Seasonal variation in kangaroo tooth enamel oxygen and carbon isotopes in southern Australia

详细信息    查看全文

• 作者：Tom H. Brookman ; Stanley H. Ambrose
• 关键词：Carbon isotopes ; Oxygen isotopes ; Seasonality ; Kangaroo ; Tooth enamel ; Paleoclimate ; Australia
• 刊名：Quaternary Research
• 出版年：2012
• 出版时间：September, 2012
• 年：2012
• 卷：78
• 期：2
• 页码：256-265
• 全文大小：976 K

文摘

Serial sampling of tooth enamel growth increments for carbon and oxygen isotopic analyses of Macropus (kangaroo) teeth was performed to assess the potential for reconstructing paleoseasonality. The carbon isotope composition of tooth enamel apatite carbonate reflects the proportional intake of C₃ and C₄ vegetation. The oxygen isotopic composition of enamel reflects that of ingested and metabolic water. Tooth enamel forms sequentially from the tip of the crown to the base, so dietary and environmental changes during the tooth's formation can be detected. ¦Ä¹³C and ¦Ä¹⁸O values were determined for a series of enamel samples drilled from the 3rd and 4th molars of kangaroos that were collected along a 900 km north-south transect in southern Australia. The serial sampling method did not yield pronounced seasonal isotopic variation patterns in Macropus enamel. The full extent of dietary isotopic variation may be obscured by attenuation of the isotopic signal during enamel mineralisation. Brachydont (low-crowned) Macropus teeth may be less sensitive to seasonal variation in isotopic composition due to time-averaging during mineralisation. However, geographic variations observed suggest that there may be potential for tracking latitudinal shifts in vegetation zones and seasonal environmental patterns in response to climate change.