ABSTRACT

Source bordering sand sheets form downwind of sandy stream beds on the Ceja Mesa escarpment in north-central New Mexico. Archaic archaeological sites are often buried in this type of deposit. A stratigraphic sequence from one site was examined using soil morphology, radiocarbon and optical dating, soil characterization, and stable isotope analyses of soil organic matter and carbonate. This geoarchaeological reconstruction documented a combination of rapid alluvial, eolian, and local hillslope sedimentation events that occurred between 4100 and 3200 years ago. These events coincided with changes in δ¹³C values that, in turn, reflect changes in local vegetation. Human occupation of the sand sheet occurred as early as 3700 years ago, and a sheetwash flooding event that altered the stratigraphic context of the site occurred sometime between 3700 and 3200 years ago. The effects of these rapid depositional and erosional processes on artifact stratigraphy and archaeological interpretations could be significant.

摘要

与沙层接壤的源头形成于新墨西哥州中北部 Ceja Mesa 悬崖上的沙质河床的顺风处。古代考古遗址经常埋藏在此类矿床中。利用土壤形态、放射性碳和光学测年、土壤特征以及土壤有机质和碳酸盐的稳定同位素分析，对一个地点的地层序列进行了检查。这项地质考古重建记录了 4100 至 3200 年前发生的快速冲积、风成和当地山坡沉积事件的组合。^{这些事件与 δ 13}的变化同时发生C 值反过来反映了当地植被的变化。人类早在 3700 年前就已经占领了沙层，而改变该地点地层背景的沙层洪水事件发生在 3700 至 3200 年前的某个时候。这些快速沉积和侵蚀过程对人工地层学和考古学解释的影响可能是巨大的。