Mineralogical Parameters Research Articles

Authigenic carbonate and barite mineralization in sediments of the Deryugin Basin (Sea of Okhostsk)

Results of the analysis of mineralogy, geochemistry, and isotope parameters (δ13C, δ34S, δ18O, and 87Sr/86Sr) of carbonates and barites from sediments of the Deryugin Basin in the Sea of Okhotsk are presented. The diagenetic nature of carbonates and barites, which are formed as a result of the prolonged activity of cold seeps acting along a fracture zone and supplying methane–and barium-saturated fluids, is determined. Any signs for hydrothermal activity were not observed.

Magnetic and mineralogical characteristics of hydrocarbon microseepage above oil/gas reservoirs of Tuoku region, northern Tarim Basin, China

The Tuoku region in northern Tarim Basin of China is a key area for studying oil/gas reservoir rocks. The magnetic and mineralogical parameters of well cuttings from two wells, well S7, situated on oil/gas field, and well S6, at an oil/water interface, were measured. The two wells are located in the same structure with similar strata and types of lithology, but well S6 is a showing well of oil and gas 5 km northwest of well S7. The purpose of this paper is to evaluate the possibility and distribution of secondary magnetic alteration that may have occurred due to hydrocarbon migration above an oil/gas accumulation. It is concluded that the magnetism of well cuttings from major strata in well S7, including source rocks, oil reservoir rocks and cap rocks, and in Quaternary (Q) soil is higher than that from well S6. The Cambrian oil-bearing strata and cap rocks have even higher magnetism in well S7. The shape and parameters of magnetic hysteresis loops indicate that soft (H c<20 mT,H s<0.3 T) ferrimagnetic components dominate the magnetic carriers within the strongly magnetic strata of well S7, whereas a mixed paramagnetic and ferrimagnetic distribution occurs in well S6 (for example, low coecivityH c and nonsaturating magnetized character). Analysis of heavy minerals shows that the contents of iron oxide (magnetite, maghemite and hematite) in well S7 are often higher than those in well S6. The magnetite content in samples of cuttings from Cambrian rocks can reach 9.7% in oil-bearing strata in well S7, and in strata Ekm and N1j are 1.215% and1.498%, respectively. Typical spherical magnetite grains are found within the main source rocks and the soils in well S7. By analysis of surface microtexture and of trace element contents, we infer that the spherical magnetite is composed of aggregates of ultrafine particles that are probably authigenic magnetite formed in a hydrocarbon halo background.

Late Quaternary precessional cycles of terrigenous sediment input off the Norte Chico, Chile (27.5°S) and palaeoclimatic implications

The palaeoclimatic conditions during the Last Glacial Maximum (LGM) of southern South America and especially latitudinal shifts of the southern westerly wind belt are still discussed controversially. Longer palaeoclimatic records covering the Late Quaternary are rare. A particularly sensitive area to Late Quaternary climatic changes is the Norte Chico, northern Chile, because of its extreme climatic gradients. Small shifts of the present climatic zonation could cause significant variations of the terrestrial sedimentary environment which would be recorded in marine terrigenous sediments. To unveil the history of shifting climatic zones in northern Chile, we present a sedimentological study of a marine sediment core (GeoB 3375-1) from the continental slope off the Norte Chico (27.5°S). Sedimentological investigations include bulk- and silt grain-size determinations by sieving, Atterberg separation, and detailed SediGraph analyses. Additionally, clay mineralogical parameters were obtained by X-ray diffraction methods. The 14C-dated core, covering the time span from approximately 10,000 to 120,000 cal. yr B.P., consists of hemipelagic sediments. Terrigenous sedimentological parameters reveal a strong cyclicity, which is interpreted in terms of variations of sediment provenance, modifications of the terrestrial weathering regimes, and modes of sediment input to the ocean. These interpretations imply cyclic variations between comparatively arid climates and more humid conditions with seasonal precipitation for northern Chile (27.5°S) through the Late Quaternary. The cyclicity of the terrigenous sediment parameters is strongly dominated by precessional cycles. For the palaeoclimatic signal, this means that more humid conditions coincide with maxima of the precession index, as e.g. during the LGM. Higher seasonal precipitation for this part of Chile is most likely derived from frontal winter rain of the Southern Westerlies. Thus, the data presented here favour not only an equatorward shift of this atmospheric circulation system during the LGM, but also precession-controlled latitudinal movements throughout the Late Quaternary. Precessional forcing of latitudinal movements of the westerly atmospheric circulation system may be conceivable through teleconnections to the Northern Hemisphere monsoonal system in the Atlantic Ocean region.

