Microcrack technology. Progress report, 1 April 1979-29 February 1980

• Main Authors: Simmons, G., Caruso, L., Padovani, E.
• Format: Report
• Language: English
• Published: Massachusetts Institute of Technology. Department of Earth and Planetary Sciences. 1980
• Subjects: Granites; Thorium; Chlorite Minerals; Rocks; Iron Carbonates; Iron Ores; Quartz; Oxides; Water; Shales; 54 Environmental Sciences; Carbonates; Hematite; North Atlantic Region; Minerals; Siderite; Cracks; Chalcogenides; Gamma Spectroscopy; Transition Element Compounds; Radionuclide Migration; Clays; 58 Geosciences; Data; Carbon Compounds; 12 Management Of Radioactive And Non-Radioactive Wastes From Nuclear Facilities; Iron Oxides; Ores; Mass Transfer; Sedimentary Rocks; Carbon Oxides; Actinides; Silicon Compounds; Spectroscopy; Silicon Oxides; Metals; Elements; New Hampshire; Data Compilation; Images; Igneous Rocks; Environmental Transport; 580300 > Mineralogy; Petrology; & Rock Mechanics > (-1989); Oxygen Compounds; Tables; Numerical Data; Uranium; Information; Conway; North Atlantic
• Online Access: https://doi.org/10.2172/5697427; https://digital.library.unt.edu/ark:/67531/metadc1090417/

Microcracks in samples of core from a 3000-foot hole in the Conway granite, near North Conway, New Hampshire, are abundant and most of them are sealed with siderite, chlorite, quartz, hematite, clay, or microbreccia. The sealed cracks are 1 to 100.mu. wide, intersect many grain boundaries, often coincide with grain boundaries, and both intersect and contain minerals that are normally rich in U and Th. The abundances of U and Th in 100-gm-bulk samples range from 0.1 to 30 ppM and from 6 to 100 ppM, respectively. The working hypothesis that U and Th have migrated through the microcracks in CO/sub 2/-rich waters is proposed. In the Redstone Quarry core, the presently open microcracks are preferentially oriented; most open cracks have horizontal surfaces. Samples of Devonian shales have been obtained for the purpose of examining microcracks in relation to the production of natural gas. The problems of sample preparation for fissile shale have been largely solved. Samples from the NTS have been prepared for the examination of microcracks in relation to possible disposal sites for radioactive waste.