Location of Repository

Aqueous alteration in primitive asteroids: High porosity ≠ high permeability

By Philip A. Bland, Matthew D. Jackson, Robert F. Coker, Barbara A. Cohen, J. Beau W. Webber, Martin R. Leese, Christian M. Duffy, Richard J. Chater, Mahmoud G. Ardakani, David S. McPhail, David W. McComb and Gretchen K. Benedix


Carbonaceous chondrite meteorites are the most compositionally primitive rocks in the solar system, but the\ud most chemically pristine (CI1 and CM2 chondrites) have experienced pervasive aqueous alteration,\ud apparently within asteroid parent bodies. Unfractionated soluble elements suggest very limited flow of liquid\ud water, indicting a closed-system at scales large than 100's μm, consistent with data from oxygen isotopes,\ud and meteorite petrography. However, numerical studies persistently predict large-scale (10's km) water\ud transport in model asteroids, either in convecting cells, or via ‘exhalation’ flow — an open-system at scales up\ud to 10's km. These models have tended to use permeabilites in the range 10−13 to 10−11m2. We show that\ud the permeability of plausible chondritic starting materials lies in the range 10−19 to 10−17m2 (0.1–10 μD):\ud around six orders-of-magnitude lower than previously assumed. This low permeability is largely a result of\ud the extreme fine grain-size of primitive chondritic materials. Applying these permeability estimates in\ud numerical models, we predict very limited liquid water flow (distances of 100's μm at most), even in a high\ud porosity, water-saturated asteroid, with a high thermal gradient, over millions of years. Isochemical\ud alteration, with flow over minimal lengthscales, is not a special circumstance. It is inevitable, once we\ud consider the fundamental material properties of these rocks. To achieve large-scale flow it would require\ud average matrix grain sizes in primitive materials of 10's–100's μm — orders of magnitude larger than\ud observed. Finally, in addition to reconciling numerical modelling with meteorite data, our work explains\ud several other features of these enigmatic rocks, most particularly, why the most chemically primitive\ud meteorites are also the most altered

Topics: QC807, QB, QC176.8.N35
Publisher: ELSEVIER
Year: 2010
OAI identifier: oai:kar.kent.ac.uk:25819