Crack location in granitic samples submitted to heating, low confining pressure and axial loading

SUMMARY Until now, observations of mechanically and thermally induced microcracks in rocks could only be carried out by indirect measurements or destructive observations on samples brought back to atmospheric pressure conditions. A special triaxial test cell was designed in order to perform direct observations during loading. The use of a cell in tomography apparatus involves new devices: (1) a movable horizontal load frame around a scanner; and (2) a test cell transparent to X-rays, able to withstand up to 28 MPa maximum confining pressure and temperatures of up to 180°C. Volumetric strains are compared with radiological density measurements. The first processed X-ray images locating microcracks during propagation are also presented. Mineralogical eVects on the crack location can be demonstrated. Strain inferred from CT density measurement is clearly correlated with the strain usually measured by a strain gauge. DiVerent phases of mechanical behaviour are described: contracted phase and failure by macrocrack formation. The principal results obtained with this tool are the description of the porosity formation and macrocracking. Results show two principal factors localizing the porosity. First, the diVused porosity volume is controlled by mineralogical parameters, quartz and plagioclase grains, and boundaries of biotite grains during the thermal and mechanical loading. Second, macrocracking begins at the perimeter of the central section of core and grows towards the sample/piston interface. It seems that the first macrocracking is not located in the high-porosity zone formed during the loading phase, but in a relatively low-porosity zone.

Structure and structure‐related characteristics of dryland and long‐term irrigated xerochrept soils

Typical soils from the Ebro Valley (NE Spain) under different land use regimes (flood irrigation for more than 100 years and dryland) were studied from various analytical data, including classical physicochemical and mineralogical parameters, and submi‐croscopic and porosimetric properties, in order to assess potential changes in soil quality (particularly soil structure). The submicroscopic study revealed marked differences in structural characteristics between the dry (uniform, complex granular structure) and the irrigated (weakly developed subangular blocky structure) soils, which may be explained in several ways. When dry soil is flooded, soil aggregates are stressed by swelling of the clay present and entrapped air causing immediate break‐up and slaking of aggregates. Another source of soil structure changes is the ploughing and traffic of agricultural machinery under moist conditions in the irrigated soil; these practices create mechanical stress in the top soil (Ap horizons) and lead to the disappearance of packing voids and the formation of a very dense fabric. The B horizons in the irrigated soil show clear signs of degradation typically associated with saline‐sodic soils irrigated with low‐salinity water (mainly structure collapse and reorganization of fine materials). The use of submicroscopic and porosimetric techniques proved very powerful for assessing soil structure degradation: It allowed detection of some processes that cannot be properly evaluated with conventional analyses. Based on the results, improved water management practices are required to avoid land degradation in semiarid irrigated areas similar to the ones studied.

Genesis and dynamics of an oxic dystrochrept and a typic haploperox from ultrabasic rock in the tropical rain forest climate of south‐east Brazil

AbstractOxisols are a product of long and intense weathering. Their actual characteristics can neither be traced back to a certain climatic period, nor do they reveal the present soil‐forming factors. In this paper, therefore, a reconstruction of the soil genesis of a strongly weathered Oxisol is attempted by comparing the present mineralogical status and the recent dynamics of selected elements with a nearby Inceptisol from the same catena. The parent rock of both soils is serpentinized dunite with nepheline‐syenitic veins; the soil moisture regime is udic. Chemical and mineralogical parameters, as well as the concentration of elements in the soil solution of a Typic Haploperox and an Oxic Dystrochrept from the same catena were analyzed for one year. The dynamics of Si and Mg strongly depended on the state of weathering. In the saprolite of the Dystrochrept, Si is partially removed and partially fixed by the formation of quartz and mixed layer minerals. Mg is first fixed in mixed layer minerals, but is during consecutive weathering leached from the transition zone from saprolite to the oxic horizon. Due to the high redox potential, Fe is not soluble, forming goethite in the upper part of the saprolite. Al is also not removed and is finally fixed in kaolinite. In the weathered upper part of both profiles the concentration of Al, Si, Mg and Fe in the soil solution is too low to perceive a further weathering.The present dynamics of Fe, Al, Mg and Si and the mineralogical status of the Dystrochrept indicate that these processes are similar to those that have led to the formation of the Haploperox. The soils, therefore, developed exclusively by the relative enrichment of Al and Fe, the partial loss of Si and the almost complete loss of Mg. Desilification and ‘laterisation’ are hence processes occurring also presently under a tropical rain forest climate.

