Sedimentology, stratigraphy, geochemistry, geochemistry and diagenesis of giant lacustrine carbonate seep mounds (Ikpiarjuk Formation), Mesoproterozoic Borden Basin, Nunavut, Actic Canada
Bibliographic record
Abstract
The Ikpiarjuk Formation consists of a group of very large (kms long and hundreds of metres thick), isolated, deep-water, vent-related dolostone mounds that are unlike any documented example of vent-related carbonate rocks in the geological record. The mounds lack ‘normal’ features of Proterozoic carbonates: the mounds contain thrombolites (microbially clotted carbonate), formed below the photic zone, and lack the stromatolitic fabric characteristic of most Proterozoic reef structures. The sedimentology, stratigraphy, geochemistry, and diagenetic history of the mounds were investigated through field work, standard petrographic methods, and various geochemical and other analytical techniques. Shale-normalised rare earth element patterns of various depositional components of the mounds depicts binary mixing between basin-water-derived precipitates and seep-fluid-derived carbonate. Basin fluid has characteristics that are consistent with deposition in an alkaline lake, and seep fluid features are consistent with circum-neutral groundwater that had interacted extensively with basement blocks before seeping into the lake bottom through faults. The sedimentology and mineralogy of the mounds indicates that they were formed by thrombolites that were made up of a microbiota that was not photosynthetic or aerobic. The Ikpiarjuk Formation thrombolite microbiota was probably dominated by an anaerobic chemoautotrophic or chemoheterotrophic metabolism, and records visible preservation of a community that has never before been described from the Mesoproterozoic. The diagenetic history of the Ikpiarjuk Formation is complicated. Dolomitisation occurred early during diagenesis, and subsequently, five different fluids flowed through primary pore space in the mounds and precipitated successive generations of cement. One of the cements contains sulphides inclusions and may correlate with base-metal bodies elsewhere in the basin.
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 | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".