INTEGRATED SEDIMENTOLOGICAL ANALYSIS: THE EOCENE OF THE BASS BASIN

1989 ◽  
Vol 29 (1) ◽  
pp. 312
Author(s):  
Peter W. Baillie ◽  
Carol A. Bacon
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Complex Mixture ◽  
Sediment Supply ◽  
Log Analysis ◽  
Core Analysis ◽  
Anaerobic Conditions ◽  
Complex Interplay ◽  
Maximum Thickness ◽  
Sand Bars

The Eocene section in the Bass Basin comprises the upper part of the siliciclastic coal- bearing Eastern View Group and the thin but regionally extensive Demons Bluff Formation.An integrated sedimentological study utilising core analysis, log analysis, palynology, coal maceral studies and geochemistry, together with sequence stratigraphy, has been used to determine Eocene sedimentation styles in the basin.The most likely environment during deposition of the Upper Eastern View Group was a tide- dominated delta consisting of a complex mixture of distributary channels, strandline sand bars, peat swamps and shallow lagoons, the sedimentary successions resulting from a complex interplay between sea- level, tectonics and sediment supply. A major coal- forming episode occurring in the interval 48- 51.5 m.y. is related to oscillations of sea- level following a major highstand.A locally developed progradational unit, Konkon Sandstone, comprising two sandy parasequences separated by a very thin shaly interval is recognised at the top of the Eastern View Group in the northwestern sector of the basin and reaches a maximum thickness of 140 m.The Demons Bluff Formation is a diachronous unit consisting dominantly of siltstone probably deposited in a barred basin with anaerobic conditions.

scholarly journals Clastic facies models, a personal perspective

2001 ◽  
Vol 48 ◽  
pp. 101-115
Author(s):  
Harold G. Reading
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Sedimentary Rocks ◽  
Sediment Supply ◽  
Personal Perspective ◽  
Sea Level Changes ◽  
Ancient Rock ◽  
Tectonic Movements ◽  
Over Time ◽  
Facies Models

Facies models evolved from classifications that were mainly descriptive, based on observable, measureable features such as the composition and texture of sedimentary rocks. As our understanding of sedimentary processes expanded, genetic facies models were developed based on the inferred process of formation. Since individual facies cannot be interpreted in isolation, they must be studied with reference to their neighbours, emphasizing the association of facies and sequences, in particular those that coarsen and fine upward. Environmental facies models are based on the interaction of studies on modern environments and ancient rock facies. Earlier facies models tended to invoke intrinsic, autocyclic controls. The advent of sequence stratigraphy led to greater emphasis on the surfaces that separate sequences and to external allocyclic controls. These were, initially, sea-level changes; later, changes in climate, tectonic movements and sediment supply were invoked. Over time, simple, all embracing models have given way to increasingly complex ones as our knowledge of the variability of nature has increased. Complex though these models are, they are only simplifications of reality. In nature there are no models and the majority of past environments differed in some respect from any modern environment. Each environment and rock sequence is unique.

DEPOSITIONAL MODELLING OF THE GIPPSLAND BASIN AND THE BARROW-EXMOUTH SUB-BASINS

1994 ◽  
Vol 34 (1) ◽  
pp. 350 ◽  
Author(s):  
Keyu Liu ◽  
Lincoln Paterson ◽  
Feng Xu Jian
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Seismic Data ◽  
High Frequency ◽  
Sedimentary Facies ◽  
Sediment Supply ◽  
Well Logs ◽  
Tectonic Movement ◽  
Depositional Processes ◽  
Gippsland Basin

