scholarly journals Geometrical Breakdown Approach to interpretation of depositional sequences

Geosphere ◽  
2021 ◽  
Author(s):  
Masoud Aali ◽  
Bill Richards ◽  
Mladen R. Nedimović ◽  
Vittorio Maselli ◽  
Martin R. Gibling
Keyword(s):  
Maximum Level ◽  
Sediment Supply ◽  
Synthetic Analogue ◽  
Analogue Model ◽  
Sequence Stratigraphic ◽  
Model Driven ◽  
Marine Deposits ◽  
Straightforward Method ◽  
Inflection Points ◽  
Depositional Units

Seismic and sequence stratigraphic analyses are important methodologies for interpreting coastal and shallow-marine deposits. Though both methods are based on objective criteria, terminology for reflection/stratal stacking is widely linked to eustatic cycles, which does not adequately incorporate factors such as differential subsidence, sediment supply, and autogenic effects. To reduce reliance on model-driven interpretations, we developed a Geometrical Breakdown Approach (GBA) that facilitates interpretation of horizon-bound reflection packages by systematically identifying upward-downward and landward-seaward trajectories of clinoform inflection points and stratal ter­minations, respectively. This approach enables a rigorous characterization of stratal surfaces and depositional units. The results are captured in three-letter acronyms that provide an efficient way of recognizing repetitive stacking pat­terns through discriminating reflection packages objectively to the maximum level of resolution provided by the data. Comparison of GBA with selected sequence stratigraphic models that include three and four systems tracts and the accommodation succession approach shows that the GBA allows a greater level of detail to be extracted, identifying key surfaces with more precision and utilizing more effectively the fine-scale resolution provided by the input seismic data. We tested this approach using a synthetic analogue model and field data from the New Jersey margin. The results demonstrate that the geometric criteria constitute a reliable tool for identifying systems tracts and provide an objective and straightforward method for practitioners at all levels of experience.

Sequence stratigraphy of the late Carboniferous Clifton Formation, New Brunswick

2020 ◽  
Vol 57 (11) ◽  
pp. 1289-1304
Author(s):  
Brandon M. Keough ◽  
Olivia A. King ◽  
Matthew R. Stimson ◽  
Page C. Quinton ◽  
Michael C. Rygel
Keyword(s):  
New Brunswick ◽  
Sediment Supply ◽  
Sequence Stratigraphic ◽  
Marine Strata ◽  
Stratigraphic Framework ◽  
Carbonaceous Shales ◽  
Study Interval ◽  
Maritimes Basin ◽  
Sequence Boundaries ◽  
Maximum Flooding Surface

The Maritimes Basin of Atlantic Canada contains a rich record of Pennsylvanian cyclothems. Previous studies have focused on rapidly subsiding depocenters in the central part of the basin where Carboniferous successions feature cyclic alternations between terrestrial and marginal marine strata. In contrast, the Pennsylvanian Clifton Formation was deposited on the relatively stable New Brunswick platform and contains almost entirely terrestrial strata. Although early studies of the Clifton Formation noted a cyclic architecture, particularly within Member B, this unit has remained understudied. We provide a sedimentological and sequence stratigraphic framework for the lower 85 m of Member B and interpret our results relative to a broader regional framework. Near the base of the study interval, the highstand systems tract is composed of red floodplain mudrocks; overlying sequence boundaries are composed of calcretes and (or) channels. The transgressive systems tract and maximum flooding surface are represented by coals and aquatic bivalve-bearing mudrocks. Moving upward through the section, the architecture of the highstand systems tract remains largely unchanged while sequence-bounding paleosols become less well developed, the transgressive systems tract becomes thinner and eventually not preserved, and the maximum flooding surface is only occasionally preserved, possibly represented by carbonaceous shales. These changes in cyclic architecture may be attributed to changes in the magnitude of glacioeustatic fluctuations, climate, and (or) the accommodation/sediment supply ratio. The results of this study show that the Clifton Formation represents the terrestrial/proximal endmember for cyclicity in the Maritimes Basin and provide new insight into paleotopography as a possible control on cyclothem architecture.

scholarly journals Multiscale Erosion Surfaces of the Organic-Rich Barnett Shale, Fort Worth Basin, USA

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Mohamed O. Abouelresh
Keyword(s):  
Sediment Supply ◽  
Energy Conditions ◽  
Barnett Shale ◽  
Sequence Stratigraphic ◽  
Fort Worth Basin ◽  
Fine Grained ◽  
Base Level ◽  
Genetic Types ◽  
Sea Level Fluctuation ◽  
Associated Surfaces

