scholarly journals Markov chains and entropy tests in genetic-based lithofacies analysis of deep-water clastic depositional systems

2016 ◽  
Vol 8 (1) ◽  
pp. 45-51
Author(s):  
Szabolcs Borka
Keyword(s):  
Markov Chains ◽  
Deep Water ◽  
Pannonian Basin ◽  
Depositional Environments ◽  
Structural Elements ◽  
Chi Square ◽  
Fine Grained ◽  
Hydrocarbon Reservoir ◽  
Depositional Processes ◽  
Chi Square Test

AbstractThe aim of this study was to examine the relationship between structural elements and the so-called genetic lithofacies in a clastic deep-water depositional system. Process-sedimentology has recently been gaining importance in the characterization of these systems. This way the recognized facies attributes can be associated with the depositional processes establishing the genetic lithofacies. In this paper this approach was presented through a case study of a Tertiary deep-water sequence of the Pannonian-basin.Of course it was necessary to interpret the stratigraphy of the sequences in terms of “general” sedimentology, focusing on the structural elements. For this purpose, well-logs and standard deep-water models were applied.The cyclicity of sedimentary sequences can be easily revealed by using Markov chains. Though Markov chain analysis has broad application in mainly fluvial depositional environments, its utilization is uncommon in deep-water systems. In this context genetic lithofacies was determined and analysed by embedded Markov chains. The randomness in the presence of a lithofacies within a cycle was estimated by entropy tests (entropy after depositional, before depositional, for the whole system). Subsequently the relationships between lithofacies were revealed and a depositional model (i.e. modal cycle) was produced with 90% confidence level of stationarity. The non-randomness of the latter was tested by chi-square test.The consequences coming from the comparison of “general” sequences (composed of architectural elements), the genetic-based sequences (showing the distributions of the genetic lithofacies) and the lithofacies relationships were discussed in details. This way main depositional channel has the best, channelized lobes have good potential hydrocarbon reservoir attributes, with symmetric alternation of persistent fine-grained sandstone (Facies D) and muddy fine-grained sandstone with traction structures (Facies F)

scholarly journals Sedimentation of deep-water turbidites in the SW part of the Pannonian Basin

2010 ◽  
Vol 61 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Boris Vrbanac ◽  
Josipa Velić ◽  
Tomislav Malvić
Keyword(s):  
Deep Water ◽  
Pannonian Basin ◽  
Eastern Alps ◽  
Turbidity Currents ◽  
Main Stream ◽  
North West ◽  
Fine Grained ◽  
The North ◽  
Sandstone Body ◽  
West Part

Sedimentation of deep-water turbidites in the SW part of the Pannonian BasinThe Sava Depression and the Bjelovar Subdepression belong to the SW margin of the Pannonian Basin System, which was part of the Central Paratethys during the Pannonian period. Upper Pannonian deposits of the Ivanic-Grad Formation in the Sava Depression include several lithostratigraphic members such as Iva and Okoli Sandstone Member or their lateral equivalents, the Zagreb Member and Lipovac Marlstone Member. Their total thickness in the deepest part of the Sava Depression reaches up to 800 meters, while it is 100-200 meters in the margins of the depression. Deposits in the depression are composed of 4 facies. In the period of turbiditic activities these facies are primarily sedimented as different sandstone bodies. In the Bjelovar Subdepression, two lithostratigraphic members (lateral equivalent) were analysed, the Zagreb Member and Okoli Sandstone Member. The thickness of the Bjelovar Subdepression ranges from 50 meters along the S and SE margins to more than 350 meters along the E margin. Generally, detritus in the north-west part of the analysed area originated from a single source, the Eastern Alps, as demonstrated by sedimentological and physical properties, the geometry of the sandstone body and the fossil content. This clastic material was found to be dispersed throughout the elongated and relatively narrow Sava Depression and in the smaller Bjelovar Subdepression. Sedimentation primarily occurred in up to 200 meters water depth and was strongly influenced by the sub-aqueous paleorelief, which determined the direction of the flow of turbidity currents and sandstone body geometries. The main stream with medium- and fine-grained material was separated by two independent turbiditic flows from N-NW to the SE-E. Variability in the thickness of sandstone bodies is the result of differences in subsidence and cycles of progradation and retrogradation of turbidite fans.

