Geochemical isolation

Sykes, G.A., Collins, M.J. and Walton, D.I. (1995). The significance of a geochemically isolated intracrystalline organic fraction within biominerals. Organic Geochemistry 23 1059-1065. 

Martian meteorites and Mars rover analyses suggest that it is a basalt-covered world, a conclusion supported by orbital measurements. Basalts of different ages appear to have distinct compositions. Since its original differentiation, the Martian mantle has remained geochemically isolated, although it is periodically melted to produce basalts. The core has an appreciable amount of sulfide, as inferred from trace elements in basalts. Water, once important in producing clays and sulfates, has now retreated into the subsurface. 

The compositions of the crusts of the Moon and Mars are distinct - one is dominated by feldspathic cumulates from an early magma ocean, and the other by basaltic lavas. Regional patterns reflect differences in subjacent mantle compositions. The compositions of the mantles and cores of these bodies can be constrained by chemical analyses of mantle-derived basalts. The interiors of both bodies have remained geochemically isolated, because of the absence of plate tectonics. 

One of the most complex separation schemes utilizes flash liquid chromatography and PLC to obtain petropophyrins both from geochemical samples or those synthesized and used subsequently as standards [110]. Ocampo and Repeta [111] described the scheme of petroporphyrins isolation in which at the first step the sediment extract is fractionated into ten fractions on silica gel using dichlo-romethane (fractions 1 to 4), a mixture of dichloromethane-acetone with increasing acetone concentrations (for fractions 5 to 9), and, at last, dichlo-romethane methanol (4 1) (fraction 10). Next, the fifth fraction was separated on silica PLC plates using dichloromethane-acetone (97.5 2.5 v v v) as a developer. Two purple bands (with Rj 0.53 and 0.50) were recovered from silica and purified further on a silica gel column with dichloromethane-acetone (97.5 2.5, v v v) as an eluent. The emiched fraction was then separated by PLC with the same solvent mixture, and the purple bands containing two bacteriopheophytin allomers were recovered with acetone. 

Poirier N, Derenne S, Rouzaud J, Largeau C, Mariotti A, Balesdent J, Maquet J (2000) Chemical structure and sources of the macromolecular, resistant, organic fraction isolated from a forest soil (Lacadee, south-west France). Org Geochem 31 813-827... 

The geochemical signature of the XY orebody within these soils is likely derived from detrital sources, not hydrochemical sources. A hydrochemical signature of the XY orebody was not isolated in these soils by this protocol. Perhaps a less aggressive partial leach protocol may be more suitable given the substrate type. 

Geochemical characterization of humic substances isolated from phosphatic pellets and their surrounding matrix, Ras-Draa, Tunisia... 

This book focuses on geochemical approaches in immobilizing, isolating, or neutralizing waste derived from energy production and consumption. 

Aiken, G. R., McKnight, D. M.,Thom, K. A., and Thurman, E. M. (1992). Isolation of hydrophilic organic acids from water using non-ionic macroporous resins. Org. Geochem. 18(4), 567-573. 

Baglieri, A., Ioppolo, A., Negre, M., and Gennari, M. (2007). A method for isolating soil organic matter after the extraction of humic and fulvic acids. Org. Geochem. 38, 140-150. 

Pettersson, C., Ephraim, J. and Allard, B. (1994) On the composition and properties of humic substances isolated from deep groundwater and surface waters. On. Geochem., 21,443-451. 

Standley, L.J. and Kaplan, L.A. (1998) Isolation and analysis of lignin-derived phenols in aquatic humic substances improvements on the procedures. Org. Geochem., 28, 689-697. 

The distribution of geochemical data may be presented, in their most basic form, through the use of dot maps in which dots, or other symbols selected by the operator, of a size proportional to concentration are plotted at geographical coordinates for each sampled site. Dot sizes may be classified by means of concentration intervals based on percentiles or other statistical methods. Dot maps are often the most suitable method to represent isolated points of a discrete set of geochemical data. 

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