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  • Articles  (62)
  • classification
  • paleontology
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  • Springer  (62)
  • American Meteorological Society
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  • 1
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    Stochastic environmental research and risk assessment 13 (1999), S. 113-130 
    ISSN: 1436-3259
    Keywords: Key words: Climatology ; meso-scale convective systems ; classification ; anisotropy ; intermittency ; ergodicity ; upscaling ; level sets.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract: The meta-Gaussian model is fitted to a set of 258 sahelian rainfields. The hypotheses underlying this model are discussed with a special emphasis on its ergodic properties, the scale of the phenomenon and the scale of observation. Then the ability of this model to reproduce some observed features, in particular upscaling properties, is checked from a distributional point of view. Finally, some simple properties of the thresholds which are linked to the area threshold method are described.
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  • 2
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    Journal of paleolimnology 3 (1990), S. 1-12 
    ISSN: 1573-0417
    Keywords: classification ; lake basins ; lacustrine deposits ; Estonia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Based on extensive data from a long-term investigation, a new genetic classification of lake basins is proposed for Estonia. Eight lake groups are distinguished, tectonic-denudation, glacial, chemical, fluvial, coastal (neotectonic), telmatogenic, cosmogenic and artificial, containing 13 subgroups and 19 basin types. Also proposed is a new lithological classification of Estonia's organic and calcareous lake sediments, based on analyses of more than 2000 sediment samples from 90 contemporary and 50 late-glacial (extinct) lakes. Of the ca. 1150 Estonian lake basins that formed on mineral substrate, the two largest basins are of preglacial, tectonic-denudation origin, later modified by glaciers. Eight hundred lakes are of glacial origin, and 300 of other origins in the Holocene. In addition, ca 20 000 bog pools formed on peat in the Holocene. Only minerogenous sedimentation occurred in the lakes in the late-glacial period. After that, organic (gyttjas) and/or calcareous sediments have formed. Azonal factors have been largely responsible for the wide variation in Estonia's lacustrine deposits.
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  • 3
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    Marine geophysical researches 15 (1993), S. 43-64 
    ISSN: 1573-0581
    Keywords: sea-bed ; classification ; power spectra ; side-scan sonar ; parametric-fitting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract This work is concerned with the automatic characterisation and classification of the sea-bed for side-scan sonar trace power-spectra. A parametric model of side-scan sonar trace power-spectra is developed from the equation for the magnitude frequency response of a Butterworth filter. The model's parameters are optimised to give a least squares fit with observed spectra. Three of the optimised parameters are used to define features. The parametric optimisation approach to feature extraction is compared to a method described by Pace and Gao (1988) in which features are defined in terms of ratios of integrals over frequency intervals of observed (specially defined) power spectra. Scatter distributions in feature space are reduced to sets of numbers that define distribution fields and these constitute seabed characteristics. A classification exercise is undertaken to demonstrate the utility of the feature extraction methods. The discrimination between sea-bed types achieved by the feature extraction methods is succintly conveyed in class discrimination matrices. The merits of the spectral modelling approach to feature extraction are: (1) the features provide a meaningful description of the spectra from which they are extracted, (2) the features enjoy a degree of immunity to changes in noise in the signal from which they are extracted, and (3) the features provide excellent discriminants. The parametric fitting process, however, is slow. An important merit of the Pace and Gao (1988) approach is that feature extraction is rapid.
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  • 4
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    Studia geophysica et geodaetica 43 (1999), S. 61-72 
    ISSN: 1573-1626
    Keywords: GPS ; ambiguity resolution ; classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Abstract In this contribution we explore the analogy between GPS ambiguity resolution on the one hand, and the problem of statistical classification, on the other hand. As classification rules we discuss the Bayes-, the MAP-, the ML- and the Minmax-rule. It is shown to what extent ambiguity resolution may be considered a classification problem. It turns out that both problems show many similarities, although some marked differences exist as well. These similarities and differences are discussed.
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  • 5
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    Mathematical geology 22 (1990), S. 573-588 
    ISSN: 1573-8868
    Keywords: classification ; regionalization ; Bayes' theorem ; geostatistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The concept of multivariate classification of “geological objects” can be combined with the concept of regionalized variables to yield a procedure for typification of geological objects, such as rock units, well records, or samples. Numerical classification is followed by subdivision of the area of investigation, and culminates in a regionalization or mapping of the classification onto the plane. Regions are subdivisions of the map area which are spatially contiguous and relatively homogeneous in their geological properties. The probability of correct classification of each point within a region as being part of that region can be assessed in terms of Bayesian probability as a space-dependent function. The procedure is applied to subsurface data from western Kansas. The geologic properties used are quantitative variables, and relationships are expressed by Mahalanobis' distances. These functions could be replaced by other metrics if qualitative or binary data derived from geological descriptions or appraisals were included in the analysis.
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  • 6
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    Mathematical geology 3 (1971), S. 227-238 
    ISSN: 1573-8868
    Keywords: classification ; data processing ; graphics ; mapping ; mathematics ; plotting ; sampling ; statistics ; sedimentology ; stratigraphy ; grain-size analysis ; textural analysis ; glacial geology ; Pleistocene stratigraphy ; till
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Relative percentages of sand, silt, and clay from samples of the same till unit are not identical because of different lithologies in the source areas, sorting in transport, random variation, and experimental error. Random variation and experimental error can be isolated from the other two as follows. For each particle-size class of each till unit, a standard population is determined by using a normally distributed, representative group of data. New measurements are compared with the standard population and, if they compare satisfactorily, the experimental error is not significant and random variation is within the expected range for the population. The outcome of the comparison depends on numerical criteria derived from a graphical method rather than on a more commonly used one-way analysis of variance with two treatments. If the number of samples and the standard deviation of the standard population are substituted in at-test equation, a family of hyperbolas is generated, each of which corresponds to a specific number of subsamples taken from each new sample. The axes of the graphs of the hyperbolas are the standard deviation of new measurements (horizontal axis) and the difference between the means of the new measurements and the standard population (vertical axis). The area between the two branches of each hyperbola corresponds to a satisfactory comparison between the new measurements and the standard population. Measurements from a new sample can be tested by plotting their standard deviation vs. difference in means on axes containing a hyperbola corresponding to the specific number of subsamples used. If the point lies between the branches of the hyperbola, the measurements are considered reliable. But if the point lies outside this region, the measurements are repeated. Because the critical segment of the hyperbola is approximately a straight line parallel to the horizontal axis, the test is simplified to a comparison between the means of the standard population and the means of the subsample. The minimum number of subsamples required to prove significant variation between samples caused by different lithologies in the source areas and sorting in transport can be determined directly from the graphical method. The minimum number of subsamples required is the maximum number to be run for economy of effort.
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  • 7
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    Mathematical geology 3 (1971), S. 297-311 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; discriminant analysis ; numerical taxonomy ; paleontology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Eighty-eight specimens of Eocene nummulitids from the Yellow Limestone Formation of northwestern Jamaica are classified according to quantitative measurements of morphologic parameters that are generally considered to be taxonomically useful. The specimens are grouped into homogeneous classes by the computer screening of differently oriented data projections. By this method, the use of similarity coefficients and the question of a priori weighting of characters, for which numerical taxonomy has been heavily criticized, are both avoided. The stability of the classes thus obtained is validated by discriminant analysis. These techniques provide an objective view of phenetic differences among specimens and show how the measured characters produce those differences. Tightness of coiling and total number of whorls, prove to be the most useful features in discriminating between groups but seem to have taxonomic value only at the specific and not at the generic level. This suggests that the generaOperculinoides andNummulites are synonymous.
