scholarly journals Forward Modelling for Structural Stratigraphic Analysis, Offshore Sureste Basin, Mexico

2021 ◽  
Vol 9 ◽  
Author(s):  
Donald N. Christie ◽  
Frank J. Peel ◽  
Gillian M. Apps ◽  
David “Stan” Stanbrook
Keyword(s):  
Deep Water ◽  
Sediment Supply ◽  
Computational Method ◽  
Gravity Flow ◽  
Model Output ◽  
Seafloor Topography ◽  
Relative Contribution ◽  
Sediment Gravity Flow ◽  
Reduced Complexity ◽  
Stratal Architecture

The stratal architecture of deep-water minibasins is dominantly controlled by the interplay of two factors, structure growth and sediment supply. In this paper we explore the utility of a reduced-complexity, fast computational method (Onlapse-2D) to simulate stratal geometry, using a process of iteration to match the model output to available subsurface control (well logs and 3D seismic data). This approach was used to model the Miocene sediments in two intersecting lines of section in a complex mini-basin in the deep-water Campeche Basin, offshore Mexico. A good first-pass match between model output and geological observations was obtained, allowing us to identify and separate the effects of two distinct phases of compressional folding and a longer-lasting episode of salt withdrawal/diapirism, and to determine the timing of these events. This modelling provides an indication of the relative contribution of background sedimentation (pelagic and hemipelagic) vs. sediment-gravity-flow deposition (e.g. turbidites) within each layer of the model. The inferred timing of the compressional events derived from the model is consistent with other geological observations within the basin. The process of iteration towards a best-fit model leaves significant but local residual mismatches at several levels in the stratigraphy; these correspond to surfaces with anomalous negative (erosional) or positive (constructive depositional) palaeotopography. We label these mismatch surfaces “informative discrepancies” because the magnitude of the mismatch allows us to estimate the geometry and magnitude of the local seafloor topography. Reduced-complexity simulation is shown to be a useful and effective approach, which, when combined with an existing seismic interpretation, provides insight into the geometry and timing of controlling processes, indicates the nature of the sediments (background vs. sediment-gravity-flow) and aids in the identification of key erosional or constructional surfaces within the stratigraphy.

Gravity flows: Types, definitions, origins, identification markers, and problems

2020 ◽  
Vol 37 (2) ◽  
pp. 61-90
Author(s):  
Shanmugam G
Keyword(s):  
Debris Flow ◽  
Deep Water ◽  
Sediment Concentration ◽  
Gravity Flow ◽  
Turbidity Currents ◽  
Hyperpycnal Flows ◽  
Gravity Flows ◽  
Sediment Gravity Flow ◽  
Aeolian Dunes ◽  
C 50

Abstract This review covers 135 years of research on gravity flows since the first reporting of density plumes in the Lake Geneva, Switzerland, by Forel (1885). Six basic types of gravity flows have been identified in subaerial and suaqueous environments. They are: (1) hyperpycnal flows, (2) turbidity currents, (3) debris flows, (4) liquefied/fluidized flows, (5) grain flows, and (6) thermohaline contour currents. The first five types are flows in which the density is caused by sediment in the flow, whereas in the sixth type, the density is caused by variations in temperature and salinity. Although all six types originate initially as downslope gravity flows, only the first five types are truly downslope processes, whereas the sixth type eventually becomes an alongslope process. (1) Hyperpycnal flows are triggered by river floods in which density of incoming river water is greater than the basin water. These flows  are confined to proximity of the shoreline. They transport mud, and they do not transport sand into the deep sea. There are no sedimentological criteria yet to identify hyperpycnites in the ancient sedimentary record.  (2) A turbidity current is a sediment-gravity flow with Newtonian rheology  and turbulent state in which sediment is supported by flow turbulence and from which deposition occurs through suspension settling. Typical turbidity currents can function as truly turbulent suspensions only when their sediment concentration by volume is below 9% or C < 9%. This requirement firmly excludes the existence of 'high-density turbidity currents'. Turbidites are recognized by their distinct normal grading in deep-water deposits.  (3) A debris flow (C: 25-100%) is a sediment-gravity flow with plastic rheology and laminar state from which deposition occurs through freezing en masse. The terms debris flow and mass flow are used interchangeably. General characteristics of muddy and sandy debrites are floating clasts, planar clast fabric, inverse grading, etc.  Most sandy deep-water deposits are sandy debrites and they comprise important petroleum reservoirs worldwide. (4) A liquefied/fluidized low (>25%) is a sediment-gravity flow in which sediment is supported by upward-moving intergranular fluid. They are commonly triggered by seismicity. Water-escape structures, dish and pillar structures, and SSDS are common. (5) A grain flow (C: 50-100%) is a sediment-gravity flow in which grains are supported by dispersive pressure caused by grain collision. These flows are common on the slip face of aeolian dunes. Massive sand and inverse grading are potential identification markers.  (6) Thermohaline contour currents originate in the Antarctic region due to shelf freezing and  the related increase in the density of cold saline (i.e., thermohaline) water. Although they begin their journey as downslope gravity flows, they eventually flow alongslope as contour currents. Hybridites are deposits that result from intersection of downslope gravity flows and alongslope contour currents. Hybridites mimic the "Bouma Sequence" with traction structures (Tb and Tc). Facies models of hyperpycnites, turbidites, and contourites  are obsolete. Of the six types of density flows, hyperpycnal flows and their deposits are the least understood.

