Abstract
Transmission electron microscope studies demonstrate a structural distinction between stoichiometric and ancient calcian dolomites of sedimentary origin. A modulated or tweed structure similar in appearance to spinodal microstructures characterizes ancient calcian dolomites, whereas stoichiometric dolomites are homogeneous. Recent calcium-rich dolomites lack a modulated structure, but have a heterogeneous microstructure with high densities of growth defects. Electron and optical diffraction and lattice imaging suggest a fluctuation in interplanar spacing in a coherent lattice. In addition, lattice imaging also reveals discontinuous faults throughout the modulated structure. Ordering and possibly incipient exsolution are suggested, ‘c’ reflections in SAD patterns of calcian dolomites document a new superstructure in at least part of the lamellar structure and raise questions of different ordering states throughout the structure.
The results provide new insight regarding the formation of sedimentary dolomites
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Aaronson HI, Lorimer GW, Champness PE, Spooner ETC (1974) On differences between phase transformations (exsolution) in metals and silicates. Chem Geol 14:75–80
Allen SM, Cahn JW (1976a) Mechanisms of phase transformations within the miscibility gap of Fe-rich Fe-Al alloys. Acta Metall 24:425–437
Allen SM, Cahn JW (1976b) On tricritical points resulting from the intersection of lines of higher-order transitions with spinodals. Scripta Metall 10:451–454
Althoff PL (1977) Structural refinements of dolomite and a magnesian calcite and implications for dolomite formation in the marine environment. Am Mineral 62:772–783
Amelinckx S, Van Landuyt J (1976) Contrast effects at planar interfaces. In: Wenk HR (ed) Electron Microscopy in Mineralogy. Springer, Berlin Heidelberg New York, pp 68–112
Barber DJ, Wenk HR (1973) The microstructures of experimentally deformed limestones. J Mater Sci 8:500–508
Barber DJ, Heard HC, Wenk HR (1981) Deformation of dolomite single crystals from 20–800° C. Gottingen Int Conf Rock Deformation Proc 1981 (in press)
Barnes I, O'Neil JR (1971) Calcium-magnesium carbonate solid solutions from Holocene conglomerate cements and travertines in the Coast Range of California. Geochim Cosmochim Acta 35:699–718
Cahn JW (1968) Spinodal decomposition. Trans Am Inst Min, Metall Pet Eng 242:166–180
Carpenter MA (1980) Mechanisms of exsolution in sodic pyroxenes. Contrib Mineral Petrol 71:289–300
Champness PE, Lorimer GW (1976) Exsolution in silicates. In: Wenk HR (ed) Electron Microscopy in Mineralogy. Springer, Berlin Heidelberg New York, pp 174–204
Cockayne DJH, Parsons JR, Hoelke CW (1971) A study of the relationship between lattice fringes and lattice planes in electron microscope images of crystals containing defects. Phil Mag 24:139–153
Cowley JM, Cohen JB, Salamon MB, Wuensch BJ (1979) Modulated Structures — 1979. Am Inst Phys, New York
Fuchtbauer H, Goldschmidt H (1965) Beziehungen zwischen Calciumgehalt und Bildungsbedingungen der Dolomite. Geol Rundschau 55:29–40
Gaines A (1974) Protodolomite synthesis at 100° C and atmospheric pressure. Science 183:518–520
Goldsmith JR (1980) Thermal stability of dolomite at high temperatures and pressures. J Geophys Res 85:6949–6954
Goldsmith JR, Graf DL (1958) Structural and compositional variations in some natural dolomites. J Geol 66:678–693
Goldsmith JR, Heard HC (1961) Subsolidus phase relations in the system CaCO3-MgCO3. J Geol 69:45–74
