No. 5 pegmatite vein, Renli Nb‐Ta deposit, Pingjiang Co., Yueyang, Hunan, Chinai

Regional Level Types
No. 5 pegmatite vein	Pegmatite
Renli Nb‐Ta deposit	Deposit
Pingjiang Co.	County
Yueyang	Prefecture-level City
Hunan	Province
China	Country

The Renli No. 5 pegmatite vein is located in the Lengjiaxi Group schist, 1.0–2.5 km away from Mufushan granite complex. The vein is 4040 m long, with the maximum thickness of 10.1 m. This vein strikes NW, and dips toward the SE with a dip angle of 25–56°. Field investigation combined with previous studies showed that mineral and textural zoning is well developed in the No. 5 pegmatite vein. The zonation sequence is as follows (from the margin to the core): The graphic-textured zone I → coarse-grain microcline-albite zone II → medium-grained muscovite-albite zone III → fine-grained garnet-muscovite-albite zone IV → lepidolite-quartz core zone V. Zone I is characterized by typical quartz + microcline + albite graphic texture, with a grain size of 3–10 mm and band width of ~0.8 m. Zone II, with a grain size of 7–15 mm and band width of ~4.7 m, is gradually transitioned from zone I. The pegmatite consists of dominantly coarse-grained microcline and albite, associated with muscovite, quartz, beryl, and tantalite. There is a gradual transition from zone II to III, as well. Zone III, with a grain size of 5–10 mm and a band width of ~5.7 m, is composed mainly of medium-grained albite, microcline, quartz, and muscovite, along with minor euhedral blue-green aquamarine. Zone IV, with a grain size of 1–5 mm and band width of ~5.7 m, has a sharp boundary with zone III. It is composed mainly of fine-grained albite, quartz, garnet, microcline, and muscovite, along with minor short columnar aquamarine and fine-grained scaly lepidolite. The lepidolite-quartz zone V has a grain size of 3–20 mm and band width of over 0.7 m. The main mineral assemblage includes lepidolite, quartz, albite, microcline, and elbaite, as well as minor morganite, Cs-garnet, manganocolumbite, and columnar aquamarine.

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