SEDPAK is a forward modelling computer program for depositional processes developed by the University of South Carolina's StratMod Group. It simulates the geometry of generalised lithofacies in a sedimentary sequence or a basin by considering principally four major geological variables: eustatic sea level, tectonic movement, sediment accumulation, and initial and evolving basin surfaces.Based on seismic data, well logs and other information from drill holes, the geometries of sedimentary sequences of the Gippsland Basin and the Barrow-Exmouth Sub-basins have been successfully reproduced on both basin and reservoir scales using SEDPAK 3.12. The simulation results indicate that eustacy, tectonics, sediment input and basin physiography can be equally important in controlling the geometry of strata and basin architecture. However, some differences exist: (1) tectonic movement normally contributes to long-term variations of the first order (megasequence) basin architecture and configuration; (2) the second order (sequence) basin architecture and stratal geometry can be controlled by either sediment supply, eustacy, tectonism or a combination; and (3) high frequency facies variations and stratal geometry within individual sequences are primarily controlled by eustatic sea level variations and basin physiography.This study has demonstrated that SEDPAK is a useful tool for reconstruction of basin evolution histories and for reservoir characterisation. It can also be used to predict sedimentary facies in undrilled exploration frontier areas. In addition, it can be used to address some critical assumptions and problems in the sequence stratigraphy concept. SEDPAK is particularly useful in the study of high frequency sequence stratigraphy and cyclicity, where various sequence or parasequence bounding surfaces and internal geometry can not be easily recognised from seismic data, well logs and outcrops.

Postrift depositional evolution and sequence stratigraphy from offshore subsurface data of the Kribi-Campo subbasin (Cameroon, West African margin)

2016 ◽  
Vol 4 (1) ◽  
pp. T79-T101
Author(s):  
Joseph Bertrand Iboum Kissaaka ◽  
Joseph Marie Ntamak-Nida ◽  
François Mvondo ◽  
Paul Gustave Fowe Kwetche ◽  
Adrien Lamire Djomeni Nitcheu ◽  
...  
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
West African ◽  
Sediment Supply ◽  
Sea Level Changes ◽  
Third Order ◽  
Normal Regression ◽  
Basin Floor ◽  
Depositional Evolution ◽  
Forced Regression

Using 2D seismic data and well logs from the Kribi-Campo subbasin in the south Cameroon margin, we have analyzed the postrift succession with the aim of deriving a chronostratigraphic chart and identifying stratigraphic traps. The Kribi-Campo subbasin related to the rifting between Africa and South America could be divided into a structurally complex eastern depocenter and a relatively less disturbed western depocenter in which a break-up unconformity approximately 107.5 Ma underlined the beginning of postrift history. We have used the modern concepts of sequence stratigraphy to identify and characterize seven second-order (SS1, SS2, SS3, SS4, SS5, SS6, and SS7) sequences and one third-order (SS8) sequences grouped into three megasequences (A, B, and C) from Albian to Recent. Sequence 1 (Albian-Cenomanian) was characterized by a retrogradation overlying a lowstand progradational pattern. The SS2 (Campanian-Maastrichtian) and SS3 (Maastrichtian) sequences were deposited during a highstand normal regression. From Paleocene to Eocene, the deposition of sequences SS4–SS5 was controlled by the development of submarine fan turbiditic system related to a forced regression of coastline. From the Middle Miocene to Recent age, the SS6, SS7, and SS8 sequences have been characterized by the development of sigmoidal-oblique clinoforms of a deltaic system well observed in the northern part of the study area. We have studied a new undocumented phase of forced regression of Mio-Pliocene in age within the postrift sequence SS7. The forced regression phases are associated with the Paleogene and Neogene uplift. Relative sea-level curves were constructed and compared with the existing published curves. The processes involved in the formation of these sequences were interpreted as a combination of tectonics, sediment supply, and sea-level changes. Potential reservoirs embedded within the sequences include channel fill, shingled turbidites, slope fan, and basin-floor fan complex.

scholarly journals Sequence Stratigraphy and Depositional Environment of the Zubair Formation in Rumaila Oilfields, Southern Iraq: Microfacies and Geochemistry

2021 ◽  
Vol 54 (2B) ◽  
pp. 28-41
Author(s):  
Hamid A. A. Alsultan
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Gamma Ray ◽  
Sediment Supply ◽  
Delta Front ◽  
Delta Plain ◽  
Quartz Arenite ◽  
Sandy Shale ◽  
Sonic Logs ◽  
Southern Iraq

