Sigmoidal Clinoforms Research Articles

From the Great Bahama Bank into the Straits of Florida: A margin architecture controlled by sea-level fluctuations and ocean currents

Research Article| June 01, 2000 From the Great Bahama Bank into the Straits of Florida: A margin architecture controlled by sea-level fluctuations and ocean currents Flavio S. Anselmetti; Flavio S. Anselmetti 1Comparative Sedimentology Laboratory, Rosenstiel School of Marine and Atmospheric Science, Division of Marine Geology and Geophysics, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, USA Search for other works by this author on: GSW Google Scholar Gregor P. Eberli; Gregor P. Eberli 1Comparative Sedimentology Laboratory, Rosenstiel School of Marine and Atmospheric Science, Division of Marine Geology and Geophysics, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, USA Search for other works by this author on: GSW Google Scholar Zan-Dong Ding Zan-Dong Ding 1Comparative Sedimentology Laboratory, Rosenstiel School of Marine and Atmospheric Science, Division of Marine Geology and Geophysics, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2000) 112 (6): 829–844. https://doi.org/10.1130/0016-7606(2000)112<829:FTGBBI>2.0.CO;2 Article history received: 05 Oct 1998 rev-recd: 06 Aug 1999 accepted: 30 Aug 1999 first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Flavio S. Anselmetti, Gregor P. Eberli, Zan-Dong Ding; From the Great Bahama Bank into the Straits of Florida: A margin architecture controlled by sea-level fluctuations and ocean currents. GSA Bulletin 2000;; 112 (6): 829–844. doi: https://doi.org/10.1130/0016-7606(2000)112<829:FTGBBI>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract High-resolution, multichannel seismic data collected across the Great Bahama Bank margin and the adjacent Straits of Florida indicate that the deposition of Neogene–Quaternary strata in this transect are controlled by two sedimentation mechanisms: (1) west-dipping layers of the platform margin, which are a product of sea-level–controlled, platform-derived downslope sedimentation; and (2) east- or north-dipping drift deposits in the basinal areas, which are deposited by ocean currents. These two sediment systems are active simultaneously and interfinger at the toe-of-slope. The prograding system consists of sigmoidal clinoforms that advanced the margin some 25 km into the Straits of Florida. The foresets of the clinoforms are approximately 600 m high with variable slope angles that steepen significantly in the Pleistocene section. The seismic facies of the prograding clinoforms on the slope is characterized by dominant, partly chaotic, cut-and-fill geometries caused by submarine canyons that are oriented downslope. In the basin axis, seismic geometries and facies document deposition from and by currents. Most impressive is an 800-m-thick drift deposit at the confluence of the Santaren Channel and the Straits of Florida. This “Santaren Drift” is slightly asymmetric, thinning to the north. The drift displays a highly coherent seismic facies characterized by a continuous succession of reflections, indicating very regular sedimentation.Leg 166 of the Ocean Drilling Program (ODP) drilled a transect of five deep holes between 2 and 30 km from the modern platform margin and retrieved the sediments from both the slope and basin systems. The Neogene slope sediments consist of peri-platform oozes intercalated with turbidites, whereas the basinal drift deposits consist of more homogeneous, fine-grained carbonates that were deposited without major hiatuses by the Florida Current starting at approximately 12.4 Ma. Sea-level fluctuations, which controlled the carbonate production on Great Bahama Bank by repeated exposure of the platform top, controlled lithologic alternations and hiatuses in sedimentation across the transect. Both sedimentary systems are contained in 17 seismic sequences that were identified in the Neogene–Quaternary section. Seismic sequence boundaries were identified based on geometric unconformities beneath the Great Bahama Bank. All the sequence boundaries could be traced across the entire transect into the Straits of Florida. Biostratigraphic age determinations of seismic reflections indicate that the seismic reflections of sequence boundaries have chronostratigraphic significance across both depositional environments. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Sequence Stratigraphic Modeling of the Lower Thamama Group, East Onshore Abu Dhabi, United Arab Emirates

