Basalt cores effects

The fissured basalt cores and bentonite were altered by placing them in an autoclave under simulated groundwater at 320°C for 30 and 60 days to simulate 1000 y and 2000 y aging, respectively The waste-form wafers for both experiments were aged in the same manner by treating them for 17 days in saturated steam at 340°C The details of these procedures and the rationale for their use have been published previously (7). The effects of saturated steam on borosilicate glass were discussed in a recent publication (8) ... 

Recently we have conducted Mossbauer studies of core-to-rim alteration of a deep sea basalt and a continental basalt (59 60). The ocean basalt from the Mariana- deep was altered by seawater, and several concentric layers with different colors could be recognized from core to rim. Based on the Mossbauer spectra and petrographic observation of these layers, chemical states of iron were characterized as ilmenite, titanomagnetite, and silicate minerals (59). The enhanced superpara-magnetic effect in the rim demonstrates that the rim of the sample pre-... 

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