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The AAPG/Datapages Combined Publications Database
AAPG Bulletin
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Grain orientations were determined quantitatively for 62 turbidite sandstone beds that exhibited sole marks (19 beds with flute casts and 43 beds with groove casts). Statistically significant alignment of elongate grains within these beds tend to parallel the trends of the sole marks on the base of the beds.
Grain fabrics of six beds were determined quantitatively for multiple levels (a minimum of four levels in each bed). The mean grain trends were observed to parallel approximately the trend of the sole marks on the base of these beds.
Deviations in the mean grain trend from the trend of the sole marks were noted for most of the beds studied, but the mean deviation for all beds was less than 10°. Moreover, there was no systematic sense of deviation such as that reported by Bouma (1962), Spotts (1964), and Spotts and Weser (1964). The deviations were grouped in normal fashion about the zero deviation point.
Dip direction of imbricate grains was determined at three levels in one of the sandstone beds studied. The imbricate grains in the middle and lower intervals dip in one direction whereas those in the upper interval dip in the opposite direction. However, statistically significant data were obtained only from the lowest interval in the bed. The current sense indicated by the dip direction of the imbricate grains in the lower and middle intervals is the same as that inferred from the flute casts on the base of the bed.
Grain fabric exhibited in the rock slices was determined according to the technique described by Spotts (1964). The statistical technique used to evaluate the grain trends was patterned after the method described by Curray (1956). The writer and his assistant, Monty Hampton, devised the statistical technique used to evaluate the dip direction of imbricate grains.
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