Seds Online Webinars
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Upcoming Webinars & Events
4 PM LONDON Wednesday 3rd March 2021
Biotic, abiotic, pre-biotic, post-biotic controls on carbonate and phosphate formation
Emilia Jarochowska – Friedrich-Alexander-University
Organisms can produce minerals with highly controlled crystallographic texture, either as a necessity resulting from growth mechanism, or to achieve desired material properties. But they will not shy away from abiotic mechanisms of crystal formation when they can exploit them. What is more, the crystallographic texture of originally highly-controlled biominerals can be altered by diagenesis. As a result, instead of a clearly defined biologically controlled and abiotic minerals, there is a spectrum of textures occurring in nature. In deep-time marine minerals, the crystallographic properties and their preservation may be the key to identifying the biotic origin of a structure and even its biological affinity (microbial or metazoan). This talk will provide a short overview of Electron Backscatter Diffraction and its use in studying fossil carbonates and phosphates, including sample preparation and data analyses important in resolving the processes of their formation.
4 PM LONDON Wednesday 10th March 2021
Coralline algae made simple: tips for using red calcareous algae for paleoenvironmental reconstruction of Miocene carbonates
Giovanni Coletti – University of Milano Bicocca
Coralline algae are one of the most common carbonate producers in shelf environment, occurring from the poles to the equator and from the intertidal zone to the lowest limit of the photic zone. Notwithstanding their abundance (and several attempts throughout the years), they remain a relatively underused instrument for studying shallow water limestones. This is mainly caused by the complicated and ever shifting taxonomy and by the inherent difficulties in dealing with a macroscopic object which requires a microscope for proper identification. This talk aims at providing a couple of useful and time-effective strategies to use coralline algae for paleoenvironmental reconstructions focusing on the Miocene, an epoch where these carbonate producers are particularly widespread and common.
4 PM LONDON Wednesday 17th March 2021
Fluvial models: how much variability should we see? Lessons from the Huesca and Salt Wash fluvial systems
Amanda Owen – University of Glasgow
Geological models are important in aiding our interpretation of the rock record, particularly where outcrops, or subsurface data, is sparse. Conceptual models have been built and published for distributive fluvial systems (e.g. fluvial fans) where a predictive downstream and temporal changes in fluvial characteristics (e.g. channel body size) are present. However, few studies have assessed how much variability is observed across such systems and therefore should be present within our predictive models. This talk will present work that assesses how much variability can be present within facies models. Focusing on recently collected data from the Huesca distributive fluvial system (Spain) with comparison to the well-documented Salt Wash distributive fluvial system (SW USA).
4 PM LONDON Wednesday 24th March 2021
The Contourite-Turbidite Controversy after 50 years
Dorrik Stow – Heriot-Watt University
Ever since the contourite revolution of the 1960s the distinction between contourites, turbidites and hemipelagites in modern and ancient deepwater systems has been controversial. This is partly because: (a) the processes themselves show a degree of overlap as part of a continuum, so that the deposit characteristics also overlap; (b) the three facies types commonly occur within interbedded sequences of continental margin deposits; and (c) much erroneous and misleading material has been published over the past five decades. However, the nature of these end-member processes and their physical parameters are becoming much better known, and the occurrence, architecture and seismic attributes are now well established. Good progress has also been made in recognising differences between end-member facies in terms of their sedimentary structures, facies sequences, ichnofacies, sediment textures, composition and microfabric. These characteristics can be summarised in terms of standard facies models, and the variations from these models that are typically encountered in natural systems. Nevertheless, it must be acknowledged that clear distinction is not always possible on the basis of sedimentary characteristics alone, and that uncertainties should be highlighted in any interpretation. Controversy remains and clearly focused new research is much needed.
4 PM LONDON Wednesday 14th April 2021
Jurassic environmental perturbations: a shallow-water perspective
Stéphane Bodin – Aarhus University
Neritic environments, host of the highest marine biodiversity, are particularly sensitive to environmental changes. Their study allows us to understand how carbonate-producing ecosystems cope with climatic upheavals, but also shed important light on the evolution of critical parameters such as global sea-level fluctuations during these contorted times. This presentation will focus on the early and middle Jurassic Era, marked by the occurrence of numerous drastic environmental changes. Two specific time intervals will be discussed: the early Toarcian, which has experienced one of the most extreme environmental change of the Mesozoic, and the early Bajocian, a more enigmatic and currently poorly understood time of environmental change. By looking at an exceptionally preserved geological record in the Central High Atlas Basin of Morocco, the role and weight of different environmental factors (such as seawater temperature, oxygen and nutrient levels, carbonate saturation state, sea-level change, etc.) on neritic carbonate production and demise will be discussed.