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  • 8
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    Mathematical geology 4 (1972), S. 147-153 
    ISSN: 1573-8868
    Keywords: classification ; statistical inference ; statistics ; geochemistry ; petrochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract This paper embodies petrographical and statistical investigations of three gabbro occurrences. The Mangaon and Kunkeri gabbros are similar in petrography and petrochemistry, whereas they are completely different from the Vajrat gabbro. Application of recently developed statistical tests help in classifying these gabbros by using three oxides, CaO, FeO, and K2O.This study shows that the evolution of the Mangaon and Kunkeri gabbros probably proceeded along different lines as compared to the Vajrat gabbro.
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  • 9
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    Mathematical geology 7 (1975), S. 191-214 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; mapping ; multivariate analysis ; pattern recognition ; point-density analysis ; geochemistry ; ore-bearing districts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Large sets of rock compositions can be grouped by the analysis of corresponding point distributions in multidimensional space, where the separate dimensions represent the chemical variables. The point density around each composition is estimated in a small, multivariate, rectangular interval. Establishment of the identity of specimens contained in the interval, and systematic comparison of the point densities surrounding each of them, leads to the recognition of density maxima, which represent the statistical modes of the rock types present in the set. The remaining specimens by the same operations can be assigned to the groups formed. Experimental results are given for two sets, one comprising a wide variety of metasedimentary and metavolcanic rocks from the ore-bearing Skellefte district and adjacent parts of Västerbotten, Sweden, and the other representing a less variable population of basic rocks from Norrbotten, Sweden. Linear discriminant analysis and existing geological information indicate that the groups obtained are statistically and geologically valid.
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  • 10
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    Mathematical geology 8 (1976), S. 183-202 
    ISSN: 1573-8868
    Keywords: Fourier analysis ; paleontology ; structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract A system of strain analysis based on the application of a homogeneous strain transformation in plane polar coordinates to match deformed shapes of the same initial form is described. Two types of transformation are derived. A simple transformation between the deformed and the undeformed states, used to compare deformed shapes with a predetermined initial configuration, is recorded in the form of a plane polar coordinate Fourier series. This method allows reliable strain estimates to be made from single specimens of a fossil in an area where sufficient consistency of original shape has been established. A transformation describing the difference in relative strain between local polar coordinate systems in the same overall homogeneous deformation field, is used to compare the members of a group of deformed shapes with one another. This transformation allows the determination of the optimum initial ‘mean shape’of a group of fossils in a deformed rock as well as giving a strain measurement. The use of parabolic integration enhances the determination of the Fourier descriptions, and allows the use of irregularly spaced data. Inherent mathematical features of the method provide controls on the accuracy of the determination. The relatively mechanical nature of the input and the general form of the solution make the method readily applicable in semiautomated systems.
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  • 11
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    Mathematical geology 4 (1972), S. 307-316 
    ISSN: 1573-8868
    Keywords: mathematics ; paleoecology ; paleontology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The equations of Moseley for the volume and surface area of a coiled shell have been rewritten in their most general forms. The general volume equation has been tested with 15 gastropods and found to give satisfactory results wherever there are no significant ontogenetic changes in the shell geometry. The equations provide a means for calculating the carbonate efficiency of a coiled shell. With this parameter analyzed into its component parts, it has been possible to understand the relationships between aspects of shell calcification and environmental factors that affect calcium carbonate availability. Preliminary studies indicate that it also may be possible to discriminate morphologically between terrestrial and aquatic gastropods, the various gastropod modes of life, and higher taxonomic categories. These equations offer possibilities for other studies concerned with the ecology, paleoecology, and evolution of coiled shells.
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  • 12
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    Mathematical geology 5 (1973), S. 27-37 
    ISSN: 1573-8868
    Keywords: autocorrelation ; classification ; principal-components analysis ; smoothing ; soil science
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Spatially distributed soil data possess a short-range erratic variation, an irregular longer range pattern, and maybe multivariate. In order to reveal a pattern or meaning in them, they are usually classified by drawing boundaries. A method is described for determining boundaries automatically on transects. A small portion of a sampled transect is taken and divided about its midpoint, and Mahalanobis' generalized distance, Dor D2,between the two halves calculated from the sample data. The procedure is repeated for portions of the same length at positions one-sampling interval apart along the transect. High peaks on the resultant series of D2 identify the boundaries. The length of portions is set equal to, or somewhat less than, the expected average distance between boundaries, and is determined by constructing correlograms of principal components. The lag distance over which fairly steady decay occurs is related closely to the distance between boundaries. The procedure is illustrated with data from a 6-km transect in Oxfordshire and shows good agreement with boundaries drawn by combined air-photo interpretation and field judgment. A means of extending the procedure to two dimensions is suggested.
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  • 13
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    Mathematical geology 8 (1976), S. 597-616 
    ISSN: 1573-8868
    Keywords: classification ; Markov processes ; geomorphology ; hillslopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract If considered as a sequence of morphological units, hillslopes can be treated as realizations of a stochastic process in which morphological units correspond to events and their attributes (e.g., slope)to values. A first-order, discrete-state, discrete-time Markov model, applied to a group of hillslopes measured in Calabria, explained a significant part of the hillslope morphology. A Markov property was determined to be present in the sequence of slopes and lengths of the morphological units. In the subsequent analysis of the Markov property in the sequence of slopes, an optimum transition scheme was developed. This indicated, inter alia,that concavity in the hillslope was most probable where the slope was in the range from 7° to 〈9°. The hillslopes were divided into classes based upon their geomorphological position. The resulting transition probability matrices and their derivatives were examined for significant differences.
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  • 14
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    Mathematical geology 7 (1975), S. 129-147 
    ISSN: 1573-8868
    Keywords: correlation ; factor analysis ; regression analysis ; statistics ; allometric growth ; paleontology ; relative growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Relative growth of the Ordovician crinoid Hybocrinus punctatus (Miller and Gurley)was studied using regression, correlation, and R-mode factor analysis. Systematic growth gradients of both initial intercepts and slopes existed throughout the calyx. Development of a single plate was best correlated with growth of the directly adjacent plates and was less well correlated with that of more distant plates. A total of 86 percent of the R-mode correlation matrix variance is associated with overall size increase of all dimensions and size-correlated shape changes. Most of the remaining variance is linked with divergent growth of small groups of specimens with respect to various shape parameters.
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  • 15
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    Mathematical geology 8 (1976), S. 113-136 
    ISSN: 1573-8868
    Keywords: Rubin—Friedmann cluster analysis ; canonical analysis ; principal component analysis ; numerical taxonomy ; paleontology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract A morphometric analysis of two closely related species Astarte omaliiand Astarte basterotiwas made. Specimens were sampled from three successive stratigraphic levels of the Pliocene deposits of northern Belgium. Two chronological subspecies were distinguished—Astarte omalii omaliiand Astarte omalii basteroti.
