Provenance and depositional environment of the Middle-Late Jurassic shales, northern Iraq

2019 ◽  
Vol 23 (5) ◽  
pp. 747-765 ◽  
Author(s):  
Faraj Habeeb Tobia ◽  
Hikmat S. Al-Jaleel ◽  
Idrees N. Ahmad
Keyword(s):  
Late Jurassic ◽  
Depositional Environment ◽  
Northern Iraq

scholarly journals The taphonomy of dinosaurs from the Upper Jurassic of Tendaguru (Tanzania) based on field sketches of the German tendaguru expedition (1909–1913)

Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 25-61 ◽  
Author(s):  
W.-D. Heinrich
Keyword(s):  
Old Age ◽  
Late Jurassic ◽  
Depositional Environment ◽  
Upper Jurassic ◽  
Skeletal Remains ◽  
Time Span ◽  
Post Mortem ◽  
Seasonal Drought ◽  
Long Time

Tendaguru is one of the most important dinosaur localities in Africa. The Tendaguru Beds have produced a diverse Late Jurassic (Kimmeridgian to Tithonian) dinosaur assemblage, including sauropods (<i>Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia</i>), theropods (e.g., <i>Elaphrosaurus, Ceratosaurus, Allosaurus</i>), and ornithischians (<i>Kentrosaurus, Dryosaurus</i>). Contrary to the well studied skeletal anatomy of the Tendaguru dinosaurs, the available taphonomic information is rather limited, and a generally accepted taphonomic model has not yet been established. Assessment of unpublished excavation sketches by the German Tendaguru expedition (1909–1913) document bone assemblages of sauropod and ornithischian dinosaurs from the Middle Saurian Bed, Upper Saurian Bed, and the Transitional Sands above the <i>Trigonia smeei</i> Bed, and shed some light on the taphonomy of the Tendaguru dinosaurs. Stages of disarticulation range from incomplete skeletons to solitary bones, and strongly argue for carcass decay and post-mortem transport prior to burial. The sauropod bone accumulations are dominated by adult individuals, and juveniles are rare or missing. The occurrence of bones in different superimposed dinosaur-bearing horizons indicates that skeletal remains were accumulated over a long time span during the Late Jurassic, and the majority of the bone accumulations are probably attritional. These accumulations are likely to have resulted from long-term bone imput due to normal mortality events caused by starvation, seasonal drought, disease, old age and weakness. The depositional environment of the Middle and Upper Saurian Bed was mainly limnic to brackish in origin, while the palaeoenvironment of the Transitional Sands was marginal marine. <br><br> Tendaguru zählt zu den bedeutendsten Dinosaurier-Lagerstätten Afrikas. Aus den Tendaguru-Schichten sind zahlreiche Skelettreste von Sauropoden (<i>Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia</i>), Theropoden (z.B. <i>Elaphrosaurus, Ceratosaurus, Allosaurus</i>) und Ornithischiern (<i>Kentrosaurus, Dryosaurus</i>) geborgen worden. Sie stammen aus der späten Jura-Zeit (Kimmeridge — Tithon). Während der Skelettbau der Tendagurusaurier gut untersucht ist, wirft die Taphonomie des Sauriervorkommens von Tendaguru noch immer Fragen auf. Unklar ist bislang, wie die enormen Anreicherungen von Dinosaurierknochen in den Tendaguru-Schichten zustandekamen. Unveröffentlichte Grabungsskizzen der Deutschen Tendaguru Expedition (1909–1913) erweitern unsere Kenntnisse über die Taphonomie der Tendagurusaurier. In den ausgewerteten Grabungsskizzen sind Knochenansammlungen von Sauropoden und Ornithischiern aus dem Mittleren und Oberen Sauriermergel sowie aus den Übergangsschichten über der <i>Trigonia smeei</i>-Schicht dokumentiert. Die Lage und der Erhaltungszustand der Funde lassen auf erheblichen Zerfall der Kadaver und post-mortalen Transport von Skelettelementen vor der Einbettung schließen. Das Vorkommen von Saurierknochen in mehreren übereinanderliegenden Profilabschnitten der Tendaguru-Schichten zeigt, daß Skelettreste während der späten Jura-Zeit über einen längeren Zeitraum hinweg akkumuliert wurden. Die Ansammlungen von Skelettresten gehen wahrscheinlich auf „normale” Sterbe-Ereignisse zurück, wie z. B. Verhungern, Verdursten, Kankheit, Altersschwäche und jahreszeitliche Dürre. Als Ablagerungsraum der Mittleren und Oberen Saurierschicht kommt ein küstennaher limnischer, zeitweise wohl auch brackischer Küstenstreifen in Betracht. Die knochenführenden Übergangsschichten unter- und oberhalb der Saurierschichten sind randlich marine Ablagerungen. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.1999.4860020102" target="_blank">10.1002/mmng.1999.4860020102</a>