In the Rumaila oilfields in southern Iraq, the Zubair Formation was deposited in a shallow environment as three main facies, delta plain, backshore, and delta front depositional conditions indicating a transition from delta front and delta plain to a highstand level due to the finning upward mode. The facies of the Zubair clasts show well-sorted quartz arenite sandstone, poorly sorted quartz arenite sandstone, clayey sandstone that has not been properly sorted, sandy shale, and shale lithofacies. The minor lithofacies were identified using well-logging methods (gamma ray, spontaneous potential and sonic logs) and petrography. The Zubair clasts are of transition environment that appears to be transported from freshwater and deposited in a marine environment forming many fourth-order cycles reflect sea level rise fluctuations and still-stand under tectonics developed the sequence stratigraphy. A misalignment between relative sea-level and sediment supply caused asymmetry sedimentary cycles. A shallower environment of shale-dominated rocks rich in organic matter and pyrite were exposed. The basinal shale of Ratawi at the Zubair bottom and the shallow carbonate of Shuaiba emplace on the Zubair represent the beginning of the delta build up (delta front and delta plain) to a highstand stage.

Late Quaternary sequence stratigraphy of the Mackenzie Delta

1996 ◽  
Vol 33 (7) ◽  
pp. 1053-1074 ◽  
Author(s):  
Philip R Hill
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Sequence Stratigraphy ◽  
Late Quaternary ◽  
Sediment Supply ◽  
Mackenzie Delta ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
Healing Phase ◽  
Late Wisconsinan

The Late Wisconsinan and Holocene sequence stratigraphy of the Mackenzie Delta provides insights into the glacial history of the region. The base of the described succession is a hummocky regional reflector interpreted to be a flooding surface formed immediately after retreat of glacial ice from the Mackenzie Trough. Above this flooding surface, two progradational parasequences are present. The first, assigned to the transgressive systems tract, is correlated with the Tutsieta Lake readvance of the ice sheet at approximately 13 000 BP. A flooding surface forming the upper boundary of this parasequence extends inland to at least Inuvik, developing as a response to glacial retreat and early Holocene relative sea level rise. The second parasequence of Holocene deltaic deposits is assigned to the highstand systems tract and is characterized by progressive progradation of the delta into the Mackenzie Trough to a position seaward of the present delta coastline. A distinct reduction in gradient of the most recent delta clinoforms is consistent with other data suggesting regional transgression and is interpreted to represent the development of a healing-phase wedge. The reasons for this recent transgression are not clear, because relative sea level rise has decreased and sediment supply probably increased over the last 2000 years. Transgression may be related to decreased efficiency of channels, increased trapping of sediments by thermokarst lakes, overspill of the delta across the eastern margin of the valley, and (or) progressively greater exposure to wave action as the delta became less sheltered by the confines of the glacial valley.

scholarly journals RELATIONSHIP BETWEEN SEQUENCE STRATIGRAPHY AND RELATIVE SEA-LEVEL CHANGES

2017 ◽  
Vol 1 (2) ◽  
pp. 38
Author(s):  
Jamaluddin . ◽  
Romuald Sohores ◽  
Muhammad Fawzy Ismullah
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Sequence Stratigraphy ◽  
Sedimentation Rate ◽  
Sediment Supply ◽  
Maximum Point ◽  
Sea Level Changes ◽  
Highstand System Tract ◽  
Accommodation Space ◽  
System Tract

The continuous sea-level rise will result in conditions where the level of accommodation space is greater than that of sediment supply produced undertransgression conditions. When the sea level reaches its maximum point, the sedimentation rate will exceed the sea level rise and aggrades becomes more dominant progradation will result in new Highstand System Tract (HST) condition. Keyword: Accommodation, Sea level changes, Sedimentation, Sequence, Stratigraphy

Chemical Composition and Antimicrobial Activity of Bark and Leaf Extracts of Cupressus sempervirens and Juniperus phoenicea Grown in Al- Jabel Al-Akhdar Region, Libya

2019 ◽  
Vol 9 (4) ◽  
pp. 268-279
Author(s):  
Mohamed E.I. Badawy ◽  
Ibrahim E.A. Kherallah ◽  
Ahmed S.O. Mohareb ◽  
Mohamed. Z.M. Salem ◽  
Hameda A. Yousef
Keyword(s):  
Antimicrobial Activity ◽  
Chemical Composition ◽  
Sea Level ◽  
Plant Extracts ◽  
Complex Mixture ◽  
Biologically Active ◽  
Cupressus Sempervirens ◽  
Leaf Extracts ◽  
Juniperus Phoenicea ◽  
The Impact

