Lithium and Brine Geochemistry in the Salars of the Southern Puna, Andean Plateau of Argentina

International audience16 The Andean plateau is a small region of South America extending between northwest 17 Argentina, southwest Bolivia and northern Chile. It concentrates the largest global resources of 18 lithium brines in its numerous salars. Of these, the giant salars in Bolivia and Chile have been 19 relatively well studied, however, only little is known about the smaller, but numerous salars in 20 the Argentine Puna region. In this article, we present the results of the first regional-scale 21 reconnaissance exploration of the twelve major salars situated in the southern part of the Puna 22 plateau (24°S-26°30'S). Hydrochemical data indicate that shallowest brines are characterized 23 by highly variable Li concentrations, with mean Li grades ranging between 57 and 570 mg L-1 , 24 and mean Li:Mg ratios from 0.01 to 1.24. A survey of the brine chemistry of the salars across 2

Litio en salares: Una fórmula muy andina

La relación entre el litio y los salares parece una receta de cocina, en la que los ingredientes son agua, sal, aridez y aislamiento, se condimenta con un poco de litio y se deja macerar –apenas– algunos millones de años. Esto es lo que se requiere para que se forme un salar que tenga el potencial de ser aprovechado para la extracción de litio. Esta receta, claro, es bastante excepcional ya que la inhabitual confluencia de estos ingredientes se da naturalmente en pocos lugares del planeta Tierra. Para nuestro deleite, el plateau andino, la región sobre elevada que incluye a la Puna argentino-chilena y al Altiplano boliviano, es una de esas raras partes del globo donde esta receta prospera.Fil: López Steinmetz, Romina Lucrecia. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Sarchi, Carisa. Universidad Nacional de Jujuy. Instituto de Geología Minera; Argentina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Franco, María Gabriela. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Constantini, Ornela Estefania. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; Argentin

Li content and Li-Sr-Nd isotope composition of salar deposits from southern Puna salars (Argentina)

The Central Andes of South America hosts the largest known lithium (Li) anomalies in a restricted area, but the primary lithium sources of the salar deposits and the mobilization process of lithium are still a matter of speculation. Chemical weathering at or near the surface and leaching in hydrothermal systems of the active magmatic arc are considered as the two main mechanisms of Li extraction from the source rock. The lithium and strontium isotope composition of typical salar deposits offer insights into the processes on how Li brine deposits in Andean evaporites are formed. To further the understanding of the different processes of Li mobilization (weathering and/or hydrothermal leaching) and accumulation that play an important role in the salars of the southern Puna in north-western Argentina, we study the Centenario, Ratones and Diablillos salars, the smallest salars that are among the world-class brine deposits in the Central Andes Li-rich salars. We use Sr isotopes (87Sr/86Sr) for source tracing and Li contents and Li isotopes (δ7Li) to constrain Li mobilization from source to deposition. Nd isotope compositions (143Nd/144Nd) were also determined in clastic sediment samples from salar to provide additional constrains to the rock sources. The studied materials include surface catchment and salar surface samples from the three studied closed basins (rocks, freshwater, brines, salts, travertine, siliciclastic sediments) and core samples (siliciclastic sediments and rocks) and fluid (brines) samples to a depth of 250 m, obtained from Salar de Diablillos (southern Puna in north-western Argentina)

Aplicación de isótopos de Li y Sr en el estudio del origen y concentración del Li en salares de la Puna

Los salares de la Puna argentina (22,5° - 27°S) constituyen parte del llamado “Triángulo del litio”, es decir que el contenido de este metal en estas cuencas es lo suficientemente elevado como para configurar depósitos de interés minero. Sin embargo, ¿Cuál es el origen de este metal? ¿Cómo se movilizó hasta los salares? ¿Mediante qué procesos pudo haberse concentrado? Todos estos interrogantes aún esperan una respuesta, la cual es clave para evaluar la sustentabilidad del litio como recurso. Nuestro grupo de investigación estudia los principales tipos de rocas presentes en la Puna y su potencialidad como fuente de Li, como así también los sedimentos, sales y salmueras provenientes de algunos salares con el objetivo de entender en qué condiciones se movilizó y concentró dicho elemento en estas cuencas. Para esto empleamos isótopos radiactivos de Sr e isótopos estables de Li. Los isótopos son átomos de un determinado elemento cuyos núcleos contienen un mismo número de protones, pero distinta cantidad de neutrones. Para el Li se han reconocido en la naturaleza dos variedades estables, 6 Li y 7 Li, siendo esta última la más abundante por amplia diferencia (6 Li 7.5%, 7 Li 92.5%). Su alta diferencia relativa de masa (aproximadamente 16%) y limitado fraccionamiento en procesos de alta temperatura los hace particularmente interesantes como trazadores de procesos de extracción-movilización en el ambiente superficial (caso de los salares puneños). Este enfoque, tiene la intención de brindar la línea de base imprescindible para estudios complementarios de proveniencia del litio en otros salares del Altiplano-Puna y su movilización, el rol de los procesos de alta temperatura en el comportamiento del litio (ej. asociado a sistemas hidrotermales) así como para comprender los mecanismos de fraccionamiento isotópico de este metal a bajas temperaturas.Fil: Sarchi, Carisa. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Meixner, Anette. Universitat Bremen; AlemaniaFil: Lucassen, Friedrich. Universitat Bremen; AlemaniaFil: Kasemann, Simone. Universitat Bremen; Alemania1er Encuentro Nacional sobre Litio: hacia una política para el desarrollo integralArgentinaUniversidad Nacional de Cuy

