Lithium isotopes of the Peace River Arch in the Western Canada Sedimentary Basin: A framework for resolving deep basin lithium sources
Bibliographic record
Abstract
Abstract Lithium (Li) enrichment in the formational brines of deep sedimentary basins has emerged as a crucial component of global Li inventories. However, the processes driving the formation of Li brines remain poorly understood. Here we use lithofacies analysis and Li isotope geochemistry to investigate the sources and emplacement mechanisms within weathered subcropping units and overlying detrital sediments of the Peace River Arch (PRA) in the Western Canada Sedimentary Basin (WCSB). We analyze data from three drill cores that traverse Precambrian basement and five of its overlying siliciclastic and carbonate units. These cores reside both within and outside of the fault zone proposed as a migration pathway for hydrothermal emplacement. Lithofacies analysis revealed that these sediments were weathered directly from crystalline basement of the cratonic uplift and transported via a fluvial-deltaic system into the surrounding shallow marine basin. Like modern weathering regimes, we find Li concentrations are strongly lithofacies dependent, ranging from 0.4 ppm to 167.3 ppm, with δ7Li values ranging from 1.5‰ to 23.5‰. Our results show that superficially weathered, coarse-grained lithologies and carbonate facies are Li-depleted and δ7Li-enriched, whereas fine-grained facies characterized by the formation of secondary clay minerals are δ7Li-depleted and exhibit the highest Li concentrations. Contrary to the prevailing model of hydrothermal emplacement, we find no visual, mineralogical, or geochemical evidence of hydrothermal alteration. Instead, Li enrichment is attributed to weathering of the crystalline basement and syndepositional emplacement during basin evolution. Sedimentation continued throughout the overall transgression of the Devonian, resulting in the interfingering of these clastics with every onlapping unit until the PRA was buried at the end of the Devonian. This study is the first to directly trace Li from source to sink in an ancient sedimentary basin, and we show that the modern distribution of Li brine concentrations can be explained by their proximity and intercalation with weathered subcropping units. Moreover, our results provide a source and mechanism of transporting dissolved Li into the restricted basin, supporting previous suggestions that Li brines toward the southeastern portion of the WCSB are the result of basin scale evaporation-concentration of paleoseawater. Our results underscore the link between the nature and distribution of basin fill sediments and the formation of Li-enriched brines. As formational brines gain prominence as future Li resources, the methodology presented here establishes a framework for characterizing Li genesis, with applications for sedimentary basins worldwide.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".