Facies analysis and depositional environment of the Geli Khana Formation (Middle Triassic), Northern Iraq

2014 ◽  
Vol 8 (7) ◽  
pp. 4765-4777 ◽  
Author(s):  
Ali Ismail Al-Juboury ◽  
Mohammed A. Al-Haj ◽  
Wrya Jihad Jabbar
Keyword(s):  
Depositional Environment ◽  
Middle Triassic ◽  
Facies Analysis ◽  
Northern Iraq

scholarly journals An Upper Jurassic ichthyosaur (Ichthyosauria: Ophthalmosauridae) from the Bowser Basin, British Columbia

2016 ◽  
Vol 53 (1) ◽  
pp. 34-40
Author(s):  
Robin L. Sissons ◽  
Michael W. Caldwell ◽  
Carol A. Evenchick ◽  
Donald B. Brinkman ◽  
Matthew J. Vavrek
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Late Jurassic ◽  
Body Shape ◽  
Depositional Environment ◽  
Upper Jurassic ◽  
Generic Level ◽  
Shallow Marine ◽  
Northwestern North America ◽  
High Diversity

Although the Jurassic was a period of high diversity in ichthyosaurs, only a small number of specimens have been recorded from Canada to date. We describe here a new occurrence of an ophthalmosaurid ichthyosaur from a shallow marine depositional environment within the Bowser Basin of northern British Columbia. Based on vertebral diameters and the size of the humerus, the ichthyosaur was relatively large compared to other contemporaneous forms, yet possessed teeth that were small for its body size. As well, the height to length ratio of the preserved vertebrae suggests it may have had a more elongate, less regionalized body shape. Although indeterminate at a generic level, the presence of Late Jurassic ichthyosaurs in nearshore waters of northwestern North America further demonstrates their cosmopolitan distribution.

scholarly journals Evaluation of Tertiary Reservoir in Hamrin Oil Field, North Iraq

2021 ◽  
pp. 3-9
Author(s):  
Faraj Ahmad AL-Sulaiman ◽  
Thamer Aadi Ahmed
Keyword(s):  
Depositional Environment ◽  
Oil Field ◽  
Tectonic Activity ◽  
Western Boundary ◽  
Shelf Area ◽  
Petrophysical Properties ◽  
North West ◽  
Northern Iraq ◽  
Well Completion ◽  
North Iraq

Hamrin oil field is one of the important oil field in northern Iraq. The field represent an asymmetrical anticline that extend North West-South East for more than 101 km, with width (4-7) km. Hamrin oil field was located at the south western boundary of foothill zone of the unstable shelf area according to the tectonic division of Iraq. The Tertiary reservoir represented by Jeribe and Euphrates formations as main reservoirs and Dhiban formation as secondary reservoir that represent an attractive petroleum completion target in Hamrin oil field. The aim of this study is to determine the petrophysical properties of these formations, using log data, because these properties affect the estimate of reserves (porosity and saturation) and well deliverability (permeability). This study shows that the petro physical properties of these formations were controlled by depositional environment, diagenesis and tectonic activity. The evaluation of the petro physical for tertiary reservoir in Hamrin oil field was necessary to choose the best interval for well completion.

scholarly journals The Geology of Basement Rocks in the Southeastern Tararua Range, North Island, New Zealand

2021 ◽  
Author(s):  
◽  
Lisa Ann Foley
Keyword(s):  
New Zealand ◽  
Early Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Depositional Environment ◽  
Active Continental Margin ◽  
Turbidity Currents ◽  
High Angle ◽  
Basement Rocks ◽  
Geochemical Analyses