scholarly journals Rose diagrams and statistical tests for archaeological orientation data: a case applied to the Southfleet Road Elephant site, Ebbsfleet, UK

2018 ◽  
Author(s):  
Richard J Hewitt ◽  
Simon A. Parfitt ◽  
Francis F. Wenban-Smith
Keyword(s):  
Best Practice ◽  
Statistical Tests ◽  
Circular Data ◽  
Preferential Orientation ◽  
Faunal Remains ◽  
Chi Square ◽  
Orientation Data ◽  
Depositional Processes ◽  
Class Frequency ◽  
Chi Square Test

Archaeologists and other fieldworkers frequently record the orientation of artefacts or faunal remains in order to understand depositional and post-depositional processes. However, analysis of this kind of data is complex and not always well-understood by investigators. For example, rose diagrams are commonly used to display orientation data. While rose diagrams are a useful and intuitive way of visualizing the data, they are not on their own sufficient except in cases where preferential orientation is very evident. Class frequency, rather than the square root of class frequency, is commonly used to interpret the results. This can give a misleading impression of preferential orientation, when in fact observed patterns do not deviate significantly from random. Conversely, data may deviate significantly from random but this may not be clear from the diagram. At the same time, classic tests like the chi-square test are not appropriate for the display of circular data and alternative approaches are needed. This paper discusses the history of the use of rose diagrams to display orientation data, briefly reviews the archaeological literature in this regard, and discusses key problems and limitations. We then make some recommendations for best practice, which we demonstrate using R software for the Lower Palaeolithic “elephant butchery site” at Southfleet Road, Ebbsfleet, UK, excavated in 2004. The methods employed are clearly explained and all data are provided to ensure that the procedure is easily repeatable without specialist knowledge or programming experience.

Low permeability Neogene lithofacies in Northern Croatia as potential unconventional hydrocarbon reservoirs

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
Tomislav Malvić ◽  
Antonija Sučić ◽  
Marko Cvetković ◽  
Filip Resanović ◽  
Josipa Velić
Keyword(s):  
Pannonian Basin ◽  
Interesting Case ◽  
Coarse Grained ◽  
Low Permeability ◽  
Water Contact ◽  
Fine Grained ◽  
Hydrocarbon Reservoir ◽  
Definition Of ◽  
Northern Croatia ◽  
Migration Pathways

AbstractWe present two examples of describing low permeability Neogene clastic lithofacies to outline unconventional hydrocarbon lithofacies. Both examples were selected from the Drava Depression, the largest macrostructure of the Pannonian Basin System located in Croatia. The first example is the Beničanci Field, the largest Croatian hydrocarbon reservoir discovered in Badenian coarse-grained clastics that consists mostly of breccia. The definition of low permeability lithofacies is related to the margins of the existing reservoir, where the reservoir lithology changed into a transitional one, which is mainly depicted by the marlitic sandstones. However, calculation of the POS (probability of success of new hydrocarbons) shows critical geological categories where probabilities are lower than those in the viable reservoir with proven reserves. Potential new hydrocarbon volumes are located in the structural margins, along the oil-water contact, with a POS of 9.375%. These potential reserves in those areas can be classified as probable. A second example was the Cremušina Structure, where a hydrocarbon reservoir was not proven, but where the entire structure has been transferred onto regional migration pathways. The Lower Pontian lithology is described from well logs as fine-grained sandstones with large sections of silty or marly clastics. As a result, the average porosity is low for conventional reservoir classification (10.57%). However, it is still an interesting case for consideration as a potentially unconventional reservoir, such as the ”tight” sandstones.