Lithium enrichment in the Salar de Diablillos, Argentina, and the influence of Cenozoic volcanism in a basin dominated by Paleozoic basement

Salars with lithium-rich brines are a characteristic feature of the Central Andes, but knowledge about the main sources of lithium and the mobilization processes of lithium in the salar deposits is still incomplete. This work focuses especially on the Salar de Diablillos (southern Puna) as part of a larger area that includes the neighboring Salar Centenario and Salar de Ratones. Building on the ability of Li as a tracer of silicate weathering, we investigate the Li content and isotope compositionof samples from the depocenter and catchment of the Diablillos basin (3-D) and conduct a surface reconnaissance in the Centenario and Ratones depocenters to identify the key metallogenic processes. Radiogenic Sr and Nd isotope compositions are also provided to discriminate the main local Li sources. The isotope data in all three depocenters show that most of theLi in the brines and evaporite deposits are derived from Cenozoic volcanic rocks, despite the dominance of the Paleozoic basement in the catchment. In the Centenario and Ratones depocenters, near-surface chemical weathering appears to be the dominant Li mobilization process. In contrast, hydrothermal mobilization of Li also plays a role in the Salar de Diablillos,possibly related to the presence of a fractured basement with pressure zones and artesian conditions in the aquifer at depth. These fluids also show a larger element contribution from the basement.Fil: Sarchi, Carisa. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Lucassen, Friedrich. Universitat Bremen; AlemaniaFil: Meixner, Anette. Universitat Bremen; AlemaniaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Kasemann, Simone A.. Universitat Bremen; Alemani

Li content and Li and Sr isotopic compositions of deep brines from wells DRC-01 and DDD-02, and core samples (sediments, and basement rocks) from core DDD-07 - Salar de Diablillos, Argentina

Sr isotopes (87Sr/86Sr), Li contents and Li isotopes (δ7Li) were determined in drill core samples (sediments and rocks) and fluid (brine) samples to a depth of 250 m, obtained from Salar de Diablillos (southern Puna in north-western Argentina). For clastic sediment samples, Nd isotope compositions (143Nd/144Nd) were also determined. The Central Andes of South America hosts the largest known lithium (Li) anomalies in a restricted area, but the primary lithium sources of the salar deposits and the mobilization process of lithium are still a matter of speculation. Chemical weathering at or near the surface and leaching in hydrothermal systems of the active magmatic arc are considered as the two main mechanisms of Li extraction from the source rock. The lithium, strontium and neodimium isotope composition of typical salar deposits offer insights into the processes on how Li brine deposits in Andean evaporites are formed

Li, δ7Li, 87Sr/86S and 143Nd/144Nd of surface samples from Salares Diablillos, Ratones and Centenario

The Central Andes of South America hosts the largest known lithium (Li) anomalies in a restricted area, but the primary lithium sources of the salar deposits and the mobilization process of lithium are still a matter of speculation. Chemical weathering at or near the surface and leaching in hydrothermal systems of the active magmatic arc are considered as the two main mechanisms of Li extraction from the source rock. The lithium and strontium isotope composition of typical salar deposits offer insights into the processes on how Li brine deposits in Andean evaporites are formed. To further the understanding of the different processes of Li mobilisation (weathering and/or hydrothermal leaching) and accumulation that play an important role in the salars of the southern Puna in north-western Argentina, we study the Centenario, Ratones and Diablillos salars, the smallest salars that are among the world-class brine deposits in the Central Andes Li-rich salars. We use Sr isotopes (87Sr/86Sr) for source tracing and Li contents and Li isotopes (δ7Li) to constrain Li mobilization from source to deposition. Nd isotope compositions (143Nd/144Nd) were also determined in clastic sediment samples from salar to provide additional constrains to the rock sources. The studied materials include catchment and basin surface samples from the three studied closed basins

