The claim by Furnes et al. (Reports, 23 March 2007, p. 1704) that Greenland metavolcanic rocks require Paleoarchean sea-floor spreading is incompatible with their own data. The purported sheeted dikes have the composition of pyroxenitic komatiite and could not have fed the adjacent ferroandesitic pillow lavas. Neither type has ophiolitic analogs, and both are likely ensialic.

Calving is an important mass-loss process at ice sheet and marine-terminating glacier margins, but identifying and quantifying its principal driving mechanisms remains challenging. Hansbreen is a grounded tidewater glacier in southern Spitsbergen, Svalbard, with a rich history of field and remote sensing observations. The available data make this glacier suitable for evaluating mechanisms and c...

In cluster analysis, it is often useful to interpret the obtained partition with respect to external qualitative variables (defining known partitions) derived from alternative information. An approach is proposed in the model-based clustering context to select a model and a number of clusters in order to get a partition which both provides a good fit with the data and is related to the external...

Nickel isotope fractionation patterns in continental ultramafic environments generally show a depletion of δ 60 Ni weathered rocks and an enrichment bedrock samples. The present study focuses on stable carbonate-rich, ophiolite samples with concomitant fluids at active serpentinization site southwestern Turkey, comparison to results from inactive the Eastern Desert Egypt carbonate-rich All soli...

the technical, allocative and economic efficiency of wheat growers in baft, kerman province were studied to analyze the degree of farmers success in the optimun allocation of their resources and the possibilities of increasing the production based on the available resources and factors of production. sampling was based on random method, so 75 farmers were selected. the stochastic frontier produ...