Huairui Wei

A new type of rare earth elements deposit in weathering crust of Permian basalt in western Guizhou, NW China

Abstract A new type of rare earth elements (REEs) deposit was discovered from the gaolinite mudstone in the weathering crust of Permian basalt, Bijie region, western Guizhou, China. It contained ΣRE2O3 0.065%–1.086%. This type of REEs deposit was widely distributed with steady horizon and thickness of 3–4 m. The ore-bearing weathering crust (kaolinite) of the three discovered REEs deposits belonged to the third episode of the Emeishan basalt eruption. The new type of REEs deposit was suggested that basalt (tuff) weathering could lead to the enrichment of the rare earth elements. Therefore, it is of important economic significance to explore REEs deposits in the weathering crust of basalt (tuffs) in Yunnan, Guizhou, and Sichuan Provinces.

Rare earth element geochemistry of Cambrian phosphorites from the Yangtze Region

Abstract Analysis on P2O5 and REE (rare earth elements) in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province contained high REE contents in phosphorites, especially those from Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province. Among them, the highest REE contents reached up to 1361.59×10−6 and P2O5 contents up to 29.45%. In contrast, phosphorites from Kaiyang, Qingzhen and Zhenyuan in Guizhou Province had relatively low total REE contents and low P2O5 contents, with the lowest total REE content of 53.19×10−6, and the lowest P2O5 content of 0.07%. REE contents exhibited a positive correlation with phosphorous contents, indicating a close genetic relationship between REE and phosphorous element. The main reason was the difference of the sedimentary environments and the contents of phosphorous and REE in deep water mass formed in upwelling currents, at an upper slope facies (Slu) in reducing condition due to relatively closed sedimentary environment. It was very difficult for the upswelling phosphorous and REE to deposit, massive phosphorous deposits were hard to be formed. At a deep water ramp facies (DRa) in the ascending process of currents, phosphorus and REE underwent differentiation rather than sedimentation. Consequently, the contents of P2O5 sediments and REE were low. At a shallow water ramp facies (including shoals and tidal flats) (SRa), with active seawater circulation and phosphatic supplement, sunny weather, high nutrition and rapid growth of algae, were benefitial for the physical enrichment of carbonate sediments. Therefore, massive phosphorite deposits were easy to be formed with abundant REE minerals, and finally turned into high REE bearing phosphorous deposits.

Discovery of an abnormally high-δ 34 S barite deposit and a new understanding of global sulfur isotope variation during geological history

The evolution of the global sulfur isotope curve was plotted based on the δ34S values of evaporates resultant from oceanic evaporation. In the long period of geological history the δ34S values showed obvious peaks for three times during the process of ancient oceans’ sulfur isotope evolution, namely the Early Cambrian (+30‰), the Late Devonian (+25‰) and the Permian-Triassic transition interval (+17‰), but the causes of the abnormal rise of sulfur isotopic values during the geological period are still in question. In this paper, 18 samples collected from a large Devonian barite deposit from Zhenning County were analyzed to determine their δ34S values, revealing that the 18 samples have very high δ34S values (δ34S=41.88‰–+68.39‰), with an average close to 56.30‰, which are higher than the isotopic values of contemporary sulfates (+17‰–+25‰). A comparative analysis was conducted of the emerging of high δ34S barite deposits (from Cambrian and Devonian) and the δ34S variation curves of the ancient oceans. The results indicate that the time when the obvious peaks of δ34S values appeared and the time of massive sedimentation of high δ34S barite deposits are very close to each other, which, in our opinion, is not a coincidence. There may exist some correlations between the sulfur isotope evolution of ancient oceans during the diverse periods of geological history and the massive sedimentation of high δ34S barite deposits. Therefore, it is inferred that perhaps it was the massive sedimentation of high δ34S barites that caused the sharp rise of δ34S values in a short period of time.

Distribution and transfer of potentially toxic metal(loid)s in Juncus effusus from the indigenous zinc smelting area, northwest region of Guizhou Province, China

We collected samples (i.e., the aerial parts and roots of Juncus effusus and their growth media) in the indigenous zinc smelting area in the northwest region of Guizhou Province, China, and we measured and analyzed potentially toxic metal(loid)s (arsenic, As; cadmium, Cd; chromium, Cr; copper, Cu; mercury, Hg; lead, Pb and zinc, Zn) in these samples. The results include the following: First, there is a high concentration of one or more potentially toxic metal(loid)s in the slag and surrounding soil in the research area. This situation might be caused by metal(loid) damage or contamination due to the circumstances. Additionally, Juncus effusus in the indigenous zinc smelting area are contaminated by some potentially toxic metal(loid)s; since they are used for Chinese medical materials, it is especially significant that their As, Cd and Pb concentrations are greater than their limited standard values. Finally, both the bioconcentration factors and transfer factors for most potentially toxic metal(loid)s in Juncus effusus are less than 1 in the study area. Therefore, we suggest that Juncus effusus could be used for phytostabilization or as a pioneer plant for phytoremediation of potentially toxic metal(loid)s because it has a tolerance and exclusion mechanism for these metal(loid)s in the research district.

Discovery and Genesis Discussion on A Early-Cambrian Large-Scale Vanadium Deposit from Eastern Guizhou, China

Recently the large scale vanadium deposit,of ZhuXi with reserves of nearly 1 tonnes: in black shales was discovered in eastern Guizhou. Sedimentology, trace element geochemistry and isotope geochemistry were applied to reveal the genesis of the ZhuXi vanadium deposit. Results show that the deposit is characterized by hydrothermal sedimentation, and the metallogenic fluid may came from the deep inflow.

GEOCHEMISTRY OF TRACE ELEMENTS OF THE QUATERNARY SEDIMENTS OF YAOSHANG FORMATION IN WEINING COUNTY, GUIZHOU PROVINCE AND ITS PALEOENVIRONMENTAL IMPLICATIONS: GEOCHEMISTRY OF TRACE ELEMENTS OF THE QUATERNARY SEDIMENTS OF YAOSHANG FORMATION IN WEINING COUNTY, GUIZHOU PROVINCE AND ITS PALEOENVIRONMENTAL IMPLICATIONS

Geochemistry of trace elements and REE of the Quaternary sediments in the Yaoshang Formation in Weining country,Guizhou,China were analyzed.Based on the previous studies about Ostracoda and pollen,we discussed the sedimentary environmental changes through the vertical variation of elements.Our results show that the 14 trace elements(eg.Li,Ba,Sr) are well correlated.Generally,∑REE is very high,and δCe and δEu are negative,except that Ce in the layers 7 and 11 are positive.LREE and HREE fractionation is obvious.And the chondrite normalized samples show a distribution pattern of LREE enrichment with gentle incline to the right.The parameter of elements ratio and REE are characterized by zonation.The content the 14 trace elements and Rb/Sr、Sr/Ba、Sr/Cu ratio indicate a relatively dry and hot climate in the layers of 2,6,8,10,12 of the Yaoshang Formation while the other layers formed undera colder and wetter climate.Sr/Cu changes between 1 and 5,indicating a humid subtropical plateau monsoon climate.Sr/Ba changing between 0.2~0.5 indicates that the Caohai sediment was deposiled in a freshwater enviroment,suggesting a very strong weathering of the parent nock of the Permian basalt which is high in REE content.The combination of Sr/Cu and Rb/Sr ratio values can be used as the indicator of climatic change.