The Pampean Pegmatite Province (Spanish: Provincia Pegmatítica Pampeana) is a geological area in central and northwestern Argentina rich in pegmatites. The province has the shape of a north-south belt located east of the Andes.[1] Most of the pegmatites crop out in the Sierras Pampeanas.[1] These pegmatites have been mined for ores of niobium, tantalum, lithium, bismuth, uranium as well as for the minerals of beryl, mica, feldspar and quartz.[2] The pegmatites cut through metamorphic rocks of medium grade and medium pressure.[2]
In terms of economic resources the province hosts valuable lithium resources. It is estimated to have a total of at least 200,000 tons of spodumene with lithium oxide (Li2O) grades varying between 5 and 8 wt.%.[1]
Some pegmatites of the province are thought to have been mined at the earliest in the late 19th century.[2] Significant small-scale mining began in the 1930s peaking between the 1960s and 1980s before declining.[1][2]
Geologist Miguel Angel Galliski lists twenty districts in the province:[2]
- Centenario
- Cerro Blanco
- El Quemado
- Quilmes
- Calchaquí
- Ambato
- La Pampa-Unquillo
- Vilismán
- El Taco
- Santa Bárbara
- Sierra Brava
- Velazco
- Valle Fértil
- Alto Gracia
- Punilla
- Comechingones
- Altautina
- La Estanzuela
- Conlara
- Totoral
Origin
Most pegmatites dykes of the Pampean Pegmatite Province formed between 530 and 440 million years ago, that is from the very latest Precambrian to the Silurian period.[1] This makes the pegmatites coeval with the Pampean and Famatinian orogenies.[1][3] The pegmatite coeval with the orogenies are thought to be derived from S-type melts.[1] A smaller group of pegmatites of the province are younger having formed around 370 million years ago in the Devonian slightly after the Famatinian orogeny in association with the cooling of post-orogenic A-type granites.[1][3]
See also
References
- ^ a b c d e f g h Galliski, Miguel Ángel; Márquez-Zavalía, María Florencia; Roda-Robles, Encarnación; von Quadt, Albrecht (2022). "The Li-Bearing Pegmatites from the Pampean Pegmatite Province, Argentina: Metallogenesis and Resources". Minerals. MDPI. 12 (7): 841. Bibcode:2022Mine...12..841G. doi:10.3390/min12070841. hdl:10810/57221.
- ^ a b c d e Galliski, Miguel Angel (1993). "La Provincia Pegmatítica Pampeana. I: Tipología y distribución de sus distritos económicos" [The Pampean Pegmatitic Province. I: Tipology and distribution of its economic fields]. Revista de la Asociación Geológica Argentina (in Spanish). 49 (1–2): 99–112.
- ^ a b Galliski, Miguel Ángel; von Quadt, Albrecht; Márquez-Zavalía, María Florencia (2021). "LA-ICP-MS U-Pb columbite ages and trace-element signature from rare-element granitic pegmatites of the Pampean Pegmatite Province, Argentina". Lithos. 386–387: 106001. doi:10.1016/j.lithos.2021.106001. S2CID 233566212.
This page was last edited on 5 January 2024, at 19:26