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Petrology and micromechanics of experimentally deformed natural rock salt: Physical processes: Topical report

Technical Report ·
OSTI ID:7243995

Effects of impurities and microprocesses on the creep of natural salt samples are presented. Salts are analyzed from four sites (Palo Duro Unit 4 and Palo Duro Unit 5, Texas; Avery Island, Louisiana; and Salina Basin, Michigan). The salts have been deformed at temperatures and pressures that simulate repository conditions. Bulk chemistry, optical petrology, and microprobe analyses are used to identify the species and to quantify the amount of each impurity. General effects of impurities on the rheology of natural salt are discussed. The physical processes that control creep deformation of salt are identified by etchpit techniques. The nature of desolation motion which controls the creep behavior of salt changes dramatically over the temperature range of 25 to 200/degree/C. Physical bases for constitutive modeling are established through observations documented in this report. Composition of the salts range from nearly pure, uniform halite to a heterogeneous composite of halite and anhydrite. Impurities evidently increase creep resistance at lower test temperatures. At higher test temperatures, creep deformation is much less sensitive to the presence of impurities. Anhydrite is the only mineral species that correlates strongly with creep response. Generally, greater amounts of anhydrite increase the creep resistance. 13 refs., 11 figs., 12 tabs.

Research Organization:
Battelle Memorial Inst., Columbus, OH (USA). Office of Nuclear Waste Isolation
DOE Contract Number:
AC02-87CH10290
OSTI ID:
7243995
Report Number(s):
BMI/ONWI/C-100; ON: TI88012352
Country of Publication:
United States
Language:
English