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    Mathematical geology 10 (1978), S. 289-299 
    ISSN: 1573-8868
    Keywords: classification ; discriminant analysis ; soil science ; autocorrelation ; boundary
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    Topics: Geosciences , Mathematics
    Notes: Abstract A linear discriminant function can be used to place the boundary between two mapping units, if multiple measurements are available for samples collected from both units. The function is calculated using samples of known group membership, then is applied to classify samples of unknown group identity. The plot of the discriminant index on a map of the study area locates the contact between the two groups. Boundary position can be evaluated by comparing data models based upon the boundary with the distributions of the original variables. This method is applied to locate the boundary between two soil mapping units. Samples of two contrasting soils were collected on a gridded sampling pattern positioned at the contact between two mapping units. Samples were analyzed for physical and chemical properties, including sand content, silt content, and pH. The boundary was located, then separately evaluated with respect to the sand, silt, and pH measurements. The discriminant score boundary corresponded closely to the sand content measurements, but did not match the silt or pH distributions.
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  • 17
    ISSN: 1573-8868
    Keywords: association analysis ; classification ; carbonates ; depositional basins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Fourteen mineralogical and petrographic variables for 82 samples of Sirban Limestone of Riasi, Jammu, and Kashmir State, and 18 mineralogical and petrographic variables for 36 samples of Bilaspur Limestone, Himachal Pradesh, India, were numerically classified based on presence-absence data using association analysis. The samples were collected along vertical profiles. The variables for the Sirban Limestone of Riasi were classified into three groups: (a) dolomite (b) micrites, and (c) terrigenous material represented by clay minerals. These three groups correspond to (a) near-shore sabkha dolomites, (b) deep water micrites, and (c) terrigenous contribution of clay minerals (except corrensite) to the carbonate depositional basin. Bilaspur Limestone samples were classified also into the same three groups. The results of the present study corroborate the earlier conclusions of the writer that the Sub-Himalayan carbonates of Northwest India generally represent rocks of shallow carbonate depositional basins, showing transition from near shore sabkha dolomites to basinal limestones and shales.
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  • 18
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    Mathematical geology 14 (1982), S. 141-159 
    ISSN: 1573-8868
    Keywords: Paired comparison models ; ranking techniques ; biostratigraphy ; paleontology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Paired comparison models can be used to study the order of stratigraphic events along a relative time scale when differences in order are observed to occur in stratigraphic sections or wells. They give parameters of (1) a binomial distribution for the probability that a given event occurred earlier than another event, or (2) a trinomial distribution for the probability of earlier, later, or simultaneous occurrences of events. In the Bradley-Terry and Davidson models differences in positions of events along a logarithmic scale are assumed to satisfy a logistic frequency distribution. In the recently developed RASC model, a normal frequency distribution along a linear scale is used. The properties of these three models are reviewed and computer algorithms used to obtain practical solutions are discussed. The three models have each been applied to three published data sets (10 highest and lowest occurrences of Eocene nannofossils in 9 wells in California; 16 lowest occurrences of Cambrian trilobites and other fossils in 7 stratigraphic sections in Texas; and 41 highest occurrences of Cenozic foraminifera and other microfossils in 16 wells, Canadian Atlantic Margin). Results of the three models are not significantly different. However, only the RASC model can be applied to large data sets because its computer algorithm avoids the use of timeconsuming iterative processes required when other models are used.
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    Mathematical geology 15 (1983), S. 701-708 
    ISSN: 1573-8868
    Keywords: shape analysis ; logarithmic spiral ; paleontology ; Cyrtograptus sakmaricus lineage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract On the basis of a mathematical study of the Cyrtograptus sakmaricuslineage, all members of this lineage have the shape of a logarithmic spiral, which may be expressed in terms of the equation ρ = A ⋅ eaθ.Tightness of coiling and the shape of the volution are determined by the value of a.This value, which controls the form and function of cyrtograptids, increases in stratigraphically higher members and may be used as a basis for dividing the genus Cyrtograptusinto various species.
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  • 20
    ISSN: 1573-8981
    Keywords: Pattern recognition ; ore field ; geochemical type ; estimation ; classification ; frequency of indicator
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    Topics: Geosciences
    Notes: Abstract The Okhotsk–Chuckchee volcanic belt (OCVB) represents a world class gold–silver province, being a well-studied part of the Circum-Pacific Rim. Extensive research, preceding the system compilation, included collection of various data on major gold–silver, silver–lead–zinc, and tin–silver ore fields (with some data on minor gold–quartz, gold–sulfide, and gold–rare-metal sites). The database consists of 129 ore fields of the OCVB and comprises 433 geological, mineralogical, geochemical, and geophysical indicators. Using the original pattern recognition programs (accounting the frequencies and correlation of the indicators), the most informative indicators were selected, their weights (both positive and negative) were identified, and an expert system (“solution tree”) was compiled. The computer system is intended to be an assistance to an expert in the ore field potential evaluation. The system includes several blocks of questions with a goal of classifying the geochemical type and size of the analyzed ore field. The questions have an indirect character, so they could be answered by an expert at early stages of exploration (before drilling). The level of recognition of sizes of the ore sites in the control populations is 95% or higher. The aim of the expert system is to reestimate a large number of known ore sites in a relatively brief period of time with the aid of the personal computer. The revealed patterns could be used in other less studied parts of the Circum-Pacific belt.
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    Mathematical geology 23 (1991), S. 71-76 
    ISSN: 1573-8868
    Keywords: bituminous coal ; dry ash-free basis volatile matterV r ; caking indexG (RI) ; classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Hundreds of samples and 17 variables collected from coalfields of major coal-bearing strata over China except for Tibet and Taiwan, were used in this study. The dry, ash-free basis volatile matter (V r) and caking index (G (RI)) were chosen by means of correlation analysis and stepwise discriminatory analysis as major indices of a new classification. By means of the optimum section, the boundary value of the axis of ordinate (G (RI)) and axis of abscissas (V r) can be determined in the classification system. Thus, aV r −G (RI) classification scheme diagram was formed and bituminous coal was divided into nine classes. Use of correspondence analysis reduced dimensions of sample-expressive space without losing initial information. The trend on the factor surface of samples shows that the classification obtained from correspondence analysis conforms to theV r −G (RI) classification result and further verified the dependability of classification by two indices. At the same time, a certain relationship between the properties of a great variety of coal and their attributes can be explained. Hence, bituminous coal classification becomes more scientific, reasonable, and practical than before.
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    Mathematical geology 3 (1971), S. 1-14 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; principal components analysis ; numerical taxonomy
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    Topics: Geosciences , Mathematics
    Notes: Abstract Numerical methods for the examination of multivariate soil samples are presented in geometric terms. Techniques of coordinate representation by principal components, by nonmetric scaling, and by a new method are discussed, as are techniques for agglomerative hierarchic cluster analysis. These are illustrated by two sets of previously published data.
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    Mathematical geology 5 (1973), S. 39-57 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; dimensionality reduction ; mapping ; multivariate analysis ; principal-components analysis ; general geology ; geochemistry ; paleontology ; petrology ; stratigraphy
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    Topics: Geosciences , Mathematics
    Notes: Abstract A new algorithm has been developed by J. W. Sammon for the nonlinear-point mapping of high-dimensional data in two dimensions such that the inherent structure of the data is approximately preserved. This paper describes results using several sets of geologic data including stratigraphic thickness, petrographic modal analysis, and morphological or geochemical measurements. Comparisons are made with hierarchical cluster analysis using dendrogram representation. Initial results are encouraging and suggest that the technique could have widespread geological applications.
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    Mathematical geology 8 (1976), S. 75-84 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; entropy ; facies analysis ; sedimentology
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    Topics: Geosciences , Mathematics
    Notes: Abstract Criteria have been suggested for the optimal partitioning of a dendrogram into sample clusters. The implementation of these criteria by means of statistical and graphical measures is considered for two dendrograms. It is shown that the optimization of criteria is conditioned by research aims.
