The stakes could hardly be higher. Global lithium consumption has exploded from less than 100 tons of lithium carbonate equivalent per year at the start of the twentieth century to more than 70,000 tons annually a century later. Production figures tell the same story: roughly 6,100 tons in 1994, swelling to an estimated 290,000 tons in 2025 according to the United States Geological Survey. Demand is projected to triple by 2030, driven overwhelmingly by electric vehicle manufacturing and grid-scale battery storage. Against that backdrop, every new prospective region matters, and Indonesia, straddling the Pacific Ring of Fire, is full of volcanic systems that have never been systematically screened for lithium.

Kulon Progo is a geologically promising place to look. Two major magmatic episodes, one in the Late Oligocene to Early Miocene roughly 25 to 30 million years ago and another in the Late Miocene about 8 million years ago, built the region’s volcanic and sedimentary framework out of calc-alkaline magmas ranging from basaltic to andesitic and dacitic in composition. The key unit is the Old Andesite Formation, a package of intrusive rocks, andesitic breccias and lava flows whose association with hydrothermal alteration makes it exactly the kind of terrain where lithium enrichment is considered plausible. The region’s layered history, from the claystone and limestone basement of the Nanggulan Formation through volcanic sequences and shallow intrusions of microdiorite, andesite and dacite, created a complex plumbing system for fluids moving through rock.

The research team, led by Asep Rohiman of the Bandung Institute of Technology and the Center for Geological Survey in Bandung, combined three analytical techniques: inductively coupled plasma optical emission spectrometry, or ICP-OES, to measure trace element concentrations; X-ray diffraction to identify mineral phases; and petrographic microscopy to characterize rock textures and alteration. In July 2023 they collected 14 water samples, including one from a saline to brackish well at Banyuasin, and rock samples from 50 stations spanning volcanic and sedimentary lithologies. Sampling sites were deliberately chosen away from domestic contamination, and water samples were acidified to pH 2 or below with nitric acid to keep dissolved cations in solution and prevent iron and manganese oxyhydroxides from scavenging trace metals during storage.

The results reveal striking spatial variability. Surface waters contained lithium at concentrations from 0.01 to 0.49 parts per million, with the highest value recorded in the Banyuasin well water, sample 23AA51A. That well also carried elevated sodium, potassium, calcium, boron and sulfur, at 1,538, 24.78, 425, 5.90 and 71 parts per million respectively, and field observers described cloudy, salty water with orange sediment and gas bubbles. Because the site sits far from the coast, the researchers argue that ancient connate formation water, trapped in sedimentary rocks during diagenesis, is a more plausible explanation than seawater intrusion. The region’s tectonic history of subsidence, uplift and renewed volcanism, combined with sea-level fluctuations, likely created the conditions for such fluids to accumulate within Oligocene to Miocene volcanic rocks of the Kebobutak Formation.

The rocks themselves tell an equally interesting story. Volcanic samples contained between 5 and 57 parts per million lithium, with the highest concentration, 57 parts per million, measured in a quartz-vein sample, 23AA09A, collected where a dacite intrusion meets the Old Andesite Formation host rock near Bagelen. Petrographic analysis showed moderate to strong alteration across the samples, with hydrothermal veins of both massive and stockwork type composed of secondary quartz, iron oxide, sericite mica, pyrite and calcite. The elemental profiles of surface waters and volcanic rocks broadly mirror each other, supporting the idea that water-rock interaction is the dominant process controlling lithium mobilization, though boron and bismuth in the waters appear to come from near-surface leaching of soils and sediments rather than directly from the volcanic rocks.

One honest limitation stands out: the team could not conclusively identify which minerals actually host the lithium. X-ray diffraction patterns showed some features resembling phases known from lithium-bearing systems, but at these trace concentrations the diagnostic peaks are swamped by abundant rock-forming minerals such as quartz, feldspar and mica. That is not surprising, because in volcanic systems lithium typically substitutes as a trace element within common silicates rather than forming its own discrete minerals. It can also concentrate in secondary clays, particularly smectite and illite, produced by weathering and hydrothermal alteration. The parallels are compelling: lithium-rich illitic claystones at Thacker Pass in Nevada and smectite-illite assemblages in Clayton Valley represent some of the most significant clay-hosted lithium resources known, both formed through alteration processes. Definitive identification in Kulon Progo will require higher-resolution techniques such as electron probe microanalysis, laser ablation ICP-MS or secondary ion mass spectrometry.

The analytical rigor behind the numbers deserves attention in its own right. To validate their measurements, the researchers sent one rock sample to five ISO/IEC 17025:2017-accredited laboratories for independent ICP-OES analysis. Three of the four comparison laboratories produced results statistically indistinguishable from the reference measurements, with relative percent differences between 1.42 and 9.52 percent, all within acceptable thresholds. One laboratory diverged substantially, with a relative difference of 45.57 percent attributed to fundamentally different analytical protocols, but the consistency of the other comparisons supports the reliability of the dataset. Quality assurance also included standard addition methods with certified reference materials and proficiency testing through interlaboratory comparisons.

Why does this matter beyond Indonesia? The study demonstrates that measuring lithium in surface waters can serve as a cheap, low-impact screening tool for early-stage exploration. Instead of exhaustive rock sampling campaigns, which are expensive and environmentally intrusive, exploration teams can analyze stream and well water to flag anomalies, then concentrate detailed work on the most promising catchments. The elevated lithium in altered andesitic rocks near Kalirejo suggests just such a link between hydrogeochemical signatures and mineral sources. For a country with limited exploration budgets and vast, roadless volcanic terrain, that approach could be transformative, and the authors point toward portable electrochemical lithium sensors, adapted from rapid diagnostic biosensor platforms, as a practical next step for field deployment.

There is also an environmental dimension that extends well beyond mining. Lithium is routinely absent from water quality monitoring programs, which traditionally focus on pH, conductivity, dissolved solids and major cations, along with well-characterized heavy metal contaminants. Yet rising battery use is increasing lithium’s footprint in the environment, and elevated lithium in drinking water raises potential health questions that remain poorly understood. The Kulon Progo dataset, the first hydrogeochemical baseline for the region, therefore does double duty: it flags a possible resource and simultaneously exposes a blind spot in how we watch our water. As the energy transition accelerates, the same element that stores clean electricity may need to be tracked as carefully in rivers and wells as lead or arsenic ever were, and this small corner of Java has just shown how to start.

Subject of Research: Lithium distribution in surface waters and volcanic rocks of the Kulon Progo region, Indonesia

Article Title: Geochemical characteristics of lithium in surface waters of the Kulon Progo volcanic region for sustainable energy applications

Article References: Rohiman, A., Setiyanto, H., Kurnia, K., Sendjaja, P., Saraswaty, V., Manurung, R. V., & Amran, M. B. (2026). Geochemical characteristics of lithium in surface waters of the Kulon Progo volcanic region for sustainable energy applications. Discover Geoscience, 4(1), Article 322. https://doi.org/10.1007/s44288-026-00693-1

Image Credits: AI Generated

DOI: 10.1007/s44288-026-00693-1

Keywords: lithium, hydrogeochemistry, volcanic rocks, Kulon Progo, Indonesia, water-rock interaction, ICP-OES, X-ray diffraction, battery metals, critical minerals, sustainable energy, geochemical exploration