Hydrogen and oxygen isotope ratios in nodular and bedded cherts

L. Paul Knauth, Samuel Epstein

Research output: Contribution to journalArticle

334 Citations (Scopus)

Abstract

Hydrogen and oxygen isotopic compositions of cherts (δD for hydroxyl hydrogen in the chert, δ18O for the total oxygen) have been determined for a suite of samples from the central and western United States. When plotted on a δD-δ18O diagram, Phanerozoic cherts define domains parallel to the meteoric water line which are different for different periods of geologic time. The elongation parallel to the meteoric water line suggests that meteoric waters were involved in the formation of many cherts. The existence of different chert δ-values for different geologic times indicates that once the granular microcrystalline quartz of cherts crystallizes its isotopic composition is preserved with time. An explanation for the change with time of the isotopic composition of cherts involving large changes with time in the isotopic composition of ocean water is unlikely since δ18O of the ocean would have had to decrease by about 3‰between Carboniferous and Triassic time and then increase about 5%.` from Triassic to Cretaceous time. Such isotopic changes cannot be accounted for by extensive glaciation, sedimentation of hydrous minerals, or input of water from the mantle into the oceans. The variation with time of the chert δ-values can be satisfactorily explained in terms of past climatic temperature fluctuations if the chert-water isotope fractionation with temperature is approximated by 1000 ln α = 3.09 × 106T-2 - 3.29. Crystallization temperatures so inferred suggest that the average climatic temperatures for the central and western U.S. decreased from about 34 to 20°C through the Paleozoic, increased to 35-40°C in the Triassic, and then decreased through the Mesozoic to Tertiary values of about 17°C. A few data for the Precambrian suggest the possibility that Earth surface temperatures may have reached about 52°C at 1.3 b.y. and about 70°C at 3 b.y.

Original languageEnglish (US)
Pages (from-to)1095-1108
Number of pages14
JournalGeochimica et Cosmochimica Acta
Volume40
Issue number9
DOIs
StatePublished - 1976
Externally publishedYes

Fingerprint

Oxygen Isotopes
oxygen isotope ratio
hydrogen isotope
Hydrogen
Water piping systems
chert
Water
isotopic composition
Chemical analysis
meteoric water
Temperature
Triassic
Oxygen
Quartz
shoreline
Fractionation
Crystallization
ocean
Sedimentation
Isotopes

ASJC Scopus subject areas

  • Geochemistry and Petrology

Cite this

Hydrogen and oxygen isotope ratios in nodular and bedded cherts. / Knauth, L. Paul; Epstein, Samuel.

In: Geochimica et Cosmochimica Acta, Vol. 40, No. 9, 1976, p. 1095-1108.

Research output: Contribution to journalArticle

Knauth, L. Paul ; Epstein, Samuel. / Hydrogen and oxygen isotope ratios in nodular and bedded cherts. In: Geochimica et Cosmochimica Acta. 1976 ; Vol. 40, No. 9. pp. 1095-1108.
@article{44dee909654645b1ab2094663bdca780,
title = "Hydrogen and oxygen isotope ratios in nodular and bedded cherts",
abstract = "Hydrogen and oxygen isotopic compositions of cherts (δD for hydroxyl hydrogen in the chert, δ18O for the total oxygen) have been determined for a suite of samples from the central and western United States. When plotted on a δD-δ18O diagram, Phanerozoic cherts define domains parallel to the meteoric water line which are different for different periods of geologic time. The elongation parallel to the meteoric water line suggests that meteoric waters were involved in the formation of many cherts. The existence of different chert δ-values for different geologic times indicates that once the granular microcrystalline quartz of cherts crystallizes its isotopic composition is preserved with time. An explanation for the change with time of the isotopic composition of cherts involving large changes with time in the isotopic composition of ocean water is unlikely since δ18O of the ocean would have had to decrease by about 3‰between Carboniferous and Triassic time and then increase about 5{\%}.` from Triassic to Cretaceous time. Such isotopic changes cannot be accounted for by extensive glaciation, sedimentation of hydrous minerals, or input of water from the mantle into the oceans. The variation with time of the chert δ-values can be satisfactorily explained in terms of past climatic temperature fluctuations if the chert-water isotope fractionation with temperature is approximated by 1000 ln α = 3.09 × 106T-2 - 3.29. Crystallization temperatures so inferred suggest that the average climatic temperatures for the central and western U.S. decreased from about 34 to 20°C through the Paleozoic, increased to 35-40°C in the Triassic, and then decreased through the Mesozoic to Tertiary values of about 17°C. A few data for the Precambrian suggest the possibility that Earth surface temperatures may have reached about 52°C at 1.3 b.y. and about 70°C at 3 b.y.",
author = "Knauth, {L. Paul} and Samuel Epstein",
year = "1976",
doi = "10.1016/0016-7037(76)90051-X",
language = "English (US)",
volume = "40",
pages = "1095--1108",
journal = "Geochmica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",
number = "9",

