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Equations describing ten microfacies of Ste. Genevieve Limestone established previously on qualitative analysis of petrographic features are derived here in terms of measured lithic parameters. Mean values of each lithic parameter for each facies comprise independent variables with eigenvalues from discriminant analysis serving as coefficients for quasifunctional equations. This provides a unique quantitative expression for each qualitative microfacies, the dependent variable. Although these equations are not truly functional equations, they do provide explicit description of Ste. Genevieve Limestone facies. Quasifunctional equations form a necessary first step toward establishment of true functional equations describing unit lithology as functions of depositional parameters. Functional equations for lithic units offer a potential for an ultimate unification of classifications for all geologic materials. An immediate value of these quasifunctional equations resides in their explicit description and identification of subjective lithic classifications (facies), their utilization in comparative studies of lithic components in one or more stratigraphie units, their facility for an objective and automated digital reduction and graphic presentation of data, and their invitation for more careful examination and critical evaluation of natural relationships. [ABSTRACT FROM AUTHOR]

A rigorous treatment of the least-squares estimation of the parameters in petrologic materials balance equations is developed to take into account the uncertainties inherent in the chemical analyses. The choice of the optimal estimation procedure for a particular problem is dependent upon the extent of the petrogenetic understanding of the exact nature of the materials balance involved. Some of the complications entailed in obtaining least-squares estimates are illustrated by the examples of magmatic differentiation and metamorphic reactions. [ABSTRACT FROM AUTHOR]

A technique for preparing contour maps is presented which has particular applicability for geophysical data. This technique derives from the assumption that each measured value is a sample from a statistical distribution which is taken to be valid in the area around that sample location. This distribution may be specified in the manner which best defines the relationship between the data and its spatial environment. Extending this principle to cover all areas to be mapped, and not just those measured, it is possible to predict values over a grid array of locations and hence to produce a contour map. Inherent in this simple procedure is: (i) the ability to adjust to the nature of the data being contoured; (ii) the elimination of edge effects; (iii) visual indication of the relative accuracy with which contours are located, at all points of the map; (iv) the automatic downgrading of data values which are in error; (v) the ability to contour combinations of measured data values without compounding errors; and (vi) a relatively simple extension to data spatially distributed in three dimensions. [ABSTRACT FROM AUTHOR]

Methods for calculating constant terminal-settling velocities (v) of spheres are examined for their validity and limitations of usefulness. A different approach is given which accurately predicts v for spheres over a wide range of hydraulic conditions based on past experimental work. The theory behind this approach is given along with the listing of a fortran program which directs the calculations of v. The practical limits of the author's method are stated, and tables of v may be generated from the program for common mineral densities over a range of sizes useful to sedimentologists. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 a t-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. [ABSTRACT FROM AUTHOR]