Age and Uranium Content of Soil Micas From Antarctica by the Fission Particle Track Replica Method

Jackson, M. L.; Lee, S. Y.; Ugolini, F. C.; Helmke, P. A.

doi:10.1097/00010694-197704000-00005

Cited by 14 publications

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“…The solutions were changed 3 times after 1 hr of contact with each fresh solution. Each disc was removed and gently pressed between filter paper to remove excess solution on the mica surface, One side of the prepared samples were cleaved off with Scotch tape and the other side (the fission tracks of which were to be replicated; Seitz and Taylor, 1974;Jackson et al, 1977) was covered with an untreated muscovite disc flake 6-mm dia. and 0.1 mm thick (No.…”

Section: Methodsmentioning

confidence: 99%

Surface Charge Density Determination of Micaceous Minerals by ²³⁵U Fission Particle Track Method

Lee

Jackson

1977

Clays and clay miner.

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Abstract--The surface charge density of mica (001) cleavages was determined by counting the number of fission particle tracks in a given area of a 6-ram muscovite disc replica with optical and scanning electron microscopy after saturation of the layer charge by washing with 0.5 M UO2(NO3)2 solution, dilution of the excess salt by washing with 0.01 M UOz(NO3) 2 in 0.005 M HNO 3 (pH 2.4), blotting off the excess liquid, thermal neutron activation in contact with the muscovite disc, etching the muscovite, and counting the 235U fission tracks/cm 2. In initial studies, the uranyl cations were found to hydrolyze from the cleavage surface continuously during the washings with water, ethanol or acetone to remove excess salts, but the urany! cations in the interlayers near broken edges and crystallographical steps were strongly retained even against washings with 0.5 M CaCI2 solution. The hydrolysis of UO~ + from the smooth portions of the flake surfaces was avoided by the use of three 1-hr final washings with the 0.01 M UO2(NO3)2 in 0.005 M HNO3 solution. Each flake was pressed between filter papers three times to remove the excess solution. A negligible amount of excess salt remained on the cover glass controls. The UO~ + cations retained (mean, 3.6 + 0.2 x 10 .7 mequiv./cm 2) on the cleavage surfaces of various micas were nearly equivalent to the theoretical surface charge (cation exchange capacity, 3.5 • 10 .7 mequiv./cm2), showing that hydrolysis was prevented. The uranium on the unblemished mica planar surfaces increased with increasing uranyl concentrations in the final washing solution, indicating that the excess salt remaining on the surfaces had become significant. With a given UO 2+ salt concentration, the uranium on the surface increased on increasing the solution pH from 2.5 to 3.5, attributable to the formation of polymeric ions such as U2025 + and U30~ + with higher uranium retention per unit positive charge equivalent to the fixed negative charge of the mineral surface. Uranyl cations replaced much of the interlayer cations from vermiculites even after K, Rb and Cs presaturation and drying from 110~ were employed. Strong adsorption of uranyl cations (in a form not replaced by washings with a neutral salt solution), which occurred in the defects of micaceous minerals, is important in the interpretation of actinide element retention in soils and sediments wherein these minerals are abundant.

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Section: Methodsmentioning

confidence: 99%

Surface Charge Density Determination of Micaceous Minerals by ²³⁵U Fission Particle Track Method

Lee

Jackson

1977

Clays and clay miner.

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“…However, Glazovskaia (1958) working with exfoliated rock crusts and minerals collected near the Russian Mirnyy Station concluded that feldspars were altered and that authigenic clay was formed. Ulterior investigations conducted on soils by Ugolini (1964); Claridge (1965); Ugolini and Anderson (1973); Jackson et al (1977); Ugolini and Jackson (1982) provided evidences that chemical weathering was occurring under the present cold-xeric environment.…”

Section: History Of Soil Investigations In Antarcticamentioning

confidence: 99%

Antarctic soils and soil formation in a changing environment: A review

2008

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“…Serpentized chlorite is also found in small amounts. Chlorite has been suggested as a product of physical weathering of rocks (Bockheim 1982), although it can be converted from biotite (Jackson et al 1977). 3.…”

Section: Particle Size and Clay Minerals: Discussionmentioning

confidence: 99%

Rock weathering in blockfields: some preliminary data from mountain plateaus in North Norway

Whalley

Rea

Rainey

et al. 1997

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The formation of blockfields is a process usually attributed to weathering. In mountain areas this is generally assumed to be mechanical weathering (frost shattering). Evidence from two high plateaus [900 and 1350 m above sea level (a.s.1.)] in North Norway (c. 70 ~ N) suggests that chemical action is at least as important as mechanical activity in blockfield formation. The bedrock in both areas consists of complex banded gabbros. Blockfields circumscribe ice masses and are generally > 1 m thick. They contain high percentages of material in the silt and clay sized fractions, including a variety of clay minerals: gibbsite, chlorite, vermiculite and kaolinite, as well as magnetite/maghemite. The blockfield thickness and presence of these weathering products suggests both a considerable (pre-Pleistocene) length of time required for development as well as warmer conditions than are found now (mean annual air temperature c. 0~ or in the period since deglaciation. It is suggested that these blockfields represent a preglacial palaeosurface which formed initially under warmer conditions and has survived, largely intact, beneath all the Pleistocene ice sheets.

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Age and Uranium Content of Soil Micas From Antarctica by the Fission Particle Track Replica Method

Cited by 14 publications

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Surface Charge Density Determination of Micaceous Minerals by ²³⁵U Fission Particle Track Method

Surface Charge Density Determination of Micaceous Minerals by ²³⁵U Fission Particle Track Method

Antarctic soils and soil formation in a changing environment: A review

Rock weathering in blockfields: some preliminary data from mountain plateaus in North Norway

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Age and Uranium Content of Soil Micas From Antarctica by the Fission Particle Track Replica Method

Cited by 14 publications

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Surface Charge Density Determination of Micaceous Minerals by 235U Fission Particle Track Method

Surface Charge Density Determination of Micaceous Minerals by 235U Fission Particle Track Method

Antarctic soils and soil formation in a changing environment: A review

Rock weathering in blockfields: some preliminary data from mountain plateaus in North Norway

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Surface Charge Density Determination of Micaceous Minerals by ²³⁵U Fission Particle Track Method

Surface Charge Density Determination of Micaceous Minerals by ²³⁵U Fission Particle Track Method