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    Mathematical geology 8 (1976), S. 151-163 
    ISSN: 1573-8868
    Keywords: Fourier analysis ; power-spectrum analysis ; paleoecology ; paleontology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Fourier analysis of shape provides a unique means of studying morphologic variation of bivalves, especially in terms of their evolution and autecology. Amplitude spectra resulting from analysis may be refined, summarized, and further evaluated by a series of statistical measures designed to extract the maximum amount of information from outline features. Root mean square error comparison of harmonics, combined with a modified analysis of variance design and Snedecor's F-test, permits identification of significant amplitudes. Intra- and interspecific variation may be expressed as variance about mean power estimates derived from significant amplitudes for each species. Variance estimates of 14 species of heterodont bivalves indicate that venerid bivalves show considerably more intraspecific shape variability than do tellinid species. In both groups, however, species characterized by more elongate shells show less intraspecific variability. Evolutionary and environmental implications of interspecific shape variance in bivalves suggest that future comprehensive examination of specimens, collected in situ, may be fruitful.
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    Mathematical geology 3 (1971), S. 357-368 
    ISSN: 1573-8868
    Keywords: multivariate analysis ; normality ; statistics ; paleontology
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    Topics: Geosciences , Mathematics
    Notes: Abstract Data on some living (salamanders and grasshoppers) and fossil (Devonian brachiopods) animals are analyzed by means of recently developed methods for the large-scale treatment of multivariate normality. Multivariate nonnormality was found to exist in all situations, even if the univariate deviations in the skewness and kurtosis statistics proved to be without significance for the most part. The effect of logarithmically transforming the data appears to be a mixed blessing. Apart from the fact that the investigator is removed one step from the biological relationships in his data by carrying out a transformation of them, the betterment in the multivariate interconnections with respect to normality tends to be slight, despite the general improvement in the univariate values. The relationship between sample size and the multivariate normality measures b1,p and b2,p are studied empirically.
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    Mathematical geology 7 (1975), S. 149-166 
    ISSN: 1573-8868
    Keywords: biostratigraphy ; numerical taxonomy ; paleontology
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    Topics: Geosciences , Mathematics
    Notes: Abstract This study was made to revise the taxonomy and biostratigraphy of Middle Cambrian trilobites from Montana and Wyoming. Both numerical and conventional analyses were made of the taxonomic and biostratigraphic data. Numerical taxonomy was performed on a sample of 210 OTU's (Operational Taxonomic Units) using 66 characters which were determined on cranidia of Middle Cambrian ptychopariid trilobites. These characters consisted of linear measurements which were transformed to indices proportional to glabellar length, quantitative-qualitative shape or angle measurements, and multistate attributes. The similarity coefficients calculated were average taxonomic distances and Pearson's product-moment correlation coefficient. The matrices of similarity coefficients were clustered by single-linkage and unweighted pair-group algorithms. The coordinates of OTU's in a three-dimensional A-space defined by the first three principal axes also were calculated. A phenogram of the distance matrix clustered by UPGMA (which yielded the highest cophenetic correlation coefficient) and a three-dimensional pin-and-ball model were used to interpret the trilobite taxonomy. Insufficiently clear clustering in both representations of taxonomic structure necessitated also a conventional taxonomic study guided by the numerical phenetics. Numerical biostratigraphy was performed with 79 collections as OTU's and 43 trilobite genera as characters. Jaccard coefficients were used as similarity coefficients, and the results were clustered by UPGMA. The resultant phenogram was readily interpretable, and seven faunal assemblage zones (Albertella, Glossopleura, Ehmaniella, Bolaspis-Glyphaspis, Ehmania, Parehmania, and Bolaspidella)are defined for the Middle Cambrian in the study area. Two of the zones (Ehmaniellaand Parehmania)are new and replace part of the previously defined “Bathyuriscus-Elrathina”zone. Bolaspis-Glyphaspis, Ehmania,and Parehmaniazones may have only regional validity.
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    Mathematical geology 5 (1973), S. 73-90 
    ISSN: 1573-8868
    Keywords: allometric equations ; correlation and regression ; principal-components analysis ; statistics ; allometric growth ; ontogeny ; paleontology ; relative growth
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    Notes: Abstract Relative growth of the Miocene pelecypod Glycymeris parilis (Conrad) was examined using allometric equations and principal components. Different parts of the shell showed contrasting growth strategies that were dictated by functional morphology and basic shell geometry. Despite the divergent developmental strategies, 93 percent of the correlation matrix variance is accounted for by overall size increase. The remaining variance mainly represents growth of the teeth, which differed considerably from other variables.
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    Keywords: discriminant function ; population ; classification
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    Notes: Abstract In the prediction of ore deposits, a series of geological, geochemical, and geophysical characters are used to describe the model of ore deposits. The problem is how to use the characters of known ore deposits to establish the model and to look for the target areas with similar geological environments. This can be done with a powerful mathematical tool—discriminant analysis. Nevertheless, there generally are too many geological variables to describe a class of ore deposits. Some of them are discrete, and the others are continuous. It is also difficult to know their distributions. A satisfactory method of discrimination has not been developed for such a complicated case. For this reason, we introduce a new method of orthogonally stepwise discrimination. We used this method to predict copper ore deposits of Dongchuan type in central Yunnan, China, with satisfactory results.
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    Mathematical geology 6 (1974), S. 311-332 
    ISSN: 1573-8868
    Keywords: canonical correlation ; cluster analysis ; correlation ; discriminant analysis ; factor analysis ; multivariate analysis ; numerical taxonomy ; principal coordinates ; regression analysis ; statistics ; allometry ; eurypterids ; integration and coordination ; ontogeny ; paleontology ; relative growth
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    Notes: Abstract Multivariate analysis is used in the search for one or more types of structure. The statistical zap applies a single method to determine one preselected type of structure. Several zaps suffice to ascertain several types of structure. The statistical shotgun represents an alternative approach. Here, a series of methods is applied to the data with the intent of ascertaining all possible types of structure that may exist. If strong structure is present, an appropriate zap will probably reveal it, and a variety of techniques will determine the same general structure. If only the main structure is required, the zap is adequate. In this situation, the shotgun will display a basic consistency which is at least reassuring. However, zaps may fail to detect a more subtle secondary structure of geological interest which will be displayed by the shotgun. For weakly structured data, a zap will only determine one type of structure but the shotgun reveals all. Study of the ontogeny of Parastylonurus myops(Clarke), a Lower Silurian eurypterid from New York (USA) shows the virtues of the statistical shotgun.
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    Mathematical geology 7 (1975), S. 295-321 
    ISSN: 1573-8868
    Keywords: data processing ; data structure ; independent events ; paleontology ; petrology ; regional mapping ; stratigraphy ; structure
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    Notes: Abstract Geological events, such as emplacement of granite or growth of slaty cleavage, may be ordered into a sequence by two methods. One is to assign each event a place in a time scale, such as years before the present, which amounts to assigning events an age designation from the set of real numbers. In ordering such a list, the algebra of real numbers applies. A second method is to determine the time relations of events in pairs, such as a fold is of type (S1, S2) or granite intrudes conglomerate. These binary relations between events may be used to order events into a sequence using the transitive properties of the relation “older than.” It is shown, however, that the binary relations between events do not follow the familiar rules for the algebra of real or integral numbers and it is necessary to erect a new system of relations called the “algebra of events.” The fundamental relation is “older than or equivalent to” and this may be used to define the relations “older than”, “younger than”, “equivalent to”, “incomparable to”, and “covers.” The essential difference from the algebra of integers is that the reflexive relation (“equal to”) is replaced by two such relations (“equivalent to” and “incomparable to”) in the algebra of events. A number of binary relations between events may be assembled into an event matrix which is basically a truth table for the relation “older than.” This may be ordered and stacked by operations termed ORDER and STACK. The relationship of each event to every other event may be determined by simple inspection of an ordered, stacked matrix, and from this a geological history may be assembled. If there are contradictions in the field data, ordering into a proper sequence is impossible and may be detected. If there are ambiguities in the field data, there are several different orders that are proper sequences so that the event matrix may be ordered. However, the ambiguities occur as voids in the stacked matrix.
