Geochemical signatures in Late Triassic brachiopods from New Caledonia

C. V. Ullmann; H. J. Campbell; R. Frei; C. Korte

doi:10.1080/00288306.2014.958175

Geochemical signatures in Late Triassic brachiopods from New Caledonia

C. V. Ullmann^*, H. J. Campbell, R. Frei, C. Korte

^*Corresponding author af dette arbejde

Geologi

8 Citationer (Scopus)

Abstract

Brachiopod fossils from the sedimentary sequences of the Téremba Terrane (New Caledonia) provide a unique opportunity to study the environmental parameters of the Late Triassic. 87Sr/86Sr ratios, δ13C and δ18O values, and Sr/Ca, Mg/Ca and Mn/Ca ratios were measured on brachiopods from Oretian to Otapirian (Norian to Rhaetian) fossil localities of the Baie de St.-Vincent area. Post-depositional impacts on the geochemical proxies were investigated by analysing calcite cements and partly recrystallized shell material. Diagenetic fluids carried strontium with a low 87Sr/86Sr ratio of c. 0.7065, and light δ13C values of c. −20‰, suggesting major contributions by oxidized organic matter. Diagenetic equilibrium was reached at δ18O values of c. −12‰, very low Sr/Ca ratios of < 0.05 mmol/mol and locally variable Mn/Ca ratios of up to 5.9 mmol/mol. Results from the best-preserved samples suggest that calcification temperatures of Warepan and Otapirian brachiopods from New Caledonia were consistently ≥ 15 °C.

Originalsprog	Engelsk
Tidsskrift	New Zealand Journal of Geology and Geophysics
Vol/bind	57
Udgave nummer	4
Sider (fra-til)	420-431
Antal sider	12
ISSN	0028-8306
DOI	https://doi.org/10.1080/00288306.2014.958175
Status	Udgivet - okt. 2014

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10.1080/00288306.2014.958175

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title = "Geochemical signatures in Late Triassic brachiopods from New Caledonia",

abstract = "Brachiopod fossils from the sedimentary sequences of the T{\'e}remba Terrane (New Caledonia) provide a unique opportunity to study the environmental parameters of the Late Triassic. 87Sr/86Sr ratios, δ13C and δ18O values, and Sr/Ca, Mg/Ca and Mn/Ca ratios were measured on brachiopods from Oretian to Otapirian (Norian to Rhaetian) fossil localities of the Baie de St.-Vincent area. Post-depositional impacts on the geochemical proxies were investigated by analysing calcite cements and partly recrystallized shell material. Diagenetic fluids carried strontium with a low 87Sr/86Sr ratio of c. 0.7065, and light δ13C values of c.-20‰, suggesting major contributions by oxidized organic matter. Diagenetic equilibrium was reached at δ18O values of c.-12‰, very low Sr/Ca ratios of < 0.05 mmol/mol and locally variable Mn/Ca ratios of up to 5.9 mmol/mol. Results from the best-preserved samples suggest that calcification temperatures of Warepan and Otapirian brachiopods from New Caledonia were consistently ≥ 15 °C.",

keywords = "Sr/Sr, Brachiopod, Diagenesis, New Caledonia, Stable isotopes, Trace elements",

author = "Ullmann, {C. V.} and Campbell, {H. J.} and R. Frei and C. Korte",

year = "2014",

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doi = "10.1080/00288306.2014.958175",

language = "English",

volume = "57",

pages = "420--431",

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TY - JOUR

T1 - Geochemical signatures in Late Triassic brachiopods from New Caledonia

AU - Ullmann, C. V.

AU - Campbell, H. J.

AU - Frei, R.

AU - Korte, C.

PY - 2014/10

Y1 - 2014/10

N2 - Brachiopod fossils from the sedimentary sequences of the Téremba Terrane (New Caledonia) provide a unique opportunity to study the environmental parameters of the Late Triassic. 87Sr/86Sr ratios, δ13C and δ18O values, and Sr/Ca, Mg/Ca and Mn/Ca ratios were measured on brachiopods from Oretian to Otapirian (Norian to Rhaetian) fossil localities of the Baie de St.-Vincent area. Post-depositional impacts on the geochemical proxies were investigated by analysing calcite cements and partly recrystallized shell material. Diagenetic fluids carried strontium with a low 87Sr/86Sr ratio of c. 0.7065, and light δ13C values of c.-20‰, suggesting major contributions by oxidized organic matter. Diagenetic equilibrium was reached at δ18O values of c.-12‰, very low Sr/Ca ratios of < 0.05 mmol/mol and locally variable Mn/Ca ratios of up to 5.9 mmol/mol. Results from the best-preserved samples suggest that calcification temperatures of Warepan and Otapirian brachiopods from New Caledonia were consistently ≥ 15 °C.

AB - Brachiopod fossils from the sedimentary sequences of the Téremba Terrane (New Caledonia) provide a unique opportunity to study the environmental parameters of the Late Triassic. 87Sr/86Sr ratios, δ13C and δ18O values, and Sr/Ca, Mg/Ca and Mn/Ca ratios were measured on brachiopods from Oretian to Otapirian (Norian to Rhaetian) fossil localities of the Baie de St.-Vincent area. Post-depositional impacts on the geochemical proxies were investigated by analysing calcite cements and partly recrystallized shell material. Diagenetic fluids carried strontium with a low 87Sr/86Sr ratio of c. 0.7065, and light δ13C values of c.-20‰, suggesting major contributions by oxidized organic matter. Diagenetic equilibrium was reached at δ18O values of c.-12‰, very low Sr/Ca ratios of < 0.05 mmol/mol and locally variable Mn/Ca ratios of up to 5.9 mmol/mol. Results from the best-preserved samples suggest that calcification temperatures of Warepan and Otapirian brachiopods from New Caledonia were consistently ≥ 15 °C.

KW - Sr/Sr

KW - Brachiopod

KW - Diagenesis

KW - New Caledonia

KW - Stable isotopes

KW - Trace elements

U2 - 10.1080/00288306.2014.958175

DO - 10.1080/00288306.2014.958175

M3 - Journal article

AN - SCOPUS:84911954439

SN - 0028-8306

VL - 57

SP - 420

EP - 431

JO - New Zealand Journal of Geology and Geophysics

JF - New Zealand Journal of Geology and Geophysics

IS - 4

ER -

Geochemical signatures in Late Triassic brachiopods from New Caledonia

Abstract

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