Lithium Occurrences in Brines from Two German Salt Deposits (Upper Permian) and First Results of Leaching Experiments

Abstract

Lithium occurrences were detected in Upper Permian (Zechstein) salt rocks and saline solutions of the Gorleben and Morsleben salt structures, northern Germany. The brine occurrences were mainly connected to anhydrite rock-bearing formations and to lithological boundaries. Most of these brines display a high Mg content and were accordingly interpreted as intrasalinar solutions, which developed during sedimentation, diagenesis, and the subsequent rock–fluid interaction. These Mg-rich brines frequently show high Li concentrations. One of the assumptions made, is that Li was leached from phyllosilicates, since no natural Li-bearing salt minerals are known to date. To improve the understanding of the origin of Li in the brines, leaching experiments were performed on the Li-bearing phyllosilicate Lepidolite. Lepidolite with a Li content of 2.42 wt. % served as an analogue material, which was exposed to 18 saline solutions of different composition for a period of three years. The most pronounced leaching effect (53.36 µg Li/g in the brine) was observed during the interaction with a 0.03 mol/kg H2O MgCl2 solution, the second most pronounced by modern seawater interaction. The experiments show that the amount of Li leached from the lepidolite is dependent on brine composition.

Groundwater in sedimentary basins as potential lithium resource: a global prospective study

“…Different processes are needed to explain the high lithium concentrations, such as water–rock interactions 34 – 40 along their flow path. Phyllosilicates and volcanic glass are suspected of contributing to the release of lithium, as their lithium content may be significant 34 – 39 . Additional sources could be clays 38 , 39 and carbonates 40 .…”

“…Phyllosilicates and volcanic glass are suspected of contributing to the release of lithium, as their lithium content may be significant 34 – 39 . Additional sources could be clays 38 , 39 and carbonates 40 . As the precise mechanisms of lithium enrichment in sedimentary formation waters remain unclear, more experimental work, aided by lithium isotope geochemistry 34 , 40 , could help to understand lithium release from host rocks.…”

Generation of Mud Volcanic Systems Sourced in Dehydrated Serpentospheric Mantle: A ‘Deep-to-Seep’ Model for the Zechstein Salines-Kupferschiefer Cu-Ag Deposits

“…Gorleben salt diapirs contain high-lithium brines that were interpreted to represent basement-sourced metamorphic brines [6] and that fit the dehydration narrative discussed below.…”

“…The concept of a deep serpentine source is supported by the frequent occurrence of talc and magnesium chlorite (clinochlore) in muds, and even serpentine (antigorite) in muds at a number of localities (Figure 1) in the Zechstein [1]. An additional serpentine mud locality was reported from the Morsleben salt diapir [6]. Both the Morsleben and Comparison of the sulfide and sulfate isotope compositions of serpentinites from Liguria, the Iberian Margin, the Atlantis Massif, and the MARK area (modified from [19] and including data from references therein).…”

“…Salt resources in the immediately overlying Zechstein saline sequence are also world-class with 102 billion metric tons of economic and subeconomic salt in Poland alone [5]. The salt deposits also contain major resources of magnesium and potassium along with elevated strontium, boron, and lithium [6].…”