Graben systems and geological history of Mbokomu Mons region, Parga Chasmata, Venus
Bibliographic record
Abstract
The relationship between chasmata (rift zones) and spatially associated volcanism (mons and coronae) on Venus has been extensively discussed but remains enigmatic. One region where these features are prominently displayed is along the 10,000 km long, WNW trending, Parga Chasmata, which connects Atla Regio with Themis Regio. The Mbokomu Mons area (located about 2200 km SE of Atla Regio) was selected for detailed study to provide insight into these relationships. More than 39,000 extensional lineaments (grabens, fissures and fractures) were mapped at 1:500,000 scale using full resolution Magellan Synthetic Aperture Radar (SAR) images and grouped into radiating, circumferential and linear systems. They are (except where noted) interpreted to represent the surface expression of underlying mafic dyke swarms, on the basis of associated volcanic features and terrestrial analogues. Radiating and/or circumferential swarms are associated with Mbokomu Mons and the four coronae in the surrounding area, Among Corona (AC), Repa Corona (RC) and two unnamed coronae (UC1 and UC2). Mbokomu Mons is unique among the tectono-magmatic features in this region of Parga Chasmata, in having both corona and mons characteristics. The initial Corona Phase consists of radiating and circumferential systems mainly preserved in an unflooded annular uplift, while the Mons Phase includes a second radiating swarm associated with a central edifice, and smaller circumferential fracture pattern near the summit that could overlie a magma reservoir. The plume or diapir that is interpreted to have been responsible for the initial Corona Phase is estimated to have had a radius of ∼150 km. Cross-cutting relationships indicate that Mbokomu Mons is younger than nearby Among, Oduduwa and Onenhtse coronae. All four centres are aligned along a WNW-trend parallel to the Parga Chasmata (rift system). Mbokomu Mons is located at, and its emplacement may be linked to, the intersection of this WNW-trending zone of weakness and the orthogonal Jokwa Linea rift system. Mbokumo Mons is also younger than the nearby parallel Penthesilia Fossa (PF) (part of the Great Dyke of Atla Regio). • Mapping grabens for dyke swarm history of Mbokomu Mons (MM) region, Parga Chasmata. • Dyke swarms show 2 stages in MM evolution: Corona and Mons stages. • Domal uplift (radial swarms), then plume spreading (circumferential swarms). • Swarms feed flows of MM at ∼1700 m elevation - imply magma reservoir at 400 m depth. • Alignment of 4 centres shows zone of lithospheric weakness parallel to Parga rift.
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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) | 0.000 | 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".