CLIMATE CHANGE EFFECTS ON SEDIMENT TRANSPORT CYCLES FROM SOURCE TO SINK

JUAN PABLO MILANA

Valparaiso

Congreso; Particles in the America 2022; 2022

Particles in the America comittee

This contribution intends to highlight the strong effects of changing climate scenarios on sediment transport systems, seen from a holistic perspective (source to sink). The understanding of climate-related sedimentary cycles has direct effects on various human activities. First is the understanding of global change. As sediments have built the most important geoarchives, the correct interpretation of the sedimentary changes preserved in each natural archive will help depicting local and regional climate changes. A few examples of these applications are given by proglacial, coastal and deltaic sedimentary systems showing that changes may be tracked down to sub-annual precision. The effects of sedimentary transport changes are also described, directly linked to average discharges and hence to climate, on depositional processes of alluvial fans, using as an example the well-known sieve-lobe dominated Trollheim fan. On the other temporal extreme, pervasive climate changes may generate more profound effects on sedimentary systems. Systems may become sedimentary overfed or starved over periods of more than a million year and create sedimentary packages associated to the well-known third-order cycles. To illustrate these processes several experimental analogue models produced in moderate sized flumes are used to show the impact that may have a change of average discharges over long time periods. In order to simulate a source to sink scenario, besides experimental runs considering only average discharge changes, more complex runs associated to a dynamic effect of fluvial discharges and sea(base)-level changes in a hypothetical glacio-eustatic cycle are also presented. Sedimentary packages were produced in these experiments resembling the building blocks sequence stratigraphy uses to organize sedimentary basins stratigraphical packages: the systems tracts. The impressive similitude between experimental results and true cases of basin stratigraphy warrants the fact that particle transport, that is primarily affected by climate change, is a primary variable defining the stratigraphic architecture of depositional basins. Hence, sedimentary transport is a necessary knowledge to understand the distribution of lithologies that has a profound impact on hydrocarbon exploration and production. Understanding the way particles are transported not only helps depicting climate change history, but also is an important asset for industry development..