The Dependence of Localized Crystallization of Halloysite and Kaolinite on Primary Minerals in the Weathering Profile of Granite

Jeong, Gi Young

doi:10.1346/ccmn.2000.0480205

Cited by 43 publications

(18 citation statements)

References 27 publications

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“…Because hornblende and plagioclase weather completely in the saprock layer , these minerals could contribute Al and Si to pore fluids in the saprock. Although some studies have linked halloysite formation to the weathering of K-feldspar (Jeong, 2000;Jeong and Kim, 2003;Papoulis et al, 2004), tubular halloysite was not observed on K-feldspar in our ESEM images and K-feldspar is a mineral with a smaller proportion (2%) in the quartz diorite than biotite (9%) . Our XRD results also are inconsistent with feldspar as the main source of halloysite formation because the secondary mineral peaks were stronger in saprolite, where biotite was the main mineral undergoing weathering.…”

Section: Discussion Bedrock Weathering and Secondary Mineral Formatiocontrasting

confidence: 66%

Halloysite Nanotubes and Bacteria at the Saprolite–Bedrock Interface, Rio Icacos Watershed, Puerto Rico

Minyard¹,

Bruns²,

Martı́nez³

et al. 2011

Soil Science Soc of Amer J

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Quartz diorite bedrock underlying the Luquillo Mountains of eastern Puerto Rico undergoes weathering at one of the fastest documented rates for granitic rocks in the world. Although tropical temperatures and precipitation promote rapid weathering in this location, increased bacterial densities in the regolith immediately above the bedrock suggest that microorganisms contribute to mineral weathering as well. Deep saprolite and saprock samples were obtained at the bedrock interface in an upland location (Guaba Ridge) in the Rio Icacos watershed for examination by environmental scanning electron microscopy (ESEM). In ESEM images, mineral nanotubes were observed ro occur frequently in association with coccus-and rod-shaped structures resembling bacteria. These nanotubes (50-140-nm width and 150-2700-nm length) were identified as halloysite using transmission electron microscopy. Observations of multiple nanotubes on the surfaces of an individual cell are consistent with the cell's exterior functional groups interacting with Si in pore water to facilitate halloysite nudeation. We propose that one mechanism by which bacteria conrdbute to the rapid weathering of quartz diorite minerals in this regolith is by lowering the free energy for secondary mineral formation. The presence of bacterial surfaces may result in more rapid removal of Si from solution, thereby increasing the dissolution rates of primary minerals.Abbreviations: EDS, energy dispersive x-ray spectrometry; ESEM, environmental scanning electron microscopy; TEM, transmission electron microscopy; XRD, x-ray diffraction.

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Section: Discussion Bedrock Weathering and Secondary Mineral Formatiocontrasting

confidence: 66%

Halloysite Nanotubes and Bacteria at the Saprolite–Bedrock Interface, Rio Icacos Watershed, Puerto Rico

Minyard¹,

Bruns²,

Martı́nez³

et al. 2011

Soil Science Soc of Amer J

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“…Islam and Lotse (1986) also observed a broad contribution to the diffraction curve, but they attributed it to randomly interstratified mica-chlorite. Halloysite is typically formed by weathering of volcanic ash materials, but it has also been reported in nonvolcanic environments ( Jeong, 2000). Taken together, the diffraction and the FT-IR data suggest that clay fractions of all soil samples contain some well crystallized clay types (illite and kaolinite) that probably originated from the soft parent rock as well as types that can be considered as decomposition products of the illite by preservation of the 2:1 layer structure (vermiculite/smectite and HIV/HIS) or by recrystallization (halloysite and gibbsite).…”

Section: Later) Thus If the Illite Contains 8% K 2 O (Fanmentioning

confidence: 99%

Weathering Intensity Controlling Sustainability of Ultisols Under Shifting Cultivation in the Chittagong Hill Tracts of Bangladesh