scholarly journals The stratigraphic evolution of onlap in siliciclastic deep-water systems: Autogenic modulation of allogenic signals

2019 ◽  
Vol 89 (10) ◽  
pp. 890-917
Author(s):  
Euan L. Soutter ◽  
Ian A. Kane ◽  
Arne Fuhrmann ◽  
Zoë A. Cumberpatch ◽  
Mads Huuse
Keyword(s):  
Deep Water ◽  
Water System ◽  
Water Systems ◽  
Sediment Supply ◽  
Seafloor Topography ◽  
Sediment Distribution ◽  
Stratigraphic Model ◽  
Basin Scale ◽  
Allogenic Processes ◽  
Basin Margin

ABSTRACT Seafloor topography affects the sediment gravity flows that interact with it. Understanding this interaction is critical for accurate predictions of sediment distribution and paleogeographic or structural reconstructions of deep-water basins. The effects of seafloor topography can be seen from the bed scale, through facies transitions toward intra-basinal slopes, to the basin scale, where onlap patterns reveal the spatial evolution of deep-water systems. Basin-margin onlap patterns are typically attributed to allogenic factors, such as sediment supply signals or subsidence rates, with few studies emphasizing the importance of predictable spatio-temporal autogenic flow evolution. This study aims to assess the autogenic controls on onlap by documenting onlap styles in the confined Eocene-to-Oligocene deep-marine Annot Basin of SE France. Measured sections, coupled with architectural observations, mapping, and paleogeographical interpretations, are used to categorize onlap styles and place them within a generic stratigraphic model. These observations are compared with a simple numerical model. The integrated stratigraphic model predicts that during progradation of a deep-water system into a confined basin successive onlap terminations will be partially controlled by the effect of increasing flow concentration. Initially thin-bedded low-density turbidites of the distal lobe fringe are deposited and drape basinal topography. As the system progrades these beds become overlain by hybrid beds and other deposits of higher-concentration flows developed in the proximal lobe fringe. This transition is therefore marked by intra-formational onlap against the underlying and lower-concentration lobe fringe that drapes the topography. Continued progradation results in deposition of lower-concentration deposits in the lobe off-axis, resulting in either further intra-formational onlap against the lobe fringe or onlap directly against the hemipelagic basin margin. Basinal relief is gradually reduced as axial and higher-volume flows become more prevalent during progradation, causing the basin to become a bypass zone for sediment routed down-dip. This study presents an autogenic mechanism for generating complex onlap trends without the need to invoke allogenic processes. This has implications for sequence-stratigraphic interpretations, basin subsidence history, and forward modeling of confined deep-water basins.

