Cenozoic Paleoclimatic Record from Paleosols of Eastern Oregon and Washington

追溯追溯到地质时代的气候变化的长期记录，对于理解全球变化的性质和方向非常重要。迄今为止，最重要的记录之一来自深海岩心的有孔虫的氧同位素组成。这里提出的为期三年的项目是为了获得相对完整和长期的陆地古气候记录。这一记录来自俄勒冈州东北部和华盛顿州东南部高地沙漠中的一长串化石土壤(古土壤)，年龄从现代到4500万年不等。用于确定古气候，特别是古降雨方式的方法，包括古土壤中钙质结核的深度和层位，以及古土壤风化部分的化学成分。作为该项目的试点研究，已经成功地研究了记录的几个部分，进展速度令人鼓舞，因为完成了4500万年的记录，解决了不超过20万年的差距。这种长期的古气候记录将与全球古气候变化的更广泛问题相关，并将对重新评估气候计算机模型和动植物共同进化的想法具有重要意义。拟议的记录也将是陆地古气候数据的一个重要的新记录，可以与现有的来自海洋的长期记录进行比较。

0000953RetallackLong records of climate change well back into geological time are important for understanding the nature and direction of global change. To date one of the most important records has come from the oxygen isotopic composition of foraminifera from deep sea cores. The three-year project proposed here is to obtain a comparably complete and long-term record of paleoclimate on land. This record comes from a long sequence of fossil soils (paleosols) ranging in age from modern back to 45 million years old in the high desert of northeastern Oregon and southeastern Washington states. The methods used to determine paleoclimate, and particularly ancient rainfall regimen, include depth tyo horizon of calcareous nodules in the paleosols and also the chemical composition of well-weathered parts of the paleosols. Several parts of the record have already been studied successfully as pilot studies for the project, and the rate of progress is encouraging for completion of a 45 million year record complete to a resolution of gaps of no more than 200,000 years. Such a long-term paleoclimatic record will be relevant to wider questions of global paleoclimatic change, and will be important for reassessing computer models of climate and ideas about plant-animal coevolution. The proposed record will also be an important new record of paleoclimatic data for land that can be compared with existing long records from the sea.