Scientific Webinars

Deep-water turbidite systems have been the focus of much research during several decades, particularly much work has been done on slope channels and associated levees and basin-floor depositional lobes, but with much less attention devoted to the channel to lobe transition zone (also known as CLTZ) that separates them. Based on detailed lithological and architectural analyses of an interval consisting of intercalated, sheet-like, sandstone-rich strata that transition upward to channelized sandstones bounded by mudstone-rich strata of the Neoproterozoic, passive-margin Windermere turbidite system in the southern Canadian Cordillera, this study provide new insights into the spatial and temporal development of an ancient channel-lobe system and its related CLTZ (s), which are here interpreted to be largely linked to major changes in sediment supply and related flow characteristics (such as flow efficiency, and bypassing versus depositional character).

In deltaic environments, distributary channel networks serve as the primary conduits for water and sediment. Once these networks are buried and translated into the subsurface, the coarse-grained channel fills serve as likely conduits for subsurface fluids such as water, oil, or gas. This talk will focus on a new method for building synthetic stratigraphy from surface imagery and will discuss how the temporal evolution of a delta topset can be used to constrain subsurface architecture.

Ariana Osman (The University of the West Indies) “The Changing Topset Regime and Clinoform Architecture on the Paleo-Orinoco Delta, Trinidad – A Story of Eustatic and Tectonic Interaction”

Sebastian Reimann (Friedrich Schiller University Jena) “Syndepositional Intrusion of the Lomati River Sill and Liked Hydrothermalism Preserves Records of One of the Earliest Benthic Ecosystems”

David Lankford-Bravo (The University of Texas at El Paso) “Investigating Permian-Aged Deposition and Deformation at the North Onion Creek Salt Shoulder”

Rock outcrops of the sedimentary-stratigraphic record often reveal bedding planes that can be considered to be true substrates: preserved surfaces that demonstrably existed at the sediment–water or sediment–air interface at the time of deposition. These surfaces have high value as repositories of palaeoenvironmental information, revealing fossilized snapshots of microscale topography from deep time. This talk will discuss ideas about how such true substrates are preserved, what they can inform us about ancient environments and stratigraphic time at outcrop, and why they seem to be so counterintuitvely abundant in the sedimentary record.

Meandering channels are ubiquitous on the surface of the Earth, both on land and on the seafloor. Although there is a large volume of published research on meandering, relatively simple questions – like the prediction of migration rates – are still considered highly complex problems with no simple solutions. A comparison of a simple curvature-based model of meandering with measurements from rivers and submarine channels suggests that, in systems unaffected by significant variation in erodibility, migration rates can be predicted relatively well, based on channel curvature alone. Plan-view meandering patterns in nature, both fluvial and submarine, show many of the characteristics of this model: a spatial phase lag between curvature and migration that has a characteristic length and results in autogenic downstream translation of many meander bends and in deposition of counter point bars. If along-channel changes in slope are added to the model, the implications of the 3D geometry for incising and aggrading channels become obvious as well. We use open-source code to visualize the 3D geometry and temporal evolution of the deposits of both subaerial and submarine meandering flows.

Seds Online Great Debate

Topic: Sea Level Drowns Reefs

Arguing for the motion: Cecilia Lopez-Gamundi, Elias Samankassou

Arguing against the motion: Edward Matheson, Peter Burgess

Continental carbonates also, controversially, often referred to as ‘non-marine carbonates’ are intriguing and deserve our full attention. These land-formed carbonates contribute to our understanding of the Earth System and its imprint in the so called ‘critical zone’. Climate, biota, CO2 fluxes, parent material, aeolian dust, hydrology and even humans, interplay to form an impressive puzzle in which necessarily calcretes and travertines must be good neighbours.

During the two decades, tsunamis have appeared to be the most disastrous natural process worldwide. The dramatic, large tsunamis on Boxing Day, 2004 in the Indian Ocean and on March 11, 2011 offshore Japan caused catastrophes listed as the worst in terms of the number of victims and the economic losses, respectively. In the aftermath, they have become a topic of high public and scientific interest. The record of past tsunamis, mainly in form of tsunami deposits, is often the only way to identify tsunami risk at a particular coast due to the relatively low frequency of their occurrence. The identification of paleotsunami deposits is often difficult mainly because the tsunami deposits are represented by various sediment types, may be similar to storm deposits, or altered by post-depositional processes. There is no simple universal diagnostic set of criteria that can be applied to interpret tsunami deposits with certainty. Thus, there is a need to develop new methods, which would enhance the ’classical’, mainly sedimentological and stratigraphic approach. During the talk I would like to present the need for geological studies of tsunami deposits, the examples of tsunami deposits (mainly from my own studies of 2004 tsunami in Thailand, 2011 tsunami in Japan, 2000 tsunami in Greenland) and their postdepositional changes, as well as I am going to outline recent progress and application of new approaches (e.g. paleogenetics).

Authors – Bart Verberne, Luuk Kleipool, Conxita Taberner, Arjan van der Linden, Fons Marcelis, Sander Hol and Axel Makurat
Understanding acoustic velocity variations in rocks is important for operation of hydrocarbon, geothermal, and CO2-storage reservoirs. Using a triaxial loading apparatus to simulate realistic subsurface stress conditions, we measured ultrasonic wave velocities of core plug samples composed of i) near-pure calcite limestone (bulk grain density ρg ≈2.70 gcm-3), characterized by widely varying pore types, and ii) dolostone-dominated samples which are compositionally varying (ρg = [2.66-2.80] gcm-3) but which are texturally relatively uniform. Comparison of wave velocity properties at selected key stress states revealed important differences between reservoir stress conditions versus near-isostatic conditions, and between limestone samples with different pore types.

Angelo Santos (McGill University) “Facies analysis of Limbunya Group in Northern Territory, Australia: A Proterozoic cyclic carbonate and siliciclastic succession”

Yu Pei (Goettingen University) “Sedimentary factories and ecosystem change across the Permian-Triassic Critical Interval”

Hermann Rivas (Heidelberg University) “Mixed-carbonate ramps in volcanic arc settings: an example from the Lower Cretaceous of southern South America (45°S)”

Buddy Price (University of Texas at Austin) “Compounding controls on mixed carbonate-siliciclastic slope and basinal sedimentation, Delaware Basin, USA”