Scientific Webinars

This work focusses on a multi-proxy approach paleoclimate reconstruction based in a speleothem from the tropical Pacific island Niue. The location of Niue Island allows to extract past climate changes records associated to the South Pacific Convergence Zone (SPCZ) and ENSO.

The origin of carbonate mud is a topic of debate between two main theories: biogenic and abiogenic origin. The biogenic side suggests that carbonate mud is primarily formed from the accumulation of skeletal debris and fecal pellets of marine organisms such as foraminifera, mollusks, and corals, among others. This position also proposes that microbial activity plays a crucial role in carbonate precipitation, dissolution, and re-precipitation.On the other hand, the abiogenic side proposes that carbonate mud is primarily formed from the precipitation of inorganic minerals, such as aragonite and calcite, through physical and chemical processes in the marine environment. This position suggests that sedimentation and diagenesis play significant roles in the formation and alteration of carbonate mud.

While both positions have some evidence to support them, the debate on the origin of carbonate mud remains in debate. Some scientists argue that both biogenic and abiogenic processes are involved in the formation of carbonate mud, and the relative contribution of each process may vary depending on local environmental conditions. Join us for an exciting debate on the origin of carbonate mud, where Linda Kah, John Reijmer, Laura O’Connell and Paul Wright will discuss and explore the evidence for both biogenic and abiogenic positions.

Extreme Events in Earth History: SOSW 7

Nick Ferry (University of Kansas), Abdul Hannan (University of Pakistan), Niraj Tamang (University of Auckland)

Submarine canyons play a fundamental role in land-to-ocean transport of sediment, pollutants and organic carbon. Moreover, canyons that are connected to terrestrial sediment sources are especially efficient in material routing. We aim to identify the main controls on (1) submarine canyon occurrence along continental margins and (2) whether a canyon head remains connected to terrestrial sediment input during sea-level rise. We assess these problems on a global scale using Bayesian regression and spatial point pattern analysis. One main conclusion is that submarine canyon occurrence increases exponentially with increasing gradient of the continental slope – a parameter that was calculated by smoothly interpolating between the shelf edge and the toe of the continental slope.

Looking forward, the field of sedimentology and its future must include advances in geoheritage, planetary exploration, and technology.

Of foremost importance, the many diverse landscapes where we conduct sedimentology research comprise our geoheritage – the geologic sites or areas with significant scientific, educational, cultural, and/or aesthetic value. Geoheritage sites are vital to advancing knowledge and for understanding geodiversity as well as the biodiversity the land supports. The sedimentary record at many geosites has implications for understanding climate change. Over the last few decades, a rising international geoconservation movement is bringing attention to special geological features with intrinsic value. Sedimentologists need to contribute to good stewardship of important geoheritage sites.

Sedimentology plays a key role in planetary explorations, with the discovery of more sedimentary rocks on Mars and the continuing search for extraterrestrial life. The potential for extraterrestrial life will be enhanced by more studies of microbial life in terrestrial authigenic minerals and their detection as biosignatures. Earth has a life bias throughout over three eons of geologic history, yet analyzing the variability of analogous Earth systems with the sedimentologic context for habitable environments will lead to a better understanding of sedimentary deposits on other planetary bodies.

Finally, technology will continue to change the way we conduct our research from data collection to archiving, processing, visualizing, and sharing. All sedimentology studies can benefit from the use of digital technology, accompanied by open data and more avenues for communicating what our science is about.

The more we can learn from geoheritage landscapes that have strong scientific value, the better we can apply knowledge to planetary explorations. The more we use new digital technologies, the more we can share and make new discoveries. It’s an exciting frontier of sedimentology futures!

Initial rift basins are characterized by heterogeneous sedimentation patters varying at very short spatial and temporal scales. The interaction and feedback between tectonics, surface processes, volcanic events, climate variations and eustasy on sediment flux, sediment deposition and basin dynamics explain their complex stratigraphic architecture. Since the early days of the continental drift theory, the Afar triangle developed into an ideal field laboratory where the onset of continental and future oceanic rifting can be studied in detail. Although known as one of the most active rift regions on Earth and being a young incipient rift basin at the transition between continental rifting and oceanization, Pleistocene and Holocene sedimentary patterns in the Danakil Depression (N Afar, Ethiopia) has been only recently mapped in detail. This presentation discusses the unique sedimentary record in the Danakil Depression and how it contributes to the understanding of the intermittent opening and closure of an incipient rift basin driven by eustatic sea-level fluctuations, multi-episodic differential uplift and volcano-tectonic processes.

Throughout the history of the Solar System, the planets have undergone quasi-periodic orbital variations dictated by gravitational forcing and chaotic interactions. In addition, the Earth has experienced changes in rotation, shape, precession, and a receding Moon. Earth’s paleoclimate system was forced by insolation, affected by the all of the aforementioned factors, and recorded as cyclostratigraphy. This talk showcases strategies to model these dynamical factors using cyclostratigraphic data, and affirms that cyclostratigraphy hosts a continuous record of Solar System and Earth-Moon dynamics through geologic time.

Gravity currents span a broad spectrum of flows with complex variable transport and depositional processes which the community has greatly improved it’s understanding of over the past few decades. However there remains a substantial gap in our understanding of very coarse grained flows with broad grain-size mixtures around the steep slopes typical of active rift margins. In this talk we’ll visit some superb exposures from the Gulf of Corinth rift, Greece and compare these to subsurface and other outcrop examples to highlight this diversity of processes that may occur as a result of the very broad grain-size range within such flows and what this could mean for the role of momentum in governing sediment bypass of different sizes beyond base of slope breaks.

Ancient climate conditions cannot be directly measured, and are rather inferred from proxy data. Proxies are not direct indicators for changes in temperature, precipitation or evaporation, but rather provide indirect evidence for how temperature and hydrological changes impacted the Earth surface or biota. Most widely used climate proxies are geochemical or biological and provide information on mean annual temperature and mean annual precipitation. Here we utilise river sedimentary facies as proxies for precipitation intensity and intermittency, and produce a more realistic representation of past and future precipitation change.

Coastal sediments can extend observations of relative sea-level changes beyond the instrumental and historical record. Extending observations with sedimentological data is important at sites without long tide gauge records and limited geological observations. In this seminar I will show how late Holocene mangrove sediment sequences provide us with a record of anomalous relative sea-level rise in Micronesia in the western Pacific Ocean.