Basaltic glasses from Iceland and the deep sea: Natural analogues to borosilicate nuclear waste-form glass. MicliMlJ.J«rcinovfc and Rodney C.Ewing D«c«mb«r,1987 BASALTIC OLACSBI FROM ICBLAHD AVD THE DB» SBA: ITOBAX. AMALOGUBf TO BOROflLICATB MUCL1AB WMT1-F0RM GLASS Michael J. J«rcinovic and Rodn«y C. Ewing D«c«mb«r, 1987 D«parta«nt of Geology Th« University of New Mexico Albuquerque, New Mexico USA 87131 11 list of Tables iv list of Figures vi Suenery xiii Abstract xvi 1 introduction 1 1.1 Alteration 6 1.1.1 Palagonitizaticn 6 1.1.2 Palagcnitizaticn Rates 9 1.1.3 Secondary Mineralization 13 1.2 Samples 21 1.2.1 Iceland 21 1.2.2 Dredge Sanples 26 1.2.3 Drill Core Samples 26 2 Techniques 29 2.1 Thin Section Preparation 29 2.2 Scanning Electron Microscopy 31 2.3 X-Ray Diffraction 31 2.4 Electron Microprobe Analysis 32 2.5 Analytical Electron Microscopy 34 3 Results 35 3.1 Icelani 35 3.1.1 General cements 35 3.1.2 Fresh Mater Alteration 36 3.1.2.1 Pleistocene Snhjiftrtnl Volcanic» 37 3.1.2.1.1 Palagonite 37 3.1.2.1.2 Cssentation 42 3.1.2.2 Tungufell 55 3.1.2.2.1 Palagcnite 55 3.1.2.2.2 Oawntation 68 3.1.3 Seawater Alteration 72 3.1.3.1 General Conomts 72 3.1.3.1.1 Palagcnite 76 3.1.3.1.2 Cementation , 92 11.' 3.2 EKedge Sau&m 107 3.2.1 ROagonite 107 3.2.2 OsasntiiHin 117 3.3 Erill Om Saaples 128 3.3.1 ffelagcnite 128 3.3.2 t 3.4 Analytical Electron Microscopy 144 3.4.1 Saaple Description 144 3.4.2 Analytical Ilectrcn Micxceoopy 147 3.4.2.1 OSMI 113521-69 147 3.4.2.2 UGM1 113715 153 3.4.3 conclusion* 156 4 Discussion 158 4.1 ROagonite 158 4.2 Secondary Mineral Authigenasis, Solution Concentrations, and Mass Balance 180 4.3 Alteration Rates 200 5 Conclusions 206 5.1 Corrosion Machanisn 206 5.2 Alteration Products 207 5.3 Mass Balance 209 5.4 Alteration Rates 210 Acknowledgements 212 213 iv Table 1. Senary of palagcritizaticr. rates. Table 2. Secondary minerals associated with altered basaltic glasses. Table 3. Samples fzen Iceland. Table 4. Deep sc\ dredge sanples. Table 5. Deep e-» ir'H oare samples. Table 6. Apr Tvtrit pnlagonite rind thicknesses in Icelandic samples. Table 7. Average microprobe analyses of glass and corresponding palagonite rinds frar Icelandic subglacial vcicanics. Table 8. Average njryoprobe artalyses of clays in Icelandic subglacial volcanics Table 9. Average oicroprobe analyses of zeolites from Iceland. Table 10. Average riToprobe analyses of glass and corresponding palagonite rinds from hyaloclastitas and pillov basalt tins at Tungufell, Iceland. Table 11. Average ndcroprcbe analyses of clays from Tungufell, Iceland. Table 12. Average mlcroprobe analyses of glass and corresponding palagonite rinds frca seawater altered nyaloclastites and pillow basalt rims in Iceland. Table 13. Average Bicroprob* analyses of clays in Icelandic seawater altered nyaloclaatif.es and pillov basalts. Table 14. Apparent palagonite rind '.'hicknesses in deep sea samples. Table 15. Average v tcroprobi anaJLyse» of glass and corresponding palagonite rinds in dv«p sea dredge tuples. Table 16. Results for constant Fa in the high-Fe, low-si deep sea dredge pal»gonite«. v Table 17. Average miexoprobe analyses of days from deep sea dredge and drill Table 18. Average aiexoprobe analyses of deep sea zeolites. Table 19. Average microprobe analyses of glass and corresponding palagonite rinds in deep ssa drill core sasples. Table 20. Compositions of phases A, B, and C of OSMf 113521-69 determined by MM. Table 21. Gompositions of different areas of U9tf 113715 determined by AIM. Table 22. Relationship between pH and aluninum spaciaticn. Table 23. ftolagonitization rates inferred for Iceland samples from apparent r«M thickness and corresponding sample age. Table 24. Palagonitization rates inferred for dredge samples from apparent rind thickness and corresponding sample age. Table 25. Palagonitization rates inferred for drill core samples frcro apparent rind thickness and corresponding sample age. VI LIST Of 7IGDRBS Figure 1. Schematic representation of a subglacially-produced table mountain (after Jones, 1970; Allen, 1980b). Figure 2. Location nap of Iceland. Figure 3. Summary of characterization scheme. Figure 4. Riotonicrograph of a palagonitized glass frcn Icelandic subglacial volcanic ridge (Trolladyngia). Figure 5. Glass normalized-palagcnite composition of Icelandic subglacial volcanics. Figure 6. Variation plots of microprobe analyses of M-l clays. Figure 7. Variation plots of microprobe analyses of M-3 clays. Figure 8. Variation plots of microprobe analyses of M-6 clays. Figure 9. Variation plots of microprobe analyses of M-7 clays. Figure 10. Variation plots of microprobe analyses of Mid.-l clays. Figure 11. Variation plots of microprobe analyses of Mid.