Ti-bearing Minerals Research Articles

Variations of terrigenous sediment supply to the southern slope of the Ulleung Basin, East/Japan Sea since the Last Glacial Maximum

In order to examine the variations of terrigenous detrital components in the core (97PC-19) sediments from the southern margin of the Ulleung Basin, we detail changes in grainsize composition and contents of major elements such as detrital SiO2 (detSiO2), TiO2, Al2O3, MgO and K2O since the Last Glacial Maximum (LGM). The variations of detrital components are characterized by the significant elevations of detSiO2/Al2O3 and TiO2/Al2O3 ratios with the concomitant increase of silt to clay ratios during the last deglaciation (10–15 ka). Such a prominent increase suggests an enhanced flux of detrital quartz and Ti-bearing minerals relative to Al-rich clay minerals which can be attributed to either aeolian transport or hemipelagic advection. Similar variations of detrital components during the last deglaciation are much more pronounced in the core 95PC-1, located more proximal to the Korea Strait, as evidenced by the high sedimentation rate and sand and silt contents. However, this temporal variation is not clearly observed in ODP site 797 far from the Korea Strait. The spatial change of the detrital components among the cores suggests a primary control of hemipelagic fluxes of riverine sediments relative to aeolian dust fluxes on the variations of detrital components since the LGM. The hemipelagic fluxes were most likely derived from the paleochannels of the Nakdong River that extended onto the shelf margin of the Korea Strait during the last sea-level lowstand and increased by shore-parallel transport of paleocurrents through the Korea Strait during the early stage of the postglacial transgression.

Authigenic Ti-Bearing Crystals in a Precambrian Clay from Buenos Aires Province, Argentina

AbstractThe Precambrian Villa Mónica Formation clay was analyzed using petrographic and scanning electron microscopy, X-ray diffraction and chemical analysis, with the aim of characterizing the Ti-bearing phases present and determining their possible origin and/or source. Two Ti-bearing minerals were found to be present, rutile and anatase. The crystals are needles between 5 and 15 µm in size, with no evidence of abrasion or corrosion. They are commonly found in association with the (001) faces of illite flakes or in the pores between the flakes. Their disposition is similar in the three quarries studied. No zonation or differential settling due to differences in specific gravity was observed. In addition, chemical analyses indicated a positive correlation between TiO2 and K2O suggesting that both oxides behave similarly after the deposition of the sediment. The TiO2 content in the bulk fraction ranges from 0.8 to 1.98 wt.%, values that are similar to those exhibited in other clay deposits from different ages and geneses.All observations are consistent with an in situ origin of these Ti-bearing phases during post-depositional processes that included recrystallization of existing minerals and crystallization of new phases. The original detrital minerals such as biotite, ilmenite as well as detrital illite, were the primary sources of the TiO2 and of the Fe oxides that coat the clay. Understanding the origin and the reaction mechanisms involved during the post-depositional alteration of the Villa Mónica Formation suggests that the Ti-bearing phases in different sediment types were formed by similar mechanisms involving redox processes at low to medium temperatures, even in Precambrian sediments where the presence of rutile could lead to an incorrect assumption of high temperatures involved.

03/01932 Incorporation of fibres in geothermal well cements: Berndt, M. L. and Philippacopoulos, A. J. Geothermics, 2002, 31, (6), 643–656

Refractory Ti-bearing minerals in the calcium-, aluminum-rich inclusion (CAI) Inti, recovered from the comet 81P/Wild 2 sample, were examined using analytical (scanning) transmission electron microscopy (STEM) methods including imaging, nanodiffraction, energy-dispersive spectroscopy (EDX) and electron energy loss spectroscopy (EELS). Inti fassaite (Ca(Mg,Ti,Al)(Si,Al)2O6) was found to have a Ti3+/Ti4+ ratio of 2.0 ± 0.2, consistent with fassaite in other solar system CAIs. The oxygen fugacity (logfO2) of formation estimated from this ratio, assuming equilibration among phases at 1509 K, is −19.4 ± 1.3. This value is near the canonical solar nebula value (−18.1 ± 0.3) and in close agreement with that reported for fassaite-bearing Allende CAIs (−19.8 ± 0.9) by other researchers using the same assumptions. Nanocrystals of osbornite (Ti(V)N), 2–40 nm in diameter, are embedded as inclusions within gehlenite, spinel and diopside in Inti. Vanadium is heterogeneously distributed within some osbornite crystals. Compositions range from pure TiN to Ti0.36V0.64N. The possible presence of oxide and carbide in solid solution with the osbornite was evaluated. The osbornite may contain O, but C is not present at detectable levels. The presence of osbornite, likely a refractory early condensate, together with the other refractory minerals in Inti, indicates that the parent comet contains solids that condensed closer to the proto-sun than the distance at which the parent comet itself accreted. The estimated oxygen fugacity and the reported isotopic and chemical compositions are consistent with Inti originating in the inner solar system like other meteoritic CAIs. These results provide insight for evaluating the validity of models of radial mass transport dynamics in the early solar system. The oxidation environments inferred for the Inti mineral assemblage are inconsistent with an X-wind formation scenario. In contrast, radial mixing models that allow accretion of components from different heliocentric distances can satisfy the observations from the cometary CAI Inti.