Goldsmith JR, Graf DL, Heard HC (1961) Lattice constants of the calcium-magnesium carbonates. Am Mineral 46:453–457
Goldsmith JR, Newton RC (1969) P-T-X relations in the system CaCO3-MgCO3 at high temperatures and pressures. Am J Sci 267A: 160–190
Graf DL, Goldsmith JR (1955) Dolomite-magnesian calcite relations at elevated temperatures and CO2 pressures. Geochim Cosmochim Acta 7:109–128
Graf DL, Goldsmith JR (1956) Some hydrothermal syntheses of dolomite and protodolomite. J Geol 64:173–186
Graf DL, Blyth CR, Stemmler RS (1967) One-dimensional disorder in carbonates. Il St Geol Surv circ 408:1–60
Harker RI, Tuttle OF (1955) Studies in the system CaO-MgO-CO2: Pt. 2: Limits of solid solution along the binary join CaCO3-MgCO3. Am J Sci 253:274–282
Heuer AH, Nord GL (1976) Polymorphic phase transitions in minerals. In: Wenk HR (ed) Electron Microscopy in Mineralogy. Springer, Berlin Heidelberg New York, pp 274–303
Hilliard JE (1970) Spinodal decomposition. In: Phase Transformations, Am Soc for Metals, Metals Park, Ohio, pp 497–560
Katz A, Matthews A (1977) The dolomitization of CaCO3: An experimental study at 252–295° C. Geochim Cosmochim Acta 41:297–308
Laughlin DE (1976) Spinodal decomposition in nickel based nickel-titanium alloys. Acta Metall 24:53–58
Lippmann F (1973) Sedimentary Carbonate Minerals. Springer, New York
McConnell JDC (1965) Electron optical study of effects associated with partial inversion in a silicate phase. Phil Mag 11:1289–1301
McConnell JDC (1969) Electron optical study of incipient exsolution and inversion phenomena in the system NaAlSi3O8. Phil Mag 19:221–229
McConnell JDC (1971) Electron optical study of phase transformations. Mineral Mag 38:1–20
Owen DC, McConnell JDC (1971) Spinodal behaviour in an alkali feldspar. Nature Phys Sci 230:118–119
Owen DC, McConnell JDC (1974) Spinodal unmixing in an alkali feldspar. In: MacKenzie WS, Zussman J (eds) The Feldspars. Manchester Univ Press, Manchester, pp 424–439
Reeder RJ (1980) Phase transformations in dolomites. PhD Thesis, University of California Berkeley
Reeder RJ, Wenk HR (1979a) Microstructures in low temperature dolomites. Geophys Res Lett 6:77–80
Reeder RJ, Wenk HR (1979b) Modulated structures in sedimentary dolomite. In: Cowley JM et al. (eds) Modulated Structures — 1979. Am Inst Phys, New York, pp 330–332
Reeder RJ, Wenk HR (in preparation) Thermal disordering in dolomite.
Reeder RJ, Nakajima Y (in preparation) Lattice imaging of APBs in dolomite.
Sinclair R, Schneider K, Thomas G (1975) Analysis of ordering in Cu3Au utilizing lattice imaging techniques. Acta Metall 23:873–883
Sinclair R, Gronsky R, Thomas G (1976) Optical diffraction from lattice images of alloys. Acta Metall 24:789–796
Spence JCH, Cowley JM, Gronsky R (1979) The effects of lens abberations on lattice images of spinodally decomposed alloys. Ultramicroscopy 4:429–433
Steinfink H, Sans FT (1959) Refinement of the crystal structure of dolomite. Am Mineral 44:679–682
Sureau JF (1977) The dolomitization of calcite: an experimental approach. Proc 2nd Int Symp on Water-Rock Interaction 2:207–217
Yund RA, McCallister RH (1970) Kinetics and mechanisms of exsolution. Chem Geol 6:5–30
Yund RA, McLaren AC, Hobbs BE (1974) Coarsening kinetics of the exsolution microstructure in alkali feldspar. Contrib Mineral Petrol 48:45–55
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Reeder, R.J. Electron optical investigation of sedimentary dolomites. Contr. Mineral. and Petrol. 76, 148–157 (1981). https://doi.org/10.1007/BF00371955
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00371955