Petrogenesis of Mesozoic pegmatites in the Dahongliutan Li-mineralized belt (Western Kunlun, NW China)

Zhao，Hui1,2; Chen，Bin2; Zheng，Beiqi3; Yang，Qian2

2024-04-01

10.1016/j.jseaes.2024.106076

Journal of Asian Earth Sciences   影响因子和分区

1367-9120

The genesis of pegmatite and the associated Li-mineralization mechanism remain debated. The intimate temporal-spatial relationship between the pegmatites in the Dahongliutan Li-mineralized belt (incl. #509 Daoban and Akshay Li-poor pegmatites, and Akshay Li-rich pegmatite) and the Dahongliutan granite pluton allows us to discuss the origin of pegmatite and the Li-mineralization mechanism by conducting detailed geochemical and geochronological investigations on the two rock units in the Western Kunlun orogen (NW China). The Li-poor pegmatites in the Dahongliutan Li-mineralized belt exhibit similar or much lower Li, Rb, and Cs compared to the adjacent granite, and their εNd(t) values (-8.7–-10.0) are significantly lower than those of the granite (-7.5–-8.1) as well. However, the Akshay Li-rich pegmatite shows extremely high Li, Rb, Nb, Ta, and initial Sr isotopic ratios (0.7223–0.7227, obtained from apatite), in contrast to the Dahongliutan granite (I = 0.7108–0.7157). The whole-rock δLi values of the Dahongliutan granite, pegmatites, and the wall-rock Bayanharshan Group metapelite are + 0.76–+5.67 ‰, +0.8–+14.4 ‰, and −4.2–+2.8 ‰, respectively. Zircon and cassiterite U-Pb dating yielded Pb/U ages of 216 ± 2 Ma and 195 ± 2 Ma for the #509 Daoban Li-poor pegmatite and Akshay Li-rich pegmatite, respectively. Modeling of trace elements and Li isotopes suggests that the pegmatites in the Dahongliutan Li-mineralized belt did not originate from fractional crystallization of granitic magma. Instead, they may have formed through direct anatexis under amphibolite-facies conditions. Abundant Li-rich claystone, occasionally accompanied by evaporite, may exist in the magma source of the Li-rich pegmatite, which is the key factor controlling pegmatitic Li mineralization.

Dahongliutan Li-mineralized belt Li mineralization Pegmatite Western Kunlun Orogen

SCI

英语

通讯

GEOSCIENCES

2-s2.0-85186087871

Scopus

1.Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming,68 Wenchang Road,650093,China
2.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,1088 Xueyuan Road,518055,China
3.School of Tourism and Geography,ShaoGuan University,Shaoguan,512005,China

Zhao，Hui,Chen，Bin,Zheng，Beiqi,et al. Petrogenesis of Mesozoic pegmatites in the Dahongliutan Li-mineralized belt (Western Kunlun, NW China)[J]. Journal of Asian Earth Sciences,2024,264.

Zhao，Hui,Chen，Bin,Zheng，Beiqi,&Yang，Qian.(2024).Petrogenesis of Mesozoic pegmatites in the Dahongliutan Li-mineralized belt (Western Kunlun, NW China).Journal of Asian Earth Sciences,264.

Zhao，Hui,et al."Petrogenesis of Mesozoic pegmatites in the Dahongliutan Li-mineralized belt (Western Kunlun, NW China)".Journal of Asian Earth Sciences 264(2024).