Lithium concentrations and isotope signatures of Palaeozoic basement rocks and Cenozoic volcanic rocks from the Central Andean arc and back-arc

We investigate the Li isotope composition and the Li concentrations of metamorphic and sedimentary rocks of the Palaeozoic (Pz) basement in the Central Andes and follow the trace of the Li in the Cenozoic volcanic rocks at the active continental margin. The average Li isotope composition of Pz-basement closely resembles global averages of upper crustal rocks with overlapping, but higher average Li content in the Pz-basement. Lithium isotope composition and content in the Cenozoic volcanic rocks of the Central Volcanic Zone (CVZ) range from mantle-like signatures to Pz-basement compositions with high δ7Li values and high Li contents. Evolutionary trends of the Li isotope composition in the CVZ volcanic rocks can be explained by assimilation of the Pz-basement. At a margin-wide scale, the abundance of Li in the CVZ volcanic rocks is higher than that of the Cenozoic volcanic rocks of the active Andean arc north and south of the CVZ. The CVZ volcanic and Pz-basement rocks are considered to be the primary source of Li in world-class Li-deposits in evaporates of the Altiplano-Puna high plateau and its western slope between ca 27° and 20° S. These deposits define the so-called “Lithium-Triangle”, between southern Bolivia, NW Argentina and NE Chile. The pivotal processes of extraction of Li from its primary rock sources and of Li migration from the source rocks to the deposits still await detailed investigation.Fil: Meixner, Anette. Universitat Bremen; AlemaniaFil: Sarchi, Carisa. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Lucassen, Friedrich. Universitat Bremen; AlemaniaFil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy; ArgentinaFil: Lindsay, Jan Marie. University of Auckland; Nueva ZelandaFil: Rosner, Martin. Isoanalysis Ug; AlemaniaFil: Kasemann, Simone A.. Universitat Bremen; Alemani

Petrogenesis of peraluminous magmas in the Central Andean backarc: the Huayra Huasi Volcanic Complex, NW Argentina

The Huayra Huasi Volcanic Complex of Miocene age (11.88±0.15 Ma U–Pb zircon) was emplaced in the Northern Puna plateau of Argentina, spatially associated with ignimbrites erupted from Altiplano–Puna Volcanic Complex calderas. The complex comprises biotite-bearing dacites and low-SiO2 rhyolites in the northern area and high-SiO2 rhyolites in the south, all with peraluminous compositions (A/CNK>1.0–1.22). The units have broadly similar initial Sr and Nd isotopic ratios ( 87Sr/86Sr ∼ 0.71013–0.71225 and εNd ∼ −5.4 to −7.0) and are composed of plagioclase, quartz, sanidine and biotite as the main phenocryst phases. All units host macroscopic microgranular enclaves and xenoliths of sillimanite–biotite schists, sillimanite- and sillimanite–garnet gneisses, as well as fbrous alumina-rich microxenoliths, the latter being especially abundant in the southern rhyolites. Petrographic, mineral and whole-rock geochemistry, geothermometric and isotopic data indicate that all units of the complex originated by contamination of andesite magmas through assimilation of upper crustal lithologies in early stages of magma evolution. The fbrous alumina-rich microxenoliths are composed almost entirely of refractory minerals (sill+Kfsp±Pl±Bt) and interpreted as peritectic or restitic products of partial melting of assimilated metasedimentary rocks similar to the unmodifed metamorphic xenoliths in the complex. Geochemical modeling indicates that, after early-stage contamination, each magmatic unit evolved separately. Whereas the northern dacites and low-SiO2 rhyolites underwent assimilation and fractional crystallization throughout their history, the southern rhyolites mainly evolved via fractional crystallization of felsic phases alone. This study shows that the peraluminous nature of felsic magmas do not necessarily originate by partial melting of crustal material but can be acquired by metaluminous magmas during later evolution. The processes shown here of assimilation and fractional crystallization and pure fractional crystallization has relevance for other igneous bodies of similar compositions in the Puna backarc and worldwide.Fil: Jofré, Cynthia Betina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Trumbull, Robert. German Research Centre for Geosciences; AlemaniaFil: Maro, Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Schmitt, Axel Karl. Ruprecht Karls Universitat Heidelberg; AlemaniaFil: Sarchi, Carisa. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Flores, Patrocinio Ismael. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Peralta Arnold, Yésica Jael. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Franco, María Gabriela. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Lucassen, Friedrich. Universitat Bremen; Alemani