Geochemistry of a chert breccia

Kolodny, Yehoshua; Chaussidon, M.; Katz, Amitai

doi:10.1016/j.gca.2004.07.010

Cited by 14 publications

(10 citation statements)

References 52 publications

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“…This value is typical of shallow sea cherts (Sharp et al, 2002;Kolodony et al, 2005), in agreement with interpretations previously drawn from field and petrographic observations of a marine origin .…”

Section: Quartzitessupporting

confidence: 91%

See 1 more Smart Citation

Oxygen isotope analyses of fine silica grains using laser-extraction technique: Comparison with oxygen isotope data obtained from ion microprobe analyses and application to quartzite and silcrete cement investigation

Alexandre

Basile‐Doelsch

Sonzogni

et al. 2006

Geochimica et Cosmochimica Acta

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The laser fluorination technique reported here for analyzing the oxygen isotope composition (d 18 O) of fine quartz size fractions 50-20, 20-10, 10-5, 5-2, 2-1 and <1 lm has been validated by comparison with the ion microprobe technique. It yields accurate d 18 O data with an external precision better than 0.15&. This is a significant methodological improvement for isotopic studies dealing with materials such as soil or biogenic oxides and silicates: particles are often too small and recovered in insufficient amount to be easily handled for ion microprobe analysis. Both techniques were used to investigate d 18 O composition of a Cretaceous quartzite and silcrete sequence from the South-East of France. Quartzite cements average 31.04 ± 1.93&. They formed from Mid-Cretaceous seawater. Higher in the series, silcretes cements average 26.66 ± 1.36&. They formed from Upper-or post-Upper-Cretaceous soil water and groundwater. Oxygen isotope data show that the silicification steps from one mineralogical phase to another and from one layer to another (including from an upper pedogenic silcrete to a lower groundwater silcrete) occurred in a closed or weakly evaporating hydrological system.

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Section: Quartzitessupporting

confidence: 91%

“…These values are close to the ones determined by Kolodony et al (2005) for a chert breccia where the fragments of chert formed from seawater (d 18 O value around 32&) and the breccia matrix formed from fresh water (d 18 O value around 26&).…”

Section: O Data Obtained From In Situ Ion Microprobe Analysissupporting

confidence: 87%

Oxygen isotope analyses of fine silica grains using laser-extraction technique: Comparison with oxygen isotope data obtained from ion microprobe analyses and application to quartzite and silcrete cement investigation

Alexandre

Basile‐Doelsch

Sonzogni

et al. 2006

Geochimica et Cosmochimica Acta

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“…This relationship between the two data sets supports the hypothesis that freshwater chert ␦ 18 O reliably reflects the large fluctuations in surface water ␦ 18 O expected in terrestrial environments. Two other isotopic studies of chert have also attributed low ␦ 18 O values to isotopically light meteroic water participation in chert diagenesis (Knauth, 1973;Kolodny et al, 2005), further supporting the idea that chert ␦ 18 O reflects variations in isotopic composition of water.…”

mentioning

confidence: 66%

Oxygen and hydrogen isotope ratios in freshwater chert as indicators of ancient climate and hydrologic regime

Abruzzese

Waldbauer

Chamberlain

2005

Geochimica et Cosmochimica Acta

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The oxygen and hydrogen isotopic composition of Eocene and Miocene freshwater cherts in the western United States records regional climatic variation in the Cenozoic. Here, we present isotopic measurements of 47 freshwater cherts of Eocene and Miocene age from the Great Basin of the western United States at two different sites and interpret them in light of regional climatic and tectonic history. The large range of ␦ 18 O of terrestrial cherts measured in this study, from 11.2‰ to 31.2‰ (SMOW: Standard Mean Ocean), is shown to be primarily the result of variations in ␦ 18 O of surface water. The following trends and patterns are recognized within this range of ␦ 18 O values. First, in Cenozoic rocks of northern Nevada, chert ␦ 18 O records the same shift observed in authigenic calcite between the Eocene and Miocene that has been attributed to regional surface uplift. The consistent covariation of proxies suggests that chert reliably records and retains a signal of ancient meteoric water isotopic composition, even though our analyses show that chert formed from warmer waters (40°C) than coexisting calcite (20°C). Second, there is a strong positive correlation between ␦ 18 O and ␦D in Eocene age chert from Elko, Nevada and Salina, Utah that suggests large changes in lake water isotopic composition due to evaporation. Evaporative effects on lake water isotopic composition, rather than surface temperature, exert the primary control on the isotopic composition of chert, accounting for 10‰ of the 16‰ range in ␦ 18 O measured in Eocene cherts. From authigenic mineral data, we calculate a range in isotopic composition of Eocene precipitation in the north-central Great Basin of Ϫ10 to Ϫ14‰ for ␦ 18 O and Ϫ70 to Ϫ100‰ for ␦D, which is in agreement with previous estimates for Eocene basins of the western United States. Due to its resistance to alteration and record of variations in both ␦ 18 O and ␦D of water, chert has the potential to corroborate and constrain the cause of variations in isotope stratigraphies.

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“…The spaces between the fragments are filled by siliceous plastic matrix cementing the fragments. The repeated cycles of in situ fragmentation followed by cementation of muddy siliceous sediment intruding from beneath the fragmented layer (Kolodny et al, 2005) formed the 5-10 m thick Brecciated Chert Unit (Soudry et al, 1985). The 11 B isotope content in the fragments (27-70 ppm) is higher than in the matrix (11-21 ppm).…”

Section: Lithofacies Of the Mishash Formationmentioning

confidence: 99%

“…However, chert, dolostone and sandstone gradually replace this pelagic chalk toward the ancient coast to the southeast and blur the distinction of the Menuha-Mishash formational boundary, for which the name Say'yarim Formation was introduced (Bartov et al, 1972). These Upper Cretaceous cherts exhibit numerous sedimentary structures which incorporate a variety of microquartz occurrences of different origins and hence properties (e.g., Kolodny et al, 1965;Kolodny, 1967;Steinitz, 1970Steinitz, , 1981Steinitz, , 1985Kolodny et al, 2005) reflecting puzzling early and late diagenetic histories. Steinitz (1981) studied these chert structures and could not find a common explanation for their formation, regarding them as enigmatic.…”

Section: Introductionmentioning

confidence: 99%

Upper Campanian suspected silicified seismite related to the Syrian Arc tectonic system in the Middle East

Lewy¹

2010

Journal of African Earth Sciences

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Geochemistry of a chert breccia

Cited by 14 publications

References 52 publications

Oxygen isotope analyses of fine silica grains using laser-extraction technique: Comparison with oxygen isotope data obtained from ion microprobe analyses and application to quartzite and silcrete cement investigation

Oxygen isotope analyses of fine silica grains using laser-extraction technique: Comparison with oxygen isotope data obtained from ion microprobe analyses and application to quartzite and silcrete cement investigation

Oxygen and hydrogen isotope ratios in freshwater chert as indicators of ancient climate and hydrologic regime

Upper Campanian suspected silicified seismite related to the Syrian Arc tectonic system in the Middle East

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