TY - JOUR
T1 - Age models for long lacustrine sediment records using multiple dating approaches - An example from Lake Bosumtwi, Ghana
AU - Shanahan, Timothy M.
AU - Peck, John A.
AU - McKay, Nicholas
AU - Heil, Clifford W.
AU - King, John
AU - Forman, Steven L.
AU - Hoffmann, Dirk L.
AU - Richards, David A.
AU - Overpeck, Jonathan T.
AU - Scholz, Christopher
N1 - Funding Information: We thank the people of Abono, Ghana and the other towns surrounding Lake Bosumtwi for their assistance during fieldwork. The research was funded in part by National Science Foundation grants NSF: EAR0602355 , EAR0601998 , ATM0401908 , ATM0214525 , and ATM0096232 .
PY - 2013/2
Y1 - 2013/2
N2 - The continuous 300-m long drill cores obtained from Lake Bosumtwi, Ghana represent one of the longest, continuous lacustrine sequences obtained from an extant lake, and contain an unprecedented record of late Quaternary climate change in West Africa. However, one of the main challenges associated with generating long paleoclimate time series from terrestrial records such as this is the development of accurate age-depth relationships because unlike marine records, lacustrine sequences cannot be tuned to global ice volume records via δ18O stratigraphy. The Lake Bosumtwi record thus offers an excellent case study for examining the potential and the challenges associated with different geochronological techniques in lacustrine systems. In the present study, we use a combination of radiocarbon, optically stimulated luminescence and U-series dating and paleomagnetic excursions to generate a chronology for the upper ca. 150 ka of sedimentation at Lake Bosumtwi and employ a Bayesian approach to generate a continuous age-depth relationship. The resultant chronology is then used to test the effectiveness of tuning of an environmental magnetic proxy for dust against a well-dated record of high latitude dust. Our approach highlights the advantages of using multiple dating approaches, and the dangers of relying on too few age constraints when dating long sedimentary sequences. However, the excellent agreement between the different approaches over most of the record suggest that well-constrained age-depth models for long sedimentary sequences can be produced using this combination of approaches. Furthermore, our data provide support for extending the chronology beyond the limit of radiocarbon, U-series and OSL in the future using paleomagnetic excursions/reversals and tuning against well-dated high latitude paleoclimate records.
AB - The continuous 300-m long drill cores obtained from Lake Bosumtwi, Ghana represent one of the longest, continuous lacustrine sequences obtained from an extant lake, and contain an unprecedented record of late Quaternary climate change in West Africa. However, one of the main challenges associated with generating long paleoclimate time series from terrestrial records such as this is the development of accurate age-depth relationships because unlike marine records, lacustrine sequences cannot be tuned to global ice volume records via δ18O stratigraphy. The Lake Bosumtwi record thus offers an excellent case study for examining the potential and the challenges associated with different geochronological techniques in lacustrine systems. In the present study, we use a combination of radiocarbon, optically stimulated luminescence and U-series dating and paleomagnetic excursions to generate a chronology for the upper ca. 150 ka of sedimentation at Lake Bosumtwi and employ a Bayesian approach to generate a continuous age-depth relationship. The resultant chronology is then used to test the effectiveness of tuning of an environmental magnetic proxy for dust against a well-dated record of high latitude dust. Our approach highlights the advantages of using multiple dating approaches, and the dangers of relying on too few age constraints when dating long sedimentary sequences. However, the excellent agreement between the different approaches over most of the record suggest that well-constrained age-depth models for long sedimentary sequences can be produced using this combination of approaches. Furthermore, our data provide support for extending the chronology beyond the limit of radiocarbon, U-series and OSL in the future using paleomagnetic excursions/reversals and tuning against well-dated high latitude paleoclimate records.
KW - Chronology
KW - Lake
KW - Lake Bosumtwi
KW - Paleoclimate
KW - West Africa
UR - http://www.scopus.com/inward/record.url?scp=84875259409&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84875259409&partnerID=8YFLogxK
U2 - 10.1016/j.quageo.2012.12.001
DO - 10.1016/j.quageo.2012.12.001
M3 - Article
SN - 1871-1014
VL - 15
SP - 47
EP - 60
JO - Quaternary Geochronology
JF - Quaternary Geochronology
ER -