Background:Plant extracts are important products in the world and have been widely used for isolation of important biologically active products. Because of their significant environmental impact, extensive research has been explored to determine the antimicrobial activity of plant extracts.Methods:Acetone extracts of the bark and leaf of Cupressus sempervirens and Juniperus phoenicea, collected from three different altitudes (125, 391, and 851 m high of sea level) at Al- Jabel Al-Akhdar area, Libya were obtained and analyzed by GC/MS. The antimicrobial activity of the extracts was further evaluated against plant bacteria Rhizobium radiobacter, Erwinia carotovora, Rhodococcus fascians and Ralstonia solanacearum and fungus Botrytis cinerea.Results:The impact of the altitude from the sea level on the quantity and chemical constituents of the extracts was investigated. The yield was largely dependent on tree species and the highest yield (6.50%) was obtained with C. sempervirens L bark of altitude III (851 m of the sea level), while the lowest (1.17%) was obtained with the leaf extract of C. sempervirens L from altitude I (125 m). The chemical composition analyzed by GC/MS confirmed that the leaf extracts of C. sempervirens and J. phoenicea contained a complex mixture of monoterpene hydrocarbons, sesquiterpenes, diterpenes, diterpenoids, terpenophenolic, steroids and phthalates. However, the bark extracts of both trees contained a mixture of sesquiterpenes, diterpenes, diterpenoids, terpenophenolics, phthalates, retinol and steroids. These constituents revealed some variability among the extracts displaying the highest interesting chemotype of totarol (terpenophenolic) in all extracts (14.63-78.19% of the total extract). The extracts displayed a noteworthy antifungal potency with varying degrees of inhibition of growth with EC50 values ranged from 78.50 to 206.90 mg/L. The extracts obtained from the leaves of C. sempervirens showed that the highest inhibitory activity was obtained with the extract of altitude II (391 m) with MIC 565, 510, 380 and 710 mg/L against E. carotovora, R. fascians, and R. radiobacter and R. solanacearum, respectively.Conclusion:Based on antimicrobial activity, raw plant extracts can be a cost-effective way to protect crops from microbial pathogens. Because plant extracts contain several antimicrobial compounds, the development of resistant pathogens can be delayed.

scholarly journals Contributions of Organic and Mineral Matter to Vertical Accretion in Tidal Wetlands across a Chesapeake Bay Subestuary

2021 ◽  
Vol 9 (7) ◽  
pp. 751
Author(s):  
Jenny R. Allen ◽  
Jeffrey C. Cornwell ◽  
Andrew H. Baldwin
Keyword(s):  
Organic Matter ◽  
Sea Level Rise ◽  
Chesapeake Bay ◽  
Sea Level ◽  
210Pb Dating ◽  
Sediment Supply ◽  
Mineral Matter ◽  
Tidal Wetlands ◽  
Vertical Accretion ◽  
Inorganic Matter

Persistence of tidal wetlands under conditions of sea level rise depends on vertical accretion of organic and inorganic matter, which vary in their relative abundance across estuarine gradients. We examined the relative contribution of organic and inorganic matter to vertical soil accretion using lead-210 (210Pb) dating of soil cores collected in tidal wetlands spanning a tidal freshwater to brackish gradient across a Chesapeake Bay subestuary. Only 8 out of the 15 subsites had accretion rates higher than relative sea level rise for the area, with the lowest rates of accretion found in oligohaline marshes in the middle of the subestuary. The mass accumulation of organic and inorganic matter was similar and related (R2 = 0.37). However, owing to its lower density, organic matter contributed 1.5–3 times more toward vertical accretion than inorganic matter. Furthermore, water/porespace associated with organic matter accounted for 82%–94% of the total vertical accretion. These findings demonstrate the key role of organic matter in the persistence of coastal wetlands with low mineral sediment supply, particularly mid-estuary oligohaline marshes.

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