Titlebook: Extinction Events in Earth History; Proceedings of the P Erle G. Kauffman,Otto H. Walliser Conference proceedings 1990 Springer-Verlag Berl

印第安人

Infirm

Infiltrate

https://doi.org/10.1007/978-981-99-2489-9n of the periodicity of the initial events. The extinctions at the Frasnian-Famennian and Devonian-Carboniferous boundary appear to be stepwise affecting preferentially tropic-subtropic fauna which is gradually replaced by the temperate one. They are thus in general similar to the Cretaceous-Tertiary or Eocene-Oligocene extinction.

准则

Mobile

Foregery

Silurian and pre-Upper Devonian bio-events,h in graptolites or other pelagic organisms, with these bio-events is not easy to see. Ranking these lower level bio-events is of questionable significance since we do not presently have any truly “objective ”criteria possessed of real biologic significance (mere taxon counting is certainly not the answer).

paroxysm

A multi-causal model of mass extinctions: Increase in trace metals in the oceans,interactions are most likely complex, one common effect might be an increase in trace metals in the earth‘s surface systems. Increased trace metals could lead to severe effects on the biota, and would exacerbate the general environmental crises at times of comet or asteroid impacts.

Immortal

The Middle Givetian ,-Events a tool for high time resolution and event-stratigraphical correlation, sedimentological features. Due to their synchronous, extremely short-term deposition the . Horizons are excellent index horizons for a basin-wide correlation of Givetian pelagic limestones and for a further refinement of the middle Givetian time-scale. An interpretation of the . Horizons as tsunami deposits is given.

Disk199

anticipate