Subterranean transport and deposition of quartz by ants in sandy sites relevant to age overestimation in optical luminescence dating

OSL chronology of middle to late Holocene aeolian activity in the St. Anthony dune field, southeastern Idaho, USA

“…Although all samples were collected from greater than 1 m stratigraphic depth to reduce bioturbation, this scatter in D e is interpreted to have been due to subtle mixing of grains due to bioturbation that was not apparent in the field. Similar grain-level mixing of aeolian sediment has been observed by others (Feathers et al, 2006;Rink et al, 2013). While the data presented here are small aliquot results, the weak luminescent character of these sediments (~20 counts/Gy) and small aliquot size (10e30 grains), likely produced near-single grain results, leading to the greater spread in D e values.…”

“…The central age model of Galbraith et al (1999) was chosen to calculate the OSL ages from these distributions because it was expected that the contribution of D e scatter from bioturbation was normally distributed (equal number of young grains moved down as old grains moved up in the profile). However, it should be noted that Rink et al (2013) observed greater number of grains from lower stratigraphic positions moving stratigraphically upward due to bioturbation by ants. Positively skewed distributions may have been produced by this mechanism.…”

The architecture of subterranean ant nests: beauty and mystery underfoot

“…Tschinkel (2004) proposed that soil carbon dioxide gradients could provide such information, but his experiments later showed this not to be true (Tschinkel 2013). Nest excavation in harvester ants occurs in part through a chain of transport in which a pellet of soil is removed, moved upward, deposited and picked up by different workers until it is finally deposited on the soil surface (Rink et al 2013). Most of how ants construct nests is still a mystery, although a few hints do exist.…”

Single-grain post-IR IRSL signals of K-feldspars from alluvial fan deposits in Baja California Sur, Mexico

“…Variation in single-grain D e values can be caused by a number of factors (Duller, 2008), including partial bleaching, bioturbation (Rink et al, 2013), dosimetric heterogeneity (Thomsen et al, 2003(Thomsen et al, , 2005, instrument reproducibility (3.3%, Thomsen et al, 2005), and (in the case of feldspars) differential fading (Auclair et al, 2003) and/or internal dose-rates (Huntley and Baril, 1997).…”