The high frequency and diversity of erosion surfaces throughout the Barnett Shale give a unique view into the short-duration stratigraphic intervals that were previously much more difficult to detect in such fine-grained rocks. The erosion surfaces in Barnett Shale exhibit variable relief (5.08–61 mm) which commonly consists of shelly laminae, shale rip-up clasts, reworked mud intraclasts, phosphatic pellets, and/or diagenetic minerals (dolomite and pyrite) mostly with clay-rich mudstone groundmass. Several factors control this lithological variation, including the energy conditions, rate of relative sea-level fluctuation, rate of sedimentation, sediment influx, and the lithofacies type of the underlying as well as the overlying beds. The erosional features and their associated surfaces make them serve at least in part as boundaries between different genetic types of deposits but with different scales according to their dependence on base level and/or sediment supply. Accordingly, the studied erosion surfaces of the Barnett Shale can be grouped into three different scales of sequence stratigraphic surfaces: sequence-scale surfaces, parasequence-scale surfaces, and within trend-scale surfaces.

scholarly journals Reply to ‘Comment on The geometry and stratigraphic position of the Maassluis Formation (western Netherlands and south-eastern North Sea)’

2005 ◽  
Vol 84 (1) ◽  
pp. 53-53
Author(s):  
H.S.M. Jansen
Keyword(s):  
North Sea ◽  
Driving Forces ◽  
Sediment Supply ◽  
Coastal Sediments ◽  
The West ◽  
Sequence Stratigraphic ◽  
Normal Transition ◽  
Stratigraphic Model ◽  
Stratigraphic Position ◽  
Age Estimates

In their comment, Wesselingh et al. say that pronounced glacioeustacy renders the detailed discussions about age intervals obsolete and that they fail to see the application of the Haq curves for age estimates in the Maassluis Formation can make much sense. We would argue the following: - Eustacy and sediment supply are the driving forces behind sequence formation and configuration. As our model shows, the overall picture of the Pliocene/Pleistocene along our transect is one of an outbuilding system, going from open marine to terrestrial deposits, which is a classic sequence stratigraphic configuration.- The lower part of the Maassluis Formation in the Noordwijk borehole lies below an unconformity and consists of open marine sediments as opposed to the coastal sediments of the upper part. Since it is the normal transition over a sequence boundary, there is reason to speculate about which sequences we are looking at here and what their age is. There is a large sedimentary wedge to the west of Noordwijk that is missing in the Noordwijk borehole.- The glacial-interglacial cycles Meijer et al. (in press) refer to are likely to be better expressed in the coastal part of the formation, i.e. from ca. 2.55 Ma. This is also the part of the formation where micro-vertebrates will be found, not the (older) marine part. These cycles do not alter the overall sequence stratigraphic model, they add a climatic overprint of smaller sedimentary cycles.

HIGH RESOLUTION SEQUENCE STRATIGRAPHY, RESERVOIR ANALOGUES, AND 3D SEISMIC INTERPRETATION—APPLICATION TO EXPLORATION AND RESERVOIR DEVELOPMENT IN THE BARYULAH COMPLEX, COOPER BASIN, SOUTHWEST QUEENSLAND

2002 ◽  
Vol 42 (1) ◽  
pp. 511 ◽  
Author(s):  
S.C. Lang ◽  
N. Ceglar ◽  
S. Forder ◽  
G. Spencer ◽  
J. Kassan
Keyword(s):  
High Resolution ◽  
Structural Features ◽  
Sediment Supply ◽  
3D Seismic ◽  
Predictive Tool ◽  
Seismic Attribute ◽  
Sequence Stratigraphic ◽  
Geological Interpretation ◽  
Reservoir Development ◽  
Cooper Basin

Gas exploration and reservoir development in the Baryulah area, Cooper Basin, southwest Queensland has focussed on the fluvial-lacustrine, Permian coal-bearing Patchawarra Formation, Murteree Shale, Epsilon and Toolachee Formations. Geological interpretation of drilling and 3D seismic data has benefitted from integration of sequence stratigraphic concepts with the judicious use of reservoir analogues and seismic attribute mapping. Initially, a coherent regional chronostratigraphic framework was established, based on broad palynological zonations, and correlating extensive lacustrine flooding surfaces and unconformities, tied to 3D seismic reflectors. This framework was subdivided by using local key surfaces identified on wireline logs (usually high-gamma shaly intervals overlying coals), resulting in recognition of numerous high-resolution genetic units. Wireline log character, calibrated by cores from analogous fields around the Cooper Basin and supported by analogue studies, forms the basis for a logfacies scheme that recognises meandering fluvial channels, crevasse splays, floodplain/basin, and peat swamps/mires. Fluvial stacking patterns (aggradational, retrogradational or progradational), produced by the ratio of sediment supply to accommodation within each genetic unit, were used to help determine depositional systems tracts (alluvial lowstand, transgressive, or highstand) and likely reservoir connectivity. Log signature maps for genetic intervals form the basis of palaeogeographic mapping. Modern and ancient depositional analogues were used to constrain likely facies distribution and fluvial channel belt widths. Syndepositional structural features, net-to-gross trends, and seismic attribute mapping are used to guide the scale, distribution and orientation of potential reservoir trends. When used in conjunction with structural and production data, the palaeogeographic maps help develop stratigraphic trap play concepts, providing a predictive tool for locating exploration or appraisal drilling opportunities.

