Weathering of Iron-Bearing Minerals in Soils and Saprolite on the North Carolina Blue Ridge Front: I. Sand-Size Primary Minerals

Graham, Robert C.; Weed, S. B.; Bowen, L. H.; Buol, S. W.

doi:10.1346/ccmn.1989.0370103

Cited by 29 publications

(19 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Magnetite particles are resistant to weathering, releasing their toxic components slowly into the environment (Graham et al 1989). However, layer silicates and carbonates are much less resistant than magnetite (Vogelein et al 2005); thus, beside water-soluble lead, they may be the potential source of mobile Pb in the TSP samples.…”

Section: Discussionmentioning

confidence: 99%

Lead isotope composition and host phases in airborne particulate matter from Budapest, Hungary

Sipos¹,

Németh²,

Kis³

2013

Central European Geology

View full text Add to dashboard Cite

Lead is a frequent, potentially toxic pollutant of the urban environment. Its risk assessment in airborne particulate matter requires data both on its speciation and potential sources. In this paper we present results of a detailed mineralogical (XRD and TEM) and geochemical (selective chemical extractions and lead isotope ratio analyses) study of total suspended particulate (TSP) matter samples from Budapest, Hungary, to fulfill these requirements.Total lead concentrations showed significant enrichment in the studied TSP samples as compared to its geochemical background value. It could be associated with several host phases. The potentially mobile fraction of lead, which could also be harmful to humans, can be as high as 16% of the total lead. This is represented by Pb sorbed on the surface of clay minerals and in the form of carbonates (and sulfates). On the other hand, between 20 and 30% of total lead of TSP material is hosted by magnetite, a highly resistant mineral. However, its rapid oxidation during combustion processes to hematite and/or weathering in the acidifying urban environment to ferrihydrite, may result in the enhanced mobilization of lead.The lead isotope composition of the TSP samples suggests the mixing of several sources for this metal, with slight variation among the sampling sites. Despite the phasing out of leaded gasoline, its contribution to the Pb content of the TSP was observed. Our data also supported that the presence of lead of gasoline origin decreases in the airborne TSP during the last decade in Budapest. Another important source for lead is found to be coal combustion linked to domestic and industrial heating. Lead isotope ratio data suggest additional source(s) for this metal, at least in certain localities, but further investigations are necessary to specify them.

show abstract

Section: Discussionmentioning

confidence: 99%

Lead isotope composition and host phases in airborne particulate matter from Budapest, Hungary

Sipos¹,

Németh²,

Kis³

2013

Central European Geology

View full text Add to dashboard Cite

show abstract

“…Le caractère hydroxy-alumineux est moins accusé dans les horizons éluviaux supérieurs, riches en matière organique et de plus faible pH (Weed et Bowen, 1990), ce qui indique une action des acides organiques dans la formation des hydroxypolymères d'aluminium entre les feuillets. La formation de la goethite et de l'hématite résulte de l'altération de la biotite, des amphiboles et du grenat (Cady, 1950 ;Graham et al, 1989aGraham et al, , 1989bRebertus et Buol, 1985a ;Velbel, 1984aVelbel, , 1984bVelbel, , 1985.…”

Section: Introductionunclassified

Interprétation géopédologique du manteau d’altération de la Blue Ridge et des collines du Piedmont appalachien de Virginie (É.-U.A.)

