Modern sedimentary processes and deposits: analogues for the rock record
Coastal to shelf environments across time and space
Dr Valentin Zuchuat1, Dr Miquel Poyatos-Moré2, Dr Liz Mahon3, Dr Anna van Yperen4, Dr Romain Vaucher5
1CSIRO, Perth, Australia, 2Universitat Autònoma de Barcelona, Spain, 3University of Utah, Salt Lake City, USA, 4University of Oslo, Norway, 5University of Geneva, Switzerland
Coastal to shelfal systems reflect a dynamic interplay of processes, including riverine flow, tidal currents, wind, wave action, storm frequency-intensity, and compaction, which exist(ed) in various geographical locations or climate conditions. These processes interact with different sediment compositions, leading to complex morphodynamics, diverse sedimentary facies and resulting in a non-unique stratigraphic architecture. Deciphering the depositional history generated by these varied and often combined processes is challenging, especially given changes in depositional controls across various timescales such as variations in relative sea level, climate, subsidence, and/or sediment supply. This amalgamation of different timescales at which each process occurs can further misrepresent what were the active or dominant processes at the time of deposition as interpreted from the sedimentary signature and architecture preserved in the rock record.
To better understand modern and ancient coastal and shallow-marine depositional systems is crucial for society. Not only will this knowledge help optimise the management of resources (water, energy fluids, critical minerals, CCS, and hydrogen storage), but it will also facilitate the present and future sustainable care and development of these areas by local communities and policymakers, ensuring their long-term protection in a context of intense and ever-increasing anthropogenic stresses.
In this session, we invite contributions of studies on coastal to shelfal systems either in the rock record or in modern examples, in any type of climatic and tectonic setting, on Earth and other planetary bodies, with data acquired from fieldwork, subsurface analysis, remote-sensing, experimental lab work, and numerical modelling. Early Career Scientists are warmly welcome to showcase their work, and we encourage them to apply for oral presentations. This session is organised under the umbrella of the SEPM Coastal Shelf Research Group (CSRG).
Mapping marine sediments in the world
Dr Xuefa Shi1, Dr Chris Jenkins2, Dr Andrew La Croix3, Dr Romain Vaucher4, Dr Joanna Pszonka5, Dr Shuqing Qiao1
1First Institute of Oceanography, Ministry of Natural Resources, China, Qingdao, China, 2University of Colorado Boulder, USA, 3The University of Waikato, New Zealand , 4University of Geneva, Switzerland, 5Colorado School of Mines, USA
The global ocean floor remains largely unexplored, and understanding its sedimentary characteristics is crucial for various disciplines, including marine geology, geophysics, ecology, and environmental science. This session aims to bring together experts from diverse backgrounds to discuss recent advancements in global marine sediment composition and distribution (e.g., organic matter, minerals, plastics, pollutants). We welcome contributions on a wide range of topics, including global-scale mapping initiatives, regional-scale studies, case studies from specific areas, high-resolution mapping techniques, data processing methods, sedimentary processes and dynamics in marine basins, and applications of marine sediment maps. By fostering collaborative knowledge exchange, this session seeks to advance the field of marine sediment mapping. We look forward to a dynamic and informative session.
Microbial architects of carbonates: Insights from modern to deep-time systems
Professor Mónica Sánchez-Román2, Professor Daniel Ariztegui1
1Department of Earth sciences, University of Geneva, Switzerland, 2Earth Science Department, Vrije Universiteit Amsterdam, The Netherlands
The dynamic interplay between microbial activity and carbonate formation spans both geological and modern timescales, shaping the evolution of carbonate systems and their associated biogeochemical cycles. This session invites contributions that explore the diverse roles of microbes in the precipitation, dissolution, and diagenesis of carbonate minerals in both modern environments and ancient records. We seek studies that address key questions about how microbial processes influence carbonate chemistry, mineralogy, and sedimentology across marine, lacustrine, and terrestrial systems.
We encourage submissions employing cutting-edge methodologies to unravel these complex interactions, such as genomics, metagenomics, and other molecular techniques that shed light on the functional roles of microbial communities. Contributions integrating high-resolution imaging, geochemistry (e.g., stable isotopes, metal concentrations), and modelling approaches to link microbial activity with carbonate formation and preservation are also highly welcomed.
