2002/06/28 by Kirk R. Johnson, Beth Ellis · 5 citations
Agricultural and Biological Sciences · Environmental Science · Biochemistry, Genetics and Molecular Biology · #Plant Diversity and Evolution #Ecology and Vegetation Dynamics Studies #Plant and Fungal Species Descriptions
paper · doi:10.1126/science.1072102
openalex publication_date 2002/06/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
An extremely diverse lower Paleocene (64.1 million years ago) fossil leaf site from Castle Rock, Colorado, contains fossil litter that is similar to the litter of extant equatorial rainforests. The presence of a high-diversity tropical rainforest is unexpected, because other Paleocene floras are species-poor, a feature generally attributed to the Cretaceous-Tertiary (K-T) extinction. The site occurs on the margin of the Denver Basin in synorogenic sedimentary rocks associated with the rise of the Laramide Front Range. Orographic conditions caused by local topography, combined with equable climate, appear to have allowed for the establishment of rainforests within 1.4 million years of the K-T boundary.