Clay fabrics in relation to the burial history of shales

ABSTRACTQuantitative appraisal of compaction strain is essential for the study of the burial history of shales in sedimentary basins. The results of a preliminary fabric analysis of Westphalian and Zechstein shales in the Campine Basin (Belgium) show that clay fabric analysis, using an X‐ray pole figure goniometer, is suitable for this purpose.Clay fabrics, in the range studied, are independent of depth and therefore cannot be used as depth indicators. This suggests that in the early stages of the burial history a stable clay fabric has to develop, which will basically remain unchanged during the subsequent burial history.The degree of clay particle preferred orientation not only reflects the compaction strain, but is also determined by mineralogical parameters: the presence of non‐platy particles and the relative concentrations of the different clay minerals. This degree of preferred orientation furthermore determines the degree of fissility of the shales.These mineralogical factors limit the use of clay fabrics as truly quantitative strain markers. Their use as semi‐quantitative strain markers remains advantageous, mainly because of the common occurrence of clay fabrics in the geological record. Moreover, the relative ease of measurement and the possibility of distinguishing compaction from tectonic strains favour the use of clay fabrics in the quantitative strain analysis of argillaceous rocks.

Contrasting low- and high-Ca granites in the Archean Barberton Mountain Land, Southern Africa

Two distinct groups of granites can be recognized among the late plutons of the Barberton Mountain Land. Discrimination between the two groups is provided by geochemical and mineralogical parameters which are considered to reflect the source material from which the magmas were derived. A high-Ca suite has geochemical parameters consistent with derivation from an igneous source (I-type), and an accessory mineral assemblage comprising zircon, apatite, allanite and sphene. A low-Ca suite contains distinctly different accessory minerals, comprising zircon, apatite, zirconosilicates, CaTh-phosphates, very rare xenotime and early monazite, and has a chemical signature consistent with derivation from a metasedimentary precursor (S-type). Major and trace element trends on Harker diagrams support the existence of two distinct granite suites. The I-type suite exhibits inverse relationships between SiO 2 and CaO, TiO 2, Fe 2O 3, MgO and P 2O 5, while Al 2O 3, K 2O and Na 2O remain relatively constant. These characteristics are consistent with magma formation from an intermediate parent composition, and in equilibrium with a hornblendite restite. The S-type granites formed by vapour-absent melting of siliceous metapelite and exhibit inverse correlations between SiO 2 and Al 2O 3, Na 2O and K 2O, with the other major elements remaining relatively unchanged. This interpretation of restite unmixing is not unambiguous since RbSr trends could be viewed as reflecting crystal fractionation and partial melting processes. High field strength elements tend to reflect the character of accessory mineral phases and are not amenable to modelling in terms of crystal-melt equilibria. The recognition of possible S- and I-type suites among the late granite plutons of the Barberton Mountain Land supports recent models which propose plate tectonic analogues in the region. The two granite suites are distributed along two subparallel linear arrays which suggests scenarios invoking subduction or hot-spot related magmatism, with the I-types forming in the time span 2740-2690 Ma along a western array. The putative S-types occurring entirely along an easterly belt were emplaced at 3074 and 2820 Ma. The presence of S-type plutons as old as 3074 Ma implies that sediments (such as the Moodies and Fig Tree Groups, or their equivalents) had been buried to depths of at least 15 km, and that by this time, at least in the Barberton area, granites had evolved beyond the TTG mode that typifies many early Archaean shield areas.

Ranking of Geological Factors Controlling the Well Productivity in Rotliegende Gas Fields of the Dutch Offshore Area

Deeply buried Rotliegende sandstones deposited in the desert environment of the Southern Permian Basin form a primary target for hydrocarbon exploration and production in northwest Europe. In the Dutch offshore sector, some highly profitable Rotliegende fields are known. However, the success rate for exploration and field development is adversely affected by the variable Rotliegende reservoir quality, with tight gas sands and productive reservoirs units adjoining each other within fields. To improve the accuracy of reservoir performance forecasts, several case histories were analyzed and the observed well productivities correlated with key mineralogical and sedimentological parameters. The overriding influence of facies is evident: the textural characteristics of the Rotliegende sand determined not only the initial porosity after deposition, but influenced also the response of the rock to burial diagenesis. The mature, better sorted sandstone facies suffered least from diagenesis, whereas the immature lithologies lost much of their porosity and permeability by pervasive diagenetic cementation and clay mineral growth. The relative influence of burial/temperature history and mineralogical and sedimentological factors on well productivity was evaluated with multivariate statistics. Three field studies from the Dutch offshore area demonstrated that the well productivity can be modeled as a function of a limited number of geologicalmore » factors. Testing the statistical formula with additional wells showed that the multivariate method improves the accuracy of reservoir quality predictions.« less