-3 clays. Figure 12. Variation plots of microprobe analyses of R-l clays. Figure 13. Variation plots of microprobe analyses of R-2 clays. Figure 14. Plot of exchangeable cations in zeolites in sample M-6 (Mosfell, Iceland). Figure 15. Sketch of a thin section of Tungufell, Iceland sample T-2. Figure 16. Glass nonnalized-palagonite composition of samples T-3 and T-4 from Tungufell, Iceland. Figure 17. Results of a microprobe traverse of a palagonite rind in sample T- 2, Tungufell, Iceland. This is Traverse 1 of 10 which were done on rinds associated with zeolite filled vesicles. vii Figure 18. Results of a microprobe traverse of a palagonite rind in sample T- 2, Tungufell, Iceland. This is Traverse 2 of 10 which were done on rinds associated with zeolite filled vesicles. Figure 19. Results of a microprobe traverse of a palagonite rind in sample T- 2, Tungufell, Iceland. This is Traverse 8 of 10 which were done on rinds associated with zeolite filled vesicles. Figure 20. Results of a aicroprobe traverse of a palagonite rind in sample T- 2, Tungufell, Iceland. This is Traverse 9 of 10 which were done on rinds associated with zeolite filled vesicles. Figure 21. Results of a microprobe traverse of a palagcnite rind in sample T- 2, Tungufell, Iceland. This is Traverse 2 of 6 which were done on rinds associated with vesicles filled with unoriented clay. Figure 22. Results of a microprobe traverse of a palagonite rind in sanple T- 2, Tungufell, Iceland. This is Traverse 4 of 6 which were done on rinds associated with vesicles filled with unoriented clay. Figure 23. Comparison of microprobe traverses of the two palagonite rind types in sample T-2, Tungufell, Iceland. Figure 24. Comparison of microprobe analyses of T-2 days, Tungufell, Iceland. Figure 25. Variation plots of aicroprobe analyses of T-3 clays. Figure 26. Variation plots of microprobe analyses of T-4 clays. Figure 27. Potassium content of zeolites (from microprobe analysis) vs. depth from the pillow surface in sample T-2, Tungufell, Iceland. Figure 28. Relationship between apparent palagonite rind thickness and vesicle size in a pillow rin from seawater altered sample Reyk.-l, Reykjanes, Iceland. viii Figure 29. Glass nornalized-palagonite ocopositions of seawater altered sanple Ko.-l, Kopavogur, Iceland. Figure 30. Glass rcrmalized-palagonite ccqposition of seawater altered samples fran Iceland. Figure 31. Results of a microprobe traverse of a palagonite rind in sanple Br.-2, Brianes, Iceland. This is Traverse 1 of 6. Figure 32. Results of a microprobe traverse of a palagonite rind in sanple Br.-2, Brumes, Iceland. This is Traverse 2 of 6. Figure 33. Results of a ndcroprobe traverse of a palagonite rind in sanple Kb.-l, Kopavogur, Iceland. This is Traverse 2 of 6. Figure 34. Results of a microprobe traverse of a palagonite >*ind in sanple Ko.-l, Kopavogur, Iceland. This is Traverse 4 of 6. Figure 35. Results of a microprobe traverse of a palagonite rind in sample Kb.-l, Kopavogur, Iceland. This is Traverse 5 of 6. Figure 36. Results of a microprobe traverse of a palagonite rind in sanple Ko.-l, Kopavogur, Iceland. This is Traverse 6 of 6. Figure 37. Results of a microprobe traverse of a palagonite rind in sample A- 1, Arnarnesvogur, Iceland. This is Traverse 1 of 6. Figure 38. Results of a microprobe traverse of a palagonite rind in sample A- 1, Arnarnesvogur, Iceland. This is Traverse 4 of 6. Figure 39. Results of a microprobe traverse of a palagonite rind in sanple Reyk.-l, Reykjanes, Iceland. This is Traverse 2 of 6. Figure 40. Results of a microprobe traverse of a palagonite rind in sample Reyk.-l, Reykjanes, Iceland. This is Traverse 4 of 6. Figure 41. Clay and zeolite conpositior» (microprobe analyses) in sample Ko.- 1, Kopavogur, Iceland. ix Figure 42. Variation plots of ndcroprobe analyses of Br.-l clays (Brimnes, Iceland). Figure 43. Variation plots of nicroprobe analyses of Br.-2 clays (Brisnes, Iceland). Figure 44. Variation plots of microprobe analyses of A-l clays (Arnarnesvogur, Iceland). Figure 45. Variation plots of microprobe analyses of Reyk.-l clays (Reykjanes, Iceland). Figure 46. Variation plots of microprobe analyses of Reyk.-2 clays (Reykjanes, Iceland). Figure 47. Scanning electron photomicrographs of zeolites in sample v~.-l, Ropavogur, Iceland. Figure 48. Scanning electron photomicrograph of a) chabazite and b) calcium- silicate in sample A-l, Arnarnesvogur, Iceland. Figure 49. Plot of exchangeable cations in zeolites in sample A-l (Arnarnesvogur, Iceland). Figure 50. Scanning electron photomicrograph of phillipsite in sample Br.-2, Brismes, Iceland. Figure 51. Plot of exchangeable cations in zeolites in sanple Br.-2 (Brimnes, Iceland). Figure 52. Glass nornalized-palagonite ccnpositions of low FeO, high SiO2 deep sea dredge samples.