... and lower-frequency third-order accommodation cycles. We used a two-dimensional forward computer simulation to compare allocyclic and autocyclic models for high-frequency cycles. The allocyclic simulation superimposes a deterministic, Milankovitch glacio-eustatic driver on a lower-frequency, third-order...

...-frequency cycles, be it an autocyclic or allocyclic mechanism. This approach has major implications for the use of high-frequency, fourth- and fifth-order cycle characteristics to identify third-order cycles in outcrops and cores of shallow-water carbonates, where stratigraphic control may be less than...

...Zoë A. Cumberpatch; Emma Finch; Ian A. Kane Abstract Subsurface salt movement in the absence of external tectonic forces can affect contemporaneous sediment deposition, mask allocyclic signals, and deform older strata. We used a discrete element model (DEM) to better understand salt-related...

... cyclicity, with elements strongly suggestive of an allocyclic origin, including (a) subaerial exposure features directly above subtidal facies within meter-scale cyclothems, (b) purely subtidal carbonate cyclothems, (c) symmetric peritidal carbonate cyclothems, and (d) continuity of cyclothems of different...

... of the processes related to infilling of interdistributary bays. Six vertically stacked heterolithic to sand-prone bayfill units are identified. A distinction is made between bayfill units and bayfill successions, based on their bounding autocyclic or allocyclic flooding surfaces. Units are bounded by high...

...-level oscillation, suggesting that partly autocyclic strata may not be inherently any less ordered than entirely allocyclic strata. Addition of stochastic processes such as mosaic carbonate production and fluctuations in regional sediment transport direction tend to decrease the level of measurable...

... sequences reflects a complex and dynamic interplay of both autocyclic and allocyclic factors. An appreciation of the relative importance of the factors which have controlled the cyclicity is important for the description and modeling of shale and sandstone geometries. The computer simulation models...

... in paleoenvironment across stratigraphic surfaces of regional significance. These changes are attributed to allocyclic processes. Based on these large-scale shifts, a threefold subdivision of the Neslen Formation into a lower, middle, and upper interval has been applied. The lower and upper Neslen intervals...

... variations in stratal geometries and changes in the apparent depositional system. With the development of sequence stratigraphic concepts and the advent of numerical simulation models, however, there has been increasing appeal to allocyclic processes, particularly those that affect accommodation space...

... of the significant peaks present across a range of frequencies, may allow identification of a “signal bump” that could be evidence of the presence and nature of allocyclic forcing. Further Lobyte3D modeling work will explore if and how the “signal bump” is preserved with input signals across a range of frequencies...

... channel-belt complexes. Controls on channel and channel-belt migration or avulsion are considered to be related to autocyclic processes. In contrast, large-scale vertical evolution and grain-size variations record allocyclic signals. In particular, gradual grain-size variations suggest a climatic control...

... for the interpretation of many fluvial deposits because it does not incorporate the effects of a variety of outside-the-basin (allocyclic) sedimentary controls. The most important of these controls is tectonics, because differential movement between basin and source area, and changes in the rate of movement, can cause...

... intrinsic controls, or allocycles, resulting from orbital forcing or tectonic movements, or both. Here, we review the criteria used in the identification of the two types of cyclicity and apply them to two newly described lower Pliensbachian outcrops in the Traras Mountains, northwestern Algeria. Throughout...

..., S2a, S2b, and S2c include features suggesting relative sea-level control (see below) and are therefore attributed to allocyclic mechanisms (note also that distinct upward-coarsening cycles coeval with sequences S2a–c are found in boreholes KB-7-OC and KB-5-OC, suggesting areally extensive variations...

...: Computer Simulations and Methods for Improved Parameter Definition: Kansas Geological Survey Bulletin , v. 233 , p. 293 – 318 . Bosellini A. 2002 , Dinosaurs “re-write” the geodynamics of the eastern Mediterranean and the paleogeography of the Apulia Platform...

...Andreas Rittersbacher; John A. Howell; Simon J. Buckley A bstract : There are numerous allocyclic and autocyclic factors which influence fluvial sandbody geometry. Unraveling the relative importance of such factors is challenging because fluvial systems can migrate and avulse across significant...

... ; Pratt et al. 1992 ) to explain their formation: the Milankovitch model and the tectonic model (which together are defined as allocyclic controls), and the autocyclic model. The Milankovitch model proposes that orbitally driven, eustatic changes repeatedly generate changes in accommodation space within...

... incorporated in this simulation is illustrated in Figure 5 . Variation of sea level in the simulation provides extrinsic controls to investigate the interplay between auto- and allocyclic processes that may cause depositional complexities not captured otherwise. In addition to sea level variations...

... helped to increase the predictability of the simulated inter-well porosity variations. Maha Al-Baghli (Kuwait Oil Company < [email protected] >) and John D. Pigott (University of Oklahoma, USA) Much previous exploration in the Minagish Field of Kuwait has concentrated upon prospectivity...

... description of reservoir heterogeneity to engineering-useable mod- els, incorporating all available information and interpretations. The first step consists of the simulation of the reservoir lithofacies, conditional to all avail- able information and data. This simulation is performed using a novel tech...