EDITORIAL

Chemical structure of the Earth's mantle defined by fast diffusion elements like helium
Yun Liu  

ORIGINAL ARTICLES 

4

A helium stratified and ingassed lower mantle: resolving the helium paradoxes
Honggang Zhu · Xuefang Li · Yingkui Xu

11

Mechanism of accelerated dissolution of mineral crystals by cavitation erosion
Haotian Su · Weijian Zhou

43

Zircon chemistry and new laser ablation U–Pb ages for uraniferous granitoids in SW Cameroon
V.F. Embui · C.E. Suh · J.M. Cottle · J. Etame · J. Mendes · C.M. Agyingi · A. Vishiti · E.M. Shemang ·B. Lehmann

67

Zircon U–Pb age and geochemical constraints on the origin and tectonic implication of the Tuotuohe Cenozoic alkaline magmatism in Qinghai–Tibet Plateau
Ye Qian · Shengnan Tian · Yujin Li · Fengyue Sun

85

Evaluation of the potential risks of heavy metal contamination in rice paddy soils around an abandoned Hg mine area in Southwest China
Bayou Adlane · Zhidong Xu · Xiaohang Xu · Longchao Liang · Jialiang Han · Guangle Qiu

96 

Low-temperature alteration of uranium–thorium bearing minerals and its significance in neoformation of radioactive minerals in stream sediments of Wadi El-Reddah, North Eastern Desert, Egypt
O.A. Ebyan · H.A. Khamis · A.R. Baghdady · M.G. El-Feky · N.S. Abed

116

Rapid estimation of soil heavy metal nickel content based on optimized screening of near-infrared spectral bands
Qian Lu · Shijie Wang · Xiaoyong Bai · Fang Liu · Shiqi Tian · Mingming Wang · Jinfeng Wang

127

Altitude-dependent distribution of 137Cs in the environment: a case study of Aragats massif, Armenia
Konstantin Pyuskyulyan · Stephen P. LaMont · Vovik Atoyan · Olga Belyaeva · Nona Movsisyan · Armen Saghatelyan

139

The occurrences and geochemical characteristics of thorium in iron ore in the Bayan Obo deposit, Northern China
Xiaozhi Hou · Zhanfeng Yang · Zhenjiang Wang · Wencai Wang

155

Guizhou Province, China: the birthplace of modern Medical Geology
Robert B. Finkelman · Jose A. Centeno