A high-resolution Sr/Ca and δ18O coral record from the Great Barrier Reef, Australia, and the 1982–1983 El Niño
A high-resolution Sr/Ca and δ18O coral record from the Great Barrier Reef, Australia, and the 1982–1983 El Niño
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DOI：
10.1016/0016-7037(94)90142-2
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发表时间：
1994-06
影响因子：
5
通讯作者：
M. McCulloch;M. Gagan;G. Mortimer;A. Chivas;P. Isdale
中科院分区：
文献类型：
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作者：
M. McCulloch;M. Gagan;G. Mortimer;A. Chivas;P. Isdale
高分辨率（近每周）Sr/Ca和氧同位素记录的珊瑚从潘多拉礁在澳大利亚大堡礁（GBR）在1978年至1984年期间。记录是很好的相关性，除了高降雨期间，河流径流显着修改的海水δ 18 O值。利用De Villierset等（1994）的Sr/Ca温度校正，Sr/Ca记录显示出受季节控制的SST（海表温度）周期变化，变化范围为~21 ~~28δC。在1982-1983年强厄尔尼诺期间，Sr/Ca系统分析表明，冬季SST急剧下降至~ 18.5δC。这表明δC的温度异常值为−3，大约是δ 18 O变化值的两倍，表明Sr/Ca系统对异常值的放大约为2倍，这可能是由于无机控制的文石海水分馏作用的优势增加所致。氧同位素系统显示温度和海水δ 18 O值变化的综合影响，后者反映了高降雨期间18 O-贫化径流的流入。由于河流径流中的Sr和Ca含量相对于海水而言非常低（~10−3），因此可以使用Sr/Ca温度计来计算与大洪水无关的温度，从而对温度变化的氧同位素记录和海水δ 18 O值的综合影响进行反卷积。使用这种方法，它是可能的，以定量再现的Burdekin河在1979年初和1981年发生的大洪水期间的径流量。本研究的结果表明，高分辨率的Sr/Ca和δ 18 O系统学在石珊瑚的组合使用是一个强大的工具，提供定量约束过去的气候。
A high-resolution (near weekly) Sr/Ca and oxygen isotopic record is presented for a coral from the Pandora Reef in the Great Barrier Reef (GBR) of Australia during the period 1978 to 1984. The records are well correlated except for periods of high rainfall when river runoff has significantly modified theδ18Ovalue of seawater. Using the Sr/Ca temperature calibration ofDe Villierset al. (1994), the Sr/Ca records exhibit seasonally controlled cyclical SST (sea surface temperature) variations of from ~21 to ~28δC. During the very strong El Niño of 1982–1983, the Sr/Ca systematics indicate a sharp drop in the winter SST to ~ 18.5δC. This represents a temperature anomaly of −3δC which is approximately twice that given by theδ18Ovariations, suggesting an ~×2 amplification of the anomaly by the Sr/Ca system, possibly due to the increasing dominance of inorganically controlled aragoniteseawater fractionation.The oxygen isotopic systematics show the combined effects of both temperature and changing seawaterδ18Ovalues, the latter reflecting the influx of18O-depleted runoff during periods of high rainfall. Due to the extremely low (~10−3) Sr and Ca contents of river run off relative to seawater, it is possible to use the Sr/Ca thermometer to calculate temperatures independent of major floods and hence deconvolve the combined effects in the oxygen isotopic record of variable temperature and theδ18Ovalue of seawater. Using this approach it is possible to quantitatively reproduce the volume of runoff from the Burdekin River during the periods of major flooding that occurred in early 1979 and 1981. The results of this study demonstrate that the combined use of high-resolution Sr/Ca andδ18Osystematics in scleractinian corals is a powerful tool for providing quantitative constraints on past climate.