Moreno,T., Amato,F., Querol,X., Alastuey,A., Elvira,J. and Gibbons,W.(2009): Bedrock controls on the mineralogy and chemistry of PM10 extracted from Australian desert sediments. Environ. Geol., 57, 411-420.

『オーストラリアの砂漠堆積物から取り出されたPM10の鉱物および化学的性質に対する基盤岩のコントロール』


Abstract
 Given the relevance of desert aerosols to environmental issues such as dust storms, climate change and human health effects, we provide a demonstration of how the bedrock geology of an arid area influences the mineralogy and geochemistry of even the finest particulate matter (i.e., the inhalable fraction <10μm in size: PM10). PM10 samples extracted from desert sediments at geologically contrasting off-road sites in central and southeastern Australia (granitic, high grade metamorphic, quartzitic sandstone) were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS
). The “granitic” PM10 are highly alkali feldspathic and illitic, with a wide range of accessory minerals including rutile (TiO2), monazite [(Ce, La, Nd, Th, Y)PO4], xenotime (YPO4), apatite [Ca5(PO4)3(F,OH,Cl)], hematite(magnetiteの間違い) (Fe3O4), zircon (ZrSiO4) and thorite (ThSiO4). This mineralogy is reflected in the geochemistry which shows notable enrichments in rare earth elements (REE) and most high field strength elements (both held in the accessory minerals), and higher than normal levels of low (<2.0) ionic potential elements (Na, K, Li, Cs, Rb: held in alkali feldspar and illite). The “metamorphic” resuspended PM10 define a mineralogy clearly influenced by local exposures of pelitic and calc-silicate schists (sillimanite, muscovite, calcite, Ca-amphibole), a dominance of monazite over other REE-bearing phases, and a geochemistry distinguished by enrichments in alkaline earth metals (Ca, Mg, Ba, Sr) and depletion in heavy REE. The “quartzite”PM10, derived from rocks already recycled by Precambrian erosion and sedimentary transport, show a sedimentologically mature mineralogy of mostly quartz and kaolinite, detrital accessory ilmenite, rutile, monazite and hematite, and the strongest geochemical depletion (especially K, Rb, Cs, Na, Ca, Mg, Ba).

Keywords: PM10; Mineralogy; Geochemistry; Australian desert dust; Resuspension』

Introduction
Materials and methods
 Sample localities
  Ormiston pound
  Wilpena pound
  Silverton
 Analytical methodology
Results and interpretations
 X-ray diffraction
 Scanning electron microscope
 Inductively coupled plasma atomic emission and mass spectrometry
Discussion and conclusions
Acknowledgments
References


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