Planimetrowanie ziaren FeNi jako metoda ustalenia stopnia wietrzenia W0–W4 chondrytów zwyczajnych

Wlotzka scale (Wlotzka 1993) is commonly used to determine the weathering grade of ordinary chondrites. The scale is descriptive and based mostly on a subjective assessment of researcher. In this paper authors define a new, quantitative method to establish the W0–W4 weathering grade, which is based on planimetry of FeNi grains. Results of planimetry are compared with average content of FeNi metal in unweathered chondrites from the same group. Weathering grade estimated by this method are consistent with, or slightly different from the official one determined in classification, what proves the efficacy of the proposed method. Moreover, the method was applied to define weathering grade of meteoritic samples not classified so far: Pułtusk (W2), Thuathe (W2), Gao-Guenie (W2/W3), NWA 5205 (W3), NWA 4505 (W3), NWA 5296 (W2).