Mineralogical evidence for red coloration of sandstones at the Chilgok Formation of the Cretaceous Hayang Group, Southeastern Korea

The present study was focused on red sandston beds occurring in the Chilgok Formation, lower Hayang Group of Cretaceous age. Red sandstones consist mainly of plagioclase, quartz, and volcanic rock fragment, with accessory minerals such as biotite, chlorite, pyroxene, hornblende, leucoxene, ilmenite, sphene, pyrite, and hematite. Volcanic rock fragments composed of pyroxene, plagioclase, and glass material are intensively altered. Reddening of sandstones was preferentially attributed to the presence of hematite, Fe- and Ti-bearing minerals. Hematite pigmentation was largely caused by post-depositional dissolution of Fe-silicates such as chlorite, biotite, and amphibole. Diagnostic alteration of mafic minerals as well as Ti-bearing minerals, together with clay minerals, indicates that pigmentary materials in the red beds inherited from diagenetic sources in the depositional basin, possibly during early diagenesis.

Three compositional varieties of perovskite from kimberlites of the Lac de Gras field (Northwest Territories, Canada)

AbstractIn hypabyssal and crater-facies kimberlites of the Lac de Gras kimberlite field, perovskite occurs as reaction-induced rims on earlier-crystallized Ti-bearing minerals (magnesian ilmenite and priderite), inclusions in atoll spinels and discrete crystals in a serpentine-calcite mesostasis. The mineral is associated with spinels, apatite, monticellite, phlogopite, baryte, Fe-Ni sulphides, ilmenite, diopside and zircon. Uncommon accessory phases found in an assemblage with perovskite include titanite, monazite- (Ce), witherite, strontium-apatite, khibinskite, djerfisherite, wollastonite, pectolite, suolunite, hydroxyapophyllite and bultfonteinite. Three types of perovskite can be distinguished on the basis of composition: (I) REE-Nb-Al-poor perovskite with relatively high Sr and K contents (up to 2.2 and 0.6 wt.% oxides, respectively) occurring as mantles on priderite and inclusions in atoll spinels; (II) perovskite with elevated Al, Fe, Nb and LREE (up to 1.4, 8.3, 9.1 and 17.0 wt.% oxides, respectively) found as discrete crystals and rims on macrocrystic ilmenite; (III) perovskite significantly enriched in Na, Sr, Nb and LREE (up to 3.3, 3.4, 13.0 and 22.6 wt.% oxides, respectively) found as rims on perovskite I and II. The overwhelming majority of perovskite is represented by discrete crystals of type II. In some occurrences, this type of perovskite also has high Th contents (up to 5.5 wt.% ThO2) and Zr contents (up to 3.7 wt.% ZrO2). Textural evidence indicates that perovskite shows an overall evolutionary trend from the most primitive type I towards type III showing the highest Na, Nb and LREE contents. Perovskite of type I probably crystallized under relatively high pressures prior to the precipitation of MUM spinels. Perovskite II crystallized after magnesiochromite, pleonaste and MUM (magnesian ulvöspinel-magnetite) spinels, under increasing fO2. The most compositionally evolved type III formed during near-solidus re-equilibration of the earlier-crystallized perovskite. The compositional variation of the Lac de Gras perovskite can be adequately characterized in terms of five major end-members: CaTiO3 (perovskite), CeFeO3, NaNbO3 (lueshite), Na0.5LREE0.5TiO3 (loparite), and CaFe0.5Nb0.5O3 (latrappite).

