..., but it was found too difficult to define the principal pole densities with sufficient accuracy from the sample sizes available. The method developed here involves the same assump- tions as March's method, namely that the elements rotating during deformation 422 G. J. Borradaile (the phenocrysts) behave passively...

... with the previous pecies, O. gracilis is found exclusively by eutrophic pools with an abundant growth of vegetation chiefly Phragmites, Carex and Typha latifolia. O. gracilis does not now live in Britain but it has a widespread istribution in central and southern Europe and, apart from one northerly outpost near...

...J. P. Syvitski; J. W. Murray ABSTRACT Separation of sediment process populations is not possible using log-probability plots of grain-size concentrations, either by sieving or by direct measurement. Sedimentation diameters with other measurable grain parameters should be used. The significance...

... are made with some Paleozoic algae; however, some of the Sturgeon Lake flora may be new species or genera. Preliminary examination of selected cores from the Ireton Formation and organic-rich Duvernay Formation in central Alberta indicates a widespread istribution of algal-derived organic matter within...

... and II and assumes that the field-size distribution is approximated by a lognormal or non- parametric distribution (Wang and Nair, 1988; Lee, 1997) and the prior number-of-fields istribution is approximated by a Poisson distribution. From these assumptions one can estimate a posterior number-of-fields...

...-networks of different ages to assess the cumulative spatial and size distributions of faults within a given study area. Differentiation of fractal versus multifractal distributions of pool and field data is a potential tool that can be used to differentiate those plays in which there are simple controls...

... controlled by environmental gradients, we carried out a correspondence analysis (CA). This analysis was preceded by a percent transformation within samples, to prevent differences in sample size from structuring the ordination space, followed by a percent maximum transformation within taxa to account...

.... In the marine environment, he "shales" in general contain less than 35 per cent clay minerals and consist largely of quartz, be it of small particle size (Foscolos, pers. comm In the deltaic environment mudstones make up the bulk of the sediment. These deltaic mudstones contain approximately the same percentage...

... then presented a joint contribution with E. H. Rutter discussing a detailed analysis of grain size and grain-size distribution from marbles surrounding a migmatite dome on the island of Naxos. The observed correlation between grain size and peak metamorphic temperature was used as a basis for the discussion...

... treatment yields samples having median particle size values in the range 8-16 microns. Table I. P article S ize D istribution of S hale S ample A fter O ne H ammer M ill P ass Size Range, Microns Amount, Weight% Greater than 250 0.9 125-250 4.4 62.5-125 11.5 31.3...

... of the deposit, (ii) a regional stratigraphic zoning system based on (i) with division of easily iden- tifiable units by visual means, (iii) a regional mineralogical examination, and (iv) experimentation designed to establish the relationship between mineral suite, grain size and soil index properties...

..., Southwest England, determined by continuous seismic profiling, side-scan sonar, and core sampling Mar Geol 1972 13 M19 M26 Krumbein W. C. Size frequency distributions of sediments J sedim Petrol 1934 4 65 77 Lewis K. B. A key to the Recent genera of the Foraminiferida Bull...

...-80 years. Character and istribution of authigenic phases Using thin sections, samples representative of availa- ble stations (c. 30) from the area were divided into one of 3 groups: (1) Collophane mudstones, (2) Pelletal phosphorites, and ( 3 ) Glauconitic pelletal phospho- rites. These categories...

... Formation in the West Midlands indicates an increase in energy of depositional environment reflecting the overall mid to late Wenlock regression evidenced throughout the Welsh Borders by both sedimentology (Scoffin 1971) and fauna1 variations (Hurst 1975). Oncoid istribution and microfacies variation...

... criteria for recognizing the age of development of these types. Explanations for the origins of the distinctive Ringnes Formation concretions must account for their abnormally large size and widespread istribution. We suggest hat the huge nodules owe their form partly to diagenetic ementation...

... trivial, it is a difficult problem. Especially, the slope b is very sensitive to the size and quality of the available data sample (e.g., Papazachos, 1974). The usual procedure isto compute the geographical dis- tribution of seismicity by separating the examined area in small seismogenic subregions...

... the year, the waters may be derived from above the thermocline and, consequently, depleted in nutrients, for example during an El Niiio event (Wyrtki 1975). The resulting reduction in primary productivity, leads to significant reductions in population size and istribution of fauna (Alejandro & Bouchon 1987...

... running parallel to the axial valley walls. This conical seamount is three times larger than other seamounts o far surveyed along the Reykjanes Ridge. Its size implies that eruptions in this region have been restricted to a point-source vent for a considerable period of time. Depth variation along...

... be mentioned. First, the role of intermedi- ate host rocks is less significant for gold than for diamond placers, perhaps because diamond is trans- ported farther in particle sizes that are economically recoverable (e.g. Sutherland 1982). Second, the fact that gold can be dissolved and re-precipitated may...

... of Lithofacies 1B and consists of several vertically stacked centimetre- to decimetre-thick beds. The bases of beds are sharply defined and marked by a signifi- cant grain-size break; in some examples basal scouring is observed. Matrix-supported conglomeratic frameworks are common in the basal portion...