Environmental Monitoring in the Mechara caves, Southeastern Ethiopia: Implications for Speleothem Palaeoclimate Studies
Environmental Monitoring in the Mechara caves, Southeastern Ethiopia: Implications for Speleothem Palaeoclimate Studies
复制标题
埃塞俄比亚东南部 Mechara 洞穴的环境监测：对 Speleothem 古气候研究的影响
DOI：
10.5038/1827-806x.37.3.5
复制
发表时间：
2008
影响因子：
1.3
通讯作者：
Mohammed Umer
中科院分区：
文献类型：
--
作者：
A. Asrat;A. Baker;M. Leng;J. Gunn;Mohammed Umer
摘要
洞穴沉积物中古气候记录的解释取决于对该地区现代气候、地质、洞穴上方水文和洞穴内气候的理解。监测洞穴内的气候变化，地球化学的洞穴积物形成滴水沃茨，以及相关的地表水和地下水，提供了一个现代的基线解释洞穴积物古水文和古气候记录。在这里，我们提出了这样的监测结果的Mechara洞穴在埃塞俄比亚东南部，2004年至2007年之间进行。结果显示，所有洞穴的洞穴内气候（温度和湿度）几乎恒定，这通常反映了地表气候;整个地区的地下水和地表水地球化学相似（除了受当地岩性变化的轻微影响）;现代滴水同位素数据接近区域大气水线，但洞穴沉积物距离平衡更远。这些洞穴的全新世和现代洞穴积物提供了高分辨率的气候记录，这意味着Mechara洞穴提供了一个合适的设置沉积每年层积的洞穴积物，可以记录在一个地区，降雨是敏感的热带辐合带的强度以及印度季风变化的表面气候变化。
Abstract
The interpretation of palaeoclimate records in speleothems depends on the understanding of the modern climate of the region, the geology, the hydrology above the caves, and the within-cave climate. Monitoring within-cave climate variability, geochemistry of speleothem-forming drip waters, and associated surface and groundwater, provides a modern baseline for interpretation of speleothem palaeohydrological and palaeoclimate records. Here, we present results of such monitoring of the Mechara caves in southeastern Ethiopia, conducted between 2004-2007. Results show nearly constant within cave climate (temperature and humidity) in all caves, which generally reflects the surface climate; groundwater and surface water geochemistry is similar across the region (except slight modification by local lithological variations); and modern drip water isotope data fall close to regional Meteoric Water Line, but speleothems further from equilibrium. The Holocene and Modern speleothems from these caves give high-resolution climate records, implying that the Mechara caves provide a suitable setting for the deposition of annually laminated speleothems that could record surface climate variability in a region where rainfall is sensitive to both the strength of the intertropical convergence zone as well as Indian Monsoon variability.