Mineralogy and geochemistry of trace elements in bauxites: the Devonian Schugorsk deposit, Russia

AbstractProcesses of mineral alteration involving the mobilization and deposition of more than 30 chemical elements during bauxite formation and epigenesis have been studied on specimens from the Devonian Schugorsk bauxite deposit, Timan, Russia. Chemical analyses of the minerals were obtained by electron microprobe and element distribution in the minerals was studied by element mapping. Interpretation of these data also utilized high-resolution BSE and SE images.The main rock-forming minerals of the Vendian parent rock are calcite, dolomite, feldspar, aegirine, riebeckite, mica, chlorite and quartz; accessory minerals are pyrite, galena, apatite, ilmenite, monazite, xenotime, zircon, columbite, pyrochlore, chromite, bastnaesite and some others. Typically, the grainsize of the accessory minerals in both parent rock and bauxite is from 1 to 40 µm. However, even within these rather small grains, the processes of crystal growth and alteration during weathering can be determined from the zonal distribution of the elements. The most widespread processes observed are: (1) Decomposition of Ti-bearing minerals such as ilmenite, aegirine and riebeckite with the formation of ‘leucoxene’, which is the main concentrator of Nb, Cr, V and W. Crystal growth can be traced from the zonal distribution of Nb (up to 16 wt.%). Vein-like ‘leucoxene’ is also observed in association with organics. (2) Weathering of columbite and pyrochlore: the source of Nb in ‘leucoxene’ is now strongly weathered columbite, while the alteration of pyrochlore is expressed in the growth of plumbopyrochlore rims around Ca-rich cores. (3) Dissolution of sulphide minerals and apatite and the formation of crandallite group minerals: ‘crandallite’ crystals of up to 40 µm size show a very clear zonation. From the core to the rim of a crystal, the following sequence of elements is observed: Ca → Ba → Ce → Pb → Sr → Nd. Sulphur also shows a zoned but more complicated distribution, while the distribution of Fe is rather variable. A possible source of REE is bastnaesite from the parent rock. More than twelve crandallite type cells can be identified in a single ‘crandallite’ grain. (4) Alteration of stoichiometric zircon and xenotime with the formation of metamict solid solution of zircon and xenotime: altered zircon rims also bear large amounts of Sc (up to 3.5 wt.%), Fe, Ca and Al in the form of as yet unidentified inclusions of 1–2 µm. Monazite seems to be the least altered mineral of the profile.In the parent rock, an unknown mineral of the composition (wt.%): ThO2 – 54.8; FeO – 14.6; Y2O5 – 2.3; CaO – 2.0; REE – 1.8; SiO2 12.2; P2O5 – 2.8; total – 94.2 (average from ten analyses) was determined. In bauxite, another mineral was found, which has the composition (wt.%): ThO2 – 24.9; FeO – 20.5; Y2O5 – 6.7; CaO 2.0; – ZrO – 17.6; SiO2 – 8.8; P2O5 – 5.4; total – 89.3 (F was not analysed; average from nine analyses). Presumably, the second mineral is the result of weathering of the first one. Although the Th content is very high, the mineral is almost free of Pb. However, intergrowths of galena and pyrite are observed around the partially decomposed crystals of the mineral. Another generation of galena is enriched in chalcophile elements such as Cu, Cd, Bi etc., and is related to epigenetic alteration of the profile, as are secondary apatite and muscovite.

Dissolution of primary minerals of basalt in natural waters: I. Calculation of mineral solubilities from 0°C to 350°C