An Investigation of Fluidized Bed Combustion By-Products from Four Iowa Power Plants

ABSTRACTFluidized bed combustion (FBC) residues from four Iowa power plants were characterized to provide background with respect to chemical, physical, mineralogical and microstructural parameters that might affect their utilization potential. Methodologies used include: bulk chemical analysis; grain size analysis; specific gravity determination; mineralogical analysis by x-ray diffraction; scanning electron microscopy; and thermal analysis.Chemical analysis of the major components showed the separation of the constituents during combustion. The bottom ash is derived from the calcined and partly sulfated limestone, thus the concentration of calcium and sulfur compounds is greater. The fly ash however is derived mostly from the coal and therefore exhibits higher concentrations of coal ash components such as silica (SiO2), alumina (Al2O3), and ferric oxide (Fe2O3). The alkalis appear to be more concentrated in the fly ash.The measured particle size distributions of the bulk samples varied greatly, from extremely coarse (mean particle size ˜2000 μm) to fine (mean particle size ˜25 μm). The size distributions also varied in breadth. Specific gravities values recorded ranged from about 2.65 to about 3.05.X-ray diffraction analyses showed that most of the FBC by-products contain, as easily detectable crystalline components, only quartz, anhydrite and lime, and as is to be expected due to the low combustion temperatures, do not show broad peaks characteristic of glass in conventional fly ashes. Scanning electron microscopy revealed the FBC by-products to be extremely intricate mixtures of particles of complex and variable composition and internal structure.FBC by-products are shown to be extremely complex mixtures of particles of variable composition and internal structure. However, despite their local variation, useful results can be obtained by overall chemical and physico-chemical analyses of their composition. The exploitable properties of FBC residue include the somewhat cementitious nature and the granularity. However, their heterogeneous nature, lack of pozzolanic properties, and elevated sulfate content may limit their uses, especially in construction.

Mineralogic Parameters Related to Amosite Asbestos-induced Fibrosis in Humans

We have previously shown that in the lungs of a group of chrysotile miners and millers, grade of interstitial fibrosis (asbestosis) is directly proportional to tremolite fiber or chrysotile fiber concentration but is inversely proportional to mean fiber length and length-related parameters. To compare the effects of the commercial amphibole asbestos amosite on parenchymal fibrosis, we histologically graded fibrosis in four different sites in the lungs of 20 shipyard and insulation workers with heavy amosite exposure and measured by analytic electron microscopy fiber concentration and size in corresponding portions of lung tissue. Fibrosis grade was found to be strongly positively correlated with amosite concentration and negatively correlated with mean fiber size parameters, including fiber length, width, surface area, and mass. A comparison of our present results with our data on the chrysotile miners and millers showed that the regression lines of fibrosis grade versus concentration for amosite, chrysotile, and tremolite were statistically different. These findings indicate that amosite concentration, like chrysotile and tremolite concentration, is closely and directly related to fibrosis at the local lung level. Furthermore, these observations again raise the possibility that short fibers may be more important than is commonly believed in the genesis of fibrosis in man. Last, the concentration comparison data indicate that, fiber for fiber, amosite is more fibrogenic than is chrysotile or tremolite, and indirectly suggest that tremolite is more fibrogenic than is chrysotile.

Soil development on stable landforms and implications for landscape studies

Abstract Soil development parameters include a wide variety of morphological, chemical, and mineralogical parameters, but some of the best indicators of time and surface stability are derived from field morphology. Over long time-spans, the most common time function for soil development is exponential or logarithmic, in which rates decrease with increasing age. Over shorter time-spans in semi-arid and moister climates, Holocene and Pleistocene soil development functions appear as linear segments, with Holocene rates about 10 to 50 times those of Pleistocene rates. In contrast to significant temporal variation in rates, geographical variation in rates within (a) the southern Great Basin and (b) the east Central Valley of California is on the order of 2 or 3 times. When comparing soil development indices of the semi-arid Great Basin to those of moister central California, Holocene rates are similar, but Pleistocene rates are more than 10 times slower in the Great Basin. In a range of climatic settings, the reasons for declining rates over time are several and are complexly related to erosional history, fluxes in water and dust related to climatic changes, rates of primary mineral dissolution, and intrinsic soil processes.

