sequence stratigraphic interpretations are useful in further deepening the knowledge of thesubsurface geology of the studiedwell in Gongola Sub Basin, Upper Benue Trough of Nigeria.Keywords: Sequence Boundary, Maximum Flooding Surface, System tracts, Depositional sequence


1996 ◽  
Vol 36 (1) ◽  
pp. 269 ◽  
Author(s):  
P.A. Arditto

This paper presents the results and conclusions of an integrated sequence stratigraphic study of the Callovian marine succession across area 'A' of the Zone of Cooperation (ZOCA). This study utilised wireline log and conventional core data from within ZOCA 91–1 and ZOCA 91–12, and incorporated trade data from adjacent permits, to generate a rational depositional model for the succession. Three distinct third-order sequences have been recognised from the detailed correlation of regional flooding surfaces recognised on wireline log motifs calibrated against conventional core and biostratigraphy. The base of the oldest third-order sequence includes section previously referred to as Plover Formation, and roughly corresponds to the W.digitata/W.indotata zone boundary. The Callovian Unconformity within the ZOCA region is thus relegated to a third-order sequence boundary or disconformity. The term Elang Formation is proposed for this Callovian succession which comprises three third-order sequences mappable across ZOCA. The well-type section for the Elang Formation is Elang-1, and an additional well reference section would be Elang-2, as both these wells contain significant and complementary cored section.Detailed sedimentological studies on conventional core reveal that the Elang Formation comprises a succession of coastal plain to nearshore marine sediments, ranging from low sinuosity fluvial channel, fluvial-dominated deltaic, proximal low sinuosity estuarine channel and distal outer bay sediments. Only minor wave-dominated, open marine shoref ace intervals were interpreted, most of the cored intervals indicating a fluvially-domi-nated shoreline with minimal wave reworking. Isopach and per cent sand maps generated for each third-order sequence comprising the Elang Formation illustrate the successive sediment distribution patterns across ZOCA during the progressive marine transgression from the top of the fluvio-deltaic Plover Formation to the base of the offshore marine Lower Flamingo Group. The sand-trend maps for the three sequences which comprise the Elang Formation indicate a fluvial/estuarine-dominated delta system, sourced from the region of the Laminaria Field, AC/P8, building east and southeast out across the ZOCA region. A modern analogue of this delta system in both size and sedimentation style may be the Brahmaputra/Ganges Delta of East Bengal.


2018 ◽  
Vol 88 (7) ◽  
pp. 753-776 ◽  
Author(s):  
Stephen N. Ehrenberg ◽  
Stephen W. Lokier ◽  
Liu Yaxin ◽  
Rulin Chen

AbstractThe upper reservoir zone of the Lower Cretaceous Kharaib Formation (46–54 m thick in the studied wells) is regarded as the upper portion of a third-order depositional sequence comprising higher-order cycles. Whereas the third-order sequence interpretation is clearly supported by the upward-shoaling trend of the reservoir zone, relationships defining the component cycles have not previously been documented and are the focus of the present study. Core descriptions from four wells in a single oilfield reveal little evidence of facies changes or trends of facies patterns indicative of high-frequency depositional cycles. Cycle boundaries could possibly be represented by the repetitive pattern of coarse beds (rudstone and floatstone) 0.1–2 m thick, commonly having sharp basal contacts and gradational upper contacts with enclosing packstone to wackestone. Because the coarse beds do not appear correlative between wells, however, we prefer the alternative interpretation that they reflect episodic storm events which locally redistributed detritus, sourced from a patchwork of low-relief lithosomes, across the flat surface of the epeiric Kharaib platform–lagoon. Although the existence of high-order eustatic fluctuations during upper Kharaib deposition is well established, low-amplitude variations in water depth may not have touched down on the sea floor to significantly affect sediment textures in contrast with the dominant storm signal.Reservoir sub-zones used for production operations, but previously suggested to be fourth-order parasequence sets, are defined by dips in porosity-log profiles, reflecting thin (approximately 1 m) intervals of increased stylolite frequency. These boundaries are thus diagenetic in character, but their correlation over tens to hundreds of kilometers indicates an underlying depositional control. We suggest that the link between sea level and diagenesis is depositional-clay content, which facilitates stylolitic dissolution. Profiles of bulk-rock alumina analyses in the studied cores show subtle indications of higher clay content at the sub-zone tops. Much greater clay peaks mark the third-order sequence boundaries, resulting in the “dense” (very low porosity) zones above and below the studied reservoir zone and the increased stylolite frequency in the upper and lower several meters of the zone. Possible factors promoting clay influx across a carbonate shelf during falls in sea level include increased stream gradients and more humid climate.


