Desert Dust: Characteristics and rates of deposition in central Arizona

Péwé, Troy L.; Péwé, Elizabeth A.; Péwé, Richard H.; Journaux, André; Slatt, Roger M.

doi:10.1130/spe186-p169

Cited by 44 publications

(13 citation statements)

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“…Illite has been reported to be a dominant clay mineral in desert regions (Claquin et al, 1999), although the absolute concentrations are not known. Kaolinite, montmorillonite, and other clays have also been reported in desert regions (Potter and Rossman, 1977;Péwé et al, 1981;Verrecchia and Le Coustumer, 1996). The tropospheric lifetime of CH 3 CCl 3 by the reaction at ground level (τ tropos ground ) was estimated from the model reported by Alyea et al (1978).…”

Section: Estimated Lifetime Through Decomposition On Clays At the Gromentioning

confidence: 99%

Laboratory study on heterogeneous decomposition of methyl chloroform on various standard aluminosilica clay minerals as a potential tropospheric sink

et al. 2003

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Abstract.Methyl chloroform (1,1,1-trichloroethane, CH 3 CCl 3 ) was found to decompose heterogeneously on seven types of standard clay minerals (23 materials) in dry air at 313 K in the laboratory. All reactions proceeded through the elimination of HCl; CH 3 CCl 3 was converted quantitatively to CH 2 =CCl 2 . The activities of the clay minerals were compared via their pseudo-first-order reaction rate constants (k 1 ). A positive correlation was observed between the k 1 value and the specific surface area (S) of clay minerals, where the S value was determined by means of the general Brunauer-Emmett-Teller (BET) equation. The k 1 value was anti-correlated with the value of n, which was a parameter of the general BET equation and related to the average pore size of the clay minerals, and correlated with the water content that can be removed easily from the clay minerals. The reaction required no special pretreatment of clay minerals, such as heating at high temperatures; hence, the reaction can be expected to occur in the environment. Photoillumination by wavelengths present in the troposphere did not accelerate the decomposition of CH 3 CCl 3 , but it induced heterogeneous photodecomposition of CH 2 =CCl 2 . The temperature dependence of k 1 , the adsorption equilibrium coefficient of CH 3 CCl 3 and CH 2 =CCl 2 , and the surface reaction rate constant of CH 3 CCl 3 were determined for an illite sample. The k 1 value increased with increasing temperature. The amount of CH 3 CCl 3 adsorbed on the illite during the reaction was proportional to the partial pressure of CH 3 CCl 3 . The reaction was sensitive to relative humidity and the k 1 value decreased with increasing relative humidity. However, the reaction was found to proceed at a relative humidity of 22% at 313 K, although the k 1 value was about one-twentieth of the value in non-humidified air. The conditions required for the reaction may be present in major desert regions of the world. A simple estimation indicates that the possible heterogeneous decomposition of CH 3 CCl 3 on the ground surface in arid reCorrespondence to: S. Kutsuna (s-kutsuna@aist.go.jp) gions is worth taking into consideration when inferring the tropospheric lifetime of CH 3 CCl 3 and global OH concentration from the global budget concentration of CH 3 CCl 3 .

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Section: Estimated Lifetime Through Decomposition On Clays At the Gromentioning

confidence: 99%

Laboratory study on heterogeneous decomposition of methyl chloroform on various standard aluminosilica clay minerals as a potential tropospheric sink

et al. 2003

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“…Yucca Mountain, Nevada, studies of calcrete formed in bedrock fractures reveal a variety of processes including dissolution of rock material, a role for bacteria in cycling the calcium trapped in oxalates into calcite, as well as ongoing calcite dissolution and then reprecipitation (Vaniman and Whelan, 1994). Dust in Arizona and elsewhere in the desert southwestern United States contains an abundant source of carbonate (Péwé et al, 1981;Schlesinger, 1985). The hypothesis proposed here is that infiltrating water dissolves carbonate from dust that moved into the narrowest and deepest section of a crevice.…”

Section: Electron Microscopy Of Rock Coatings On Fracture Wallsmentioning

confidence: 99%

“…They are not the fracture fills found in saprolite and other in situ weathered rock (Thoma et al, 1992;Frazier and Graham, 2000). Instead, the mixture of eolian silt and rock fragments is found in fractures of all different orientations and sizes, but only in warm deserts where fractures accumulate dust (Goudie, 1978;Bullard and Livingston, 2009) -including the region studied here, Arizona and southwestern USA (Péwé et al, 1981;Brazel, 1989). This paper's purpose rests in re-examining dirt-cracking processes.…”

Section: Introductionmentioning

confidence: 94%

Revisiting dirt cracking as a physical weathering process in warm deserts

Dorn

2011

Geomorphology

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“…In general, dust generated to atmosphere has diameter of less than 20 m [23]. Therefore, diameters of 5, 10, 15, and 20 m were tested while using a constant dust density of 2.6 g/cm 3 as shown in Fig.…”

Section: Sensitivity To Dust Particle Mean Diametermentioning

confidence: 99%

“…Dust flux has been measured and modeled for different applications such as human health impact, air quality, soil formation, and transportation visibility. Several experimental studies have measured dust deposition rates as an average over fairly short time periods in areas such as North Africa, America, the Middle East, and Asia [16][17][18][19][20][21][22][23]. Additionally, dust atmospheric models have been designed to predict dust emission, concentration and deposition [24][25][26].…”

Section: Introductionmentioning

confidence: 99%