Late Pleistocene Latitudinal Gradients in North America Interpreted From Stable Isotopes of Fossil Equus Teeth

从化石的稳定同位素解释北美晚更新世的碳酸盐组成地球化学研究表明，碳酸盐组成的原始同位素记录保存在化石哺乳动物牙齿中。 牙齿化石中的碳含量表明了食草动物的食物，而氧含量则表明了环境温度。 在更新世晚期，马的化石分布在北美各地，先前的研究表明它主要是一种食草动物。 本研究的目的是分析化石马牙齿的碳和氧含量从广泛的地方在更新世，以确定在南北纬度梯度的C3和C4草分布和温度的变化。 将使用批量分析或连续切片技术进行1000次同位素分析。 这项研究产生的分析数据将通过建立地理信息系统数据库与其他全球变化参数结合起来。 最后一个完整的冰川（ca。20，000年至15，000年前）将与最后一次晚冰期（约20，000年至15，000年前）进行比较。15，000至10，000）。 据预测，全球纬度气候带相对压缩（即，更多的C3草，更冷，更季节性）在最后一个完整的冰川。 这项研究将对重建晚更新世大陆范围内的古气候和古生态学产生广泛的影响。

Late Pleistocene Latitudinal Gradients in North America Interpreted from Stable Isotopes of Fossil Equus TeethBruce J. MacFadden 9909186Geochemical studies have shown that the original isotopic record of carbonate composition is preserved in fossil mammal teeth. The carbon content of fossil teeth indicates the plant diet of herbivores and the oxygen indicates ambient temperature. During the late Pleistocene, the fossil horse Equus was very widespread throughout North America, and previous studies have shown that it was predominantly a grazer. The goal of this study is to analyze the carbon and oxygen content of fossil Equus teeth from widespread localities during the Pleistocene to determine changes in N-S latitudinal gradients of C3 and C4 grass distribution and temperature. One-thousand isotopic analyses will be conducted using either bulk analysis or serial sectioning techniques. The analytical data produced from this study will be integrated with other global change parameters through the establishment of a GIS (Geographic Information Systems) database. Results from the last Full Glacial (ca. 20,000 to 15,000 years ago) will be compared to those of the last Late Glacial (ca. 15,000 to 10,000). It is predicted that global latitudinal climatic belts were relatively compressed (i.e., more C3 grasses, colder, and more seasonality) during the last Full Glacial. This study will have broad ramifications with regard to reconstruction continental-wide paleoclimates and paleoecology during the late Pleistocene.