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Record W7034223162

A Systematic Study of the Correlations Between Meteorite Impacts and Soot Formation

2000· article· en· W7034223162 on OpenAlex

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.

aboutThe title or abstract carries a Canadian signal from the geographic lexicon.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueDigital Commons - IWU (Illinois Wesleyan University) · 2000
Typearticle
Languageen
FieldSocial Sciences
TopicScience and Science Education
Canadian institutionsnot available
Fundersnot available
KeywordsSootMeteoriteDeposition (geology)Carbon fibersSedimentary rockExtinction (optical mineralogy)Extinction eventBoundary (topology)
DOInot available

Abstract

fetched live from OpenAlex

A massive extinction of more than 50 percent of existing life forms on Earth occurred 65 million years (Ma) ago. This event is marked in the geological record by the Cretaceous-Tertiary (KT) boundary and corresponds to the Chicxulub meteorite impact in the Yucatan Peninsula. Since 1985, large quantities ofreduced elemental carbon in the form of characteristic spheroidal clusters of soot have been found in twelve KT boundary sites from across the globe. Because ofthe wide geographic distribution ofthese sites, the data was interpreted to indicate that deposition ofsoot was a global phenomenon. The source of this global soot layer is suspected to be eolian (airfall) deposition of fine-grained particles resulting from widespread wildfires. A global soot concentration of 2.2 ± 0.7 . mg/cm2 has been estimated from these studies. As a systematic study of the correlation between meteorite impact and soot formation, five sedimentary sequences ofmeteorite impact-related samples were analyzed for the presence ofelemental carbon in the form of soot. Two KT boundary sedimentary sequences from the Berwind, Colorado, and Madrid, Colorado sites were analyzed as continuations of previous KT boundary studies. Soot concentrations of 3000 ± 0 parts per million (ppm) and 780 ± 90 ppm, respectively, were found in the KT boundary sediments ofthese sequences. These concentrations are similar to those found in previous KT boundary studies and further refine the KT boundary global soot concentration value. Likewise, samples from Deep Sea Drilling Project (DSDP) Core 465-A were analyzed as a determination ofthe global nature ofthe soot layer. A soot concentration of 550 ± 750 ppm was found, again similar to those found in previous KT boundary studies. The mid-Pacific location of Core 465-A rules out the possibility ofsoot deposition from' groundwater runoff and indicates that eolian transport is the most probable mecharllsm for soot deposition. Therefore, the presence of soot in boundary sediments in DSDP Core 465-A supports the theory that the KT boundary soot layer is global. In addition, samples related to two other impact events of differing size and age were analyzed for evidence ofwildfires. In the first study, samples were analyzed from the Sudbury, Ontario impact structure. This structure is the result of an impact similar in size to the Chicxulub event occurring 1850 Ma ago. These sediments were found to contain soot similar in concentrations to those found in KT boundary studies, ranging from 2300 ± 200 ppm soot to 3000 ± 300 ppm soot across the post-impact sedimentary sequence. The presence of soot in these sediments further strengthens the correlation between meteorite impact and soot formation. In a second study, samples were analyzed from the Gardnos impact structure, Norway. This structure is the result ofan impact at least one order ofmagnitude smaller than the Chicxulub event occurring between 900 and 400 Ma ago~ No appreciable amounts of soot were found in sediments directly related to the impact event. The absence ofsoot in Gardnos samples suggests that an impact event ofthis size is below the impact threshold required for ignition of soot-producing wildfires.

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 imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.181
Threshold uncertainty score0.855

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.002
Science and technology studies0.0010.000
Scholarly communication0.0000.002
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.030
GPT teacher head0.257
Teacher spread0.227 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it