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Recrystallization of dolomite: evidence from the Monterey Formation (Miocene), California

Publication ,  Journal Article
MALONE, MJ; BAKER, PA; BURNS, SJ
Published in: Sedimentology
January 1, 1994

Dolomites from the upper calcareous‐siliceous member of the Miocene Monterey Formation exposed west of Santa Barbara, California, were analysed for geochemical, isotopic and crystallographic variation. The data clearly document the progressive recrystallization of dolomite during burial diagenesis in marine pore fluids. Recrystallization is recognized by the following compositional and crystallographic variations. Dolomites have decreasing δ18O and δ13C compositions, decreasing Sr contents and increasing Mg contents with increasing burial depths and temperatures from east to west in the study area. δ18O values vary from 5·3‰ in the east to − 5·5‰ PDB in the west and are interpreted to reflect the greater extent and higher temperature of dolomite recrystallization in the west. δ13C values correlate with δ18O and decrease from 13·6‰ in the east to − 8·7‰ PDB in the west. Sr concentrations correlate positively with δ18O values and decrease from a mean of 750 ppm in the east to a mean of 250 ppm in the west. Mol% MgCO3 values inversely correlate with δ18O values and increase from a minimum of 41·0 in the east to a maximum of 51·4 in the west. Rietveld refinements of powder X‐ray diffraction data indicate that the more recrystallized dolomites have more contracted unit cells and increased cation ordering. The fraction of the Ca sites in the dolomites that are occupied by Ca atoms increases slightly with the approach to stoichiometry. The fraction of the Mg sites occupied by Mg atoms strongly correlates with mol% MgCO3. Even in early diagenetic, non‐stoichiometric dolomites, there is little substitution of Mg in Ca sites. During recrystallization, the amount of Mg substituting for Ca in Ca sites decreases even further. Most of the disorder in the least recrystallized, non‐stoichiometric dolomites is related to substitution of excess Ca on Mg sites. Copyright © 1994, Wiley Blackwell. All rights reserved

Duke Scholars

Published In

Sedimentology

DOI

EISSN

1365-3091

ISSN

0037-0746

Publication Date

January 1, 1994

Volume

41

Issue

6

Start / End Page

1223 / 1239

Related Subject Headings

  • Geology
  • 3705 Geology
  • 0403 Geology
 

Citation

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ICMJE
MLA
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MALONE, M. J., BAKER, P. A., & BURNS, S. J. (1994). Recrystallization of dolomite: evidence from the Monterey Formation (Miocene), California. Sedimentology, 41(6), 1223–1239. https://doi.org/10.1111/j.1365-3091.1994.tb01450.x
MALONE, M. J., P. A. BAKER, and S. J. BURNS. “Recrystallization of dolomite: evidence from the Monterey Formation (Miocene), California.” Sedimentology 41, no. 6 (January 1, 1994): 1223–39. https://doi.org/10.1111/j.1365-3091.1994.tb01450.x.
MALONE MJ, BAKER PA, BURNS SJ. Recrystallization of dolomite: evidence from the Monterey Formation (Miocene), California. Sedimentology. 1994 Jan 1;41(6):1223–39.
MALONE, M. J., et al. “Recrystallization of dolomite: evidence from the Monterey Formation (Miocene), California.” Sedimentology, vol. 41, no. 6, Jan. 1994, pp. 1223–39. Scopus, doi:10.1111/j.1365-3091.1994.tb01450.x.
MALONE MJ, BAKER PA, BURNS SJ. Recrystallization of dolomite: evidence from the Monterey Formation (Miocene), California. Sedimentology. 1994 Jan 1;41(6):1223–1239.
Journal cover image

Published In

Sedimentology

DOI

EISSN

1365-3091

ISSN

0037-0746

Publication Date

January 1, 1994

Volume

41

Issue

6

Start / End Page

1223 / 1239

Related Subject Headings

  • Geology
  • 3705 Geology
  • 0403 Geology