Causes of varied sediment gravity flow types on the Alsek Prodelta, northeast Gulf of Alaska

1988 ◽  
Vol 7 (4) ◽  
pp. 317-342 ◽  
Author(s):  
William C. Schwab ◽  
Homa J. Lee ◽  
Bruce F. Molnia
Keyword(s):  
Gulf Of Alaska ◽  
Gravity Flow ◽  
Sediment Gravity Flow

Slumping and a sandbar deposit at the Cretaceous-Tertiary boundary in the El Tecolote section (northeastern Mexico): An impact-induced sediment gravity flow

Geology ◽  
2001 ◽  
Vol 29 (3) ◽  
pp. 231 ◽  
Author(s):  
Ana R. Soria ◽  
Carlos L. Liesa ◽  
Maria Pilar Mata ◽  
José A. Arz ◽  
Laia Alegret ◽  
...  
Keyword(s):  
Gravity Flow ◽  
Sediment Gravity Flow ◽  
Northeastern Mexico

scholarly journals Giant meandering channel systems controlled by sediment supply to the deep-water Campos basin

2019 ◽  
Author(s):  
Jacob Covault ◽  
Zoltan Sylvester ◽  
Daniel Carruthers ◽  
Dallas Dunlap
Keyword(s):  
Deep Water ◽  
Sediment Supply ◽  
Meandering Channel ◽  
Campos Basin ◽  
Channel Systems

The Influence of Main Factors on Deepwater Sediments

2021 ◽  
Author(s):  
Anton Khitrenko ◽  
Adelia Minkhatova ◽  
Vladimir Orlov ◽  
Dmitriy Kotunov ◽  
Salavat Khalilov
Keyword(s):  
Sequence Stratigraphy ◽  
Deep Water ◽  
Western Siberia ◽  
Reservoir Characterization ◽  
Water Reservoir ◽  
Shelf Break ◽  
Sediment Supply ◽  
Reservoir Quality ◽  
Geological Uncertainty ◽  
Forced Regression

Abstract Western Siberia is a unique petroleum basin with exclusive geological objects. Those objects allow us to test various methods of sequence stratigraphy, systematization and evaluation approaches for reservoir characterization of deep-water sediments. Different methods have potential to decrease geological uncertainty and predict distribution and architecture of deep-water sandstone reservoir. There are many different parameters that could be achieved through analysis of clinoform complex. Trajectories of shelf break, volume of sediment supply and topography of basin influence on architecture of deep-water reservoir. Based on general principles of sequence stratigraphy, three main trajectories changes shelf break might be identified: transgression, normal regression and forced regression. And each of them has its own distinctive characteristics of deepwater reservoir. However, to properly assess the architecture of deepwater reservoir and potential of it, numerical characteristics are necessary. In our paper, previously described parameters were analyzed for identification perspective areas of Achimov formation in Western Siberia and estimation of geological uncertainty for unexplored areas. In 1996 Helland-Hansen W., Martinsen O.J. [5] described different types of shoreline trajectory. In 2002 Steel R.J., Olsen T. [11] adopted types of shoreline trajectory for identification of truncation termination. O. Catuneanu (2009) [1] summarize all information with implementation basis of sequence stratigraphy. Over the past decade, many geoscientists have used previously published researches to determine relationship between geometric structures of clinoforms and architecture of deep-water sediments and its reservoir quality. Significant amount of publications has allowed to form theoretical framework for the undersanding sedimentation process and geometrical configuration of clinoforms. However, there is still no relationship between sequence stratigraphy framework of clinoroms and reservoir quality and its uncertainty, which is necessary for new area evaluation.

scholarly journals Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic

2015 ◽  
Vol 11 (4) ◽  
pp. 669-685 ◽  
Author(s):  
C. Consolaro ◽  
T. L. Rasmussen ◽  
G. Panieri ◽  
J. Mienert ◽  
S. Bünz ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbon Isotope ◽  
Deep Water ◽  
Planktonic Foraminifera ◽  
Sediment Supply ◽  
The Arctic ◽  
Fram Strait ◽  
The North ◽  
Carbon Isotope Excursion

Abstract. We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dates reveal a detailed chronology for the last 14 ka BP. The δ 13C record measured on the benthonic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values termed carbon isotope excursion (CIE I and CIE II, respectively). The values were as low as −4.37‰ in CIE I, correlating with the Bølling–Allerød interstadials, and as low as −3.41‰ in CIE II, correlating with the early Holocene. In the Bølling–Allerød interstadials, the planktonic foraminifera also show negative values, probably indicating secondary methane-derived authigenic precipitation affecting the foraminiferal shells. After a cleaning procedure designed to remove authigenic carbonate coatings on benthonic foraminiferal tests from this event, the 13C values are still negative (as low as −2.75‰). The CIE I and CIE II occurred during periods of ocean warming, sea-level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic, suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

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