}

TY - JOUR

T1 - Hydrogen and oxygen isotope ratios in nodular and bedded cherts

AU - Knauth, L. Paul

AU - Epstein, Samuel

PY - 1976

Y1 - 1976

N2 - Hydrogen and oxygen isotopic compositions of cherts (δD for hydroxyl hydrogen in the chert, δ18O for the total oxygen) have been determined for a suite of samples from the central and western United States. When plotted on a δD-δ18O diagram, Phanerozoic cherts define domains parallel to the meteoric water line which are different for different periods of geologic time. The elongation parallel to the meteoric water line suggests that meteoric waters were involved in the formation of many cherts. The existence of different chert δ-values for different geologic times indicates that once the granular microcrystalline quartz of cherts crystallizes its isotopic composition is preserved with time. An explanation for the change with time of the isotopic composition of cherts involving large changes with time in the isotopic composition of ocean water is unlikely since δ18O of the ocean would have had to decrease by about 3‰between Carboniferous and Triassic time and then increase about 5%.` from Triassic to Cretaceous time. Such isotopic changes cannot be accounted for by extensive glaciation, sedimentation of hydrous minerals, or input of water from the mantle into the oceans. The variation with time of the chert δ-values can be satisfactorily explained in terms of past climatic temperature fluctuations if the chert-water isotope fractionation with temperature is approximated by 1000 ln α = 3.09 × 106T-2 - 3.29. Crystallization temperatures so inferred suggest that the average climatic temperatures for the central and western U.S. decreased from about 34 to 20°C through the Paleozoic, increased to 35-40°C in the Triassic, and then decreased through the Mesozoic to Tertiary values of about 17°C. A few data for the Precambrian suggest the possibility that Earth surface temperatures may have reached about 52°C at 1.3 b.y. and about 70°C at 3 b.y.

AB - Hydrogen and oxygen isotopic compositions of cherts (δD for hydroxyl hydrogen in the chert, δ18O for the total oxygen) have been determined for a suite of samples from the central and western United States. When plotted on a δD-δ18O diagram, Phanerozoic cherts define domains parallel to the meteoric water line which are different for different periods of geologic time. The elongation parallel to the meteoric water line suggests that meteoric waters were involved in the formation of many cherts. The existence of different chert δ-values for different geologic times indicates that once the granular microcrystalline quartz of cherts crystallizes its isotopic composition is preserved with time. An explanation for the change with time of the isotopic composition of cherts involving large changes with time in the isotopic composition of ocean water is unlikely since δ18O of the ocean would have had to decrease by about 3‰between Carboniferous and Triassic time and then increase about 5%.` from Triassic to Cretaceous time. Such isotopic changes cannot be accounted for by extensive glaciation, sedimentation of hydrous minerals, or input of water from the mantle into the oceans. The variation with time of the chert δ-values can be satisfactorily explained in terms of past climatic temperature fluctuations if the chert-water isotope fractionation with temperature is approximated by 1000 ln α = 3.09 × 106T-2 - 3.29. Crystallization temperatures so inferred suggest that the average climatic temperatures for the central and western U.S. decreased from about 34 to 20°C through the Paleozoic, increased to 35-40°C in the Triassic, and then decreased through the Mesozoic to Tertiary values of about 17°C. A few data for the Precambrian suggest the possibility that Earth surface temperatures may have reached about 52°C at 1.3 b.y. and about 70°C at 3 b.y.

UR - http://www.scopus.com/inward/record.url?scp=0000202022&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000202022&partnerID=8YFLogxK

U2 - 10.1016/0016-7037(76)90051-X

DO - 10.1016/0016-7037(76)90051-X

M3 - Article

AN - SCOPUS:0000202022

VL - 40

SP - 1095

EP - 1108

JO - Geochmica et Cosmochimica Acta

JF - Geochmica et Cosmochimica Acta

SN - 0016-7037

IS - 9

ER -