Sediment yield over glacial cycles: A conceptual model

Abstract

The temporal variability in sediment export yield from glaciers over a timescale of multiple glacial cycles (e.g. 1 × 102 − 1 × 106 years) is of interest for a wide range of applications in glaciology, sedimentology, geomorphology, climatology and environmental engineering. However, the time required for the products of glacial erosion to be transferred through glaciated catchments and the extent to which glacially-conditioned sediment can be transiently stored within them are still poorly constrained and a matter of debate within the community. We propose a conceptual model of the variability in sediment exported from glaciers over multiple glacial cycles based on a literature review. Sediment yield is likely to be highly variable through a glacial cycle, notably between phases of glacier advance, retreat and re-advance due to changes in ice velocity and erosion rates, ice and meltwater transport capacity, and in glacially-conditioned sediment accessibility at the bed. Typically, early phases of glacier retreat and re-advance are expected to lead to the highest increase in sediment yield due to the ease with which the products of bedrock erosion can be accessed and reworked. In contrast, later phases of glacial (re)advance, once glacially-conditioned sedimentary sources become exhausted, may be characterized by intermediate rates of sediment export yield maintained through bedrock erosion. The latest phases of deglaciation, once glacially-conditioned sedimentary sources are either exhausted, stabilized or disconnected from active processes of sediment transfer, are likely to have the lowest rate of export. The conceptual model proposed in this paper fills a gap in the literature by developing a continuous pattern of sediment yield rate variability over the course of multiple glacial cycles, with wider implications for future research. However, its systematic applicability to various glacier settings and glaciations needs more field and modeling data to validate it.

Temporal Relationship of Increased Palaeodischarges and Late Glacial Deglaciation Phases on the Catchment of River Maros/Mureş, Central Europe

“…At the same time, the braided pattern of palaeochannels from this period suggests a high availability of sediments on the catchment that can be partly caused by coarse grain sediments released from previously glaciated valleys on the upland catchment (Antoniazza and Lane, 2021), and the time lag between the adaptation of vegetation to climate change (Vandenberghe, 2008). Both leading to the initiation of sediment pulses towards the alluvial fan.…”

“…According to Starkel (2002Starkel ( , 2007 and Vandenberghe (2008), in Eastern and Northern Europe the periods of the most intensive fluvial activity can be related to the beginning of interstadials, partly as a consequence of the accelerated retreat of ice sheets and mountain glaciers. This hypothesis however needs to be attested at different catchments at different latitudes (Antoniazza and Lane, 2021). The key to this question is to find relationships between archives located on upland catchments and on alluvial fans.…”

“…For example, the climatic fluctuations of the Pleistocene and parallel variations of runoff and vegetation cover resulted a cyclic change in the activity of Eastern European sub-basins, which could lead to the formation of sediment pulses (e.g. Starkel et al, 2007, Antoniazza andLane, 2021). Furthermore, changing runoff and sediment conditions could also affect the number of sediment cycles observed along rivers.…”

Volume, formation and sedimentation of future glacier lakes in Switzerland

“…As for c sed,in , we are aware that c sed,out may be subject to temporal variations but we assume these to be dampened by the lakes and to be relatively small in absolute terms. In our approach, c sed,in will be subject to major variations depending on the sediment sinks above the considered lake, as well as due to the erodibility of the basin which is influenced by factors such as slope, recently exposed proglacial area, and the height of the headwall (Ballantyne, 2002;Benn and Evans, 2010;Costa et al, 2018;Antoniazza and Lane., 2021;Carrivick and Tweed, 2021). In order to estimate c sed,in , we parameterize three main processes: (1) subglacial abrasion, (2) the increase in deglacierized area, and (3) glacial and periglacial erosion.…”

Spatial and temporal controls on proglacial erosion rates: A comparison of four basins on Mount Rainier, 1960 to 2017

“…Glacier retreat is often associated with the onset of a paraglacial period, during which the exposure of unstable glacial sediments and high meltwater discharges are expected to result in relatively high sediment yields (e.g., Antoniazza & Lane, 2021;Ballantyne, 2002a).…”