Research on verification of natural heavy sand anomaly of pyrope and chrome spinel in Xiawengshao area, Shibing County, Guizhou Province

A comprehensive utilization of the previous data shows that the placer anomaly with high content of chromium-bearing pyrope and chrome spinel exists in Xiawengshao area, Shibing County, Guizhou Province. The source and diamond exploration problems remain unexplained. Because the previous data were obtained during the "Cultural Revolution" period, the reliability of data is doubtful. Targeted field investigation and sampling analysis prove that the placer anomaly is objective and reliable. The high content placer anomalies are very rarely seen. The anomaly is located in the upper part of the slope which is 200 m higher than the elevation of the modern river bed. Residual deposits were deposited in the alluvial deposits of sand and gravel in the ancient channel. Mineralogical analysis shows no obvious traces of transport and abrasion. Electron microprobe analysis indicates G9 pyrope and S5 chrome spinel, which should be mainly derived from garnet-spinel-lherzolite, being the weathering product of the parent rock-lamproite.