Holtite and dumortierite from the Szklary Pegmatite, Lower Silesia, Poland
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract The Szklary holtite is represented by three compositional varieties: (1) Ta-bearing (up to 14.66 wt.% Ta 2 O 5 ), which forms homogeneous crystals and cores within zoned crystals; (2) Ti-bearing (up to 3.82 wt.% TiO 2 ), found as small domains within the core; and (3) Nb-bearing (up to 5.30 wt.% Nb 2 O 5 ,) forming the rims of zoned crystals. All three varieties show variable Sb+As content, reaching 19.18 wt.% Sb 2 O 3 (0.87 Sb a.p.f.u.) and 3.30 wt.% As 2 O 3 (0.22 As a.p.f.u.) in zoned Ta-bearing holtite, which constitutes the largest Sb+As content reported for the mineral. The zoning in holtite is a result of Ta-Nb fractionation in the parental pegmatite-forming melt together with contamination of the relatively thin Szklary dyke by Fe, Mg and Ti. Holtite and the As- and Sb-bearing dumortierite, which in places overgrows the youngest Nb-bearing zone, suggest the following crystallization sequence: Ta-bearing holtite → Ti-bearing holtite → Nb-bearing holtite → As- and Sb-bearing, (Ta,Nb,Ti)-poor dumortierite → As- and Sb-dominant, (Ta,Nb,Ti)-free dumortierite-like mineral (16.81 wt.% As 2 O 3 and 10.23 wt.% Sb 2 O 3 ) with (As+Sb) > Si. The last phase is potentially a new mineral species. Al 6 □☐(Sb,As) 3 O 15 , or Al 5 ☐ 2 B(Sb,As) 3 O 12 (OH) 3 , belonging to the dumortierite group. The Szklary holtite shows no evidence of clustering of compositions around ‘holtite I’ and ‘holtite II'. Instead, the substitutions of Si 4+ by Sb 3+ +As 3+ at the Si/Sb sites and of Ta 5+ by Nb 5+ or Ti 4+ at the Al(l) site suggest possible solid solutions between: (1) (Sb,As)-poor and (Sb,As)-rich holtite; (2) dumortierite and the unnamed (As+Sb)-dominant dumortierite-like mineral; and (3) Ti-bearing dumortierite and holtite. i.e. our data provide further evidence for miscibility between holtite and dumortierite, but leave open the question of defining the distinction between them. The Szklary holtite crystallized from the melt along with other primary Ta-Nb-(Ti) minerals such as columbite-(Mn), tantalite-(Mn), stibiotantalite and stibiocolumbite as the availability of Ta decreased. The origin of the parental melt can be related to anatexis in the adjacent Sowie Mountains complex, leading to widespread migmatization and metamorphic segregation in pelitic-psammitic sediments metamorphosed at ∼390—380 Ma.
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.
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) | 0.006 | 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 it