Relationship Between Dolomite Nonstoichiometry and Carbonate Facies Parameters

Lumsden, David N.; Chimahusky, J.S.

doi:10.2110/pec.80.28.0123

Cited by 88 publications

(77 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Other explanations for the absent of calcite in some of the Montney Formation samples may be due to the fact that several cations, principally, Fe, Sr, Na, and Mn, substitute for calcite in many dolomites [58]. Significant amount of Fe, Sr, Na, and Mn in this study ( Figure 5) support such possibility of substitution for calcite [58].…”

Section: Carbon and Oxygen Isotope Geochemistrymentioning

confidence: 56%

“…The phenomenon of the present/absent of calcite/dolomite in the Montney Formation proves that dolomites commonly depart from stoichiometric composition of an excess of calcium, which is accommodated in the magnesium layers [56,57,59]. Other explanations for the absent of calcite in some of the Montney Formation samples may be due to the fact that several cations, principally, Fe, Sr, Na, and Mn, substitute for calcite in many dolomites [58]. Significant amount of Fe, Sr, Na, and Mn in this study ( Figure 5) support such possibility of substitution for calcite [58].…”

Section: Carbon and Oxygen Isotope Geochemistrymentioning

confidence: 98%

See 1 more Smart Citation

Isotopes (13C and 18O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Egbobawaye¹

2017

View full text Add to dashboard Cite

show abstract

Section: Carbon and Oxygen Isotope Geochemistrymentioning

confidence: 56%

Section: Carbon and Oxygen Isotope Geochemistrymentioning

confidence: 98%

Isotopes (13C and 18O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Egbobawaye¹

2017

View full text Add to dashboard Cite

show abstract

“…El carácter micrítico de la dolomita explica la composición no estequiométrica de este mineral en las muestras obtenidas en la sección de Valdeinfierno, con enriquecimiento en calcio y pobre ordena-miento del carbonato (Lumsden y Chimahusky, 1980). Comparativamente y dentro de los niveles más ricos en dolomita, se ha observado un enriquecimiento en δ 18 O en los carbonatos de la unidad U2 en relación con los de la unidad U3.…”

Section: Discussionunclassified

Untitled

Pozo¹,

Casas²,

Medina³

et al. 2006

Estud. geol.

View full text Add to dashboard Cite

RESUMENEn la zona de canteras de Valdeinfierno, en el sector de Batallones-Malcovadeso, parte centro-meridional de la Cuenca de Madrid, se ha reconocido una serie de depósitos carbonáticos que presentan geometría dómica y estructura interna columnar. Dentro de estos depósitos de carbonato se distinguen dos unidades. La inferior (U2) es mayoritariamente dolomítica y de estructura brechoide, y petrográfica-mente consiste en dolomicritas con cemento calcítico. La superior (U3) está formada tanto por dolomita como por calcita, y se caracteriza por el desarrollo de morfologías columnares de aspecto travertínico. Petrográficamente, los depósitos de esta unidad consisten en caliza con texturas alveolar y biogénica. Entre las columnas de carbonato se distinguen abundantes masas arcillosas. Hacia la base de estas unidades carbonáticas se sitúa una unidad detrítica (U1), formada por arenas feldespáticas y a su techo se dispone un conjunto lutítico con alguna intercalación carbonática de composición dolomítica (Unidad U4) y, por encima de estas lutitas, un conjunto calizo (Unidad U5). Las arcillas presentes en la unidad U3 tienen una composición (sepiolita > esmectita trioctaédrica ± illita) netamente diferente a las de la unidad U4 (esmectita dioctaédrica > illita ± caolinita). La composición isotópica de los carbonatos de las unidades U2 y U3, así como de los niveles carbonatados de la unidad U4, es bastante similar en el caso de la dolomita, con valores δ 13 C que oscilan entre -6,21 y -7,78‰ y entre -3,23 y -4,05‰ para el δ 18O. Por otro lado, desde un punto de vista de su composición isotópica, se diferencian los carbonatos de la unidad 4 y del techo de la unidad 2, exclusivamente calcíticos, en los que los valores de δ 13 C oscilan entre -8,07 y -11,75‰, y los de δ 18O entre -5,27 y -7,35‰. La calcita existente en los niveles dolomíti-cos presenta valores intermedios entre los dos grupos anteriores. Los rasgos de la sucesión sedimentaria y los resultados analíticos obtenidos indican una fase de expansión lacustre en la zona estudiada con un cambio en la química de las aguas, todo ello favorecido por la entrada de aguas subterráneas a través de surgencias.Palabras clave: Cuenca de Madrid, seepage-mounds, travertinos, análisis isotópico. ABSTRACTCarbonate deposits showing domic shape and columnar internal structure have been recognized in the Valdeinfierno quarries (Batallones-Malcovadeso area, central-southern Madrid Basin). Two lithological units (U2 and U3) are differentiated in the carbonates. Unit U2 is mainly brecciated dolomite that consists of dolomicrite with calcite cements. Unit U3 is made up of both calcite and dolomite and is characterized by columnar shapes resembling travertine. Under the microscope, the carbonates consist of limestones with alveolar and biogenic textural features. Abundant clayey masses have been observed within and between the columns. The carbonate units are underlain by a detrital unit (U1) composed of feldspar-rich sandstones. The upper part of the section shows a mudstone unit with...

