Bibliographic record
Abstract
Although Norman Newell’s pioneering research was published in 1967, general interest in mass extinctions provoked by catastrophic changes in the environment was not aroused until 1980, when a paper appeared in the journal Science proposing that the end-Cretaceous extinction was caused by the impact of a huge asteroid. Before this time several people had suggested an extra-terrestrial cause for particular mass extinctions. Thus, in the middle of the twentieth century, the German palaeontologist Otto Schindewolf, who had long been preoccupied with the marine mass extinction at the end of the Palaeozoic era, concluded on the evidence of fieldwork in the Salt Range of Pakistan that the event must have been a catastrophic one for which he could literally conceive no earthly explanation. He was consequently led to speculate that the causal factor was a nearby supernova explosion. The increased cosmic radiation impinging on the Earth could, he thought, have destroyed the ozone shield and have led to lethal exposure of numerous organisms. A few other such speculations invoking some kind of extraterrestrial factor were put forward at about the same time, and in 1970 Digby McLaren, an expatriate British palaeontologist who had risen to become Director of the Canadian Geological Survey, made a startling proposal. He was an expert on the late Devonian marine mass extinction at the end of the penultimate, Frasnian, stage. Like Schindewolf, he agreed that the event was much too wide spread, dramatic, and ‘geologically instantaneous’ to have been caused by a merely terrestrial process, and he speculated that the world’s ocean of the time had been severely disturbed by the impact of a giant meteorite. Three years later, the American chemist Harold Urey, a Nobel Prize-winner, published a paper in the journal Nature in which he argued that several extinction events within the past 50 million years had been caused by the impact of comets. These various suggestions, together with a few others invoking increases in radiation from outer space, either in the form of cosmic radiation or solar protons, were virtually ignored. This is unsurprising in view of the almost total absence at that time of any supporting evidence, with the possible exception of a few tektite layers in Tertiary deposits.
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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.000 | 0.004 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
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".