Title: Kimberlites and their ultramafic xenoliths from western Kenya
Abstract: Three western Kenya kimberlites, YlBl, Y1B3 and YA17, were found in the Nyanzian greenstone belt to the north of Winam Gulf by exploration-drillings.The localities are as follows; YlBl Hole, 34°11.2'E,0°4.7'S,Y1B3 Hole, 34°14.0'E,0°3.^'S and YA17 Hole, 34°30.9'E,0°9.5'N.Though the western Kenya kimberlites were intruded into the Archean rocks of (2.71 +0.34) xlo^Ma (Yanagi et al., 1981), their exact age of intrusions can not be defined.However, owing to alignment of these western Kenya kimberlite-localities