Holocene Paleoclimatic History of the Rainfall Gradient in the Southern Great Plains: Evidence from Stable Isotopes in Land Snail Shells

Glenn A. Goodfriend，首席研究员（PI） G.L. Ellis， Co-PI Texas历史委员会南部大平原降水梯度的全新世古气候历史大平原代表了湿润的北美东部和半干旱的北美西部之间的气候转变。这个项目研究了在全新世（最后一个冰河时代结束后的一万年）期间大平原南部降雨梯度的气候历史。根据该地区晚第四纪记录中丰富的地螺（Rabdotus）壳碳酸盐组分的稳定同位素组成进行古气候重建。来自德克萨斯州四个地点的样本跨越了该地区的现代降雨梯度，分析了稳定的碳和氧同位素比率。这些比率可以作为确定植物类型和季节温度变化的代理。记录这一降雨梯度的近代史（最近1万年）对于评估全新世的古气候模式和了解未来该梯度如何响应人类引起的变化具有至关重要的意义。这些数据还为重新解释和完善目前对该地区文化适应模式的理解提供了基础。

SBR-9510869 Glenn A. Goodfriend, Principal Investigator (PI) G.L. Ellis, Co-PI Texas Historical Commission Holocene Paleoclimatic History of the Rainfall Gradient in the Southern Great Plains The Great Plains represent the climatic transition between moist eastern and semiarid western North America. This project investigates the climate history of this rainfall gradient in the southern Great Plains over the course of the Holocene (the period following the end of the last ice age or the last 10,000 years). The paleoclimate reconstruction is based on the stable isotope composition of the carbonate fraction of shells of the land snail, Rabdotus, which is abundant in the late Quaternary record of the region. Samples from four Texas sites spanning the modern rainfall gradient in the region are analyzed for stable carbon and oxygen isotope ratios. These ratios serve as proxies for determining plant types and seasonal variations in temperature. Documenting the recent history (last 10,000 years) of this rainfall gradient is of critical importance in evaluating paleoclimatic models of the Holocene and understanding how the gradient could change in the future in response to human-induced modifications. The data also provides a basis for reinterpreting and refining current understanding of the patterns of cultural adaptation in the region.