We present a revised 87Sr/86Sr-curve for marine-Sr in the interval 2.5–4.5 Ma using analysis of Orbulina universa from the Middle Pliocene type section in Sicily (Punta Piccola section) and a mixed assemblage of planktonic foraminifera from ODP Site 758A and B. The new calibration is used, together with new 87Sr/86Sr analysis of pectenid calcite from Cockburn Island, Antarctica, to confirm an age of 4.7 Ma for the pectenids of the Cockburn Island Formation (formerly the Pecten Conglomerate), a unit important in marking a period of warmth and possible glacial retreat in Antarctica. Finally, to aid interlaboratory comparison of 87Sr/86Sr data, we calibrate a value of 0.709174 for EN-1 against a value of NIST 987 of 0.709248.
A revised Pliocene record for marine-Sr-87/Sr-86 used to date an interglacial event recorded in the Cockburn Island Formation, Antarctic Peninsula
RIO, DOMENICO;MASSARI, FRANCESCO;
2006
Abstract
We present a revised 87Sr/86Sr-curve for marine-Sr in the interval 2.5–4.5 Ma using analysis of Orbulina universa from the Middle Pliocene type section in Sicily (Punta Piccola section) and a mixed assemblage of planktonic foraminifera from ODP Site 758A and B. The new calibration is used, together with new 87Sr/86Sr analysis of pectenid calcite from Cockburn Island, Antarctica, to confirm an age of 4.7 Ma for the pectenids of the Cockburn Island Formation (formerly the Pecten Conglomerate), a unit important in marking a period of warmth and possible glacial retreat in Antarctica. Finally, to aid interlaboratory comparison of 87Sr/86Sr data, we calibrate a value of 0.709174 for EN-1 against a value of NIST 987 of 0.709248.
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