Ultrabasic

Talc and pyrophylUte are found in metamorphic rocks that are rich in Mg and Al, respectively. Talc is most common in metamorphosed ultrabasic rocks and in metamorphosed siUceous dolomite. PyrophylUte is found in metapeUtes, including metabauxites and metakaoUnites, and in rocks enriched in Al by hydrothermal processes (106). 

O Hara MJ (1968) The bearing of phase equilibria studies in synthetic and natural systems on the origin and evolution of basic and ultrabasic rocks. Earth Sci Rev 4 69-133 O Nions RK, McKenzie D (1993) Estimates of mantle thorium/uranium ratios from Th, U and Pb isotope abundances in basaltic melts. Phil Trans Royal Soc 342 65-77 Oversby V, Gast PW (1968) Lead isotope compositions and uranium decay series disequilibrium in reeent volcanic rocks. Earth Planet Sci Lett 5 199-206... 

Cobalt is the 30th element in the earth s crust with an average of 20-30 mg/kg (Bowen, 1979 Vinogradov, 1959). Ultrabasic rocks and their metamorphized serpentines contain 100-200 mg/kg Co, followed by basic igneous rocks (30-45 mg/kg), while acid rocks have the lowest Co... 

Soil is a mixture of solid materials, air and, usually, water and organic matter. The radium content of soil often reflects that of the rocks from which the solid materials are derived by physical and chemical activity. The observed ranges are from 0 to 20 Bq kg for ultrabasic rocks (dunite) to 1 to 1835 Bq kg for igneous metamorphic rocks (gneiss) (Wollenberg, 1984). While these ranges are broader than those for measured for soils, the mean values for rocks, excluding alkali rocks, is consistent with the means observed for soils. 

Igneous rocks (i.e., rocks of magmatic origin) are classified chemically according to their percentage silica (Si02). Those with more than 66% are generally termed acidic, between 66% and 52% intermediate, basic between 52% and 45% and ultrabasic less than 45% (Read, 1970 204). They may additionally be... 

Arndt, N. T. (1977). Partitioning of nickel between olivine and ultrabasic and basic komatiitic liquids. Carnegie. Inst. Washington Year Book, 76, 553-57. 

Pearce, T. H. (1978). Olivine fractionation equations for basaltic and ultrabasic liquids. Nature, 276, 771-4. 

Basic and ultrabasic rocks (peridotites, serpentinites), kimberlitic xenolites, rodingites, eclogites... 

Ferguson J. and Currie K. L. (1971). Evidence of liquid immiscibility in alkaline ultrabasic dikes at Callender Bay, Ontario. J. Petrol, 12 561-585. 

Selandian Rb-Sr ages of 59.6 2.8 Ma and 60.3 0.8 Ma were determined for the K1A and K19 bodies, respectively these bodies occur in the southwestern part of the field and are either barren of diamond or have the poorest diamond results within this field (Hood McCandless 2004 Fig 1). Mineralogical (e.g., amphibole, sanidine) and geochemical evidence (e.g., flatter chondrite-normalized REE pattern versus the steep profile of typical kimberlite) enticed Eccles et al. (2008) to conclude that these rocks are better referred to as hybrid kimberlite-ultrabasic rocks. 

Oxidized upper zones of Fe-rich rocks with high concentrations of Fe oxides are found in pyritic (gossan) and ultrabasic rocks. These rocks are often the subject of exploration owing to their content of such non-ferrous metals as Cu, Co, Ni and Zn. These metals are intimately associated with the iron oxides, mainly goethite and he-... 

ULTRABASIC. A term proposed by Judd, in 1881. for exceedingly mafic igneous rocks composed largely, if not entirely, of llie ferromag-nesium minerals such as olivine and pyroxene. The limiting figure of total silica is approximately 45%, or barely sufficient to supply the needs of the... 

An HPLC assay was described as a routine method for the determination of FLU and its hydroxylated metabolite 7-OH FLU in pig kidney tissues (188). The sample was extracted with ethyl acetate after evaporation, the residue was dissolved in MeCN-oxalic acid (1 1). Analytical separation was performed using fluorimetric detection under gradient elution. The authors recommended an Ultrabase C-18 column, which allowed the work to be carried out at extreme pH values, ranging from 2 to 8. The assay was specific and reproducible within the range 50-2500 yug/kg recovery was 94.8%. 

Thyroxine and thyroxine glucuronide were separated on a C]8 Ultrabase column (4.6 mm X 250 mm, 10 p.m). Solvent A was a 35 65 (v/v) mixture of methanol and 20 mM potassium phosphate buffer (pH 7.0) containing 1% triethylamine. Solvent B was methanol. A linear gradient from 0 to 100% B was run in 15 minutes. Elution was completed by maintaining 100% B for 5 minutes. Two methods of on-line radiochemical detection was used liquid scintillation using a 2 mL detection cell, and solid scintillation using lithium scintillator glass in an effective cell volume of 400 p-L. The latter method was most convenient. 

Ultrabasic Bodies in Unst, Shetland, Contrib. Mineral. Petrol. (1969) 24,275. 

The fourth and main zone is the Krivoy Rog-Kremenchug, developed 1800-2000 m.y. ago. The accumulation of rocks began here, as in the other zones, with the eruption of metabasic and ultrabasic rocks, which then probably were locally succeeded by rocks of the keratophyre series. Most of the iron cherts, however, are not related to the initial but rather to the middle stage of development of the zone, when the sedimentary cherty iron-formation proper of the Middle suite of the Krivoy Rog group was formed. Maximum development of iron cherts is characteristic of the Saksagan and Kremenchug basins (Fig. 3). 

The cherty iron-ultrabasite formation (CIU) is not very widespread only in the Konka syncline and in the Kudashev sector of the Verkhovtsevo syncline are low-grade banded cherty iron intercalations of no great thickness encountered, interbedded with apo-ultrabasic schists. 

An analysis of sedimentation in the Precambrian made by Tugarinov and Voytkevich (1966) on the basis of a summary of recent geochemical data gives a clear picture of the directionality and irreversibility of the geologic evolution of the Earth s crust. Whereas in the Early Precambrian the composition of the sedimentary-metamorphic complexes is characterized by the predominant development of basic and ultrabasic effusives, altered... 

The BIF of the greenstone belts of Southern Africa are very old (older than 3.3- yr). Beukes (1973) mentions that in the lower part of the section of the Hooggenoeg formation of this belt, carbonaceous cherts completely devoid of iron appear in a thick sequence of metamorphosed tholeiitic basalts with intercalations of ultrabasic and acid lavas. The first signs of iron appear in the upper part of the section in a banded chert directly underlying the BIF. In this chert, small segregations of iron-rich material are closely associated with black bands of carbonaceous chert or replace them. 

Treiman A. H. (1986) The parental magma of the Nakhla achondirte ultrabasic volcanism on the shergottite parent body. Geochim. Cosmochim. Acta 50, 1061-1070. 

Williams D. A., Davies A. G., Keszthelyi L. P., and Greeley R. (2001a) The summer 1997 eruption at Pillan Patera on lo implications for ultrabasic lava flow emplacement. J. Geophys. Res. Planets 106, 33105-33119. 

Benson W. N. (1926) The tectonic conditions accorrrpanying the intrusion of basic and ultrabasic igneous rocks. Natl. Acad. Sci. Mem. 19, 1-90. 

Den Tex E. (1969) Origin of ultramafic rocks, their tectonic setting and history a contribution to the discussion of the paper The origin of ultramafic and ultrabasic rocks by P. J. Wylhe. Tectonophysics 7, 457-488. 

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