TS4 – Interplay between Tectonics and Surface Processes
Tectonics, erosion, and climate in orogenic settings: evolution and interactions determined from sediment records
The interlinked influences of tectonics, erosion and climate govern the topographic and debatably also structural evolution of mountain belts. In turn, the evolution of any given mountain belt can influence the development of the regions’ climate, erosion and sedimentation patterns. Sedimentary records can preserve a rich archive of a region’s tectonics, erosion and/or climate history that can be interrogated through application of a number of approaches utilising, for example, sediment provenance, detrital thermochronology, determination of sedimentation rates and facies, and stable isotope studies. Suitable continental records may exist in foreland basins and retro-arc settings located proximal to the mountain sources, and scientific drilling has been important in recovering records from the modern oceans. Located potentially far from the mountains, many submarine fans may preserve more complete and readily dated sedimentary sections. Analysis and comparison of strata across different parts of a mountain belt can potentially allow a more detailed spatial and temporal understanding of climatic and tectonic evolution of a region as an orogen uplifts and subsequently collapses. Although the Asian Monsoon-Himalayan system is the classic example of tectonic-erosion-climate interactions, similar relationships have been invoked in South America, Papua New Guinea, Taiwan and the Pyrenees during the Cenozoic alone. We invite contributions that utilise sediment records to unravel the links and relationships between tectonics, erosion or climate change, in recent or ancient orogenic settings, using traditional and novel application of field, laboratory and/or modelling techniques.
From earthquake rupture to landscape building - Deformation of the Earth’s surface over multiple timescales
Understanding how successive earthquakes accrue on individual faults to produce kilometer-scale displacements, build landscapes and activate cascades of geomorphological processes is still poorly understood. While large-scale geodynamic processes like subduction and orogenesis can be considered continuous over geological timescales (100 ka to Ma), they mostly operate discretely over shorter timescales (< 100 ka). Apparent quiescence is transiently interrupted by pulses of localised tectonic and geomorphic activity, which repeatedly interact and shape the landscape. Long-term permanent crustal deformation forms landscapes, yet geodesy primarily records short-term elastic strain. In this context, the surface expression on individual faults or active margins contains valuable information on both the endogenous and the exogenous processes at work, the complexity of which may be studied in long-term features (e.g. landscape evolution, mountain building, basin formation) as well as short-term data (e.g. geodetic monitoring, paleoseismology).
The scope of this session is to bring together state-of-the-art research efforts to better understand how the short-term rate variability that is often recorded on the Earth’s surface integrates to produce uniform large-scale active tectonic processes (i.e. subduction, collision, rifting, transform faulting). We welcome contributions combining observations and analogue & numerical modelling. We would also particularly value studies that bridge deformational processes operating over different spatial and temporal scales.
Interaction of tectonics, climate, topography and surface processes from mountain belts to basins
Landscape evolution is driven by surface processes that are forced by the interaction of climate, tectonics and topography. In this session we will explore records of these interactions from mountain belts to basins. Presentations cover both well established and novel techniques that utilize geomorphic, erosional, and sedimentary records to quantify rates and styles of deformation, climatic changes, and topographic impacts on surface processes. Presentations are arranged around three themes: (1) Topographic stress control on surface processes: Tectonic and topographically generated stress fields affect the rate of local surface processes. Surface processes in turn modulate these stress fields and shape landscapes. Theoretical and numerical models as well as laboratory and field studies explore these controls and potential feedbacks. (2) Tectonic and climatic influence on eroding landscapes: The coupling between tectonic deformation and climate governs the rate of surface processes. Morphometric analyses, low-temperature thermochronology, and cosmogenic nuclides all provide useful insights into the rates at which surface processes occur and the feedbacks among tectonics and climate. (3) Morphometric and basin records of landscape evolution: Erosional products of surface processes modulated by climate, tectonics and topography are routed through rivers to depositional sinks, which themselves may be subsequently affected by tectonic deformation. This topic explores how sedimentary records and morphometric analyses can be used to reconstruct climatic and tectonic forcing of landscapes.
A wide variety of erosional processes and sediment transport processes act to shape landscapes and generate the sedimentary record. Often, the most sensitive records of sediment production, transport, and deposition are found within detrital archives, which include (but are not limited to) physical sedimentology and textural analyses, detrital thermochronometry, cosmogenic nuclides and other geochemical tools, and stratigraphic analyses.
This session examines how detrital records can be used to study erosion, sedimentation, and sediment provenance. We seek studies that use detrital tools to address open questions in geomorphology and sedimentology, such as: (i) signal propagation through landscapes; (ii) the climatic and tectonic controls on sediment production and transport; (iii) variability in the processes and rates of erosion; (iv) decoding basin deposits for information about past environments; and (v) thresholds governing surface processes. Contributions are welcome from field, experimental, and modelling studies across all temporal and spatial scales.
The ocean floor hosts a tremendous variety of forms that reflect the action of a range of tectonic, sedimentary, oceanographic and biological processes at multiple spatio-temporal scales. Many such processes are hazards to coastal populations and offshore installations, and their understanding constitutes a key objective of national and international research programmes and IODP expeditions. High quality bathymetry, especially when combined with sub-seafloor and/or seabed measurements, provides an exciting opportunity to integrate the approaches of geomorphology and geophysics, and to extend quantitative geomorphology offshore. 3D seismic reflection data has also given birth to the discipline of seismic geomorphology, which has provided a 4D perspective to continental margin evolution.
This interdisciplinary session aims to examine the causes and consequences of geomorphic processes shaping underwater landscapes, including submarine erosion and depositional processes, submarine landslides, sediment transfer and deformation, volcanic activity, fluid migration and escape, faulting and folding, and other processes acting at the seafloor. The general goal of the session is to bring together researchers who characterise the shape of past and present seafloor features, seek to understand the sub-surface and surface processes at work and their impacts, or use bathymetry and/or 3D seismic data as a model input. Contributions to this session can include work from any depth or physiographic region, e.g. oceanic plateaus, abyssal hills, mid-ocean ridges, accretionary wedges, and continental margins (from continental shelves to abyss plains). Datasets of any scale, from satellite-predicted depth to ultra high-resolution swath bathymetry, sub-surface imaging and sampling, are anticipated.
This session is organised by the IAG Submarine Geomorphology Working Group.