Comment on "Geochronology and geochemistry of submarine volcanic rocks in the Yamansu iron deposit, Eastern Tianshan Mountains, NW China: Constraints on the metallogenesis" by Tong Hou, Zhaochong Zhang, M. Santosh, John Encarnacion, Jiang Zhu, Wenjuan Luo [Ore Geology Review, 56(2014):487-502]

Guangrong Li (1, 2) , Changzhi Wu (3) , Yannick Branquet (2)

1 Fundamental Science on Radioactive Geology and Exploration Technology Laboratory
2 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
3 State Key Laboratory for Mineral Deposits Research

In a recent paper, Hou et al., (2014) presented their study on the Yamansu iron deposit in eastern Tianshan Mountains, NW China. Hou et al., (2014) proposed a genetic model for the iron mineralization in Yamansu, which was based on geochronology and geochemistry study on volcanic rocks and skarns. In their paper, they gave an excellent discussion on the geochemistry data of basalt. However, we would like to address the following arguments: (1) What are meanings of zircon U-Pb ages derived from the basalt and skarn? (2) Did the Yamansu basalts provide the source of iron for the skarn mineralization? 2 What are meanings of zircon U-Pb ages derived from the basalt and skarn? Hou et al., (2014) separated zircons from basalt and garnet skarn, and then dated by LA-ICP-MS. These zircons yielded coeval ages of 324.4 ± 0.94 and 323.47 ± 0.95 Ma for the basalt and skarn, respectively. These ages lead them to make the conclusion that the skarn formation in Yamansu deposit is related to subaqueous volcanism. Here, we may ask what the relations between the basalt and the skarn are. In addition, we need to know what the protolith of these skarn is, and what triggered the skarnization. If observations in the field proof the skarn were obviously later than the basalt, Hou's conclusion seems untenable.

Domaines: Tectonique; Milieux et Changements globaux

Guangrong Li, Changzhi Wu, Yannick Branquet. Comment on "Geochronology and geochemistry of submarine volcanic rocks in the Yamansu iron deposit, Eastern Tianshan Mountains, NW China: Constraints on the metallogenesis" by Tong Hou, Zhaochong Zhang, M. Santosh, John Encarnacion, Jiang Zhu, Wenjuan Luo [Ore Geology Review, 56(2014):487-502]. Ore Geology Reviews, 2014, 63, pp.343-345. ⟨10.1016/j.oregeorev.2014.04.014⟩. ⟨insu-00990100⟩