The solubilities of forsterite, fayalite, enstatite, ferrosilite, hedenbergite, diopside, anorthite, high-albite, magnetite, hematite, ulvöspinel, ilmenite, F-apatite and OH-apatite and olivine, plagioclase, orthopyroxene, clinopyroxene and Fe–Ti oxide solid solutions of fixed composition were calculated in the temperature range 0–350°C at saturated water vapour pressure. The thermodynamic database used for end-member minerals was that of Robie and Hemingway [Robie, R.A., Hemingway, B.S., 1995. Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (105 Pascals) pressures and at higher temperatures. U.S. Geol. Surv. Bull. 2131, 461 pp.] except for plagioclases [Arnórsson, S., Stefánsson, A., 1999. Assessment of feldspar solubility constants in water in the range of 0° to 350°C at vapor saturation pressures. Am. J. Sci. 299, 173–209.] and that of Shock and Helgeson [Shock, E.L., Helgeson, H.C., 1988. Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: correlation algorithms for ionic species and equation-of-state predictions to 5 kb and 1000°C. Geochim. Cosmochim. Acta 53, 2009–2036.] and Shock et al. [Shock, E.L., Oelkers, E.H., Johnson, J.W., Sverjensky, D.A., Helgeson, H.C., 1992. Calculation of the thermodynamic properties of aqueous species at high pressures and temperatures: effective electrostatic radii, dissociation constants, and standard partial molal properties to 1000°C and 5 kbar. J. Chem. Soc., Faraday Trans. 88, 803–826.] for most aqueous species. For aqueous Fe(OH) 4 − and Al(OH) 4 −, the thermodynamic properties reported by Diakonov et al. and Pokrovskii and Helgeson [Pokrovskii, V.A., Helgeson, H.C., 1995. Thermodynamic properties of aqueous species and the solubilities of minerals at high pressures and temperatures: the system Al 2O 3–H 2O–NaCl. Am. J. Sci. 295, 1255–1342], respectively, were used. In the present study, the standard partial molal properties and the HKF equation-of-state parameters for aqueous H 4SiO 4 0 were revised to better describe the recent experimental results at low temperatures. For H 4SiO 4 0, the new parameters are also consistent with quartz solubility experiments up to 900°C and 5 kbar. Further, the HKF equation-of-state parameters for aqueous Ti(OH) 4 0 were estimated from rutile solubility [Ziemniak, S.E., Jones, M.E., Combs, K.E.S., 1993. Solubility behaviour of titanium (IV) oxide in alkaline media at elevated temperatures. J. Sol. Chem. 22, 601–623.], which enables the calculations of the solubility of Ti-bearing minerals at elevated temperatures and pressures. Much higher solubilities were found for the silicate minerals below 100°C than previously reported, which is related to higher quartz solubility at low temperature and correspondingly new data on the thermodynamic properties of H 4SiO 4 0. The present results are particularly important for the stabilities of primary basaltic minerals of natural composition under weathering conditions. They are also of importance for the study of equilibrium/dis-equilibrium conditions in active geothermal systems.

Temperature and pressure dependence of intervalence charge transfer bands in spectra of some Fe- and Fe, Ti-bearing oxygen-based minerals

Temperature and pressure dependence of intervalence charge transfer bands in spectra of some Fe- and Fe, Ti-bearing oxygen-based minerals

Anomalously low Al 2O 3/TiO 2 values for Archean cherts from the Pilbara Block, Western Australia—possible evidence for extensive chemical weathering on the early earth

Geochemical, sedimentological and mineralogical features of 3.0 Ga Archean cherts and intercalated BIFs from the Pilbara Block, Western Australia, were studied. Chert layers that are well exposed at Point Samson, 20 km north-northeast of Roebourne consist of various types of chert: white-light gray chert, brownish-yellow chert, gray chert, dark gray chert, massive black chert, and light gray chert. The cherts other than brownish-yellow chert consist mostly of microcrystalline quartz with a minor amount of fine silicate minerals and carbonates. The brownish-yellow chert is characterized by a high concentration of goethite. Most cherts contain thin layers characterized by high concentrations of Ti-bearing minerals such as rutile (anatase), FeTi aggregates, and fine TiO 2 grains. Accordingly, Al 2O 3/TiO 2 values in some samples are very low (<1.0), indicating that these samples contain more TiO 2 than Al 2O 3. This geochemical feature is attributed mainly to the supply of detrital materials with high Ti-bearing minerals to the site of deposition, because the Ti-bearing minerals are generally associated with detrital quartz and zircon. Ti-enriched detrital materials are possibly formed by AlTi fractionation during: (1) extensive chemical weathering, or (2) hydrothermal alteration of the source rocks. In the first hypothesis, which we prefer, it is suggested that low pH values (<4) of meteoric waters accelerated the decomposition of rock-forming minerals and prevented precipitation of dissolved Al 3+. Such low pH values of meteoric waters could have been attributed to more violent volcanic activities issuing acid materials (e.g., H 2S and HCl) and/or a higher concentration of atmospheric CO 2 in the Archean than today.

