Strata: Movies

Movie 1: Simulation of the Balitmore Canyon, Offshore New Jersey

Glenn Spinelli and Roberta Hotinski, students in Advanced Stratigraphy, produced this movie as the result of an attempt to model the architecture of the New Jersey margin using realistic input parameters inferred from seismic sections and well log data.

“Clastic input was determined by dividing the area of sediment deposited during the Miocene (since Strata is a 2-D model) by the duration of this period. A rough subsidence rate was then calculated by dividing the height of the platform by the duration of the Miocene and correcting for isostatic effects. In order to achieve lateral progradation of the platform, 200 m of accommodation space was supplied at the beginning of the simulation and the resulting “hole” was allowed to subside at a rate of 0.0675 mm/yr with isostatic effects and compaction to provide the rest of the necessary accommodation space. Finally, a sealevel curve for the platform was derived from times of first onlap and thicknesses of successive sequences. The simulated platform shown in the movie has the approximate dimensions and foreset angles of the actual platform. Highstand system tracts, though, are not as well preserved as in the real platform. This is due in part to the fact that Strata cannot simulate the local incision of channels on the platform when sealevel falls. Instead the entire shelf is eroded as baselevel is lowered, removing a significant portion of the previous highstand systems tract which would be preserved in an actual platform.”
– Roberta Hotinski

Movie 2: Simulation of mixed carbonate and siliciclastic deposition (Central, PA)

The second movie was created by Roberta Hotinski and Andrew Hoover as part of a project for a Carbonate Sedimentology class.

“This movie shows our best effort to simulate mixed carbonate-siliciclastic deposition as expressed in Middle to Late Ordovician deposits of central Pennsylvania. This period is characterized by a transition from peritidal carbonates to siliciclastic domination, with intermediate interlayered clays and carbonates. The sequence is believed to have been caused by the influence of the Taconic orogeny on the Great American Carbonate Bank; tectonic and clastic loading first deepened the basin in which the carbonates were forming, then clastic material shed from the orogen swamped the platform. We expected to reproduce a gently sloping carbonate platform which first gradually deepened, then showed mixed carbonate-clay deposition, and finally was overwhelmed by siliciclastic depositon. Reasonable values were chosen for carbonate deposition rate and subsidence and the basin was allowed to subside using the passive margin profile. The foreland basin-type profile was created by supplying a sufficient clastic load to depress the lithosphere in the east. Once this basic model had been established, carbonate deposition rates, diffusion rates, and subsidence were adjusted in attempt to simulate Middle to Late Ordovician deposition. Carbonate productivity and subsidence rate had to be balanced so that neither flooding nor exclusively supratidal carbonate deposition occurred, so the flexibility of these parameters was limited. What proved to be surprisingly important was the diffusion rate, which controls the erosion of deposited sediment. One rate controls both carbonate and clastic sediments, which made it difficult to preserve the carbonate platform while transporting clastic material far enough across the basin to interfinger with carbonate deposits. The movie shows our best attempt to flux material from east to west while preserving the western carbonate platform. Carbonate/clastic interaction does occur in this simulated foreland basin, but it is relegated to the toe of the carbonate platform where diffused carbonate sediments are deposited with deep-water siliciclastic sediments. Because carbonate and clastic compositions are not distinguished by Strata2.1, this interaction is not visible in the model output.”
-Roberta Hotinski

Movie 3: Low flux continental margin.

Movie 4: Low flux thermal history.

This illustrates the thermal evolution through time of the sedimentary basin. The temperature is approximately linearly proportional to depth. As the basin subsides the temperature of the sediments increase. So-called ‘thermal blanketing’ is a key control on the generation of petroleum by the ‘cooking’ of organic material.

Movie 5: High Flux continental margin.

This contrasts the first example by showing the evolution of a continental margin when there is a larger sediment supply. The shelf-slope transition is shifted oceanward.

Movie 6: High flux thermal history.

With more sediment, the basin is deeper and the sediments are hotter than in the previous example.

Please see The Strata User Manual to get more information and to download the program.

Last Modified: 07:00 pm EST, March 26, 1996 – Steven E. Nelson