Geochemical Characteristics of Longxi Nephrite in Wenchuan and Origin of Sansandui and Jinsha Jades

Sichuan Longxi nephrite played an important role in ancient Sichuan culture. In order to investigate the geochemical characteristics of Longxi nephrite and its relationship with Sanxingdui and Jinsha jade, the mineral and chemical composition of Longxi nephrite were analyzed by X-ray diffraction, X-ray fluorescence, an electron probe microanalyzer, and inductively coupled plasma mass spectrometry. Longxi nephrite is a tremolite jade similar to marble that contains a minor amount of calcite, dolomite, steatite, apatite, and rutile. It typically has a dark green-yellow green-light green-offwhite color ring. The geochemical properties include high P, Mn, V, Cr, Ni and U content, and low δCe values, and an LREE/HREE ratio close to 1. The REE partition curve is seagull-like, with clear Ce and Eu negative anomaly characteristics. The Longxi nephrite has gemological characteristics similar to the Jinsha and Sanxingdui jades and rare earth element properties that are extremely consistent with the Jinsha jades. Considering the geographical location between the three places, it is speculated that Jinsha and Sanxingdui jades may be sourced from Longxi nephrite.