Chlorine, titanium and barium-rich biotites: factors controlling biotite composition and the implications for garnet-biotite geothermometry

Barium-, Cl- and Ti-rich biotite occurs together with garnet, plagioclase and amphibole within narrow shear zones in 1800 Ma old noritic granulites in the Flakstadoy Basic Complex, Lofoten, north Norway. The granulite facies assemblage, plagioclase, clinopyroxene, orthopyroxene, biotite and ilmenite, was replaced by an amphibolite facies mineral assemblage including Ba-, Cl- and Ti-rich biotite during ductile deformation. Biotite shows complex compositional variations with respect to the contents of Ba, K, Cl, Ti, Al, Fe, Mg and Si. There are correlations between Si, AlIV, K, Ba and Cl and between AlVI and Ti. Titanium and Cl are uncorrelated. The Fe and Mg are correlated to both Cl and Ti. Multivariate analysis shows that most of the compositional variation of biotite can be described by two exchange reactions. This indicates that most of the variation in biotite composition was controlled by two chemical variables of the system. The content of the first exchange component (Ti1.0 Fe0.6 Al -1.1 VI Mg-0.8) in biotite can be related to the original distribution of Ti-bearing minerals in the igneous protolith. The content of the second exchange component (Al 0.4 IV Fe0.8 Ba0.5 Cl1.0 Si-0.4 Mg-1.0 K-0.5 OH-1.0) is related to compositional variations of an externally derived Ba- and Cl-bearing fluid in equilibrium with biotite. The initially low Cl-content of the externally derived fluid was increasing during bioite forming reactions, because OH was preferentially incorporated, relative to Cl, into biotite. Continued hydration/chloridisation reactions resulted in a gradual consumption of the free fluid phase, resulting in local fluid-absent conditions. The composition of biotite reflects the composition of the last fluid in equilibrium with the mineral, i.e. the composition of the fluid immediately before the grain boundaries were fluid-undersaturated. Thus, the variations in biotite composition reflect how the fluid was gradually consumed throughout the shear zone rock. The correlations between Fe, Mg, Ba, K and Cl can be attributed to differences between the structure of the crystal lattices and the sizes of the cation sites of OH-phlogopite and Cl-annite. The dependency of the Fe/Mg ratios of biotite on the Cl-and Ti-content has a strong effect on the Fe−Mg partitioning between biotite and garnet. The relationship between lnKD, X Ti Bt and X Cl Bt can be expressed by the regression equation: lnK′ D =-1.82+2.60X Ti Bt +5.67X Cl Bt

Uranium Redistribution Under Oxidizing Conditions in Oklo Natural Reactor Zone 2, Gabon

AbstractThis mineralogical study was completed to elucidate the relationships between uranium distribution and alteration products of the host rock of natural reactor zone 2 at Oklo. The samples used were from the reactor core and reactor zone clays just below the reactor core. Uraninite is preserved without any alteration in the reactor core. Uranium minerals found to be present in the fractures in the reactor zone clays associated with iron-mineral veins, galena and Ti-bearing minerals. Uranium, for which the phases could not be identified, occurs in iron-mineral veins and the iron-mineral rim of pyrite grains in the reactor zone clays. Uranium is not associated with granular iron minerals occurring in the illite matrix of the reactor zone clays. The degree of crystallinity and uranium content of the three iron-bearing alteration products suggest that they formed under different conditions; the granular iron minerals, under alteration conditions where uranium was not mobilized while the iron-mineral veins and the iron-mineral rim of pyrite, under conditions in which uranium is mobilized after the formation of the granular iron minerals.

Geochemical discrimination of Silurian mudstones according to depositional process and provenance within the Southern Welsh Basin