Deep-water syn-rift sedimentary response to alternating Late Quaternary palaeoenvironments in the Gulf of Corinth (Greece)

2021 ◽  
Author(s):  
Natacha Fabregas ◽  
Sofia Pechlivanidou ◽  
Robert Gawthorpe ◽  
Mary Ford ◽  
Richard Collier
Keyword(s):  
High Resolution ◽  
Deep Water ◽  
Late Quaternary ◽  
Discrete Events ◽  
Climatic Fluctuations ◽  
Fine Grained ◽  
Sea Level Fluctuations ◽  
Gulf Of Corinth ◽  
Depositional Processes ◽  
Unit Scale

<p>Relatively few detailed studies exist of rift axis depositional systems and the controls on their sedimentology and stratigraphy. Cores from the IODP Expedition 381 (Corinth Active Rift Development) provide a continuous high resolution stratigraphic record of depositional processes operating within this deep-water rift. During the Late Quaternary, the Gulf of Corinth alternated between marine and isolated/non-marine conditions due to intermittent connection with the open ocean across a sill driven by climate-related sea-level fluctuations. In this study we performed bed scale logging of the sedimentary deposits within the eastern Gulf of Corinth in order to understand key controls on sedimentation during the Late Quaternary. High resolution, mm-scale analysis was performed on the first 300 m of core from Site M0079 that records the last two glacial-interglacial cycles and the Holocene (Marine Isotope Stages 1 to 7). The succession is dominated by fine-grained gravity flows (event beds) and hemipelagic sediments. Event beds result from discrete events that interrupt/overprint ongoing low energy sedimentation. As such, these have been abstracted in order to define three main sedimentary unit types. Unit-scale logging was extended to the rest of the succession and to the other drill sites to build a stratigraphic and depositional model covering the last ca. 700 kyr of deposition. Our results show that during interglacial periods (i.e. marine conditions), the sediment record consists mainly of highly bioturbated mud with rarer occurrences of coarser grained sediment. Sedimentary structures and identifiable event beds have largely been lost due to the high degree of bioturbation. In contrast, during glacial periods (i.e. isolated/semi-isolated lake conditions) the deposits are well bedded with a low bioturbation index and background muds alternate with event beds. Transitional strata, between marine and non-marine units, show finely laminated beds rich in aragonite, often becoming more organic rich toward the top. The deepest parts of the core penetrate slumped units and thicker gravity flow deposits. This study allows us to recognise the response to high frequency climatic fluctuations recorded in the sedimentary succession of this deep-water rift.</p>

Variability of fine-grained basin floor turbidites and evaluation of controls on their development: Late Pleistocene, Gulf of Corinth, Greece

2020 ◽  
Author(s):  
Natacha Fabregas ◽  
Robert Gawthorpe ◽  
Mary Ford ◽  
Martin Muravchik ◽  
Sofia Pechlivanidou ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Deep Water ◽  
Rift Basins ◽  
Fine Grained ◽  
Sea Level Fluctuations ◽  
Sediment Routing ◽  
Gulf Of Corinth ◽  
Depositional Processes ◽  
Energy Flows ◽  
Basin Floor