Jolicoeur¹,

Bouchard²,

Kimpe³

2007

gpq

View full text Add to dashboard Cite

Dans la Blue Ridge et les collines du Piedmont appalachien de Virginie centrale, le régolite est en grande partie constitué par un manteau d'altération. Son épaisseur diminue vers les sommets, mais il peut atteindre plus de 7 m au bas des versants. Le front d'altération est irrégulier et l'altérite forme des poches où l'on distingue une isaltérite sableuse et une alterite sablo-limoneuse à texture modifiée. La fraction argileuse est dominée par la kaolinite et l'halloysite. L'analyse thermogravimétrique d'échantillons totaux indique que la proportion de phyllosilicates 1/1 augmente de l'isaltérite à l'altérite à texture modifiée et aux horizons pédologiques. Elle atteint 37 % dans les horizons Bt de certains Ultisols. La gibbsite est un minéral important de plusieurs des profils étudiés. Dans les sols, les interstratifiés mica/vermiculite et la vermiculite, à caractère hydroxy-alumineux, constituent une part importante de la fraction argileuse, résultant d'une brunification acide. L'évolution géochimique globale est caractérisée par une perte précoce des bases, un appauvrissement modéré en Si et un enrichissement corrélatif en Al et en Fe. La partie supérieure du manteau d'altération est tronquée par endroits et des colluvions superficielles le recouvrent parfois en bas de pente. Des Inceptisols et des Ultisols se sont développés sur ces matériaux. Leur distribution actuelle relève d'une déstabilisation des pentes qui pourrait être contemporaine du dernier maximum glaciaire. La formation des altérites les plus évoluées remonterait au moins au Sangamonien, mais il manque de repères chronologiques et de datations absolues pour ces formations et la déstabilisation des versants dans cette région.In the Blue Ridge and Piedmont foothills of central Virginia, a widespread weathering mantle has developed in granitoid rocks. It thins out towards higher elevations but may reach values of at least 7 m at footslopes. The weathering front is irregular, limiting residuum pockets of sandy saprolite, corestones, and loamy sand nonsaprolite residuum. Kaolinite and halloysite are dominant secondary minerals in the clay fraction. DTG analysis of whole-residuum and whole-soil samples shows that 1/1 phyllosilicate contents increase upwards from saprolite to nonsaprolite residuum and to soil profiles, reaching 37 % in Bt horizons of some Ultisols. Gibbsite is a significant constituent in several profiles. In soil horizons, Al-vermiculite and Al-mica-vermiculite are major clay minerals, indicating that present pedogenetic processes are that of an acid brunification. Bulk geochemical evolution is characterized by a sharp early loss of bases, moderate depletion in Si and concomitant enrichment in Al and Fe. The residuum cover has been eroded in its upper part and is sometimes covered by thin colluvium deposits at footslopes. Inceptisols and Ultisols have developed upon both residuum and colluvium. Their present spatial distribution is related to a regional destabilization of slopes to be correlated with the last glacial maximum. Age of p...

show abstract

“…Others have precipitated from solution in the soil, e.g., gibbsite and goethite (Calvert et al, 1980;Schwertmann and Taylor, 1977). Graham et al (1989) described the weathering morphologies and associated alteration products of the sandsize primary minerals in soils and saprolite on the Blue Ridge Front and provided information on the sources of the secondary minerals. The clay-size fraction of the soils and saprolite contains the minerals most responsible for their chemical behavior, and in this paper the origin and characteristics of these minerals, particularly the Fe-bearing minerals, are reported.…”

Section: Introductionmentioning

confidence: 99%

“…The physical setting of the study area is more completely described elsewhere (Graham, 1986). Characteristics of the mica gneiss and schist bedrock are reported by Graham et al (1989).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Weathering of Iron-Bearing Minerals in Soils and Saprolite on the North Carolina Blue Ridge Front: II. Clay Mineralogy

Graham

1989

Clays and clay miner.

Self Cite

View full text Add to dashboard Cite

Abstract--The mineralogy of the clay fraction was studied for soils and saprolite on two Blue Ridge Front mountain slopes. The clay fraction contained the weathering products of primary minerals in the mica gneiss and schist parent rocks. Gibbsite is most abundant in the saprolite and residual soil horizons, where only chemical weathering has been operable. In colluvial soil horizons, where both physical and chemical weathering have occurred, the clay fraction consists largely of comminuted primary phyllosilicates--muscovite, chlorite, and possibly biotite--and their weathering products: vermiculite, interstratified biotite/vermiculite (B/V), and kaolinite. The clay-size chlorite contains Fe 2 § as indicated by MSssbauer spectroscopy, and is more resistant to weathering than biotite. The vermiculite and B/V, both weathering products of biotite, contain Fe 3 § Vermiculite in colluvial soils and, especially, surface horizons is weakly hydroxy-interlayered. The kaolinite in the clay fraction resulted at least partly from the comminution of kaolinized biotite in coarser fractions.The hematite content ranged from 0 to 8% of the clay fraction and strongly correlates (r = .95) with dry clay redness, as measured by the redness rating: RR = (10 -YR hue) x (chroma) + (value). The hematite is largely a product of the weathering of almandine; thus, the soil redness is dependent on the amount of almandine in the parent materials and its degree of weathering in the soils. Goethite (13-22% of the clay fraction) imparts a yellow-brown hue to soils derived from almandine-free parent rocks. The release of Fe in relatively low concentrations during the weathering of Fe-bearing primary minerals, particularly biotite, appears to have promoted the formation of goethite.

show abstract

Weathering of Iron-Bearing Minerals in Soils and Saprolite on the North Carolina Blue Ridge Front: I. Sand-Size Primary Minerals

Cited by 29 publications

References 25 publications

Lead isotope composition and host phases in airborne particulate matter from Budapest, Hungary

Lead isotope composition and host phases in airborne particulate matter from Budapest, Hungary

Interprétation géopédologique du manteau d’altération de la Blue Ridge et des collines du Piedmont appalachien de Virginie (É.-U.A.)

Weathering of Iron-Bearing Minerals in Soils and Saprolite on the North Carolina Blue Ridge Front: II. Clay Mineralogy

Contact Info

Product

Resources

About