Abundance of chromium and other transition metals in ceramic clays from Westerwald (GFR)

Ten commercial clay samples, coming from the Westerwald deposit, have been selected to represent practically all the compositional variety of the raw materials used to obtain white ceramic bodies for pottery. For each sample, the concentration of chromium and some other trace elements has been determined and examined with reference to the main chemical and mineralogical composition. The fraction less than 2 μm from two clay samples have been investigated in the same way. Kaolinite, quartz and illite in different proportions are the principal mineral constituents of the samples, while abundant smectite is contained in only one sample; little amounts of feldspars have been found in a lot of cases. The chromium content ranges between about 40 and 210 ppm, but its variations do not show a good correlation with those of any other principal chemical or mineralogical parameters of the samples. It is concluded that chromium is contained in mineral of its own which is present in trace amounts; that mineral, probably a chromium oxide or hydroxide, is quite uniformly dispersed in the clay fraction and in the coarsest one. From a practical point of view, the results suggest that it is possible to select clay raw materials with low chromium content to avoid the appearance of yellow blots on the glazed surface of ceramic articles made of an earthenware-type body.

Mineralogical composition of the clay bodies used in the Italian tile industry

The aim of this study is to differentiate mineralogically the clay bodies employed at present in Italian ceramic tile production. A collection of sixteen representative samples of various types of products has been analyzed. The relevant data have been used in the discussion on the mineralogical differences between the various types of products. Ternary diagrams, constructed on the basis of mineralogical parameters, are a useful reference for tile production and a contribution to a more general classification of the ceramic bodies made of clays and complementary raw materials. The bodies for the ceramic tile industry show markedly different mineralogical characteristics, especially when the “coloured” bodies are compared with the “white” or “light coloured” ones, or when different shaping techniques are considered.

Characterization of Lithology and Reservoir Rock for Deep Gas Drilling in Siljan Impact Structure, Sweden: ABSTRACT

The Gravberg 1 well in the Siljan impact structure in Sweden has been drilled entirely in granite and dolerite intrusions of Precambrian age to a present depth of 6.6 km. Study of the cuttings at the well site included a lithologic description, with emphasis on quantifying mineralogical, textural, and pore-space parameters that affect porosity and permeability and that can indicate the potential presence of a fractured reservoir. Important mineral parameters are epidote, reddish feldspar, chlorite, and other alteration products. Textural parameters include the presence of fractures, cataclastic and brecciated graikns, vugs, and drusy crystals. Although rare, the presence of drusy crystals clearly shows that open fractures are present. The study is also geared to identify minerals that affect wireline logs (e.g., alteration products such as chlorite,sericite, and illite, and heavy minerals such as pyritic and magnetite4). Cuttings examination is crucial as relatively few cores or sidewalls have been recovered. Laboratory studies incorporating capillary pressure tests, SEM, and thin-section petrography (in polarized and fluorescent light) reveal that the samples contain a bimodal pore structure composed of larger pores representing the microfractures and smaller pores representing the intercrystalline microporosity developed within altered grains. Porosity in the granites averages 0.96% (typical Swedish granitemore » is 0.5%), and the permeability is 0.003-0.027 md.« less

Influence of sedimentological features on the distribution of trace metals in marine sediments

The most important parameters influencing trace metal distribution in sediments are reviewed. The accent is put on sedimentation rate, grain size distribution and the knowledge of past events through sedimentological and mineralogical parameters. It is concluded that chemical data must be compared to sedimentological data before being interpreted.

Differentiation of Lithologically Similar Soil Parent Materials

Differentiation of soil parent materials or demonstrating parent material uniformity is of prime importance in many soil genesis studies. It is necessary in order to determine whether observed differences in morphological, physical, chemical, or mineralogical parameters are the result of genetic processes or to differences inherited from the materials. Often differences in soil parent materials are not clear, especially when mixing or extensive weathering has occurred. Therefore, a method to help sort out such differences or uniformities would be a useful tool. In this study, discriminant analysis was utilized along with other related statistical methods to determine if glacially derived loess, siltstone residua, and lacustrine silts could be differentiated effectively. Elemental contents of the 5 to 50µm fraction of the materials were found to be more diagnostic in differentiation than textural or mineralogical parameters. Using the Zr, Ti, and K contents, these lithologically similar, but genetically different materials could be differentiated with significant differences > 0.01 level.

