Sudden Changes in the Environment and Life in the Geological Past

The current environment that we live in is subject to many changes which have analogues in those of deep past. These changes are slow or relatively rapid, extreme and catastrophic. The latter ones are events (or crises) in geological terminology, and the major events were of global significance. A huge amount of information is contained in marine limestone deposits where remained well recognizable "imprints" of nearly all processes in ambient environments. The potential impacts of events are quite variable, but the anomalous temperatures, changes of seawater compositions and stratification or sea level flucuations are common and obvious. These anomalous conditions have impacts on many forms of life in seas and on the land. They relate to causes of extinction or rapid evolution of new species, and they were recorded in chemical, mineralogical and particulate compositions of sedimentary units. The Choteč Event (close below the Lower/Middle Devonian boundary) belongs to major crises on the Earth, being reported from the territories of the Czech Republic, Germany, France, Spain, Russia, Morocco and Bolivia. The causes and continuance of this events can be best assessed using a combination of the data provided by paleontology (faunal assemblages and migration routes), geochemistry (concentrations of trace elements and REE, organic compounds or isotope ratios of O, C, S, Sr, Nd), geophysics (magnetic susceptibility and radioactivity of rocks) and petrography (data related to sedimentology and diagenesis). The complex study on the nature of the Choteč Event will contribute our knowledge about causes of faunistic changes and, most likely, also the understanding the basic evolution mechanisms.

CONTACT PERSON:

Mgr. Leona Koptíková
phone: 233 087 252
e-mail: koptikova@gli.cas.cz
http://www.gli.cas.cz/Departments/310/