Climate-independent paleoaltimetry using stomatal density in fossil leaves as a proxy for CO2 partial pressure
Climate-independent paleoaltimetry using stomatal density in fossil leaves as a proxy for CO2 partial pressure
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DOI：
10.1130/g20915.1
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发表时间：
2004-12
期刊：
影响因子：
5.8
通讯作者：
J. McElwain
中科院分区：
文献类型：
--
作者：
J. McElwain
确定古高程的现有方法主要受到以下限制：（1）大误差（±450 m），（2）依赖于不正确的假设，即陆地温度的递减率以全球可预测的方式随海拔降低，和/或（3）固有地依赖于气候。在这里，我提出了一种新的古海拔工具，基于一个可预测的，全球保守的减少CO2分压（p CO2）与海拔高度，植物叶片的气孔频率增加所示。该方法进行了验证，使用历史种群的黑橡树（Quercus kelloglio）。这些分析表明气孔频率与pCO 2之间存在极显著的负相关关系（r2> 0.73），与生态或当地气候变化无关。因此，这是第一个全球适用且独立于长期新生代气候变化的古植物学方法。此外，对已知海拔的现代叶的测试表明，种特异性应用于Q的化石记录。kellogalus（= Q. pseudolyrata）将产生平均误差为±300 m的古高程估计值，与大多数现有方法相比，其精度有了显著提高。
Existing methods for determining paleoelevation are primarily limited by (1) large errors (±450 m), (2) a reliance on incorrect assumptions that lapse rates in terrestrial temperature decrease with altitude in a globally predictable manner, and/or (3) are inherently climate dependent. Here I present a novel paleoelevation tool, based on a predictable, globally conserved decrease in CO 2 partial pressure ( p CO 2 ) with altitude, as indicated by increased stomatal frequency of plant leaves. The approach was validated using historical populations of black oak ( Quercus kelloggii ). These analyses demonstrate highly significant inverse relationships between stomatal frequency and p CO 2 ( r 2 > 0.73), independent of ecological or local climatic variability. As such, this is the first paleobotanical method to be globally applicable and independent of long-term Cenozoic climate change. Further, tests on modern leaves of known elevations indicate that species-specific application to the fossil record of Q. kelloggii (= Q. pseudolyrata ) will yield paleoelevation estimates within average errors of ∼±300 m, representing a significant improvement in accuracy over the majority of existing methods.