Carbon-13—Rich Diagenetic Carbonates in Miocene Formations of California and Oregon

Murata, K. J.; Friedman, Irving; Madsen, Beth M.

doi:10.1126/science.156.3781.1484

Cited by 33 publications

(17 citation statements)

References 12 publications

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“…Another more speculative possibility for the enrichment of 13 C in the early atmosphere is that Mars originally had a methane-dominated reduced early atmosphere and minor CO 2 in equilibrium with this atmosphere would have δ 13 C values near +35 h due to the mass balance between CO 2 and CH 4 (Galimov 2000). A similar mechanism has also been proposed for a terrestrial deposit of δ 13 C-rich carbonates (+5.4 h to +19.0 h) associated with natural gas-rich shales (Murata et al 1967). Finally, the possibility exists that the magmatic CO 2 on Mars is substantially enriched in 13 C compared to the Earth.…”

Section: Formation Environments and Insight Into Martian Climate Historymentioning

confidence: 79%

Geochemistry of Carbonates on Mars: Implications for Climate History and Nature of Aqueous Environments

Niles¹,

Catling²,

Berger³

et al. 2012

Quantifying the Martian Geochemical Reservoirs

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Ongoing research on martian meteorites and a new set of observations of carbonate minerals provided by an unprecedented series of robotic missions to Mars in the past 15 years help define new constraints on the history of martian climate with important cross- cutting themes including: the CO 2 budget of Mars, the role of Mg-, Fe-rich fluids on Mars, and the interplay between carbonate formation and acidity.Carbonate minerals have now been identified in a wide range of localities on Mars as well as in several martian meteorites. The martian meteorites contain carbonates in low abundances (<1 vol.%) and with a wide range of chemistries. Carbonates have also been identified by remote sensing instruments on orbiting spacecraft in several surface locations as well as in low concentrations (2-5 wt.%) in the martian dust. The Spirit rover also identified an outcrop with 16 to 34 wt.% carbonate material in the Columbia Hills of Gusev Crater that strongly resembled the composition of carbonate found in martian meteorite ALH 84001. Finally, the Phoenix lander identified concentrations of 3-6 wt.% carbonate in the soils of the northern plains.The carbonates discovered to date do not clearly indicate the past presence of a dense Noachian atmosphere, but instead suggest localized hydrothermal aqueous environments with limited water availability that existed primarily in the early to mid-Noachian followed by low levels of carbonate formation from thin films of transient water from the late Noachian to the present. The prevalence of carbonate along with evidence for active carbonate precipitation suggests that a global acidic chemistry is unlikely and a more complex relationship between acidity and carbonate formation is present.

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Section: Formation Environments and Insight Into Martian Climate Historymentioning

confidence: 79%

Geochemistry of Carbonates on Mars: Implications for Climate History and Nature of Aqueous Environments

Niles¹,

Catling²,

Berger³

et al. 2012

Quantifying the Martian Geochemical Reservoirs

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show abstract

“…Muller et al (1972) reported that the primary magnesite and nesquehonite(MgCO 3 3H 2 O) precipitate when the Mg/Ca ratio in the water is greater than 20, whereas dolomite precipitates when the ratio is between 2 and about 12. The Mg/Ca ratio of the seawater is about five, and indeed, dolomite is the most common, magnesium-bearing, diagenetic carbonate found in organic-carbon-rich marine sediments, such as in the Neogene biosiliceous sections of the circum-Pacific region (e.g., Pisciotto and Mahoney, 1981), On'nagawa Formation in northern Japan (Matsumoto and Matsuda, 1987), and the Monterey Formation in California (e.g., Murata et al, 1969;Baker and Burns, 1985). Why did lansfordite or magnesite form instead of dolomite in the upper middle and upper Miocene and Pliocene sediments at Site 799?…”

Section: Lansfordite and Magnesite Formationmentioning

confidence: 99%

“…Dolomite beds and concretions are common in the Miocene to Pliocene siliceous sediments exposed at nearby land sections in northern Japan (On'nagawa and Funakawa Formations and their equivalents) (e.g., Matsumoto and Matsuda, 1987). Miocene Monterey Formation in California also contains numerous dolomite beds and concretions (e.g., Murata et al, 1969Murata et al, ,1972Garrison and Graham., 1984;Kastner et al, 1984). Thus, the diagenetic dolomite is rather common in the Neogene biosiliceous sediments of the circum-Pacific region, and the presence of abundant dolomites in the organic-matter rich, sediments at Site 799 is not surprising.…”

