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The case for extraterrestrial causes of extinction
1Department of Geophysical Sciences, University of Chicago, Illinois 60637.
Summary
Large meteorite impacts may cause extinctions, but precisely dating them is difficult. Fossil data, affected by range truncation, can inaccurately represent extinction timing, hindering impact-extinction link confirmation.
Area of Science:
- Paleontology
- Geology
- Extinction Events
Background:
- Growing evidence links large-body impacts to Earth's extinction events.
- Establishing a direct causal link is challenging due to difficulties in synchronizing impacts with extinctions.
Purpose of the Study:
- To investigate the impact of range truncation on the perceived timing of fossil taxa extinctions.
- To demonstrate how fossil data can be misinterpreted regarding extinction events.
Main Methods:
- Analysis of biostratigraphic data, focusing on fossil occurrences.
- Experimental application of range truncation effects on Cretaceous ammonite data from Spain.
Main Results:
- Range truncation, caused by sedimentation gaps or preservation issues, can distort extinction patterns.
- Sudden extinctions may appear gradual, and gradual extinctions may seem sudden due to data limitations.
- Stepwise extinctions can be an artifact of range truncation.
Conclusions:
- Fossil data, particularly last occurrences, often underestimate true extinction times.
- Accurate assessment of extinction timing requires new methods for analyzing biostratigraphic data.
- Addressing range truncation is crucial for understanding the relationship between impacts and extinctions.
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