Patterns of the Distribution of Rare-Earth Elements in Waters of Mud Volcanoes

The original data on the distribution of rare-earth elements in waters of mud volcanoes of Sakhalin Island, Taman Peninsula, and Azerbaijan are presented. It has been shown that the mud volcano waters with a sum of rare-earth elements less than 0.5 μg/l are enriched with heavy lanthanides and characterized by a deficiency of Ce. As illustrated by the Yuzhno-Sakhalinsk mud volcano, the content of rare-earth elements is higher in active gryphons.