GeoArabia ◽  
2012 ◽  
Vol 17 (3) ◽  
pp. 85-128 ◽  
Author(s):  
Michael Obermaier ◽  
Thomas Aigner ◽  
Holger C. Forke

ABSTRACT The investigated Middle to Upper Triassic Upper Mahil Member, representing a Jilh outcrop equivalent in the Northern Oman Mountains, illustrates the proximal portion of a flat epeiric carbonate ramp. A sedimentological study of well-exposed outcrops in Wadi Sahtan may serve as a reference section for a sequence-stratigraphic framework and detailed facies description of the Upper Mahil Member. It also provides an insight into the seal and reservoir potential of carbonates in a low-accommodation inner ramp setting. Outcrop observations and thin section analyses yielded 14 different lithofacies types ranging from a supratidal marsh to high-energy subtidal shoal environment. Vertical facies stacking patterns show three basic small-scale cycle motifs (fifth-order). While mud-rich backshoal cycles with claystone intercalations and rooted/bioturbated mud-/wackestones illustrate potential baffles and seal units around the center of the Upper Mahil, potential reservoir units occur stratigraphically in the upper part of the formation. There, a few meter-thick trough cross-bedded oolitic-/peloidal-rich grainstone depicts maximum accommodation within backshoal to shoal cycle types below the erosional base-Jurassic unconformity. The investigated outcrop section in Wadi Sahtan was subdivided into nine almost complete third-order sequences. Two to four of these sequences are further stacked into three second-order super-sequences which are well reflected in the gamma-ray pattern. The highest reservoir potential occurs around second-order maximum floodings. Internal seals can be observed at third-order sequence boundaries where shales and muddy carbonates are up to 20 m thick. A regional correlation with subsurface data from Yibal and Lekhwair in Oman shows that the apparent thickness changes in the Upper Mahil (Jilh) are mainly determined by the Late Triassic/Early Jurassic erosional truncation. The occurrence of thick anhydrite units in the subsurface indicates a more proximal setting towards the southwest.


GeoArabia ◽  
2002 ◽  
Vol 7 (4) ◽  
pp. 699-718 ◽  
Author(s):  
Jean M. Philip ◽  
Jack Roger ◽  
Denis Vaslet ◽  
Fabrizio Cecca ◽  
Silvia Gardin ◽  
...  

ABSTRACT The Aruma Formation is a predominantly carbonate lithostratigraphic unit of Late Cretaceous age that crops out in Saudi Arabia. It consists of three members: from base to top they are Khanasir Limestone Member, Hajajah Limestone Member, and Lina Shale Member. In order to establish a stratigraphic revision of the Formation, a reference section near Al Kharj, southeast of Riyadh in central Saudi Arabia, was logged and a hierarchical organization of the depositional sequences established. The Aruma corresponds to four third-order cycles bounded by erosional unconformities. Integrated biostratigraphical data mainly based on ammonites, nannoflora, rudists, and larger foraminifera point to a Maastrichtian age for the Khanasir and Hajajah members, and a Paleocene age for the Lina Member. Regional stratigraphic correlations were established within the outcropping Aruma Formation in Saudi Arabia. Biostratigraphy and sequence stratigraphy allowed a correlation framework to be proposed between the Aruma and the Qahlah and Simsima formations of the United Arab Emirates and the Oman Mountains, and with the Sharwayn Formation of the Hadramawt and Dhofar. The high-resolution stratigraphic scheme established for the Aruma Formation in Saudi Arabia is expected to be useful for subsurface correlations and in petroleum exploration.


2018 ◽  
Vol 10 (1) ◽  
pp. 250-260 ◽  
Author(s):  
EnZhao Xiao ◽  
Khalid Latif ◽  
Muhammad Riaz ◽  
Yinglun Qin ◽  
Hao Wang

Abstract In order to study the sedimentological response of the first episode of “cyanobacteria calcification event” in Phanerozoic, we studied the microbialites from Furongian Series in Qijiayu section, Hebei Province, which is located in the central part of the North China Platform. Cambrian Furongian Series is made up of three third-order depositional sequences, Depositional Sequence 1 (DS1) in Changshan Formation and DS2 and DS3 in Fengshan Formation. Two beds of massive limestone of a shallow ramp facies developed in Changshan Formation and the first third-order sequence of Fengshan Formation. Both of them contains many dome-shaped carbonate structures that formed as a result of forced regression. These structures can be described as leiolitic bioherms, with a morphology like string of beads. In the current study, microorganisms such as Epiphyton, Girvanella and Renalcis are reported from the leiolitic bioherms. This provides not only documentation for the model of cyanobacteria calcification, but also describes the genesis of leiolitic bioherms by microbial processes inside cyanobacteria dominated microbial mats. Moreover, the diverse emergence of the calcified microorganisms represents the fossil evidence of calcified microorganisms’ blooms in Cambrian Furongian and offers a reference for studying the complex microbial processes in such old carbonate depositions.


2014 ◽  
Vol 898 ◽  
pp. 428-431
Author(s):  
Qian Zhang

According to core, logging and seismic data, using tectonic-stratigraphic and sequence stratigraphic analysise theories in Qingshankou Formation of division and comparison, and the sequence boundary and sequence unit to be optimized, in order to carry out seismic deposition. By determining the levels of sequence interface on seismic, logging and faces reflecting characteristics of the study area to build sequence interface identifier. In the course of practical work, identified the continental basin of the more common of the one to three levels of sequence interface, system interface and the parasequence set interface. In Songliao Basin, second-order sequences often corresponding to the tectonic evolution of the basin episodic stage, and in each period of prototype basin internal episodic tectonic extension or episodic of tectonic inversion is consistent, in Qingshankou Formation in the development of one second-order sequence boundary SB11 (T11), three third-order sequence boundary, there are SB12 (T12), SB13 (T13) and SB2 (T2), seven forth-order sequence boundary. In the plane, using the data of 256 wells, analysis of the distribution characteristics of the sedimentary facies of the first member of Qingshankou-Formation.


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