Gafur¹,

Koch²,

Borggaard³

2004

Soil Science

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S OILS in the monsoon-affected regions of Asia develop under seasonally very high rainfall and general high soil temperatures which promote (i) soil acidification because of intense biological activity and leaching, (ii) dissolution reactions causing release of essential plant nutrients, Steep slopes and very high rainfall (nearly 3000 mm yr Ϫ1 ) concentrated within a few months (monsoon) suggest that the practice of slash-andburn agriculture (known locally as Jhum) in the Chittagong Hill Tracts (CHT) region of Bangladesh will induce severe erosion losses. This is particularly so in recent years because high population pressure has reduced the fallow period from 10 to 15 years to 3 to 5 years. A 2-year study of soil composition and erosion comparing a Jhum cultivated catchment and a neighboring non-burnt catchment showed additional loss by runoff of about 30 Mg ha Ϫ1 (41.1 from the burnt site minus 11.5 from the nonburnt site) of upland soil, containing substantial amounts of plant nutrients, as a result of burning. The main loss occurred within 2 to 3 months after burning, but after 1 year, losses in the Jhum cultivated catchment were the same as in the non-burnt catchment. Furthermore, as almost half of the sediment was deposited in lower parts of the catchment, the net loss (export) was 15.5 Mg ha Ϫ1 , which corresponds to only 3 times the upper critical limit (about 5 Mg ha Ϫ1 yr Ϫ1 ) of sustainability, indicating that Jhum fallowed for more than 3 years may be sustainable. The ash from the burnt vegetation was found to add more available Ca, Mg, K, S, Fe, Mn, and Zn to the soil than was removed in runoff sediments, whereas soil C, N, P, and Cu contents decreased. X-ray diffraction, Mössbauer and infrared spectroscopy, and total chemical analysis of the clay fractions from selected soil samples in profiles from upper, middle, and lower parts of a slope in the Jhum catchment showed composition and properties of the fractions that were almost identical, irrespective of soil depth and site position. The high clay contents (31-51%), the rather unique clay mineralogy (gibbsite, goethite, halloysite, HIV/HIS, illite, kaolinite, vermiculite/smectite), and the horizontal and vertical uniformity are clear indicators of intensive and fast weathering. The fast and profound weathering results from a combination of an easily weatherable parent rock (micaceous shale) exposed to a hot alternating very wet and very dry climate and vigorous vegetation. This combination and the resulting soil development may, in turn, explain the observed high degree of hydraulic and chemical resilience associated with Jhum in CHT. However, more studies over longer periods of time are needed to determine whether current Jhum, with fallow periods of only 3 to 5 years, is sustainable in the long run. (Soil Science 2004;169:663-674)

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“…The SEM reveals that these clay minerals have an exfoliated "booklet-type" morphology ( Fig. 5f), which is commonly observed for kaolinite crystallizations in altered rocks (Jeong 2000;Papoulis et al 2004).…”

Section: Plagioclase Weathering Microsystemsmentioning

confidence: 77%

Sorption and distribution of Zn in a sludge-amended soil: influence of the soil clay mineralogy

Proust

2014

J Soils Sediments

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Purpose Conventional pedological survey generally assesses soil metal pollution by comparing total metal concentrations in soil to geochemical baselines in parent rock. This global approach overlooks the sorption capacities of the clay minerals which form at micrometric scale in weathering microsystems and are essential for the behaviour of metals in soil. Therefore, our aim was to investigate the impact of these weathering microsystems and their clay mineralogy upon Zn sorption and distribution throughout a sludgecontaminated soil. Materials and methods Two soil profiles with the same diorite parent rock were sampled: (i) an amended soil profile (AS) that received for 10 years wet sewage sludges heavily loaded with Zn and (ii) a control soil profile (CS) free of sludge spreading. Soil samples were carefully collected as undisturbed blocks using plastic core samplers to prevent sample metal contamination. Each sample was further divided into two subsamples: the first was devoted to bulk chemical analyses, mineral grains separation and X-ray diffraction (XRD) analyses, whereas the second part was used for thin-section preparation and electron probe microanalyses (EPMA). Results and discussion Zn in the control soil is inherited from the weathering parent rock, whereas it is supplied at the surface of the amended soil by sludges spreading. Each rock-forming mineral weathers into specific clay minerals: amphibole into saponite and montmorillonite and plagioclase into montmorillonite and kaolinite. Each clay mineral, with its specific sorption capacity, controls the Zn distribution within the soil: the smectites produced by the amphiboles have high sorption capacity and favour Zn retention in the upper horizons of the soil; the kaolinites produced by the plagioclases have lower sorption capacity, do not retain Zn in the surface horizons and allow it to migrate to deeper horizons where it is sorbed onto the montmorillonites. Conclusions The clay minerals appear to be important soil components controlling the mobility of Zn in the contaminated soils. The micrometric mineralogical approach proves to be relevant to describe the importance of the clay mineral species in the Zn fixation at the solid/solution interface. When applied to a wider range of heavy metals and clay minerals, it could be a useful improvement in the surface complexation modelling used to explain metal cation sorption in soils.

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The Dependence of Localized Crystallization of Halloysite and Kaolinite on Primary Minerals in the Weathering Profile of Granite

Cited by 43 publications

References 27 publications

Halloysite Nanotubes and Bacteria at the Saprolite–Bedrock Interface, Rio Icacos Watershed, Puerto Rico

Halloysite Nanotubes and Bacteria at the Saprolite–Bedrock Interface, Rio Icacos Watershed, Puerto Rico

Weathering Intensity Controlling Sustainability of Ultisols Under Shifting Cultivation in the Chittagong Hill Tracts of Bangladesh

Sorption and distribution of Zn in a sludge-amended soil: influence of the soil clay mineralogy

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