AbstractA preliminary geochemical investigation of Silurian (Llandovery) basinal mudstones (turbidites and hemipelagites) from the Southern Welsh Basin is described. Turbidite mudstones show higher concentrations of Fe2O3, MgO, TiO2, MnO, LOI, Zn and Zr than laminated hemipelagites. This is consistent with the observed higher concentrations of chlorite and Ti-bearing minerals in turbidite mudstones. Laminated hemipelagites show higher values of REEs (Ce and La), concentrated within authigenic monazites, and Ni, As, Cu and Pb within sulphide minerals (pyrite and galena) reflecting the influence of primary organic carbon levels and anoxic bottom waters on early diagenesis. Deposition of hemipelagites under oxidizing conditions is reflected in lower concentrations of authigenic sulphide mineral hosted elements compared with laminated hemipelagic lithologies. There is a distinct geochemical difference between mudstones of easterly and southerly provenance in the Southern Welsh Basin. This is shown for both turbidites and hemipelagites. The differences are due to the increased input of illite and the chemical elements associated with this mineral (K2O, A12O3, Rb and Ba). Turbidite mudstones sourced from the south show increased levels of heavy minerals, especially those associated with Ti-rich minerals. There is also an increase in elements associated with detrital monazites: Th and Y. The hemipelagites show higher values of REE and chalcophile elements consistent with their more reduced nature.

MINERALOGY AND WEATHERING OF A TRINIDAD ULTISOL DEVELOPED IN PORCELLANITE

We sampled a pedon representing the Non Pareil series, which was developed from porcellanite, an unusual soil parent material, and analyzed for selected physical, chemical, and mineralogical properties. The soil is highly weathered with predominantly quartz and smaller amounts of mica in the sand fraction, which constitutes about 40% of the sample. The silt fraction amounts to about 25% of the soil's weight and contains mainly quartz and iron oxide nodules, with substantial amounts of biogenic opal. Opals are most abundant in the 10− to 20-μm separate. Kaolinite comprises about 70% of the crystalline clays of the upper solum. Smectite and illite occur in smaller amounts. The presence of interstratified smectite/illite suggests the progressive formation of the former from the latter. Judging from the amounts of mineral species in the parent rock, we speculate that kaolinite is being formed in the soil by the weathering of smectite and illite and, perhaps, the weathering of cristobalite, which decreases markedly from the parent rock. Weathering and subsequent leaching has markedly redistributed the alkali and alkaline-earth elements, moving most of them out of the solum. Molar weathering ratios based on Zr reflect this substantial weathering and leaching that has taken place to at least 152 cm in depth. The Ti to Zr ratio in the surface horizon, which is one-fifth of its value in the parent rock, suggests weathering and leaching of Ti-bearing minerals in this freely draining, oxidizing, and strongly acid environment.

Parent material uniformity and degree of weathering in a soil chronosequence, northwestern Italy

The uniformity of the parent material and degree of weathering of the soils of a chronosequence developed during the Pleistocene were investigated using optical microscopy, X-ray fluorescence and scanning electron microscopy (SEM) techniques. Uniformity of the parent material was assessed by two criteria: the ratios of resistant minerals, and their specific elements, in the heavy fraction (S.G. > 2.96 g · cm −3). There was some variation between heavy mineral ratios but there was less variation between ratios from the chemical data, and on this basis it was concluded that the parent material of each of the three soils in the sequence was uniform. SEM examination confirmed that the resistant minerals had remained unaltered although some Ti-bearing minerals showed some alteration. The degree of chemical weathering, as expressed by the ratio of mobile to non-mobile elements, and by Parker's Index, increased from the youngest to the oldest soil.

Determining Ti source and distribution within a Paleustalf by micromorphology, submicroscopy and elemental analysis

Titanium and zirconium were initially determined in a soil formed from granodiorite to assess parent material uniformity. The Ti distribution in the less than 2.0 mm fraction did not support parent material uniformity as did the Zr distribution and field morphology. Titanium source and distribution were subsequently determined to evaluate weathering of Ti-bearing minerals and mobility of Ti. Titanium contents measured by X-ray spectroscopy increased from the silt to the clay fraction from the C through the A horizons. Using petrographic microscope, X-ray diffraction, scanning electron microscope, and energy dispersive analysis of X-rays, ilmenite was identiffed as a Ti-bearing mineral, but Ti also occurred in discrete biotite, hornblende, sphene, opaque mineral particles, and in plasma, and cutans and subcutanic features. Oxalate extraction of the total soil produced small but notable amounts of Ti, especially in the Bt horizons. The data indicated that ilmenite, biotite, hornblende, and sphene may weather to produce Ti in argillans, ferriargillans, ferrans, neo- and quasiferrans, noncrystalline materials, and clay size particles in plasma. The data also indicated the mobility of Ti within and a net loss of Ti from the profile by translocation and leaching processes.