Aeolian dust

One of the characteristic features of Reg soils is the vesicular nature of the uppermost soil horizon. The size distribution of the vesicles is up to a few mm in diameter. Similar vesicular structures were also observed in lithosols and takyr-like alluvial soils and were always associated with the presence of stones or thin, hard crusts that sealed the soil surface. It forms mostly through accumulation of aeolian dust (McFadden et al., 1998). 

South America. The influence of aeolian dust transport on the surfece ocean iron deposition rates and concentrations is shown in Figures 11.4c and 11.4d. 

The overall effect of the terrestrial weathering reactions has been the addition of the major ions, DSi, and alkalinity to river water and the removal of O2, and CO2 from the atmosphere. Because the major ions are present in high concentrations in crustal rocks and are relatively soluble, they have become the most abimdant solutes in seawater. Mass-wise, the annual flux of solids from river runoff (1.55 x 10 g/y) in the pre-Anthropocene was about three times greater than that of the solutes (0.42 x 10 g/y). The aeolian dust flux (0.045 X 10 g/y) to the ocean is about 30 times less than the river solids input. Although most of the riverine solids are deposited on the continental margin, their input has a significant impact on seawater chemistry because most of these particles are clay minerals that have cations adsorbed to their surfaces. Some of these cations are desorbed... 

Because of the high iron demand by the nitrogenase enzyme, iron availability is thought to potentially be controlling where and when N2 fixation takes place. In the surfece waters, this supply is controlled by the aeolian dust flux. In deep waters,... 

Leinen, M., J. M. Prospero, E. Arnold, and M. Blank, Mineralogy of Aeolian Dust Reaching the North Pacific Ocean. 1. Sampling and Analysis, J. Geophys. Res., 99, 21017-21023 (1994). 

The origin of Aeolian dust from Chinese desert to Japanese islands was studied with ESR of dust, mostly fine grains of quartz.132 Suspended particulate matter (SPM) collected by environmental protection agency was measured with ESR.133 Dust soot of automobiles was also measured to check the motor combustion rate. Adsorption of NO, Mn2+ and Gd3 on clay minerals, bentonite and se-piolite134 has been studied using paramagnetic ions as tracers for radioactive elements. And studies have been carried out on how divalent and trivalent cations diffuse and blocked by surrounding clay minerals, in the context of their leak from nuclear waste repository to the environment.135... 

Goossens D, Gross J, Spaan W (2001) Aeolian dust dynamics in agricultural land areas in lower Saxony, Germany. Earth Surf Process Landforms 26 701-720... 

The in situ chemical controls on oceanic N2 fixation, in particular iron and phosphorus, are the topic of much current research effort and debate. Fueling these efforts has been the observation of extensive areas of excess N (relative to Redfield regeneration stoichiometry, often expressed as positive N anomalies) relative to P in subeuphotic zone waters in the North Atlantic that roughly correspond to regions which receive substantial aeolian dust deposition (Michaels et al, 1996 Gao et al, 2001 Gruber and Sarmiento, 1997). Wet and dry deposition of mineral aerosols fertilize the surface ocean with Fe (along with N and P) (Mahowald et al, 1999). 

McMuny PH, Woo KS, Weber R, Chen DR, Pui DYH (2000) Size distributions of 3-10 mu atmospheric particles Implications for nucleation mechanisms. Philos Trans Roy Soc Lond A 358 2625-2642 Merrill J, Arnold E, Leinen M, Weaver C (1994) Mineralogy of aeolian dust reaching the north pacific-ocean. 2. Relationship of mineral assemblages to atmospheric transport patterns. J Geophys Res 99 21025-21032... 

Studies carried out in Antarctic snow and ice (52, 53) on the isotopic composition of Pb have proved unequivocally that recent snow layers, and hence the present Antarctic troposphere are contaminated by anthropogenic Pb. Isotopic fingerprinting also proved two different sources a natural component associated with aeolian dust and an anthropogenic component. The possible origin of this Pb-rich aerosol is hypothesised to be South America. 

Villa, N., Dorn, R.I. Clark, J. (1995) Fine material in rock fractures aeolian dust or weathering In Tchakerian, V.P. (Eds) Desert Aeolian Processes. London Chapman and Hall, pp. 219-231. 

Hoelzmann (personal communication) suggest that climate change at the end of the mid-Holocene was faster in the western than in the eastern Sahara. Indeed, deMenocal et al. (2000) report of an abrupt decline in aeolian dust transport off the Northwest African Atlantic coast 5500 years ago. This reconstruction is consistent with the hypothesis of multiple equilibria in the western, not in the eastern Sahara. 

Pye, K., 1987. Aeolian dust and dust deposits. Academic Press, London, New York, Toronto, 334 pp. 

The dispersion of bulk powders is important for a number of applications including particle characterization, powder transformation from a dense phase to a lean phase, aeolian dust formation, and the delivery of therapeutic drugs via the lung using dry powder inhalers (DPIs). Calvert et al. [85] have studied the dispersion... 

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