<p>Basement rocks within the southeastern Tararua Range belong to two associations: a sedimentary association (greywacke, argillite, calcareous siltstone, conglomerate and olistostrome) and a volcanogenic association (metabasite, chert, red argillite and limestone). Rocks of the sedimentary association are more abundant and have been deposited by turbidity currents and debris flows in a deep water, marine environment. Three turbidite and two intercalated non-turbidite lithofacies are recognized. Sedimentological data suggest that the sediment was deposited in a submarine fan system (mid-fan environment), probably in a trench. The alternating greywacke-argillite beds have detrital compositions which are essentially quartzo-feldspathic. Framework mode and geochemical analyses indicate that the sediment was derived from an active continental margin that was shedding detritus of mainly acid-volcanic and metamorphic origin. Rocks of the volcanogenic association, although volumetrically minor, are widely distributed. Geochemical analyses of metabasites suggest that they were erupted in an oceanic environment, both at a mid-ocean ridge and an intra-plate setting. The presence of radiolaria skeletons in red argillite and chert indicates a hemiplagic depositional environment for these rocks. Rocks of the volcanogenic association often have conformable contacts. These rocks have a related depositional environment and represent seafloor material. Where observed, contacts between rocks of the two associations are always faulted. Deformation in the field area is characterized by development of the following types of structures: several generations of folds, faults at both a low angle and high angle to bedding, shear foliation and melange. The region has undergone the following deformational events, outlined from oldest to youngest: 1) folding with at least two fold generations present. 2) fragmentation and disruption of the beds by faults. Low-angle to bedding faults and high-angle to bedding faults have disrupted the bedding. Where these structures have occurred to a great extent, a chaotically disrupted unit, melange, has formed. 3) post-melange folding. 4) recent faulting related to the present strike-slip regime in New Zealand. Rocks have undergone prehnite-pumpellyite facies metamorphism. The rock types, their field relationships and the deformation that the area has undergone is consistent with accretion at a convergent plate margin. Radiolaria were extracted from two red chert samples. In the study the radiolaria define a Middle Jurassic age, which indicates that the sediments in the southeastern Tararua Range must be of Middle Jurassic in age or younger (possibly Cretaceous). A similar sample from the Manawatu Gorge to the north of the study area contained radiolaria of Late Jurassic-Early Cretaceous age. Sediments in both areas therefore belong to fossil zone 5 (Late Jurassic-Early Cretaceous) of MacKinnon (1983).</p>

scholarly journals Sequence Stratigraphy of the Fatha Formation in Shaqlawa Area, Northern Iraq

2021 ◽  
Vol 54 (2F) ◽  
pp. 13-21
Author(s):  
Hamid Alsultan ◽  
Karrar Awad
Keyword(s):  
Depositional Environment ◽  
Sedimentary Facies ◽  
Third Order ◽  
Northern Iraq ◽  
Depositional Settings ◽  
Surface Section ◽  
Continental Sabkha ◽  
Bounded Below ◽  
Marly Limestone ◽  
System Tract

A surface section of the Fatha Formation (Middle Miocene) was studied in the Shaqlawa area, Erbil, Northern Iraq. It consists of siliciclastic silt, evaporates, and carbonates in a mixed siliciclastic silt composition. The Fatha Formation in the study area can be divided into two members of variable thickness based on rocky differences. Depositional settings ranged from shallow open-marine and restricted-hypersaline to supratidal and continental (sabkha, fluvio-deltaic, and exposure). It is bounded below by a type one sequence boundary above the Eocene Pila Spi Formation and marked by conglomerates. The upper sequence boundary with the Injana Formation is conformable. Thirteen sedimentary facies were distinguished in the Fatha Formation within the Shaqlawa region of northern Iraq and include sandstone to mudstone, wavy bedded sandstone to mudstone, Flaser bedded sandstone to mudstone, Marl, sandstone, cross lamination sandstone, Trough cross bedded sandstone, Planar cross bedded sandstone, marly limestone lithofacies, bioclastic grainstone to packstone microfacies, bioclastic lime mudstone to wackestone microfacies, lime mudstone-wackestone microfacies, and gypsum lithofacies. The depositional environment of the formation was inferred based on the facies association concepts. The succession formation can be divided into several third-order cycles, which reflect fluctuations in the relative sea-level rise. High-frequency cycles of transgressive System Tract and Highstand System tract. Fundamental to the evolution of the sequence, in this case, is the local tectonic component.

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