Redetermination and reevaluation of compositional variations in metamorphosed sediments of the Littleton Formation, New Hampshire

In a study of metamorphosed pelites of the Devonian-aged Littleton Formation, New Hampshire, Shaw (1954) found little evidence for large scale compositional change other than devolatilization. Because his data are still used for such studies, his original samples have been reanalysed using more precise methods and for additional elements to provide a more useful data set. The new data show statistically unambiguous differences between sample sets in average concentration ratios to Al₂O₃ or TiO₂ for several elements. The data do not, however, show systematic compositional differences as a function of metamorphic grade. There is no compelling evidence in support of metamorphic gain or loss of the elements studied, but taken at face value, the statistical uncertainties would allow considerable gain or loss of most elements during metamorphism of Littleton pelites. -from Authors