<p>The Gulf of Corinth is one of the World’s fastest extending continental rift basins. During the Late Pleistocene, it alternated between marine and lacustrine conditions due to climate-driven sea-level fluctuations connecting or isolating/semi-isolating it from the open ocean. Core from IODP Expedition 381 (Corinth Active Rift Development) provide a continuous record of depositional processes operating within this deep-water rift and the interaction of tectonic and climate drivers controlling deep-water deposition over the Middle to Late Pleistocene. Subaqueous sediment density flows affect the Gulf of Corinth and are classified either by physical flow properties and grain support mechanisms or by depositional processes. Existing classifications mainly describe deposits from decimetre to 10’s of meter scale with an emphasis on sandy beds. Thinner (millimetre to centimetre scale) and finer (muddy to sandy) subaqueous sedimentary density flows beds are understudied. Low energy flows and tail of flow processes need a better understanding and are the target of this work. The aim of this study is to characterise the variability of fine-grained subaqueous sedimentary gravity flow deposits and the controls on their development based on core data from Site M0079 (IODP Expedition 381).  This site is located in the deepest part of the Gulf of Corinth (857 m water depth), in the most distal part of the sediment routing system. Analyses were performed within a 100 m interval covering Marine Isotope Stages 6 and 7 (from ~130 to ~250 ka). Detailed, sub-centimetre visual logging recorded over 2 000 beds classified according to (1) the presence/absence of a coarse base, (2) the grain-size (silty or sandy) of the base (if any), (3) the presence/absence of laminations within the muddy intervals, (4) sedimentary structures. The bed types reflect the diversity of the sedimentary processes and the subaqueous sediment density flows are thus organised within the depositional model. Bed frequency analysis provides insight into the variability between marine and lacustrine conditions. Relative chemical composition obtained from high resolution (2 mm) X-ray fluorescence scanning is used: (1) to examine the interactions between tail of the flow and background sedimentation in the basin and (2) to assess the provenance of the sediments.</p>

Turbidite origin of some laminated mudstones

1972 ◽  
Vol 109 (2) ◽  
pp. 115-126 ◽  
Author(s):  
David J. W. Piper
Keyword(s):  
Deep Water ◽  
Deep Sea ◽  
Careful Examination ◽  
Turbidity Currents ◽  
Granular Bed ◽  
Terrigenous Sediment ◽  
Fine Grained ◽  
Depositional Processes ◽  
Lower Palaeozoic

SummaryMany deep water marine muds, including lower Palaeozoic mudstones from Britain, have thin graded beds in which mud and silt laminae alternate, with the silt becoming finer and less abundant upwards. Of the known deep-sea depositional processes, turbidity currents are the most likely cause of such graded laminated beds. The lamination may be produced by alternating cohesive and granular bed conditions. Much more careful examination of laminated fine grained terrigenous sediment is needed.

Clay mineralogy and geochemistry of early Jurassic sedimentary rocks from the Moezian Platform, northern Bulgaria

Clay Minerals ◽  
2002 ◽  
Vol 37 (3) ◽  
pp. 413-428 ◽  
Author(s):  
E. Hrischeva ◽  
S. Gier
Keyword(s):  
Clay Minerals ◽  
Clay Mineral ◽  
Sedimentary Rocks ◽  
Depositional Environments ◽  
Early Jurassic ◽  
Source Rocks ◽  
Shallow Marine ◽  
Fine Grained ◽  
Depositional Processes ◽  
Mineral Assemblages

AbstractClay minerals in early Jurassic sequences of shales, siltstones and sandstones deposited in non-marine, transitional and shallow marine environments have been examined by X-ray diffraction, electron microscopy and chemical analysis to study the relationship between clay minerals, their environment of deposition and subsequent diagenetic modifications.The inherited clay mineral composition of the fine-grained sediments reflects the influence of climate, relief, source rocks and depositional processes. Inhomogeneous clay mineral assemblages, comprising abundant kaolinite and varying proportions of illite, I-S, chlorite and vermiculite, characterize fine-grained sediments from the non-marine and transitional environments. In shallow marine depositional environments clay mineral assemblages are more uniform, dominated by illite+I-S with minor kaolinite and chlorite.The principal diagenetic process affecting fine-grained sedimentary rocks is the smectite–illite transformation. In sandstones, the authigenic formation of kaolinite, chlorite and illite appears to have been primarily determined by the environment of deposition.

scholarly journals The Campanian–Maastrichtian foraminiferal biostratigraphy of the basement sediments from the southern Pannonian Basin (Vojvodina, northern Serbia): implications for the continuation of the Eastern Vardar and Sava zones

2017 ◽  
Vol 68 (2) ◽  
pp. 130-146 ◽  
Author(s):  
Milena Dunčić ◽  
Ivan Dulić ◽  
Olivera Popov ◽  
Goran Bogićević ◽  
Alan Vranjković
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Pannonian Basin ◽  
Sedimentary Cover ◽  
Planktonic Foraminifera ◽  
Depositional Environments ◽  
Calcareous Nannoplankton ◽  
Southeastern Part ◽  
Geological Conditions ◽  
Shallow Water Sediments