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    Keywords: classification ; cluster analysis ; discriminant analysis ; ordination analysis ; grain size ; sedimentology
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    Notes: Abstract A multivariate statistical strategy for classifying paleoenvironments is effective for studying modern sedimentary processes in western Great South Bay and South Oyster Bay, New York. The 13 whole phi weight percent variables were tested for redundancy with R-mode cluster analysis. The samples were partitioned statistically into five environmentally significant facies using Q-mode cluster analysis: (A)sandy gravel, (B)sandy silt, (C)silty sand, (D)slightly gravelly sand, and (E)fine sand. An ordination depicted gradational relationships among the samples and the facies. It was used to evaluate the environmental and textural parameter gradients within the sample space. Interpretations obtained in this manner and by examination of the grain-size curves suggest that these sediments were deposited by waves and currents on beaches and in wave zones (facies C and E),shoal areas (facies B),and tidal channels (facies A and D).Tidal currents, wave action, and eelgrass control the distribution of sediments within the two bays.
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    Mathematical geology 5 (1973), S. 163-177 
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    Keywords: classification ; discriminant analysis ; geochemistry ; numerical taxonomy
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    Notes: Abstract The technique of instrumental neutron activation analysis (INAA) has been used to analyze chip samples of geological material for 12 elements. Discriminant analysis has been used to classify the unknown chip samples to the correct stratum in a sedimentary succession.
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    Mathematical geology 6 (1974), S. 135-152 
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    Keywords: classification ; cluster analysis ; numerical taxonomy
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    Notes: Abstract Coefficients of association have been widely employed in cluster analysis. However, their use has been, for the most part, restricted to binary data. This limitation can be overcome by redefining positive and negative matches and mismatches in terms of minimum and maximum values of paired elements of parallel vector arrays. Rewriting the algorithms of coefficients of association with these new components gives the new “quantified” coefficients general utility for binary, ordered multistate, and quantitative data, while retaining their original analytic properties. Quantified coefficients of association avoid several problems of shape and size that are associated with correlation coefficients and measures of Euclidean distance. However, when measuring similarity, quantified coefficients weight each attribute of an object by that attribute's magnitude. A related set of similarity indices termed “mean ratios” is introduced; these indices give each attribute equal weight in all situations. Both quantified coefficients of association and mean ratios are related to a number of measures of similarity introduced to various fields of scientific research during the past 50 years. A review of this literature is included in an attempt to consolidate methodology and simplify nomenclature.
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    Mathematical geology 8 (1976), S. 669-681 
    ISSN: 1573-8868
    Keywords: classification ; factor analysis ; economic geology ; mineralization ; petrology
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    Notes: Abstract Geological descriptions of unmineralized and mineralized ultrabasic and basic complexes were collected on a world-wide basis from published literature in the framework of the research project “Basimine.”Its aim is the discovery of controls governing the existence of mineralization in certain complexes and subsequently the development of working hypotheses for nickel prospection. Files were created containing geological and petrological data for each complex. In order to gain an understanding into the relationship existing between variables and complexes, correspondence analysis was applied to various data sets taken from the files. The results indicated criteria, either favorable or unfavorable, for the presence of mineralization in the complexes, and pointed out certain unmineralized complexes which could well be mineralized due to their position as regards known ore deposits in the plan of the factorial axes.
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    Keywords: classification ; cluster analysis ; numerical taxonomy
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    Notes: Abstract A method is described for testing the distinctness of two clusters in Euclidean space. One first calculates the projections, q,of the N1 and N2 members of the clusters onto the line joining the cluster centroids. From the distributions of qan index of disjunction, W,is calculated, which corresponds to an index of overlap, VG.The quantity W√(N1+N2)is distributed as noncentral tsubject to assumptions on the multivariate normal distribution of the clusters. This allows a test of whether the observed disjunction is significantly greater than a chosen figure, which is equivalent to testing whether the overlap of the clusters is significantly less than a corresponding value of VG.Two clusters that appear distinct may be produced simply by the partitioning of a homogeneous swarm into two contiguous regions. Provided that the clusters form a dichotomy in a dendrogram, and that the clustering method yields geometrically convex clusters, a conservative test of this situation can be derived by determining the excess of Wover the value expected for a rectangular distribution.
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    Mathematical geology 9 (1977), S. 619-633 
    ISSN: 1573-8868
    Keywords: probability ; paleontology
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    Notes: Abstract A new method of measuring the relative abundance of microorganisms by using a set of interrelated coefficients, termed “abundance coefficients” or “AC”, is proposed. These coefficients provide a means of recording abundance for geometric density categories, and each density measurement represents an approximation of the Poisson parameterλt. The AC is the natural logarithm of a “characteristic value,” which is a particular number for each geometric density category. The “characteristic values” are based upon a probabilistic error statement derived from the Poisson formula, and they present evidence for separation of the geometric category boundaries bye = 2.71828. The proposed AC provide a means for recording species abundance in a manner suitable for arithmetic manipulation, for population structure studies, and for the determination of practical limits for defining the presence or absence of a species. Further, these coefficients provide for both intrasample and intersample abundance comparisons.
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    Mathematical geology 10 (1978), S. 111-139 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; principal components ; morphometrics
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    Notes: Abstract An artificial data set is used to illustrate the morphologic properties of some common multivariate techniques and consideration of three common situations. The first concerns a sample showing no obvious groupings. In this situation principal components (or coordinates) and factor analyses give a logical ordination of form variation; cluster analysis produces sizedominated groups. The second situation considers an homogeneous sample where size and shape have important implications. Principal components are tested for association with size and shape, both of which can be isolated if isometry exists; if allometry is present, isolation of shape is possible only by size elimination, e.g., conversion to ratios. The third situation examines a sample of unknown groupings in which shape variation is the only interest. Aside from ratios, two other methods which produce shape-dominant clusters are assessed. Some of the options available in cluster analysis are also examined.
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    Mathematical geology 12 (1980), S. 69-77 
    ISSN: 1573-8868
    Keywords: dynamic clustering ; classification ; geochemical data ; sedimentology
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    Notes: Abstract The purpose of typological factor analysis is to detect, within a multidimensional sample, the existence of subsets characterized by different maximal elongation directions. The method which has been successfully applied in the field of pattern recognition can be considered from two points of view: (1) an automatic classification or “dynamic clustering” technique: and (2) a form of factor analysis. Using this form of analysis nuclei of affine varieties (points, axes, planes, etc) are identified. Different case studies were analyzed in order to establish the advantages of the method compared to other methods. Geochemical analyses of rock samples; that is, rhyolites, mafic, and intermediate rocks of the Normetal (Abitibi) area were subjected to typological factor analysis for the purpose of classification of geological deposits and detection of geochemical anomalies. The method was also applied to the classification of sediments from the Barataria Bay area in Louisiana.
