Origin and composition of hydrothermally‐influenced sediments at Aurora Vent Field, southwestern Gakkel Ridge (82.9°N)
Bibliographic record
Abstract
ABSTRACT Slow–ultraslow spreading ridges represent half of the total length of the global mid‐ocean ridge system and have been recognized to host hydrothermal activity. Their role as a source versus sink of elements in the oceans remains poorly constrained. Here, we present the first sediment data from the Aurora Vent Field (~3900 m depth) on the ultraslow spreading Gakkel mid‐ocean ridge and the northernmost active vent field (82.9°N) explored to date. We interpret the composition of the cores at various distances from the vents based on physical parameters (P‐wave velocity, gamma density, magnetic susceptibility, acoustic impedance and fractional porosity), mineralogy and (in)organic geochemistry (elemental analysis via X‐Ray fluorescence and carbon–nitrogen systematics). Metalliferous sediments in two blade cores at <10 m from a black smoker are dominated by Fe‐hydroxides (goethite) and Cu‐Fe‐bearing sulphide minerals (mainly chalcopyrite) that are rich in Co and Zn. These sediments form a friable crust associated with yellow microbial mats visible on the seafloor with the remotely operated vehicle imagery. Near‐field plume deposits form an ~50 cm thick unit at the top of gravity cores close to the vents (<500 m). This unit transitions at further distance into laminated plume fallout deposits marked by high magnetic susceptibility and elevated ln(Fe/Ti), ln(Cu/Ti) and ln(Zn/Ti) values in the XRF profiles. Sedimentary organic matter in the investigated cores is dominated by a marine source, which is overprinted by microbial mats in the surface sediments of the blade cores. In one blade core, we found evidence of thermal alteration of the organic matter, typified by elevated C/N ratios and heavier δ 13 C TOC . Radiocarbon dating of foraminifera in a gravity core yielded an age of 27 230 cal bp , evidence for protracted vent activity preceding the Last Glacial Maximum 23 to 19 ka. Finally, we propose a sedimentological model for the Aurora hydrothermally influenced system that can be potentially exported to analogues 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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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 teacher head, 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".