Provenance of fluvial terrace sediments within the Waipaoa sedimentary system and their importance to New Zealand source-to-sink studies

The river it goes right on: Post-glacial landscape evolution in the upper Waipaoa River basin, eastern North Island, New Zealand

“…Once rates of uplift outpaced rates of incision, the channel gradient presumably increased (cf. Pazzaglia et al, 1998); but nevertheless we observe that the median particle size (D 50 ) and D 90 of gravel clasts at the airstrip (Waipaoa-1) terrace site are in the same range (34 ± 6 and 69 ± 11 mm, respectively) as surficial bed material in the contemporary channel (Gomez et al, 2001;Marsaglia et al, 2010). In the modern aggrading river, coarse material is systematically removed from transport by deposition; and at the downstream end of the fluvial system, the boundary of the Matokitoki gravel is close to the present location of the gravel-sand transition (Fig.…”

“…Litchfield and Berryman, 2006). Bedload over-capacity was replaced by undercapacity after the glacial-interglacial transition, when podocarp forest took the place of open vegetation on hillslopes, the erosion regime became more focused, and gullies in the Cretaceous Whangai Formation replaced periglacial processes (and deposits) as the major source of coarse sediment (Wright et al, 1995;McGlone, 2001;Marsaglia et al, 2010). As the supply regime changed, the alluvial cover was depleted; and once the river reestablished contact with bedrock it began to recuperate the time lost to vertical incision.…”

A source-to-sink perspective of the Waipaoa River margin

“…Late Pleistocene aggradational-terrace levels in the upper reaches of the river catchment linked to colder climate episodes (Berryman et al, 2010;Marden et al, 2008a) contain higher proportions of sandstone clasts, suggesting that gullying was a less important source of sediment at that time (Marsaglia et al, 2010). During the last glacial period, the river was actively aggrading until ~18 ka (Marden et al, 2008a).…”

“…Concentrations of meteoric 10 Be in stream sediments vary by more than an order of magnitude across the Waipaoa with lowconcentration samples reflecting a 20 times increase in sediment production from heavily gullied catchments (Reusser and Bierman, 2010). In addition, fluvial terrace sediments differ in composition from their modern river counterparts, likely reflecting the historical development of major gullies (Marsaglia et al, 2010).…”

Long-term controls on continental-scale bedrock river terrace deposition from integrated clast and heavy mineral assemblage analysis: An example from the lower Orange River, Namibia

“…Terrace deposits within bedrock river systems provide a fragmented archive of landscape evolution in the sediment transfer zone (e.g., Bridgland and Westaway, 2008;Wegmann and Pazzaglia, 2009). Therefore, improved understanding of these records in sites dominated by erosion will help to constrain controls on long-term changes in ancient river system character and provenance, and to predict and unravel the downstream depositional record of quasi-contemporaneous marine sediments (Pazzaglia and Gardner, 1993;Aalto et al, 2008;Marsaglia et al, 2010;Kuehl et al, 2016). Analysis of clast assemblages is the most common approach used to investigate changes in provenance of fluvial gravels and to establish the denudation and evolution of drainage basins (Gibbard, 1979;Green et al, 1982;Bridgland, 1999).…”