Intra-annual perturbations of stable isotopes in tufas: Effects of hydrological processes

M. Hori, T. Kawai, J. Matsuoka, Akihiro Kano

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Tufas, which are freshwater carbonates, are potential archives of terrestrial paleoclimate. Time series of stable isotopic compositions commonly show regular seasonal patterns controlled by temperature-dependent processes, and some perturbation intrinsic to the locality. We examined three tufa-depositing sites in southwestern Japan with similar temperate climates, to understand the origin of local characteristics in the isotopic records. Seasonal change in the oxygen isotope is principally reflected by temperature-dependent fractionation between water and calcite but was perturbed after heavy rainfalls overwhelming the stability of the δ18O value of the groundwater at one site. Isotopic mass balance indicates an undersaturated and relatively small aquifer at this locality. Water δ18O values at the other two sites were stable, reflecting a regular seasonal change in the δ18O value of tufa. Perturbation of the δ13C values in tufa is largely due to CO2 degassing from the stream, which significantly increases the δ13C values of dissolved inorganic carbon (DIC). At a site with remarkably high pCO2 in springwater and a sensitive response of flow rate to rainfall, the amount of CO2 degassing changed distinctly with flow rate. In contrast, the other two sites having low pCO2 springwater reflect a regular seasonal pattern of δ13C in DIC and tufa specimens.

Original languageEnglish
Pages (from-to)1684-1695
Number of pages12
JournalGeochimica et Cosmochimica Acta
Volume73
Issue number6
DOIs
Publication statusPublished - Mar 15 2009

Fingerprint

tufa
Degassing
Isotopes
Rain
stable isotope
Carbon
Oxygen Isotopes
Flow rate
perturbation
Water
Calcium Carbonate
Carbonates
dissolved inorganic carbon
Fractionation
degassing
Aquifers
Groundwater
Time series
Temperature
rainfall

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology

Cite this

Intra-annual perturbations of stable isotopes in tufas : Effects of hydrological processes. / Hori, M.; Kawai, T.; Matsuoka, J.; Kano, Akihiro.

In: Geochimica et Cosmochimica Acta, Vol. 73, No. 6, 15.03.2009, p. 1684-1695.

Research output: Contribution to journalArticle

Hori, M. ; Kawai, T. ; Matsuoka, J. ; Kano, Akihiro. / Intra-annual perturbations of stable isotopes in tufas : Effects of hydrological processes. In: Geochimica et Cosmochimica Acta. 2009 ; Vol. 73, No. 6. pp. 1684-1695.
@article{f7cb2aec70a54b7bac10bef18d2665fc,
title = "Intra-annual perturbations of stable isotopes in tufas: Effects of hydrological processes",
abstract = "Tufas, which are freshwater carbonates, are potential archives of terrestrial paleoclimate. Time series of stable isotopic compositions commonly show regular seasonal patterns controlled by temperature-dependent processes, and some perturbation intrinsic to the locality. We examined three tufa-depositing sites in southwestern Japan with similar temperate climates, to understand the origin of local characteristics in the isotopic records. Seasonal change in the oxygen isotope is principally reflected by temperature-dependent fractionation between water and calcite but was perturbed after heavy rainfalls overwhelming the stability of the δ18O value of the groundwater at one site. Isotopic mass balance indicates an undersaturated and relatively small aquifer at this locality. Water δ18O values at the other two sites were stable, reflecting a regular seasonal change in the δ18O value of tufa. Perturbation of the δ13C values in tufa is largely due to CO2 degassing from the stream, which significantly increases the δ13C values of dissolved inorganic carbon (DIC). At a site with remarkably high pCO2 in springwater and a sensitive response of flow rate to rainfall, the amount of CO2 degassing changed distinctly with flow rate. In contrast, the other two sites having low pCO2 springwater reflect a regular seasonal pattern of δ13C in DIC and tufa specimens.",
author = "M. Hori and T. Kawai and J. Matsuoka and Akihiro Kano",
year = "2009",
month = "3",
day = "15",
doi = "10.1016/j.gca.2008.12.024",
language = "English",
volume = "73",
pages = "1684--1695",
journal = "Geochmica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",
number = "6",

}

TY - JOUR

T1 - Intra-annual perturbations of stable isotopes in tufas

T2 - Effects of hydrological processes

AU - Hori, M.

AU - Kawai, T.

AU - Matsuoka, J.

AU - Kano, Akihiro

PY - 2009/3/15

Y1 - 2009/3/15

N2 - Tufas, which are freshwater carbonates, are potential archives of terrestrial paleoclimate. Time series of stable isotopic compositions commonly show regular seasonal patterns controlled by temperature-dependent processes, and some perturbation intrinsic to the locality. We examined three tufa-depositing sites in southwestern Japan with similar temperate climates, to understand the origin of local characteristics in the isotopic records. Seasonal change in the oxygen isotope is principally reflected by temperature-dependent fractionation between water and calcite but was perturbed after heavy rainfalls overwhelming the stability of the δ18O value of the groundwater at one site. Isotopic mass balance indicates an undersaturated and relatively small aquifer at this locality. Water δ18O values at the other two sites were stable, reflecting a regular seasonal change in the δ18O value of tufa. Perturbation of the δ13C values in tufa is largely due to CO2 degassing from the stream, which significantly increases the δ13C values of dissolved inorganic carbon (DIC). At a site with remarkably high pCO2 in springwater and a sensitive response of flow rate to rainfall, the amount of CO2 degassing changed distinctly with flow rate. In contrast, the other two sites having low pCO2 springwater reflect a regular seasonal pattern of δ13C in DIC and tufa specimens.

AB - Tufas, which are freshwater carbonates, are potential archives of terrestrial paleoclimate. Time series of stable isotopic compositions commonly show regular seasonal patterns controlled by temperature-dependent processes, and some perturbation intrinsic to the locality. We examined three tufa-depositing sites in southwestern Japan with similar temperate climates, to understand the origin of local characteristics in the isotopic records. Seasonal change in the oxygen isotope is principally reflected by temperature-dependent fractionation between water and calcite but was perturbed after heavy rainfalls overwhelming the stability of the δ18O value of the groundwater at one site. Isotopic mass balance indicates an undersaturated and relatively small aquifer at this locality. Water δ18O values at the other two sites were stable, reflecting a regular seasonal change in the δ18O value of tufa. Perturbation of the δ13C values in tufa is largely due to CO2 degassing from the stream, which significantly increases the δ13C values of dissolved inorganic carbon (DIC). At a site with remarkably high pCO2 in springwater and a sensitive response of flow rate to rainfall, the amount of CO2 degassing changed distinctly with flow rate. In contrast, the other two sites having low pCO2 springwater reflect a regular seasonal pattern of δ13C in DIC and tufa specimens.

UR - http://www.scopus.com/inward/record.url?scp=60449095395&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=60449095395&partnerID=8YFLogxK

U2 - 10.1016/j.gca.2008.12.024

DO - 10.1016/j.gca.2008.12.024

M3 - Article

AN - SCOPUS:60449095395

VL - 73

SP - 1684

EP - 1695

JO - Geochmica et Cosmochimica Acta

JF - Geochmica et Cosmochimica Acta

SN - 0016-7037

IS - 6

ER -