Sediment-derived granites as the precursor of rare-metal pegmatites in the Paleo-Tethys tectonic zone - evidence from the Bailongshan Li-Rb-Be pegmatite ore field and factors controlling mineralization

doi:10.1007/s00126-024-01311-1

	Sediment-derived granites as the precursor of rare-metal pegmatites in the Paleo-Tethys tectonic zone - evidence from the Bailongshan Li-Rb-Be pegmatite ore field and factors controlling mineralization
	Yan, Qing-He 1,2; Chi, Guoxiang 3; Wang, He 2; Chen, Chen4 ; Zhou, Kailin 2; Liu, Mengfan 1
	2024-09-24
发表期刊	MINERALIUM DEPOSITA
ISSN	0026-4598
页码	22
通讯作者	Yan, Qing-He([email protected]) ; Wang, He([email protected])
摘要	The Paleo-Tethys tectonic zone has been recognized as a world-class rare-metal (Li-Rb-Be-Nb-Ta) pegmatite belt. Previous studies indicate that the rare-metal pegmatite mineralization is related to the Late Triassic-Early Jurassic granitoids. However, it remains debated which granites, among the various coeval I-, A- and S-type granitoids in the tectonic belt, are responsible for the rare-metal pegmatite mineralization. We address these questions through a systematic geochemical study of the Bailongshan granite complex, which is composed of both biotite granites and two-mica granites and is related to the largest Li deposit in this zone. The similarities in Sr-Nd-Hf-O isotopic compositions between the two-mica granites (ISr=0.7176 to 0.7183, epsilon Nd(t)= - 10.7 to - 10.1, epsilon Hf(t)= - 14.12 to - 4.58, delta 18O = 10.11 to 13.46 parts per thousand) and rare-metal pegmatites (ISr=0.7181 to 0.7189, epsilon Nd(t)= - 11.72 to - 10.68, epsilon Hf(t)= - 12.15 to - 5.37, delta 18O = 10.37 to 12.37 parts per thousand), both showing affinity with sedimentary source, provide convincing evidence that the rare-metal pegmatites were derived from the two-mica granites. The differences in these parameters between the two-mica granites and the biotite granites (ISr=0.7083 to 0.7086, epsilon Nd(t)= - 5.9 to - 5.7, epsilon Hf(t)= - 6.64 to - 1.50, delta 18O = 7.27 to 9.36 parts per thousand, characteristic of I-type granites) indicate that they were derived from different sources. Trace element modeling indicates that the pegmatites were produced via extremely high fractional crystallization (> 90%) of the two-mica granites, which is also supported by the difference in delta 7Li values between the two-mica granites (-0.6 to 0.5 parts per thousand) and pegmatites (2.04 to 4.94 parts per thousand). Comparison of the geochemical data between the two-mica granites and metasedimentary rocks in the area suggests that the rare metals in the mineralizing magmas were most likely derived from the partial melting of metapelites of the Triassic Bayanharshan Group. The relatively high temperatures (771 to 830 degrees C) estimated from the Ti-in-zircon thermometer for the two-mica granites favor extraction of rare metals from both biotite and muscovite in the source rocks during the partial melting. The results of this study, together with published data of Late Triassic to Early Jurassic granitoids in the Paleo-Tethys tectonic zone, indicate that the rare-metal pegmatite mineralization is related to S-type granites, but not all S-type granites are fertile. The combination of rare-metal-rich source rocks (metapelites), high temperatures due to an external heat source favoring the release of rare metals from the source rocks, and high degrees of fractional crystallization facilitating further enrichment of rare-metals in the pegmatite magmas, is critical for the rare-metal mineralization.
关键词	Rare-metal pegmatite Fertile granite Bailongshan Western Kunlun orogenic belt Paleo-Tethys S-type granite Songpan-Ganzi belt
DOI	10.1007/s00126-024-01311-1
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[42272085]; National Natural Science Foundation of China[91962215]; National Natural Science Foundation of China[42303042]; Yunnan Basic Research Project[202301AT070309]; Project Funds of Xingdian Talent Support Program
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001319004400002
出版者	SPRINGER
WOS关键词	NORTHERN TIBET IMPLICATIONS ; TRIASSIC GRANITOIDS ; BLACK-HILLS ; ISOTOPE GEOCHEMISTRY ; CONTINENTAL-CRUST ; WORKING REFERENCE ; FOLD BELT ; S-TYPE ; PB ; ZIRCON
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/199027
专题	深海极端环境与生命过程研究中心
通讯作者	Yan, Qing-He; Wang, He
作者单位	1.Yunnan Univ, Sch Earth Sci, Dept Geol, Kunming 650091, Peoples R China 2.Chinese Acad Sci, CAS Key Lab Mineral & Metallogeny, Guangzhou Inst Geochem, Guangzhou 510640, Peoples R China 3.Univ Regina, Dept Geol, Regina, SK S4S 0A2, Canada 4.Chinese Acad Sci, Ctr Deep Sea Res, Inst Oceanol, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Yan, Qing-He,Chi, Guoxiang,Wang, He,et al. Sediment-derived granites as the precursor of rare-metal pegmatites in the Paleo-Tethys tectonic zone - evidence from the Bailongshan Li-Rb-Be pegmatite ore field and factors controlling mineralization[J]. MINERALIUM DEPOSITA,2024:22.
APA	Yan, Qing-He,Chi, Guoxiang,Wang, He,Chen, Chen,Zhou, Kailin,&Liu, Mengfan.(2024).Sediment-derived granites as the precursor of rare-metal pegmatites in the Paleo-Tethys tectonic zone - evidence from the Bailongshan Li-Rb-Be pegmatite ore field and factors controlling mineralization.MINERALIUM DEPOSITA,22.
MLA	Yan, Qing-He,et al."Sediment-derived granites as the precursor of rare-metal pegmatites in the Paleo-Tethys tectonic zone - evidence from the Bailongshan Li-Rb-Be pegmatite ore field and factors controlling mineralization".MINERALIUM DEPOSITA (2024):22.