show abstract

“…Dolomite and calcite stoichiometry (percentage magnesium composition) was calculated using the shift of their respective 104 lines from ideal stoichiometric composition (Lumsden and Chimahusky, 1980). Trace dolomite observed in the uppermost part of the Pliocene-Pleistocene strata displays near ideal stoichiometry, typical of Paleozoic dolomites, indicating a likely detrital origin and possible derivation from Paleozoic sediments in nearby Ireland.…”

Section: Petrographic and X-ray Diffraction Analysesmentioning

confidence: 99%

Data report: dolomite in Neogene sediments of the Belgica carbonate mound province, Porcupine Seabight, North Atlantic

Gregg¹,

Frank²

2009

Proceedings of the IODP

View full text Add to dashboard Cite

Dolomite was observed, using petrography, X-ray diffraction (XRD), and scanning electron microscopy (SEM), in cored Neogene sediments from the Porcupine Seabight in the north Atlantic Ocean, Integrated Ocean Drilling Program Expedition 307 Sites U1316, U1317, and U1318, ~100 km off the west coast of Ireland. Trace amounts (<10% of total carbonate component) of dolomite were observed in Challenger Mound, a deep coldwater mixed silicaclastic-carbonate mud mound located in the Porcupine Seabight. Significant dolomitization (>50% of total carbonate component) was observed primarily in Miocene strata in submound and off-mound sediments.Petrographic examination of smear slides indicates that dolomite is composed of micrometer-to decimicron-sized, limpid, rhombic crystals. XRD analysis indicates that the dolomite is calcium rich and poorly ordered. SEM confirms light petrographic analysis of size and morphology of dolomite crystals, and electron microprobe analysis indicates that the dolomite is ferroan and displays distinct compositional zoning. Microbes and associated microbial filamentous structures were observed associated with dolomite crystals.Saturation indexes of carbonate minerals calculated for interstitial waters collected from the three sites are consistent with the petrographic and XRD observation of dolomite.

show abstract

Relationship Between Dolomite Nonstoichiometry and Carbonate Facies Parameters

Cited by 88 publications

References 0 publications

Isotopes (<sup>13</sup>C and <sup>18</sup>O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Isotopes (<sup>13</sup>C and <sup>18</sup>O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Untitled

Data report: dolomite in Neogene sediments of the Belgica carbonate mound province, Porcupine Seabight, North Atlantic

Contact Info

Product

Resources

About

Relationship Between Dolomite Nonstoichiometry and Carbonate Facies Parameters

Cited by 88 publications

References 0 publications

Isotopes (&lt;sup&gt;13&lt;/sup&gt;C and &lt;sup&gt;18&lt;/sup&gt;O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Isotopes (&lt;sup&gt;13&lt;/sup&gt;C and &lt;sup&gt;18&lt;/sup&gt;O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Untitled

Data report: dolomite in Neogene sediments of the Belgica carbonate mound province, Porcupine Seabight, North Atlantic

Contact Info

Product

Resources

About

Isotopes (<sup>13</sup>C and <sup>18</sup>O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada

Isotopes (<sup>13</sup>C and <sup>18</sup>O) Geochemistry of Lower Triassic Montney Formation, Northeastern British Columbia, Western Canada