第八届青年地学论坛

第四纪时期，罗布泊发育世界罕见的巨量钙芒硝沉积，其成因一直是地质学家关注的焦点。本文对罗布泊盐湖LDK01钻孔典型的石膏、钙芒硝沉积物首次开展了微量元素分析。结果显示，两者都具有明显的轻稀土富集及Eu负异常特征。钙芒硝轻、重稀土含量都显著高于石膏。结合Sr/Ca、Mg/Ca等环境指标参数，初步认为，两者稀土元素富集受盐度影响较小，钙芒硝和石膏晶体晶型的差异以及表面吸附作用是导致两者稀土元素差异富集的重要原因。
关键词：稀土元素，蒸发岩，盐湖，罗布泊

The unique giant glauberite sediments formed in Lop Nur playa during the Quaternary period and their formation mechanism has been a major concern for geologists. In this paper, for the first time we conducted the trace element analysis of typical gypsum and glauberite samples from core LDK01 in Lop Nur. Our results show that both gypsum and glauberite with different stratigraphic depth exhibit similar REEs (rare earth elements) distribution patterns, enriched LREEs (light rare earth elements) and negative Eu anomaly. However, glauberite sediments have an obvious higher content of HREEs (heavy rare earth elements) and LREEs than that of gypsums. Combined with Sr/Ca and Mg/Ca value, we preliminarily suggested brine salinity had little contribution on the abundance of REE of evaporite, instead crystallographic control and related surface scavenging probably played critical role in REE fractionation during the glauberite and gypsum precipitation.     
Key words：Lop Nur；Environmental evolution；Salt lake；Rare earth element；Trace element


 

稀土元素，蒸发岩，盐湖，罗布泊