Abstract Micropalaeontological and biostratigraphical studies included Campanian-Maastrichtian complexes from five oil exploration wells drilled in northern Serbia (Vojvodina): the first is a carbonate-clastic complex and second is a complex containing ophiolites intercalated with hemipelagic and pelagic sediments. Within the studied complexes, rich associations of planktonic and benthic foraminifera, calcareous nannoplankton, palynomorphs, as well as shallow and deep-water fossil detritus were determined. The presence of relatively rich associations of planktonic foraminifera allowed recognition of two biozones: the Globotruncana ventricosa Zone, observed in the sediments of the carbonate-clastic complex and the Gansserina gansseri Zone, observed in both complexes. Except biozones, based on documented index species, for some units in both complexes, larger benthic foraminifera species had special biostratigraphical value, and in some of them, the calcareous nannoplankton zones were recognized. The studied complexes represent deep-water formations, generated in oceanic island arc and trough zones. The presence of limestones, which originate from destroyed rudist reefs, is explained by transfer by means of gravitational transport mechanisms of shallow-water sediments to deep-water depositional environments. In this paper, the results of more detailed biostratigraphical and palaeo-ecological studies of foraminifera associations in Campanian-Maastrichtian complexes in Vojvodina are presented. Combined with lithological studies, seven units were determined within the complexes. The obtained results are important as a part of multidisciplinary, regional exploration of both complexes, generated in specific geological conditions, that today constitute a part of the pre-Neogene basement complex in the southeastern part of the Pannonian Basin. The Campanian- Maastrichtian carbonate-clastic complex represents sedimentary cover of the Eastern Vardar Ophiolitic Unit, while the ophiolites intercalated with hemipelagic and pelagic limestones belongs to the Sava Zone.

Depositional environments along a carbonate ramp to slope transition in the Silurian of Washington Land, North Greenland

1983 ◽  
Vol 20 (3) ◽  
pp. 473-499 ◽  
Author(s):  
John M. Hurst ◽  
Finn Surlyk
Keyword(s):  
Deep Water ◽  
Debris Flows ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Carbonate Ramp ◽  
Fine Grained ◽  
Large Channel ◽  
Reef Tract ◽  
North Greenland ◽  
Deep Water Basin

During the earliest Silurian, subsidence and tilting of a relatively flat carbonate platform produced a homoclinal carbonate ramp transitional to the slope of a deep-water basin. Further subsidence, associated with a flexure, differentiated the slope from the carbonate ramp. Subsequently, a linear reef tract developed along part of the flexure, producing a steep reef-scarp slope at the outer homoclinal carbonate ramp margin and accentuating the initial basin slope. Isolated reefs also developed on the slope. The reef tract, which influenced slope depositional environments considerably, marked the transition from the shallow homoclinal carbonate ramp facies to the deeper slope environments. Background slope sedimentation was primarily terrigenous mudstone deposited out of suspension and by very dilute muddy turbidity flows. Superimposed were calcarenites and conglomerates, derived from the carbonate ramp margin and reefs, deposited by low- to high-density turbidity flows, debris flows, and possibly grain and liquefied flows. Sedimentation patterns along the incipient slope reflect both shallow carbonate ramp and deep basinal influences. With continued subsidence and differentiation of slope and ramp, slumping of carbonate blocks occurred at the ramp margin. Disorganized talus wedges developed as circular fringes around reefs on the slope, and a fine-grained talus wedge developed along the base of the main precipitous reef scarp at the ramp margin. A large channel cut down and across the slope and eventually became choked with ramp-margin reef and top-of-slope material. Finally, abrupt subsidence, which generated an olistostrome containing a minimum of [Formula: see text] of debris, drowned all reefs and the slope became essentially starved of resedimented carbonate debris.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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