TY - JOUR
T1 - Chronostratigraphy of a 270-ka sediment record from Lake Selina, Tasmania
T2 - Combining radiometric, geomagnetic and climatic dating
AU - Lisé-Pronovost, Agathe
AU - Fletcher, Michael Shawn
AU - Simon, Quentin
AU - Jacobs, Zenobia
AU - Gadd, Patricia S.
AU - Heslop, David
AU - Herries, Andy I.R.
AU - Yokoyama, Yusuke
AU - team, Aster
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/3
Y1 - 2021/3
N2 - Lake sediment archives covering several glacial cycles are scarce in the Southern Hemisphere and they are challenging to date. Here we present the chronostratigraphy of the oldest continuous lake sediment archive in Tasmania, Australia; a 5.5 m and 270 ka (Marine Isotope Stage 8) sediment core from Lake Selina. We employ radiometric dating (radiocarbon and optically stimulated luminescence) and relative dating (geomagnetic and climate comparisons). Bayesian modeling of the radiometric ages reaches back to 80 ka (1.7 m) and relative dating using a dynamic programing algorithm allows dating of the full sequence. Elemental data, magnetic properties and beryllium isotopes from Lake Selina reveal a close fit to Antarctic ice core climate proxies. Weaker correlation during the Last Glacial Period (MIS 2–4) is attributed to additional local factors impacting Lake Selina proxies at a time of climate changes and human arrival into Tasmania. Over that period, full vector paleomagnetic records and authigenic 10Be/9Be ratios are combined to identify the Laschamp geomagnetic excursion for the first time in Australia and constrain the chronology. The multi-method approach provides two preferred age models, indiscernible within their uncertainties, which allows the use of a geomagnetic dipole-independent (full archive) or a climate-independent (111 ka to present) age model.
AB - Lake sediment archives covering several glacial cycles are scarce in the Southern Hemisphere and they are challenging to date. Here we present the chronostratigraphy of the oldest continuous lake sediment archive in Tasmania, Australia; a 5.5 m and 270 ka (Marine Isotope Stage 8) sediment core from Lake Selina. We employ radiometric dating (radiocarbon and optically stimulated luminescence) and relative dating (geomagnetic and climate comparisons). Bayesian modeling of the radiometric ages reaches back to 80 ka (1.7 m) and relative dating using a dynamic programing algorithm allows dating of the full sequence. Elemental data, magnetic properties and beryllium isotopes from Lake Selina reveal a close fit to Antarctic ice core climate proxies. Weaker correlation during the Last Glacial Period (MIS 2–4) is attributed to additional local factors impacting Lake Selina proxies at a time of climate changes and human arrival into Tasmania. Over that period, full vector paleomagnetic records and authigenic 10Be/9Be ratios are combined to identify the Laschamp geomagnetic excursion for the first time in Australia and constrain the chronology. The multi-method approach provides two preferred age models, indiscernible within their uncertainties, which allows the use of a geomagnetic dipole-independent (full archive) or a climate-independent (111 ka to present) age model.
KW - Australia
KW - Authigenic 10Be/9Be ratio
KW - Lake sediment
KW - Optically stimulated luminescence
KW - Paleomagnetism
KW - Pleistocene
KW - Radiocarbon
UR - http://www.scopus.com/inward/record.url?scp=85100637400&partnerID=8YFLogxK
U2 - 10.1016/j.quageo.2021.101152
DO - 10.1016/j.quageo.2021.101152
M3 - Article
SN - 1871-1014
VL - 62
JO - Quaternary Geochronology
JF - Quaternary Geochronology
M1 - 101152
ER -