Correlations between pyrolysis mass spectra of Rocky Mountain coals and conventional coal parameters

Correlations between Curie-point pyrolysis m.s. data on 102 coal samples from the US Rocky Mountain coal province and a set of 25 conventional parameters, including ultimate, proximate, petrographic and mineralogic measurements, obtained from the Penn State Coal Data Bank were investigated using computerized multivariate statistical analysis techniques. Strong correlations were found between both data sets with regard to rank-related parameters as well as sulphur parameters, whereas moderately strong correlations exist with regard to petrographic and mineralogical parameters as well as nitrogen content. Independent factor analysis of both data matrices provides factor score plots showing remarkably similar relations between samples from different coal regions, fields and seams. In fact, up to 80% of common variance is found in the conventional and pyrolysis m.s. data sets. The large proportion of variance common to both data sets permits the calculation of numerical models which enable direct prediction of technologically important parameters such as rank, calorific value and, possibly, aromaticity from pyrolysis m.s. patterns.

Geochemical and mineralogical investigations of the Lower Jurassic flint-clay bearing Mishhor and Ardon Formations, Makhtesh Ramon, Israel

The Lower Jurassic section at Makhtesh Ramon, in the northeastern Negev of Israel, comprises a sequence of fluviatile sediments of laterite composition. Post-depositional chemical weathering has resulted in marked facies changes whereby the clastic sequence passes laterally into high-alumina flint clays and bauxites (Goldbery, 1979). A geochemical and mineralogical investigation was initiated on 216 samples from several key sections of the facies change to obtain a more refined definition of the diagenetic overprint, to reconstruct the history of chemical weathering and finally to recognize the parent material of the unaltered laterite sediments. Results are presented herein on major and trace-element composition, normative mineralogical composition, kaolinite crystallinity and porosity and density measurements. Kaolinite crystallinity values proved to be a good indicator of intensity of leaching, showing a marked decline in ordering with increase of diagenetic reorganization. On the basis of mineralogical parameters it was possible to subdivide the section of flint clays and bauxites, generated under karstic conditions, into four units. Bivariate plots of Al 2O 3 vs. several elements within the section, plotted into four distinctive fields coinciding with the subdivision. Enrichment/depletion ratios, calculated from the element concentrations within these flint clays against element concentrations of the clastic parent material of the karstic infill, led to the reconstruction of a multi-cyclic leaching event, whose “signature” is left in each of the four units. At least 3 individual episodes of leaching, related to a rising water table and punctuated by “still-stands” could be recognized. Zr/TiO 2: Nb/Y plots of stable elements, using the diagram of Floyd and Winchester (1978) for determination of source rocks, indicated a rhyolite or alkaline rhyolite provenance for the clastic laterite detritus.

Characteristics of the Colo Soil Series as Mapped in the North Central Region

AbstractThe Colo soil series (fine‐silty, mixed, mesic Cumulic Haplaquoll) was sampled and studied in areas mapped as Colo in the North Central Region (NCR). Within this broad geographic area, there are variations in climate, vegetation, parent material, relief, and time—the five soil‐forming factors. This soil is mapped on floodplains of streams and in drainageways of various size. Forty‐seven soil profiles from five states were described and sampled to determine selected physical, chemical, and mineralogical properties and the ranges of these properties in this series.The principal objectives of this investigation were to (i) study one soil series and characterize the series as mapped, (ii) compare Colo soil properties with associated upland soils, and (iii) develop a model to better understand the genesis of soils derived from alluvial sediments in the NCR.Depth distribution of selected chemical and physical properties in some Colo profiles indicated some degree of horizon differentiation. Clay, total phosphorus (TP), inorganic phosphorus (IP), and available phosphorus (AVP) depth distributions in many profiles had a zone of eluviation and illuviation, indicating redistribution of these constituents within the profile. One possible interpretation of the redistribution is that the soils are on landforms that have been stable for some period of time. Total carbon (TC) content usually decreased regularly with increasing depth. Clay mineralogical analyses indicated a dominance of interstratified clay minerals. Smectite, kaolinite‐chlorite, and illite are minor clay minerals in these soils as interpreted from relative peak heights. For most profiles, clay mineralogy was similar with increasing depth.Statistical model equations involving several physical, chemical, and mineralogical parameters, as dependent or independent variables, were developed.