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  • paleontology  (8)
  • 2020-2024
  • 1975-1979  (8)
  • Geologie und Paläontologie  (8)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 8 (1976), S. 183-202 
    ISSN: 1573-8868
    Schlagwort(e): Fourier analysis ; paleontology ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 7 (1975), S. 129-147 
    ISSN: 1573-8868
    Schlagwort(e): correlation ; factor analysis ; regression analysis ; statistics ; allometric growth ; paleontology ; relative growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 8 (1976), S. 113-136 
    ISSN: 1573-8868
    Schlagwort(e): Rubin—Friedmann cluster analysis ; canonical analysis ; principal component analysis ; numerical taxonomy ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 8 (1976), S. 151-163 
    ISSN: 1573-8868
    Schlagwort(e): Fourier analysis ; power-spectrum analysis ; paleoecology ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 7 (1975), S. 149-166 
    ISSN: 1573-8868
    Schlagwort(e): biostratigraphy ; numerical taxonomy ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 7 (1975), S. 295-321 
    ISSN: 1573-8868
    Schlagwort(e): data processing ; data structure ; independent events ; paleontology ; petrology ; regional mapping ; stratigraphy ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 9 (1977), S. 619-633 
    ISSN: 1573-8868
    Schlagwort(e): probability ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 11 (1979), S. 285-297 
    ISSN: 1573-8868
    Schlagwort(e): multivariate normality ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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