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    Mathematical geology 11 (1979), S. 285-297 
    ISSN: 1573-8868
    Keywords: multivariate normality ; paleontology
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    Notes: Abstract Data of a microfossil group, the planktonic foraminifera, have been tested to determine the conformity of various real data distributions to univariate and multivariate normality and the effects that standard transformations have upon the distributions. Studies of two bivariate samples, one trivariate sample, and two quadrivariate samples of size data indicate that distributions frequently deviate greatly from multivariate normality. Univariate distributions are generally positively skewed and show a tendency for leptokurtosis. A logarithmic transformation improved both univariate and multivariate distributions but the number of distributions conformable to normality increased only slightly—from zero to one in the multivariate case and from one to four in the univariate case (totally 15 distributions). Arcsine (p/100) 1/2 transformations of percentage data in two samples including 16 and 23 species, respectively, decreased highly significant deviations from multivariate normality but distributions remained greatly non-normal. Although markedly positively skewed and leptokurtic univariate distributions were improved in most instances, the number of normal distributions (two) did not change. It follows that neither of the transformations caused significant increases in the number of normal distributions but if it is assumed that the consequences of non-normality are less severe as the deviation from normality decreases, the transformations are justified.
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    Mathematical geology 16 (1984), S. 283-301 
    ISSN: 1573-8868
    Keywords: Bayesian classifiers ; classification ; cluster analysis ; cluster validity ; fuzzyc means ; fuzzyc varieties ; fuzzy covariances ; geochemical prospecting ; glacial till ; kriging
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    Notes: Abstract To evaluate the provenance of glacial till, the trace element content of magnetite was used. Magnetite was present in all known rock types and all till samples in the area investigated. By using fuzzy-set theory it was possible to group samples of magnetite taken from bedrock into relatively homogeneous and geologically meaningful groups and also, by fuzzy classification, to relate the till samples to the rocks in such a way that the relative contribution of each rock type to the till is estimated. Each rock and till sample is assigned a membership value between 0 and 1 for each rock type. The membership values, for a certain rock type in the till, are then interpolated by kriging onto maps. Magnetites from skarns associated with sulfide ores especially are rather distinct, and so a map of such membership values for till unveils all known ore deposits some 1–5 km “downstream”in the general direction of the ice flow. Other anomalies show up which cannot be related to hitherto known ores or mineralizations.
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    Mathematical geology 18 (1986), S. 3-32 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; significance tests ; multivariate normality ; minimum spanning trees
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    Notes: Abstract A significance test is presented for whether, based on levels of branches in a dendrogram, a cluster is from a multivariate normal distribution. The method compares the observed cumulative graph of number of branches with a graph derived from a simple logistic function. Provided the number of objects or variables is not small, the difference between graphs can be tested by the Kolmogorov-Smirnov, Cramér-von Mises, and Lilliefors statistics. Logistic functions were obtained by simulation and are available for three similarity measures: (1) Euclidean distances, (2) squared Euclidean distances, and (3) simple matching coefficients, and for five cluster methods: (1) WPGMA, (2) UPGMA, (3) single linkage (or minimum spanning trees), (4) complete linkage, and (5) Ward's increase in sums of squares. For simple matching coefficient, the mean intracluster similarity also is required. The method allows a test of whether the dendrogram could be from a cluster of smaller dimensionality due to character correlations. Good fit of the data to abnormally large or small dimensionality provides an important warning to interpretation of the dendrogram. Quantiles of test statistics were found by simulation to be well-approximated by logistic functions. The Lilliefors test is recommended for general use; if a conservative test is required, the two-tailed Kolmogorov-Smirnov test is most suitable. The method is suitable for use with a hand calculator, and a computer program for it is available from the author.
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    Mathematical geology 19 (1987), S. 539-547 
    ISSN: 1573-8868
    Keywords: classification ; entropy ; hierarchical decomposition ; information theory ; spatial pattern ; spatial relationships
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    Notes: Abstract A method for determining the most appropriate scale for presentation of spatial relationships between two variables combines the principle of entropy decomposition with Phipps' entropy-based method for determining mutual information of landscape patterns. The method enables determination of the optimal level of detail for maps, data matrices, or other depictions of two spatially associated phenomena. An example from wetland mapping is given.
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    Mathematical geology 5 (1973), S. 1-10 
    ISSN: 1573-8868
    Keywords: classification ; data processing ; information exchange ; general geology ; groundwater ; numerical taxonomy
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    Notes: Abstract The definition of objectives and question of interpretation must be considered when setting up data banks. The objective will determine the type of data to be collected. A hierarchy of data-processing systems exists where the amount of interpretation in the data increases as the order of the system increases. The remarkable continuity of basic data can be embodied in the axiom: “Any fundamental data free of interpretation cannot be discontinuous.” The measurement of space and time remain invariant for all orders of data systems and are essential for relating data containing various amounts of interpretation. In general, only basic data should be exchanged. Where this is not feasible the object described should be clearly defined in space and time.
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    Mathematical geology 5 (1973), S. 285-296 
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    Keywords: classification ; cluster analysis ; semiobjective
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    Notes: Abstract A simple, semiobjective method is described to reduce the number of groups in a classification to an arbitrary level without losing contact with the geologic information contained in the evolving groups. The method, operated in a stepwise or cyclic manner, employs some of the commonly used numerical techniques, but avoids strict adherence to them to obtain geologically more meaningful results. The method is illustrated in a facies study of the upper Paleozoic rocks of southeastern Utah.
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    Mathematical geology 5 (1973), S. 351-363 
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    Keywords: classification ; factor analysis ; mapping ; oceanography ; sedimentology
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    Notes: Abstract Factor analysis utilizing textural data from 81 bottom samples was used to analyze the surficial sediments covering a 40,000-sq km area, which is one input data point per 500 km. On the other hand, the surficial geology of the area studied is complex as some map units are only 1 km wide in places. Under these circumstances it is interesting to determine that factor analysis nonetheless aims toward a reasonable geological solution. If the premise is accepted that factor analysis provides a solution “best-fitted” to the data, the geologist has carried his research one step further and is left with the problem of interpreting the results of factor analysis correctly. In this experiment, the interpretation of the factors representing the gravel and the mud is relatively simple, although the two factors representing sands are more difficult to explain. The proper interpretation of factors leads naturally to an inquiry on the optimum number of factors to use, but this problem can be solved objectively by considering the factor loadings.
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    Mathematical geology 6 (1974), S. 1-15 
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    Keywords: factor analysis ; paleoecology ; paleontology
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    Notes: Abstract A factor-analytic approach (varimax rotated factors) was used in studying the benthonic foraminiferal associations of the Mid-Tertiary Edegem Sands at Terhagen (near Antwerpen) Belgium. The fauna can be described by two groups. The lower and upper part of the stratigraphic section are characterized by one group and the middle transitional part by a second group. The results can be correlated with the number of the planktonic forms and with the fossil richness of the sediment.
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    Mathematical geology 6 (1974), S. 59-72 
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    Keywords: classification ; discrimination ; binary data
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    Notes: Abstract An iterative method of adaptive pattern recognition is used to allocate unclassified individuals to an a priori classification. The model is similar in form to a linear discriminant function, but the coefficient vector is determined by iteration. The method can be used with binary data, and with variables whose statistical distributions are not normal; it is therefore a useful technique for geologists.
