No abstract

Ocean Drilling Program Leg 102 returned to Hole 418A 8 yr after it was originally drilled and retrieved a borehole water sample at a depth of ca. 350 m into basaltic basement. Chemical analysis for the major constituents and strontium isotopes indicates that substantial changes in the chemical composition of originally introduced surface seawater are principally due to diffusive exchange with surrounding formation waters. These changes include an increase in dissolved calcium and decreases in dissolved magnesium, sodium, and potassium, as well as in the 87 Sr/ 86 Sr ratio of dissolved strontium. Extrapolation of the data to zero magnesium yields dissolved calcium concentrations predicted by a diffusive exchange model, which is consistent with high dissolved calcium concentrations observed at other sites that show complete depletion of dissolved magnesium in the interstitial waters in sediments intercalated in basaltic basement.

The Indonesian meteorites, Selakopi, and Glanggang, in an H-5 chondritic matrix, were recovered on the same day from sites only 50 km apart. The textures and compositions of Selakopi and the H-5 portion of Gianggang are very similar, indicating that they are closely related. The bulk chemistry ofthe H-6 portion ofGlanggang is also very similar to that of the samples mentioned. It has therefore been concluded that Selakopi and the Glanggang breccia fragments were derived from the same source area and were probably ejected at the same time. Minor differences in bulk composition and texture among the three samples may be attributed to local variations on the parent body. However. for reasons stipulated in the conclusion, we recommend that separate names be maintained for these meteorites until further, more definitive investigations have been made.