European glacial dust deposits: Geochemical constraints on atmospheric dust cycle modeling

Abstract

For a long time global paleodust numerical simulations have greatly underestimated dust sources other than modern deserts. Recent modeling experiments incorporating glaciogenic sources of dust have positively improved the agreement between model and paleodust data. This highlights the importance of accurately representing all areas potentially subjected to deflation during an investigated interval. Geochemical results, obtained from European loess sequences collected along a 50°N transect, combined with dust emission simulations reveal the geographical distribution of the most important European dust sources between 34 ka and 18 ka. We demonstrate that most European dust traveled only a few hundred kilometers or less within the boundary layer from its source before deposition. We conclude that our results encourage acquisition of similar geochemical data for other relevant areas in the world. Further, they could provide critical constraints to benchmark atmospheric models, contributing to improve their performance in simulating dust cycle and associated climate feedbacks.

New perspectives on the Li isotopic composition of the upper continental crust and its weathering signature

“…These Quaternary deposits can be divided into two distinct types: (1) periglacial loess, derived from glacial outwash and transported by winds over limited distances (Haase et al, 2007;Rousseau et al, 2014), and (2) desert loess, transported over longer distances, typically several hundreds of kilometers (Ding et al, 1999), from desert regions.…”

“…fragments derived from the source (Swineford and Frye, 1955;Garçon et al, 2014); a "nugget effect" i.e. the over-concentration of heavy minerals associated to quartz grains or reflect the preservation of inherited isotopic variability from the source rocks due to short transport distances (Rousseau et al, 2014).…”

Periodic input of dust over the Eastern Carpathians during the Holocene linked with Saharan desertification and human impact

“…This is especially important in the Carpathian region, given the extensive loess cover in the area (Marković et al, 2015) -a fundamental factor in sustaining high agricultural production. Additionally, the sensitivity of loess to moisture availability and water stress during dry periods may turn this region and other surrounding loess belts into major dust sources (Kok et al, 2014;Rousseau et al, 2014;Sweeney and Mason, 2013). This is particularly true under semi-arid (Edri et al, 2016), or agriculturally altered conditions (Korcz et al, 2009), as is the case with the major dust fields of eastern Eurasia (Buggle et al, 2009;Smalley et al, 2011;Újvári et al, 2012).…”

First isotope analysis and new radiocarbon dating of Trypillia (Tripolye) farmers from Verteba Cave, Bilche Zolote, Ukraine

“…Rousseau et al (2014) demonstrate that for European loess between 48°N and 52°N, the major sources were in the same latitudinal band and that the loess Figure 6.a documents the narrow range of variation present and the close correspondence between the faunal and human values. There are no obvious outliers in the strontium isotope data, and the human enamel values appear very homogeneous.…”