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    Mathematical geology 6 (1974), S. 333-352 
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    Keywords: classification ; cluster analysis ; discriminant analysis ; multivariate analysis ; ordination ; numerical taxonomy ; paleoecology ; sedimentology
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    Notes: Abstract A multivariate analytical strategy is proposed for aiding the investigator in extracting maximum information from environmental data. Data are carefully coded and scaled and are tested for redundancy using R-mode cluster analysis. The samples are partitioned into environmental classes using Q-mode cluster analysis. Q-mode ordination facilitates interpretations, which usually can be verified by comparison with field relationships. Discriminant analysis serves as an identification procedure for extending the classification to unknown samples. The strategy is demonstrated by application to Cape Hatteras microorganism distributions and Devonian sedimentary facies.
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    Mathematical geology 5 (1973), S. 213-223 
    ISSN: 1573-8868
    Keywords: classification ; cluster analysis ; numerical taxonomy ; mineral exploration
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    Topics: Geosciences , Mathematics
    Notes: Abstract This paper presents a technique for evaluating the similarity of ore deposits utilizing several geological variables. Information on tungsten mines in North America, taken from published literature, was used for a cluster analysis to group samples according to their similarity based on a simple matching coefficient. It was possible to interpret and evaluate different ore environments that clustered according to age, mineralogy, and other variables. Cluster analysis may be important in mineral exploration where considerable amounts of data are available for analysis. Subtle relationships that might be overlooked because the data are too voluminous can be isolated using this technique. It also can be used to establish exploration priority in unknown areas on the basis of similarity to known metallogenetic provinces.
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    Mathematical geology 5 (1973), S. 297-311 
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    Keywords: statistics ; general geology ; paleontology
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    Topics: Geosciences , Mathematics
    Notes: Abstract The basic principals of hypothesis testing are reviewed, including the development of the hypothesis, the statistical assumptions made, and the test of the hypothesis. The appropriate experimental design and sampling technique for evaluation of hypotheses posed are discussed. Because the analysis of variance involving the F-test should be used in a wide variety of geological experiments, emphasis is placed on this analysis. Many geological experiments result in the measurement of one or more factors on a continuous scale, whereas others are recorded in a discrete fashion. This necessitates the use of a covariance analysis to evaluate the effect of discrete and continuous factors in the same model. Orthogonal comparisons are discussed as they are used to evaluate specific hypotheses following the general test of hypothesis in the analysis of variance or covariance. All procedures discussed are illustrated using actual palynofloral data.
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    Mathematical geology 24 (1992), S. 711-717 
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    Keywords: geophysical data ; geophysical mapping ; pattern recognition ; man-and-machine technology ; feature selection ; geological forecasting ; ranging ; clustering ; classification ; control set
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    Notes: Abstract To predict secondary geological structures that control the localization of mineral deposits in areas of cover, it is practical to use complex geophysical data. The prediction process is iterative and employs pattern recognition techniques. Each iterative cycle can include the procedure of location and ranging according to their appropriateness to the problem. The quality of the prediction is a function of the suitability of the geological environment under investigation and of the anomalies contained in the geophysical data and their selection.
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  • 53
    ISSN: 1573-8868
    Keywords: cherts ; Fe/Mg ratio ; pelagic clay minerals ; correlation coefficient ; goodness-of-fit ; classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Modern marine sediments can be classified into terrigenous, hemipelagic, and pelagic types according to the distances from the land for the sites recovered and in terms of lithological characteristics of sediments. Ancient cherts are the best sedimentary rocks to reconstruct ancient depositional environments and hemipelagic and pelagic cherts can be identified in terms of lithologic and stratigraphic characteristics. However, geochemical characteristics of modern sediments and ancient cherts can discriminate them into these three types. Particularly, the degree of correlation between Fe and Mg in clay minerals is the most effective criterion for the classification, because the concentration of pelagic clay minerals in which the Fe/Mg ratio is constant may become indices for the classification into the three types. The correlation coefficient and goodness-of-fit to a certain regression line were used as indices of the classification and calculated for several sets of modern sediments and ancient cherts totalling to more than 400 samples. The correlation coefficients and the student-t values for the coefficients become better classification indices than the goodness-of-fit andF-values of the analysis of variance. Goodness-of-fit andF-values can be only used as subsidiary indices for the main classification indices of the correlation coefficients. The classification on the basis of the degree of correlation between Fe and Mg is effective and this approach can be used for other major chemical elements such as Al, K, and Na, if some sequential values of chemical analyses are available.
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  • 54
    ISSN: 1573-8868
    Keywords: classification ; spatial structure analysis ; geostatistics ; bathymetry ; Atlantic ; automatization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Seafloor classification is aimed at quantitatively characterizing seafloor properties such as roughness and anisotropy, and at using such spatial characteristics to distinguish geological provinces automatically. From geostatistical principals, a variogram method is developed for seafloor classification and it is demonstrated for data from the western flank of the Mid-Atlantic Ridge at 25°45′N to 26°40′N. This study uses HYDROSWEEP bathymetric data which have been ping-edited to flag erroneous data records, and navigation corrected. The classification method can handle the resultant data gaps inside the survey swaths as well as interpret data from several swaths. For a suite of test areas representative of different geological provinces, directional variograms are calculated, and characteristic parameters are extracted for the classification. Examples include a sediment pond, abyssal hill terrain in several segments and of variable spacing, inside and outside corners of ridge discontinuities, and mixed morphological forms. The dependency of the results on random or regular subsampling and on the size of the test area is investigated.
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  • 55
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    Mathematical geology 25 (1993), S. 937-947 
    ISSN: 1573-8868
    Keywords: classification ; geothermal field ; map comparison ; multivariate statistics ; spatial analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Quantitative approaches to data analysis in the last decade have become important in basin modeling and mineral-resource estimation. The interrelation of geological, geophysical, geochemical, and geohydrological variables is important in adjusting a model to a real-world situation. Revealing the interdependences of variables can contribute in understanding the processes interacting in sedimentary basins. It is reasonably simple to compare spatial data of the same type but more difficult if different properties are involved. Statistical techniques, such as cluster analysis or principal components analysis, or some algebraic approaches can be used to ascertain the relations of standardized spatial data. In this example, structural configuration on five different stratigraphic horizons, one total sediment thickness map, and four maps of geothermal data were copared. As expected, the structural maps are highly related because all had undergone about the same deformation with differing degrees of intensity. The temperature gradients derived (1) from shallow borehole logging measurements under equilibrium conditions with the surrounding rock, and (2) from non-equilibrium bottom-hole temperatures (BHT) from deeper depths are mainly independent of each other. This was expected and confirmed also for the two temperature maps at 1000 ft which were constructed using both types of gradient values. Thus, it is evident that the use of a 2-point (BHT and surface temperature) straightline calculation of a mean temperature gradient gives different information about the geothermal regime than using gradients from temperatures logged under equilibrium conditions. Nevertheless, it is useful to determine to what a degree the larger dataset of nonequilibrium temperatures could reflect quantitative relationships to geologic conditions. Comparing all maps of geothermal information vs. the structural and the sediment thickness maps, it was determined that all correlations are moderately negative or slightly positive. These results are clearly shown by the cluster analysis and the principal components. Considering a close relationship between temperature and thermal conductivity of the sediments as observed for most of the Midcontinent area and relatively homogeneous heat-flow density conditions for the study area these results support the following assumptions: (1) undifferentiated geothermal gradients, computed from temperatures of different depth intervals and differing sediment properties, cannot contribute to an improved understanding of the temperature structure and its controls within the sedimentary cover, and (2) the quantitative approach of revealing such relations needs refined datasets of temperature information valid for the different depth levels or stratigraphic units.