ABSTRACT The Lower Cretaceous (Berriasian to Valanginian) Habshan Formation (Lower Thamama Group) of Abu Dhabi was deposited on a broad carbonate shelf. In east onshore Abu Dhabi, the Habshan Formation consists mainly of limestone and dolomite reaching a thickness of more than 1,100 feet. The depositional environment ranged from shallow-water peritidal to deeper shelf basin. The integration of seismic-stratigraphic, biostratigraphic, lithostratigraphic and electric log data reveals three sequences (I to III) and three shelf edges within the Habshan Formation in east onshore Abu Dhabi. These high energy shelfal sediments prograde toward the basin to the east and northeast with their shelf edges trending north-northwest to south-southeast. The seismic data indicates that the basin was filled in the east during the Hauterivian, after the deposition of Sequence IV (equivalent to the Zakum formation). Good reservoir development is found in the carbonates deposited in the high energy environment along the shelf edge of the Habshan sequence, particularly within the oblique and sigmoidal clinoforms, whereas potential source rocks are expected to be developed basinward. This combination renders the Habshan and Zakum sequences an attractive exploration target, both as structural and stratigraphic traps. Recent exploration activity in the area established the presence of hydrocarbons within the Habshan Sequence III in east onshore Abu Dhabi.

Computer modelling of the influence of tectonics on sequence architecture of coarse-grained fan deltas

Fan delta deposition and extensional faulting are combined in a computer model using a general tectonosedimentary forward modelling equation. Fan delta forms and architectures resulting from tectonic activity are investigated using this model. Fan deltas formed during periods of tectonic quiescence are shown to have a sheet-like form and grow mainly as a result of progradation. Topset development is limited, resulting in the development of oblique to sigmoidal clinoforms. Fan deltas formed during periods of tectonic activity have a more wedge-shaped form and are restricted to a region adjacent to the controlling fault. These fan deltas grow as a result of both progradation and aggradation, resulting in the development of sigmoidal clinoforms. Under conditions of constant tectonic subsidence and sediment supply, fan deltas are shown to undergo a brief period of progradation followed by aggradation and a long period of retrogradation. This is a consequence of an increasing amount of sediment being deposited as topset material as the delta progrades and the position of the offlap break being displaced basinward during hangingwall subsidence. Other controls on fan delta architecture, such as variations in sediment supply and sea/lake level, are also considered. Pleistocene-Recent, Gilbert-type fan deltas from the southern margin of the Gulf of Corinth rift, Greece contain many of the features described above and modelling is used to investigate whether it is possible to identify the controls on their sequence architectures.

A Sequence Stratigraphic Interpretation of the Eastern Gippsland Basin

The Latrobe stratigraphic section subcropping the 'Top Coarse Clastics Unconformity' in the eastern Gippsland Basin consists of three depositional sequences of Maastrichtian to Palaeocene age. A Lower Palaeocene sequence illustrates the sedimentological and seismic relationships typical of these sequences. It has been further subdivided into three seismically mappable depositional units. Unit C is a 40 m basal sandstone section characterised seismically by high frequency sigmoidal clinoforms. It is interpreted to represent lowstand fan deposition prior to a marine transgression. Unit B consists of a 50 m argillaceous siltstone overlain by a 70 m coarsening upward sandstone section, characterised seismically by high frequency and high amplitude sigmoidal reflections. It is the product of marine transgression and subsequent highstand progradation. Unit A consists of a thin argillaceous siltstone overlain by a coarsening upwards sandstone deposited during a minor transgression and continued progradation. Unit A also consists of interbedded sands, shales and coals producing parallel, often high amplitude reflections. Deposition of this facies occurred in a coastal plain environment behind the prograding shoreline. The mapping of these seismic facies allow prediction of stratigraphy and reservoir and seal quality in an area of little well control, the deep water part of the Gippsland Basin. Stratigraphic pinchout plays of Unit B shoreface sandstones prograding into offshore siltstones and claystones and Unit C lowstand fan sandstones into Unit B offshore siltstones and claystones are also identified.

Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Current/Gulf Stream circulation

