Monday, May 3, 1999 Published at 22:40 GMT 23:40 UK
Early volcano victims discovered
Whole populations may have been wiped out simultaneously
Whole communities of ape-like creatures may have been killed in volcanic disasters that struck East Africa 18 million years ago, according to new research.
It follows a study of rock deposits close to the once active volcano Kisingiri. These contained fossils of what is believed to be a forerunner of humans called Proconsul.
These creatures livid in a semi-arid environment close to the mountain and the research suggests they may have been caught by a pyroclastic flow. These are clouds of hot gas, dust and rubble which travel at huge speeds from erupting volcanoes.
Scientists, who report their findings in the Journal of the Geological Society, believe the abundance of the hominoid fossils may represent "death assemblages" - whole populations wiped out simultaneously by "glowing cloud" eruptions.
It is thought that many of the victims found in Pompeii and Herculaneum who died in the AD79 eruption of Vesuvius were killed by pyroclastic flows.
The basis for the new revelation comes from Early Miocene age rocks of the Rusinga Group, on the shores of Lake Victoria in Kenya.
The rock formation contains evidence of pyroclastic flows and ash-fall deposits.
Research shows that in between eruptions, the landscape became covered in mostly dry, deciduous, single-canopy woodland, with some evergreen forest in restricted, low-lying areas.
Primates are thought to have evolved and thrived mainly in forest habitats from the Eocene age, through part of the Miocene age.
During the Miocene age, conditions became more open, culminating in the expansion of grasslands.
The fossils of the Rusinga Formation form a crucial link between the early primates of the forest habitats, and human forerunners of the more open-country habitat.
The new research on the fossils shows that these human forerunners lived in drier conditions than had been supposed, on a landscape that experienced repeated volcanic eruption.