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  • 56
    ISSN: 1573-8868
    Keywords: electrofacies ; kriging ; classification ; regionalization ; geostatistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Regionalized classification of electrofacies utilizes the statistical relationships between laboratory determined hydrologic properties and field-measured geophysical properties to estimate spatial distributions of porosity, permeability, and diagenetic characteristics. The method, illustrated with an application to the St. Peter Sandstone in the Michigan basin, combines techniques for multivariate analysis and spatial estimation. Core plug and borehole geophysical data are clustered into electrofacies that reflect the hydrologic properties and diagenetic characteristics of the formation. Electrofacies characteristics then are used to assign a class membership probability at locations where only geophysical data are available. Three-dimensional estimation of electrofacies occurrence is done by kriging datasets containing the probability of electrofacies membership at borehole locations. The discretization and kriging geometry allow three-dimensional estimation of hydrologic parameters for a large region that incorporates meter-scale heterogeneity. Finally, permeability and porosity are estimated at each grid location by probability-weighting. Because the electrofacies carry information about both the hydrologic and lithologic properties, the resulting spatial distributions provide an understanding of both the present-day flow characteristics and the extent of processes that control them.
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  • 57
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    Mathematical geology 8 (1976), S. 413-427 
    ISSN: 1573-8868
    Keywords: Witwatersrand System ; geochemistry ; discriminant analysis ; classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Powdered rock samples from strata of the Witwatersrand System's sedimentary succession have been analyzed by x-ray fluorescence and optical spectroscopy techniques for nineteen elements. Using discriminant analysis it is possible to identify strata based on their trace-element compositions.
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  • 58
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    Mathematical geology 9 (1977), S. 77-98 
    ISSN: 1573-8868
    Keywords: classification ; factor analysis ; association analysis ; binary data ; Recent carbonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The shallow shelf area to a water depth of 40 m off Ras Burka, Gulf of Elat, comprises several depositional zones. In order of increasing water depth these include: sand dune (on shore); swash; dead reef platform; sand channel; live coral reef; Cymodoceaslope; reef knolls; and Halophilalawn. The abundance of 64 biogenic constituents, comprising 48 genera of Foraminifera and a variety of other taxa, was recorded in 16 samples representing the sediments presently forming in the various environments. Nodal ordination and association analysis were applied to classify the samples and to examine whether the present day zonation of sedimentary environments can be objectively recognized on the basis of the assemblages of biogenic constituents. The analyses classified the samples consistently into three classes, identified as the shallow near-shore, the upper slope, and the lower slope zones. Association analysis, utilizing only discrete binary presence or absence scores, yielded better results than nodal ordination analysis utilizing continuous metric modal data. In the study area, biogenic grains other than Foraminifera do not contribute to the environmental discrimination. The results suggest that crude presence scores, as contrasted with refined metric data, are informative enough for differentiating sedimentary environments.
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  • 59
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    Earth, moon and planets 89 (2000), S. 91-115 
    ISSN: 1573-0794
    Keywords: Appearance ; boulders ; classification ; comet evolution ; disappearing comets ; double nuclei ; dynamics ; fragmentation models ; Kreutz group comets ; split comets ; striae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Splitting events affect cometary nuclei to a different level of severity ranging from complete disruption of the nucleus (e.g., C/1999 S4 LINEAR) to separation of major fragments (e.g., 73P/Schwassmann-Wachmann 3) and spill-offs of smaller boulders (e.g., C/2001 A2 LINEAR).Fragmentation of comets produces secondary products over a wide range of sizes (from cometesimals to sub-micron dust). It is detectable through the presence of fragments (with own comae and tails) in the coma of the parent nucleus, through outbursts in its activity and through arc-lets (“coma wings”)associated with fragments. The secondaries have different life times and show different non-gravitational forces. Nucleus splitting is also considered to generate whole families of comets (Kreutz group) or — if gravitational bound — multiple nuclei (e.g., C/1995 O1 Hale-Bopp). It may explain the striae phenomena seen in dust tails of bright comets (C/1995 O1 Hale-Bopp) and the detection of chains of impact craters onother bodies in the solar system. As process of significant mass loss it is relevant for the scenario of nucleus extinction, at the same time it also plays a role for the number statistics of existing (observable) comets and for the size distribution of comet nuclei. Various model scenarios for nucleus splitting are proposed: tidal disruption, rotational splitting, break-up due to internal gas pressure, fragmentation due to collision with other bodies. Only in one case, Comet D/1993 F1Shoemaker-Levy 9, the physical process of fragmentation could be undoubtedly identified. In any case, comet splitting provides important insights inthe internal structure, surface layering and chemistry of comet nuclei.
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  • 60
    ISSN: 1573-0840
    Keywords: classification ; neural network ; explosion quakes ; volcano ; Stromboli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The application of neural networks as classifiers of seismic events is described with the aim of developing an automatic system for the classification of ‘explosion quakes’ at the Stromboli volcano. The architecture of the network that we trained to identify four different classes of shocks was a Multi-Layer Perceptron, using the Back Error Propagation algorithm. Five different approaches for representing the information embedded in the seismograms, both in the time and in the frequency domain, were considered, and the results compared. The direct use of the time series of the shocks was not satisfactory. The auto-correlation function worked well, but in some cases it was misleading. A better performance was obtained with a frequency domain representation. Finally, the use of the envelope function did not work well. Combining parameters such as the auto-correlation and envelope functions can improve one source of error, but it may introduce new ones. The performance obtained highlights the importance of the data attributes used for the training of the network. Topologies with eight neurons in a single hidden layer gave, on average, the best results among the considered neural network structures. The overall results provide a large number of events (89% with the best performance) correctly classified, indicating that this automatic technique is reliable, and encouraging further applications in the field of volcanic seismology.
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  • 61
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    Netherlands journal of geosciences 78 (1999), S. 255-260 
    ISSN: 1573-9708
    Keywords: vertebrate palaeontology ; fossil fish ; anatomy ; cladistics ; classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
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  • 62
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    Netherlands journal of geosciences 78 (1999), S. 231-251 
    ISSN: 1573-9708
    Keywords: Anaspida ; correlation ; Gnathostomata (Acanthodii ; Osteichthyes?) ; Heterostraci ; Osteostraci ; paleontology ; Pridolian ; Thelodonti
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Fish microfossils were extracted from an erratic. The taxa from the rich microvertebrate fauna of late Pridolian (latest Silurian) age ( P. punctatus Zone) are listed. A full description is given of two new Gomphonchus taxa, G. mediocostatus and G. boekschoteni. On the basis of old and new material, ‘Gomphonchus hoppei’ is redescribed, interpreted as a porosiform poracanthodid, and assigned to Gomphonchoporus gen. nov. This interpretation necessitates redefinition of the Poracanthodidae VERGOOSSEN 1997 to include scales without a pore-canal system. The type genus, Poracanthodes, is redefined to include only punctatiform poracanthodids sensu Vergoossen 1997. Discovery of previously undescribed scale forms of the type species, P. punctatus BROTZEN 1934, results in an extended diagnosis for this biozonal index fossil. A new poracanthodid genus, Radioporacanthodes, is erected for the porosiform poracanthodids sensu Vergoossen 1997, with type species R. porosus (BROTZEN) 1934 s.s. Brief palaeontological and distributional comments on other microvertebrate taxa from the list are included, as well as a section on the biostratigraphical and correlational implications of the present and similar faunas from erratics for the East Baltic standard succession.
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