Suggested articles



  1. (2007). A cornucopia of presolar and early Solar System materials at the micrometer size range in primitive chondrite matrix. doi
  2. (1975). A Galerkian-finite element analysis of the hydrothermal system at Wairakei, New Zealand. doi
  3. (2001). A terrestrial origin for sulphate veins in CI1 carbonaceous chondrites. doi
  4. (1970). Apollo 11 soil mechanics investigation. doi
  5. (1989). Aqueous alteration on the hydrous asteroids: results of EQ3/6 computer simulations. doi
  6. (1979). Are carbonaceous chondrites primitive or processed? A review. doi
  7. (2000). Bleached chondrules: evidence for widespread aqueous processes on the parent asteroids of ordinary chondrites. doi
  8. (2006). Brecciation and chemical heterogeneities of CI chondrites. doi
  9. (2003). Carbonates in CM2 chondrites: constraints on alteration conditions from oxygen isotopic compositions and petrographic observations. doi
  10. (1967). Chemical fractionations in meteorites — II. Abundance patterns and their interpretation. doi
  11. (2004). Chondrule glass alteration in type
  12. Complément d'observations sur la chute de météorites qui a eu lieu le 14 mai 1864 aux environs d'Orgueil
  13. (2003). Conditions for pore water convection within carbonaceous chondrite parent bodies — implications for planetesimal size and heat production. doi
  14. (1984). Degassing of meteorite parent bodies. doi
  15. (1974). Early chemical history of the solar system. doi
  16. (2004). Entry of alkalis into type-I chondrules at both high and low temperatures.
  17. (1999). Fluid flow in chondritic parent bodies: deciphering the composition of planetesimals. doi
  18. (2007). Fluid flow on carbonaceous chondrite parent bodies. Lunar Planet.
  19. (2004). Formation of Fe-enrichment boundary zones between chondrules and their fine-grained rims in the CM2 chondrite,
  20. (1995). Fractionation of volatile elements in the early Solar System: Evidence from heating experiments on primitive meteorites. doi
  21. (2002). Gas breakthrough experiments on fine-grained sedimentary rocks. doi
  22. (1996). Grain size distributions and textures in the matrices of metamorphosed CO3 chondrites.
  23. (1985). Hydraulic and acoustic properties as a function of porosity in Fontainebleau sandstone. doi
  24. (2005). Hydrothermal convection in carbonaceous chondrite parent bodies. doi
  25. (1989). Impact cratering: A geological process. doi
  26. (2005). Localized chemical redistribution during aqueous alteration
  27. (1979). Magnetite in CI carbonaceous meteorites: origin by aqueous activity on a planetesimal surface. doi
  28. (2005). Microcrystals and amorphous material in comets and primitive meteorites: keys to understanding processes in the early Solar System. In:
  29. (1995). Mineralogical and chemical modification of components in CV3 chondrites: nebular or asteroidal processing? doi
  30. (2006). Mineralogy and petrology of Comet 81P/Wild 2 nucleus samples. doi
  31. (2004). Modal mineralogy of carbonaceous chondrites by X-ray diffraction and Mössbauer spectroscopy. doi
  32. (2009). Modal mineralogy of CM2 chondrites by X-ray diffraction (PSD-XRD), Part 1: total phyllosilicate abundance and the degree of aqueous alteration. doi
  33. (2001). Modeling aqueous alteration of CM carbonaceous chondrites. doi
  34. (2000). Modeling of liquid water on CM meteorite parent bodies and implications for amino acid racemization. doi
  35. (2003). Nebular versus parent-body processing. In: Davis, doi
  36. (2008). Nuclear magnetic resonance cryoporometry. doi
  37. (2005). On the behaviour of phosphorus during the aqueous alteration of CM2 carbonaceous chondrites.
  38. (1999). Oxygen isotope studies of carbonaceous chondrites. doi
  39. (1977). Permeability from resistivity and pore shape. doi
  40. (1988). Permeability, conductivity, and pore geometry of sandstone. doi
  41. (1992). Porous media: fluid transport and pore structure. doi
  42. (1993). Size distributions in two porous chondritic micrometeorites. doi
  43. (1969). Soil Mechanics. doi
  44. (2003). Solar System abundances of the elements. In: Davis, doi
  45. Space Phys. doi
  46. (2003). Stony meteorite porosities and densities: a review of the data through doi
  47. (2007). Temperatures of aqueous alteration and evidence formethane generation on the parent bodies of the CM chondrites. doi
  48. The carbonaceous chondrite groups. doi
  49. (1981). The compositional classification of chondrites — I. doi
  50. (1998). The density and porosity of meteorites from the Vatican collection. doi
  51. (2001). The effect of liquid transport on the modelling of CM parent bodies.
  52. (1983). The equivalent channel model for permeability and resistivity in fluid-saturated rock — a re-appraisal. doi
  53. (2001). The hydrology of carbonaceous chondrite parent bodies and the evolution of planet precursors. doi
  54. (2001). The hydrology of carbonaceous chondrite parent bodies and the evolution of planet progenitors. doi
  55. (1984). The oxygen isotope record in Murchison and other carbonaceous chondrites. doi
  56. (1997). The oxygen isotopic composition of olivine and pyroxene from CI chondrites. doi
  57. (2002). The oxygen isotopic composition of water from Tagish Lake: its relationship to low-temperature phases and to other carbonaceous chondrites. doi
  58. (1997). The porosity and permeability of chondritic meteorites and interplanetary dust particles. doi
  59. (1998). The relation between porosity, permeability, and specific surface of chalk from the Gorm field, Danish North Sea. doi
  60. (2004). The role of water in determining the oxygen isotopic composition of planets.
  61. (2007). The solar chemical composition. doi
  62. (2002). Thermal evolution models of asteroids.
  63. (1994). Utilitarian models of the solar nebula. doi
  64. (2005). Volatile fractionation in the early Solar System and chondrule/matrix complementarity. doi
  65. (1989). Water and thermal evolution of carbonaceous chondrite parent bodies. doi
  66. (2002). Zoned chondrules in Semarkona: evidence for high- and low-temperature processing. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.