scholarly journals Evolution of the passive margin of the peripheral foreland basin: an example from the Lower Miocene Carpathian Foredeep (Czech Republic)

2016 ◽  
Vol 67 (1) ◽  
pp. 41-68 ◽  
Author(s):  
Michal Francírek ◽  
Slavomír Nehyba
Keyword(s):  
Depositional Environment ◽  
Foreland Basin ◽  
Passive Margin ◽  
Basin Evolution ◽  
Marine Deposits ◽  
Thrust Front ◽  
Outer Western Carpathians ◽  
Carpathian Foredeep ◽  
Depositional Units ◽  
Flysch Rocks

Abstract The Karpatian deposits of the central part of the Carpathian Foredeep in Moravia, which are deeply buried under the Outer Western Carpathians, provide a unique opportunity to reconstruct the former evolutionary stages of this peripheral foreland basin and its paleogeography. A succession of three depositional units characterized by a distinct depositional environment, provenance, and partly also foreland basin depozone, have been identified. The first depositional unit represents a proximal forebulge depozone and consists of lagoon-estuary and barred coastline deposits. The source from the “local” crystalline basement played here an important role. The second depositional unit consists of coastline to shallow marine deposits and is interpreted as a forebulge depozone. Tidalites recognized within this unit represent the only described tide-generated deposits of the Neogene infill of the Carpathian Foredeep basin in Moravia. The source from the basin passive margin (the Bohemian Massif) has been proved. The third depositional unit is formed by offshore deposits and represents a foredeep depozone. The provenance from both passive and active basin margin (Silesian Unit of the Western Carpathian Flysch Zone) has been proved. Thus, both a stepwise migration of the foredeep basin axis and shift of basin depozones outwards/cratonwards were documented, together with forebulge retreat. The shift of the foreland basin depozones more than 50 km cratonward can be assumed. The renewed thrusting along the basin’s active margin finally completely changed the basin shape and paleogeography. The upper part of the infill was deformed outside the prograding thrust front of flysch nappes and the flysch rocks together with a strip of Miocene sediments were superposed onto the inner part of the basin. The width and bathymetric gradient of the entire basin was changed/reduced and the deposition continued toward the platform. The basin evolution and changes in its geometry are interpreted as a consequence of the phases of the thrust-sheet stacking and sediment loading in combination with sea-level change.

scholarly journals Are seismic/depositional sequences chronostratigraphic units?

1992 ◽  
Vol 6 ◽  
pp. 264-264
Author(s):  
R. W. Scott
Keyword(s):  
Gulf Coast ◽  
Regional Scale ◽  
Sediment Supply ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
Time Correlations ◽  
Research Problems ◽  
Global Events ◽  
Depositional Systems ◽  
Depositional Models

Sequence Stratigraphic Analysis is claimed to be a “new globally valid system of stratigraphy … a precise methodology to subdivide, correlate and map sedimentary rocks” (Vail et al., 1991, p. 622). Sequence stratigraphic units, such as depositional sequences, depositional systems tracts, and parasequences, are time-equivalent rocks of specific durations controlled by cyclical changes in sediment supply related to eustasy. These units are bounded by regionally extensive unconformities with erosion beneath and onlapping strata above, or by physical surfaces separating either different patterns of stratal geometry or shoaling-up facies units. According to this school, precise correlations are based upon inferred time relations within depositional models.Several key concepts of sequence stratigraphy have their origins in early geological studies. For many years geologists have separated time-equivalent strata by regional unconformities related to changes in climate or sea level, e.g., J. Woodward, 1695 and T. C. Chamberline, 1909. Stratal surfaces, such as bentonites and limestone markers, have been used in place of fossils for time correlations since the first wells were drilled. Stratigraphic models have strongly influenced how we correlate strata since the time of William Smith.Two developments are, indeed, new and have sparked the current resurgence in stratigraphic research. One is the seismic technology to test the physical continuity of strata on a regional scale (50-100 km), and to test the stratal geometry of genetically related depositional packages. The second is the chart of global coastal onlap events and eustasy (Haq et al., 1988).Some key research problems are: (1) how to identify unique, time-significant stratal surfaces; (2) how to test their physical continuity; (3) how to test the time relations within depositional models; and (4) how to identify the unique, time-significant global events recorded in the stratigraphic record. These stratigraphic concepts can be tested by graphic correlation, which is a powerful technique of high precision, quantitative stratigraphy. Its application in Cretaceous sections of the Gulf Coast and Oman, and in the Plio-Pliestocene of the Gulf Coast aids the distinction between synchronous surfaces and diachronous boundaries.

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