On the Isotopic Chemistry of Carbonates and a Paleotemperature Scale

McCrea, J. M.

doi:10.1063/1.1747785

Cited by 3,438 publications

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“…Slabbed spec i mens (with other slabs used to pro duce stan dard thin sec tions) have been sam pled se lectively and a 1.5 mm di am e ter stain less steel drill with tung sten car bide coat ing was used for ma te rial ex trac tion from the surfaces of the spec i mens. CO 2 gas was ex tracted from the samples by re ac tion of cal cite with H 3 PO 4 (McCrea, 1950) at 25°C in a vac uum line, fol low ing the stan dard pro ce dure. In ad di tion, a small amount of fresh P 2 O 5 was used, and CO 2 was in con tact with it for only a few sec onds prior to the usual trap ping at -80°C (this was only to make sure no wa ter was re leased e.g., from liq uid in clu sions in the sam ples ana lysed into the rest of the prep line, which was con stantly kept un der vac uum and free of mois ture; the frac tion ation re lated to P 2 O 5 was tested on refer ence ma te ri als, and no sta tis ti cally sig nif i cant shifts were found).…”

Section: Methodsmentioning

confidence: 99%

Carbon isotope stratigraphy of the basal Zechstein (Lopingian) strata in Northern Poland and its global correlation

Peryt¹,

Durakiewicz²,

Kotarba³

et al. 2012

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The Kupferschiefer (T1) re cords a pe riod of ba sin-wide euxinic con di tions, and is thus con sid ered an ex cel lent time-marker in the Zechstein (Lopingian) ba sin. Pre vi ous stud ies in di cated that both the Kupferschiefer and Marl Slate and the over ly ing Zechstein Limestone (Magnesian Lime stone) show re mark able changes in car bon iso to pic com po si tion to wards higher 13 C carb val ues. We have ex amined the Kupferschiefer of the Zdrada IG 8 bore hole that has re cently been stud ied in de tail by Pašava et al. (2010) aim ing to use the car bon iso tope data from the basal Zechstein for strati graphic cor re la tion of the Zechstein ba sin with the global iso to pic curve for Late Perm ian. The d 13 C val ues in the Zdrada IG 8 change from +0.7‰ at the Kupferschiefer base to +5.4‰ in its mid dle part, then de crease to +1.7‰ at the Kupferschiefer top and next rap idly in crease to +3.5‰ (in the low est part of the Zechstein Lime stone) and fi nally to +5.1‰ (0.5 m above). This in creas ing trend con tin ues into the Zechstein Lime stone; all sub se quent Zechstein ma rine car bon ates show highly pos i tive d 13 C val ues. The d 13 C curve that best shows the Zechstein base may lie near a se quence bound ary in the up per Guadalupian of South China that post dates the mid-Guadalupian ex tinc tion, but the early Wuchiapingian cono donts re ported from the basal Zechstein de pos its else where ex clude such an in ter pre ta tion. The in crease re corded in the in ter val from the Kupferschiefer to the Main Do lo mite fits well the in crease of the d 13 C val ues ob served af ter Iso tope Event 0 (some 258 Ma) of the iso to pic curve for the Late Perm ian, al though the in crease in the Zdrada IG 8 is clearly more sig nif i cant than that of the global d 13 C curve. In turn, the sub se quent slight fall that ac cel erated af ter Iso tope Event 1 fits the more sig nif i cant fall in the Platy Do lo mite. Re search In sti tute, Rakowiecka 4, Po land, slawomir.oszczepalski@pgi.gov.pl; Tomasz Durakiewicz, Los Alamos Na tional Lab o ra tory, Los Alamos, NM87545, USA, Maciej J. Kotarba, Fac ulty Tadeusz M. Peryt and S³awomir Oszczepalski, Pol ish Geo log i cal In sti tute -Na tional of Ge ol ogy, Geo physics and En vi ron men tal Pro tec tion, AGH Uni ver sity of Sci ence and Tech nol ogy,

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Section: Methodsmentioning

confidence: 99%

Carbon isotope stratigraphy of the basal Zechstein (Lopingian) strata in Northern Poland and its global correlation

Peryt¹,

Durakiewicz²,

Kotarba³

et al. 2012

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“…The conversion of carbonates to CO 2 was done by reaction with 100% orthophosphoric acid (McCrea 1950). The results of isotope analyses are conventionally expressed in delta (δ) notation as per mil (‰) deviation from commonly used standards (PDB, SMOW).…”

Section: Methodsmentioning

confidence: 99%

Genesis of Syntectonic Hydrothermal Veins in the Igneous Rock of Teschenite Association (Outer Western Carpathians, Czech Republic): Growth Mechanism and Origin of Fluids

