The Li-Bearing Pegmatites from the Pampean Pegmatite Province, Argentina: Metallogenesis and Resources

Abstract

The Li-bearing pegmatites of the Pampean Pegmatite Province (PPP) occur in a rare-element pegmatite belt developed mainly in the Lower Paleozoic age on the southwestern margin of Gondwana. The pegmatites show Li, Rb, Nb ≤ Ta, Be, P, B, Bi enrichment, and belong to the Li-Cs-Ta (LCT) petrogenetic family, Rare-Element-Li (REL-Li) subclass; most of them are of complex type and spodumene subtype, some are of albite-spodumene type, and a few of petalite subtype. The origin of the pegmatites is attributed predominantly to fractionation of fertile S-type granitic melts produced by either fluid-absent or fluid-assisted anatexis of a thick pile of Gondwana-derived turbiditic sediments. Most of the pegmatites are orogenic (530–440 Ma) and developed during two overlapped collisional orogenies (Pampean and Famatinian); a few are postorogenic (~370 Ma), related to crustal contaminated A-type granites. The pegmatites were likely intruded in the hinterland, preferably in medium-grade metamorphic rocks with PT conditions ~200–500 MPa and 400–650 °C, where they are concentrated in districts and groups. Known combined resources add up 200,000 t of spodumene, with variable grades between 5 and 8 wt.% Li2O. The potential for future findings and enlargement of the resources is high, since no systematic exploration program has yet been developed.

Process Mineralogy of Lithium and Rubidium in the Diantan Polymetallic Mining Area, Tengchong, Southwest China

“…Based on our research, the following conclusions can be drawn: (1) As is well known, there is no independent mineral of rubidium in nature, but rather potassium is substituted in the lattice of mica or feldspar in the form of isomorphism [26][27][28]. Lithium mainly exists in Li-rich mica [29][30][31]. The average Rb 2 O content in the mica samples from the two mining areas is relatively similar, with values of 0.55 and 0.53%, respectively (Figure 10).…”

Hydrothermal enrichment of lithium in intracaldera illite-bearing claystones

“…The acquisition routine included analysis of 6 Li + , 11 B + , 30 Si + , 35 Cl + , 85 Rb + , 89 Y + , 90 Zr + , and 139 La + . The 2018 session also included measurement of 24 Mg 16 O + , 47 Ti + , and 54 Fe + , and the 2019 session also included 9 Be + , 93 Nb + , 133 Cs + , and 238 U 16 O + . Lithium was the primary focus of these measurements; other elements were measured to monitor if the spot overlapped with nonclay material (e.g., Fe, Y, and La) and to evaluate if other fluid-related trace elements correlated with Li-enrichment.…”

Garnet composition from the Reflejos de Mar LCT-pegmatite, Ancasti district, Argentina and its implication for exploration of primary deposits of lithium

“…The mineralogy of the pegmatites in this district includes K-feldspar, quartz, and plagioclase as essential minerals and muscovite, biotite, beryl, garnet, spodumene, tourmaline, triplite, triphyllinelithophyllite, amblygonite-montebrasite, apatite, and zircon as accessory minerals (Galliski, 1999). The pegmatites of the Sierra de Ancasti can be classified as belonging to the class of rare elements and to the beryl, spodumene or albite-spodumene types (Galliski, 1994(Galliski, , 1999Galliski et al, 2022) according to the classification of Černý and Ercit (2005).…”

“…The central zone is about 2 m thick and shows the largest granulometry of the body with some crystals with more than 1 m in length (Sardi et al, 2013), composed essentially of quartz, spodumene and albite (cleavelandite). Particularly for the Reflejos de Mar pegmatite, Galliski et al (2022) add as accessory minerals, columbite-tantalite group minerals, triplite, triphylite and amblygonite.…”