A Jurassic counterpart for modern kopara of the Pacific atolls
| Autor: | C. Defarge, Alain Trentesaux, J. Trichet, Nicolas Tribovillard |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
010506 paleontology
geography geography.geographical_feature_category Paleontology Atoll Ecological succession 010502 geochemistry & geophysics Oceanography 01 natural sciences Pacific ocean Anoxic waters chemistry.chemical_compound chemistry Bacterial activity Carbonate 14. Life underwater Ecology Evolution Behavior and Systematics Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Palaeogeography, Palaeoclimatology, Palaeoecology. 156:277-288 |
| ISSN: | 0031-0182 |
| DOI: | 10.1016/s0031-0182(99)00145-5 |
| Popis: | Two types of laminated sediments are compared in this paper: the Kimmeridgian bituminous laminites of Orbagnoux (French Southern Jura Mountains) and the present-day ‘kopara’ of the French Polynesia atolls or Kiritimati (Christmas) Island from the Pacific Ocean. The kopara is made of laminated sediments, several tens of centimetres thick, that cover the floors of most shallow ( 3 -rich laminae. The top few centimetres host a succession of bacterial populations, from aerobic to strictly anoxic. Most carbonate grains are precipitated in situ, due to bacterial activity (s.l.). The Kimmeridgian bituminous laminae of Orbagnoux are partly made of flat stromatolites that show many similarities with the kopara. This analogy allows us to refine the interpretation of the Southern Jura platform where laminated, organic matter-rich, carbonates were deposited in many places. |
| Databáze: | OpenAIRE |
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