Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-10T10:59:53.630Z Has data issue: false hasContentIssue false
  • English
  • Français

The progressive crystallization and ordering of low-temperature dolomites

Published online by Cambridge University Press:  05 July 2018

Hartmut Schneider
Hartmut Schneider*
Affiliation:
Mineralogisches Institut der Universität Karlsruhe, Germany
Get access Rights & Permissions [Opens in a new window]

Summary

The progressive crystallization of dolomite has been investigated in the temperature range of 90 to 410°C by means of X-ray powder diffraction, electron microscopy, and infra-red spectroscopy.

Short-time, low-temperature experiments (≤ 145°C yielded dolomites with a high defect density. In detail, lattice faults can be described as: Random succession of more or less ordered cation domains, producing a long-range mosaic-type disorder; cation ordering may take place along <101̄0> and <112̄0> tilting and dislocation of individual CO3 groups; and irregular interstratification of dolomite layers of different chemical compositions in the crystallographic c-directions.

Dolomites produced in experiments of longer duration are composed of an interstratification of essentially two chemically different dolomite layers, of which the stacking sequence is more perfect than it is at lower crystallization degrees. Both components grow rapidly at the expense of dolomites of intermediate composition. Finally, long-term low-temperature (145°C) experiments produced two independent, coexistent dolomite phases. Within single dolomite layers cations now lie very close to their theoretical positions. CO3-tilting and dislocation decreases markedly.

Hydrothermal runs at temperatures > c. 145°C yielded one single, nearly stoichiometrie, highly ordered dolomite phase. Finally, dolomites synthesized at temperatures > c. 200°C are of an ideal chemical composition and have perfect lattice ordering.

Type
Research Article
Information
Mineralogical Magazine , Volume 40 , Issue 314 , June 1976 , pp. 579 - 587
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1976

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Adler, (H. H.) and Kerr, (P. F.), 1963. Amer. Min. 48, 839-53.Google Scholar
Althaus, (E.), 1969. Neues Jahrb. Min. Abh. 111, 74-110.Google Scholar
Füchtbauer, (H.) and Müller, (G.), 1970. Sedimente und Sedimentgesteine. Stuttgart (Schweizerbart).Google Scholar
Goldsmith, (J. R.), Graf, (D. L.), arid Joensuu, (O. J.), 1955. Geochimica Acta, 7, 212-30.CrossRefGoogle Scholar
Graf, (D. L.), 1961. Amer. Min. 46, 1283-1316.Google Scholar
Graf, (D. L.), 1969. Ibid. 54, 325.CrossRefGoogle Scholar
Graf, (D. L.), Blyrh, (C. R.), and Stemmler, (R. S.), 1967. Illinois State Geol. Survey Circ. 408.Google Scholar
Graf, (D. L.) and Goldsmith, (J. R.), 1956. Journ. Geol. 64, 173-86.CrossRefGoogle Scholar
Lippmann, (F.), 1973. Sedimentary carbonate minerals. Berlin-Heidelberg-New York (Springer).CrossRefGoogle Scholar
Nakagawa, (I.) and Walrek, (J. L.), 1969. Journ. Chem. Phys. 43, 1389-97.CrossRefGoogle Scholar
Plihal, (M.) and Schaack, (G.), 1970. Phys. star. solids, 42, 485-96.CrossRefGoogle Scholar
Steinfink, (H.) and Sans, (F. J.), 1959. Amer. Min. 44, 679-82.Google Scholar