caliche

1. Covered with caliche, a hard calcium-carbonate encrusted soil.
   被硝酸钠，和硬碳酸钙覆盖的土壤。
2. Image scanning analysis of caliche MICRO-LAMINATION and its significance to the dating method
   砾石钙膜显微纹层的扫描图像分析及其测年意义
3. Carbon-oxygen isotopic characteristics of the caliche from the Huanghai Sea
   黄海钙结体的碳氧同位素特征
4. Caliche crusts are secondary products formed by the dissolution of meteoric water on former lithified sediments and rocks during their exposure into subaerial vadose environments.
   钙结壳是土壤层之下的岩石在出露地表渗流带环境内受大气雨水的溶解，并通过上覆土壤层的淋滤而成的产物。
5. ESR dating of caliche in lake deposit from the Yanqing basin, beijing
   北京延庆盆地湖相钙质层的电子自旋共振（ESR）测年研究

noun

1. nitrate-bearing rock or gravel of the sodium nitrate deposits of Chile and Peru

2. crust or layer of hard subsoil encrusted with calcium-carbonate occurring in arid or semiarid regions

   Synonym:    hardpan