Urubek¹,

Dolníček²,

Kropáč³

2015

Geologica Carpathica

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Hydrothermal mineralization hosted by the Lower Cretaceous igneous rock of the teschenite association at Jasenice (Silesian Unit, Flysch Belt, Outer Western Carpathians) occurs in two morphological types -irregular vein filled by granular calcite and regular composite vein formed by both fibrous and granular calcite and minor chlorite, quartz, and pyrite. Crosscutting evidence indicates that the granular veins are younger than the composite vein. The composite vein was formed by two mechanisms at different times. The arrangement of solid inclusions in the marginal fibrous zone suggests an episodic growth by the crack-seal mechanism during syntectonic deformation which was at least partially driven by tectonic suction pump during some stages of the Alpine Orogeny. Both the central part of the composite vein and monomineral veins developed in a brittle regime. In these cases, the textures of vein suggest the flow of fluids along an open fracture. The parent fluids of both types of vein are characterized by low temperatures (Th =66-163 °C), low salinities (0.4 to 3.4 wt. % NaCl eq.), low content of strong REE-complexing ligands, and δ 18 O and δ 13 C ranges of + 0.2/+12.5 ‰ SMOW and -11.8/-14.1 ‰ PDB, respectively. The parent fluids are interpreted as the results of mixing of residual seawater and diagenetic waters produced by dewatering of clay minerals in the associated flysch sediments. The flow of fluids was controlled by tectonic deformation of the host rock.

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“…Powders of silicate rocks were reacted with BrF, at 600 °C in nickel vessels (Clayton & Mayeda, 1963), and the released oxygen was quantitatively converted to carbon dioxide by reaction with carbon at dull red heat. Carbonates (calcite) were reacted with '100%' phosphoric acid at 25 °C for 24 hours (McCrea, 1950;Wachter & Hayes, 1985). Isotope analyses were performed on a VG Micromass 602 ES mass spectrometer.…”

Section: Methodsmentioning

confidence: 99%

The tectono-metamorphic evolution of a dismembered ophiolite (Tinos, Cyclades, Greece)

et al. 1996

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-The six exposures of the Upper tectonic Unit of the Cycladic Massif occurring on the island of Tinos are shown to comprise a metamorphosed dismembered ophiolite complex. The common stratigraphic section consisting of tens-of-metres-thick tectonic slices of mafic phyllites overlain by serpentinites and gabbros is considered to have been derived by a combination of thrusting during obduction and subsequent attenuation by low-angle normal faults. All rock types show evidence of a phase of regional greenschistfacies metamorphism, which in the case of the phyllites is accompanied by penetrative deformation. The greenschist-facies metamorphism in gabbros is preceded by high temperature sea-floor amphibolite-facies alteration, whereas in the serpentinites, the antigorite + forsterite greenschist-facies assemblage overprinted an earlier low temperature lizardite serpentinite. Trace element patterns of the mafic phyllites and a harzburgitic origin of meta-serpentinites suggest a supra subduction zone (SSZ) affinity for the ophiolitic suite. 5"O values of phyllites, gabbros and serpentinites range from 6 to 15%o. Model calculations indicate that such values are consistent with low temperature (50-200 °C) alteration of parent rocks by sea-water at varying water/rock ratios. This would agree with the early low temperature mineralogy of the serpentinites, but the early high temperature alteration of the gabbros would require the presence of "O-enriched sea-water.The following overall history is suggested for Tinos ophiolitic slices.(1) Oceanic crust was generated at a supra-subduction zone spreading centre with high temperature alteration of gabbros. (2) Tectonic disturbance (its early hot stages recorded in an amphibolitic shear zone at the base of serpentinites) brought the already cooled ultramafics into direct contact with sea-water and caused low-7* serpentinization. (3) Tectonism after cooling involved thrusting which caused repetition and inversion of the original order of the oceanic suite. (4) Regional metamorphism of all the ophiolite components at greenschist-facies conditions (~450 °C) overprinted the early alteration mineralogy. It was probably induced by continued thrusting and piling up of nappes. The Tinos ophiolite, dated as late Cretaceous and genetically related to other low pressure rock-units of the same age in the Aegean, differs in age and degree of dismemberment and metamorphism from ophiolites in mainland Greece.

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On the Isotopic Chemistry of Carbonates and a Paleotemperature Scale

Cited by 3,438 publications

References 10 publications

Carbon isotope stratigraphy of the basal Zechstein (Lopingian) strata in Northern Poland and its global correlation

Carbon isotope stratigraphy of the basal Zechstein (Lopingian) strata in Northern Poland and its global correlation

Genesis of Syntectonic Hydrothermal Veins in the Igneous Rock of Teschenite Association (Outer Western Carpathians, Czech Republic): Growth Mechanism and Origin of Fluids

The tectono-metamorphic evolution of a dismembered ophiolite (Tinos, Cyclades, Greece)

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