This session aims to foster interdisciplinary dialogue and present innovative perspectives on the microbial impact on carbonate formation, emphasizing how advances in methodology can bridge the gap between present-day observations and the interpretation of ancient records. By exploring these microbial-mineral interactions, we aim to deepen our understanding of their implications for carbon cycling, climate reconstructions, and the evolution of Earth's biosphere.
The complexity of braided rivers that reach the base level: braid deltas present and past
Dr Jason Muhlbauer1, Dr Christopher Fedo2, Hamilton Allport3, Yorick Veenma3
1Boise State University, United States, 2University of Tennessee, Knoxville, United States, 3University of Cambridge, United Kingdom
Where braided rivers reach base level and sediment supply matches or exceeds accommodation development, braid deltas with a substantial range of morphologies prograde under normal or forced regressive conditions. Though less abundant than their common delta counterparts, modern braid deltas are nonetheless found on all continents in both transitional marine and lacustrine settings, including the coastlines and lakes of Te Waipounamu / South Island, New Zealand. Given the non-cohesive nature of their sediment, owed to limits on clay deposition and plant growth, braid deltas preserve climate-sensitive information and may occur as transitory or long-lived systems. Present-day braid deltas represent analogues for non-vegetated deltaic systems that dominated much of Earth history before the emergence and dispersal of vascular plants in the Silurian. When preserved, they provide a detailed sedimentary record of sea-level fluctuations and depositional processes in an environment associated with elevated clastic sediment transfer and burial.
On Earth today, numerous braid deltas mark high-latitude coastal settings of interest in a deglaciating world as the interface of outwash with the marine realm. In arid regions, braided rivers prograde into closed basins that are drying because of desertification coupled with increasing demand for irrigation and drinking water. Where these avulsive and non-cohesive systems intersect with human development, delta plains may be heavily engineered, potentially generating hazards associated with flood mitigation, transportation, and commercial shipping. This session welcomes research investigating present-day braid deltas, their use as analogues to past environments, and pre- or post-vegetation braid deltas in the deep-time rock record. Submissions that explore recent climatic modeling or anthropogenic modifications involving the braid-delta environment are encouraged.
Transport of Mud and Deposition of Mudstones - The State of the Art
Professor Juergen Schieber1, Dr. Yifan Li2, Dr. Gabriele Gambacorta3, Dr. Joe Macquaker4
1Indiana University, Bloomington, United States, 2China University of Geosciences, Beijing, China, 3University of Florence, Italy, 4ExxonMobil, Houston, United States
Mud is everywhere. Much of the Earth is covered by it, on land as well as under the sea. It influences what crops we can grow, how stable our landscapes are, the navigability of our rivers, how much effort we have to expend to keep open harbors and canals, as well as the habitability of shelf seas and the deep oceans for benthic life (shellfish, crabs, etc.) and associated fish crops. Mud is the main substrate for the microbial biomass of Earth, and as such is intricately woven in with biogeochemical cycles that exert control on the composition of atmosphere and ocean. Mud is important. When buried mud becomes mudstone, a fine-grained sedimentary rock composed dominantly of clay-sized (< 4 μm) and silt-sized (4 - 62.5 μm) particles that constitutes 2/3 of the sedimentary rock record and contains the lion’s share of recorded geologic time. For petroleum systems, mudstones are essential as source rocks and seals, and more recently also as unconventional hydrocarbon reservoirs.
The last two decades have seen much progress in understanding, driven by the role that mudstones play in contemporary petroleum geology, where they are a key resource that we need to be able to read accurately if we are to make correct predictions about the economic viability of hydrocarbon production in sedimentary basins. The first step towards that goal is to abandon long held notions about mud accumulation and embracing new emerging paradigms about energetic and dynamic mud transport and depositional processes. In this session we hope to bring together experimentalists, marine geologists, students of the rock record, and exploration geologists to discuss a future conceptual framework for mudstone sedimentology that provides physical constraints on facies development and that allows us to make predictions about the spatial distribution of the various types of mudstone facies within sedimentary basins, from the shoreline to the deep sea.