Section: Introductionmentioning

confidence: 99%

Diagenetic Dolomite, Calcite, Rhodochrosite, Magnesite, and Lansfordite from Site 799, Japan Sea-Implications for Depositional Environments and the Diagenesis of Organic-Rich Sediments

Matsumoto¹

1992

Proceedings of the Ocean Drilling Program

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Abundant and various diagenetic carbonates were recovered from a 1084-m-thick, Quaternary to lower Miocene section at ODP Site 799 in the Japan Sea. Petrographic, XRD, SEM, EDS-chemical, and isotopic analyses revealed wide variations in occurrence and textural relations and complex mineralogy and chemistry. Diagenetic carbonates include calcite, calcium-rich rhodochrosite, iron-and manganese-rich magnesite, iron-and manganese-rich dolomite and ankerite, and iron-and manganeserich lansfordite (hydrous Mg-carbonate).Rhodochrosite commonly occurs as small, solid nodules and semi-indurated, thin layers in bioturbated, mottled sediments of Units I and II (late Miocene to Quaternary). Lansfordite occurs as unindurated nodules and layers in Unit II (late Miocene and Pliocene), whereas magnesite forms indurated beds a few centimeters thick in slightly bioturbated-to-faintly laminated sediments of Unit III (middle and late Miocene). Some rhodochrosite nodules have dark-colored, pyritic cores, and some pyrite-rhodochrosite nodules are overgrown by and included within magnesite beds. Dolomite and ankerite tend to form thick beds (>IO cm) in bedded to laminated sediments of Units III, IV, and V (early to late Miocene). Calcite occurs sporadically throughout the Site 799 sediments. The δ 18 θ values of carbonates and the interstitial waters, and the measured geothermal gradient indicate that almost all of the Site 799 carbonates are not in isotopic equilibrium with the ambient waters, but were precipitated in the past when the sediments were at shallower depths. Depths of precipitation obtained from the δ 18 θ of carbonates span from 310 to 510 mbsf for magnesite and from 60 to 580 mbsf for dolomite-ankerite. Rhodochrosite and calcite are estimated to have formed within sediments at depths shallower than 80 mbsf.Diagenetic history in the Site 799 sediments have been determined primarily by the environment of deposition; in particular, by the oxidation-reduction state of the bottom waters and the alkalinity level of the interstitial waters. Under the well-oxygenated bottom-water conditions in the late Miocene and Pliocene, manganese initially accumulated on the seafloor as hydrogenous oxides and subsequently was mobilized and reprecipitated as rhodochrosite within the shallow sulfate-reduction, sub-oxic zone. Precipitation of lansfordite occurred in the near-surface sediments with abundant organic carbon and an extremely high alkalinity during the latest Miocene and Pliocene. The lansfordite was transformed to magnesite upon burial in the depth interval 310 to 510 mbsf. Dolomite first precipitated at shallow depths in Mn-poor, anoxic, moderately biocalcareous sediments of early to late Miocene. With increasing temperature and depth, the dolomite recrystallized and reequilibrated with ambient waters at depths below about 400 mbsf.

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“…A second explanation for dolomites with variable heavy carbon and relatively constant heavy oxygen was presented by Murata et al (1969) The isotopic values of the samples from Core 11 and Sidewall Core (SW) 25 are for the diagenetic, platy dolomite. They are not particularly unusual values for a deep-sea dolomite, although the carbon-13 content indicates a partial biogenic origin of CO 2 (Fontes and Desforges, 1975).…”

Section: Lago Mare Carbonatesmentioning

confidence: 99%

Carbon-13—Rich Diagenetic Carbonates in Miocene Formations of California and Oregon

Cited by 33 publications

References 12 publications

Geochemistry of Carbonates on Mars: Implications for Climate History and Nature of Aqueous Environments

Geochemistry of Carbonates on Mars: Implications for Climate History and Nature of Aqueous Environments

Diagenetic Dolomite, Calcite, Rhodochrosite, Magnesite, and Lansfordite from Site 799, Japan Sea-Implications for Depositional Environments and the Diagenesis of Organic-Rich Sediments

Stable Isotopic Investigation of Carbonate Samples Related to the Messinian Salinity Crisis from DSDP Leg 42A, Mediterranean Sea

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