Research Article| June 01, 1987 Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Current/Gulf Stream circulation HENRY T. MULLINS; HENRY T. MULLINS 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244 Search for other works by this author on: GSW Google Scholar ANNE F. GARDULSKI; ANNE F. GARDULSKI 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244 Search for other works by this author on: GSW Google Scholar SHERWOOD W. WISE, Jr.; SHERWOOD W. WISE, Jr. 2Department of Geology, Florida State University, Tallahassee, Florida 32306 Search for other works by this author on: GSW Google Scholar JOE APPLEGATE JOE APPLEGATE 2Department of Geology, Florida State University, Tallahassee, Florida 32306 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1987) 98 (6): 702–713. https://doi.org/10.1130/0016-7606(1987)98<702:MMOEIT>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation HENRY T. MULLINS, ANNE F. GARDULSKI, SHERWOOD W. WISE, JOE APPLEGATE; Middle Miocene oceanographic event in the eastern Gulf of Mexico: Implications for seismic stratigraphic succession and Loop Current/Gulf Stream circulation. GSA Bulletin 1987;; 98 (6): 702–713. doi: https://doi.org/10.1130/0016-7606(1987)98<702:MMOEIT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Analysis of ∼1,500 km of high-resolution, single-channel air-gun seismic-reflection profiles, correlated with two drill cores, demonstrates that the central west Florida carbonate-ramp slope experienced an oceanographic event in the middle Miocene that resulted in a major stratigraphic break or succession of depositional sequences. During the long-term eustatic sea-level rise in the early to middle Miocene, carbonate shelf-margin deposition was characterized by seaward-prograding, sigmoidal clinoforms that built both laterally and vertically. Shelf-margin sediments were relatively fine grained and rich in dolomite, total organics, and clay minerals.Approximately 12–15 m.y. ago, tectonically controlled oceanographic closure of the Isthmus of Panama, and/or increased climatic gradients, resulted in an intensification of oceanic circulation. Increased flow velocity of the Loop Current truncated antecedant clinoforms along the mid-Miocene shelf margin as the Loop Current, for the first time, became a dynamic oceanographic barrier to off-shelf sediment transport. Carbonate deposition along the west Florida slope changed dramatically from a series of prograding clinoforms to a pelagic slope-front-fill system bounded on its landward margin by contour-current flow of an invigorated Loop Current. Shelf-margin sediments, presently represented as a condensed sequence, became more carbonate rich, coarser grained, lower in organic content, and depleted in dolomite.Our results suggest that oceanographic events can generate major seismic stratigraphic breaks that result in the succession of depositional sequences and systems along continental margins and that they may be as important as eustatic oscillations. Our data also suggest that “modern” Loop Current/Gulf Stream circulation was initiated in the middle Miocene, controlled by tectono-oceanographic and/or climatic processes. The challenge now is to identify seismic stratigraphic-scale oceanographic events in the rock record, differentiate them from eustatic responses, and evaluate their paleoenvironmental significance. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Stratigraphic Reconstruction Using Digitized Well Logs: Lewis Shale, South-Central Wyoming: ABSTRACT

Advances in manipulating and displaying log data and improved methods of well-log digitizing have greatly enhanced explorationists' ability to incorporate large volumes of well data into basin-wide stratigraphic reconstructions. Computer manipulation of digital traces expedites construction of cross sections, generation of log-derived lithologic columns, normalization of log response, and updating of regional studies. The ease and speed with which cross sections can be changed and printed allow use of numerous datums to test correlations and permits construction of paleoslope configurations. Additionally, the ability to reduce a large cross section to a single field of view, without loss of definition, produces enhanced basin-side perspective and reveals stratigraphic rel tionships not apparent at larger scales. The approach proved critical in depositional reconstruction of the Maestrichtian-aged Lewis Shale in the Washakie and Red Desert basins, Wyoming. Deep-water sandstones within the Lewis are hydrocarbon reservoirs at Wamsutter and Hay Reservoir fields. Core data, cross section thickness patterns, and lithology computed from logs show the Lewis to consist of a thin transgressive shale overlain by progradational sequences. Progradation occurred as deltas entered the basin initially from the northeast and later from the south. Correlation of log response indicative of volcanically derived clay-rich layers results in stratigraphic patterns on log cross sections similar to patterns on seismic sections. The transgressive shale onlaps the Almond Sandstone; progradational sequences are depicted as irregular, sigmoidal clinoforms. Patterns indicate high sediment input and very rapid basin subsidence. End_of_Article - Last_Page 843------------

Synthetic Passive Margin Stratigraphy

Synthetic stratigraphic cross sections are derived mathematically for a variety of simple conditions. The variables considered in the mathematical model include variations in sea level, rate of tectonic subsidence, rate of sedimentation, and rate of erosion. Derived stratigraphic relationships include unconformities, correlative conformities and disconformities, coastal onlap, coastal toplap, erosional truncation, pinch-out, and sigmoidal progradational clinoforms. An important conclusion is that the rate of erosion is a dominant variable in determining the type of stratigraphic section observed. The proposed approach may provide the basis for either a forward or inverse modeling of seismic stratigraphic sections.