by Robert Sepehr

February 2003
 

• 3600 Years Ago:
  
  -  In the July 15, 1999 paper published by the journal, Geophysical Research Letters, the Sahara desert's arid climate change occurred quickly and dramatically 4000 to 3600 years ago. A team of researchers headed by Martin Cluassen of Germany's Potsdam Institute for Climate Impact research analyzed computer models of climate over the past several thousand years. They concluded that the change to today's desert climate in the Sahara was triggered by changes in the Earth's orbit and the tilt of Earth's axis. The switch in North Africa's climate and vegetation was abrupt. In the Sahara, "we find an abrupt decrease in vegetation from a green Sahara to a desert scrubland within a few hundred years" scientists reported. No longer were grasses and other plants collecting water and releasing it back into the atmosphere; now sand baked in the stronger sun and rivers dried up. The scientists do not say what caused the change in the tilt of Earth's axis.
  
  -  An unknown civilization with an alphabet that has yet to be deciphered lived in the Indus Valley (W. Pakistan). Around 1550 BC they disappeared.
  
  -  In the twenty-ninth year of King Chieh [the last ruler of Hsia, the earliest recorded Chinese dynasty], the Sun was dimmed... King Chieh lacked virtue... the Sun was distressed... during the last years of Chieh ice formed in [summer] mornings and frosts in the sixth month [July]. Heavy rainfall toppled temples and buildings... Heaven gave severe orders. The Sun and Moon were untimely. Hot and cold weather arrived in disorder. The five cereal crops withered and died. Written during the reign of Emperor Qin c.1600 B.C.
  
  -  Around 1500 BC a civilization arose on the banks of the Hwang Ho River in north central China.
  
  -  The 1st dynasty of Babylon ended in 1595 BC.
  
  -  In the Semitic culture, Hyksos was deposed in 1570 BC, and the Jewish exodus led by Moses happened shortly thereafter. This featured a river Nile filled with "blood" and water they could not drink.
  
  -  The Cycladic settlement on the island of Thera was destroyed by a great volcanic eruption about 1600 BC.
  
  -  Hittite internal strife caused great disorder and ended in 1525 BC with King Telipinu.
  
  -  China gave birth to one of the earliest civilizations and has a recorded history that dates from some 3,500 years ago.
  
  -  Pottery pieces found in Fiji suggest the islands were settled in the west from Melanesia at least 3,500 years ago.
  
  -  Iron manufacturing originated about 3,500 years ago when iron ore was accidentally heated in the presence of charcoal.
  
  -  The Tongon and Samoan islands were probably settled from Fiji about 3,500 years ago.
  
  -  The Santorini eruption (about 1500 BC) was several times greater in scope than the 1883 Krakatoa eruption.
  
  -  Research by W. A. Johnston of the Niagara River bed disclosed that the present channel was cut by the falls less than 4000 years ago. Careful study of the Bear River delta by Hanson showed the age of this delta was 3,600 years.
  
  -  A study by Claude Jones of the Great Lakes showed that these lakes have existed only 3,500 years. This is confirmed by several geographic historical maps of Michigan available in Michigan libraries. Gales obtained the same result on Owen Lake in California. Van Winkle obtained the same result on Albert and Summer lakes in Oregon.
  
  -  Radiocarbon analysis by Libby also indicates that plants associated with mastodons in Mexico are probably only about 3,500 years old. Similar conclusions concerning the late survival of the Pleistocene fauna were drawn by various field workers in many parts of the American continent.
  
  -  From observations on beaches throughout the world, Daly concluded that there was a change in the ocean level, which dropped sixteen to twenty feet 3,500 years ago. Kuenen and others confirmed Daly’s findings with evidence derived from Europe.
   

• 7200 Years Ago:
  
  -  According to Basil Davidson, author of Lost Cities of Africa, new types of humanity appeared in Africa around 5,000 BC
  
  -  According to Ancient Europe by Stuart Pigget, stone using agricultural peasantry began in Europe near 5,000 BC
  
  -  According to December 17, 1996 New York Times article titled Black Sea Deluge May Be Tied to Spread of Farming in Europe, an international team of geologists and oceanographers reconstructed the history of a catastrophic flood from data gathered by a Russian research ship in 1993. Seismic soundings and sediment cores revealed traces of the sea's former shorelines, showing an abrupt 500-foot rise in water levels. Radiocarbon dating of the transition from fresh water to marine organisms in the cores put the time of the event at about 7,700 years ago (5,500 BC).
  
  -  According to the September 10, 1996 issue of the Seattle Times: the research ship JOIDES (Joint Oceanographic Institutions for the Deep Earth Sampling) Resolution "could easily see the light colored ash deposited from the eruption of Oregon’s Mount Mazama 6,950 years ago. That titanic eruption created Crater Lake and threw out at least 40 times as much magma as Mount St. Helens did in 1980 and serves as a useful marker to date mud layers. JOIDES is a Hubble telescope for the ocean, the most advanced drilling vessel in the world". It has 12 laboratories, more than 100 research computers and can drill in water up to 27,000 feet deep. "The planet appears to operate in a quasi-stable mode and pops up to a new state,” said NSF’s Corell.
  
  -  A giant wave flooded Scotland about 7,000 years ago, a scientist revealed on Friday. The tsunami left a trail of destruction along what is now the eastern coast of the country. Scientists believe a landslide on the ocean floor off Storegga, southwest Norway, triggered the wave. Speaking at the British Association Festival of Science in Glasgow, Professor David Smith said a tsunami could strike again in the area but the probability was extremely unlikely. Radiocarbon dating of sediments taken from the coastline of eastern Scotland put the date of the event at about 5,800 BC. At the time, Britain was joined to mainland Europe by a land bridge. Settlers at the time would have had little warning of the disaster, scientists believe. But a scattering of tools found in the sand at a hunting camp in Inverness yields some clues. 'Very destructive' "It looks as if those people were happily sitting in their camp when this wave from the sea hit the camp," Professor Smith of the department of Geography at Coventry University told BBC News Online. "We're talking about two, three or four large waves followed by little ones, that would have been 5-10 meters high. “These waves do strike with such force that they are very destructive," he added. "It's like being hit by an express train."
  
  The research provides an opportunity to assess the hazard of tsunamis in more detail. They occur frequently in the Pacific Ocean due to underwater earthquakes, landslides and volcanic explosions. Long, uncertain history Scientists hope to find more evidence of similar past tsunamis in eastern Scotland to predict the frequency of the destructive waves. Studies of coastal sediments show that it may be possible to develop a record of past tsunamis extending back several millennia. Dr Ted Nield, of the Geological Society of London, said: "These events have a long and uncertain time scale. While there is no reason for mass panic, the possibility exists that the Storegga slide will go again, and it would be imprudent to ignore that fact."
   

• 10,800 Years Ago:
  
  -  The discovery of a forest 11,000 years old buried intact in Michigan, with treetops poking through the sand, has raised alarm about the possible speed of global warming. The five-acre forest of hundreds of spruce, just over ten miles from the shore of Lake Superior, was covered with sand and water when a nearby glacier melted at the end of the Ice Age. What has shocked scientists is that analysis of the tree-rings shows that the climate warmed so rapidly that it left no mark on the normal growth of the trees before they were flooded. "It's kind of scary. The conclusion, based on the tree rings, is that there was no real warning of the dramatic warming that caused the glacier to melt," Theodore Bornhorst, Professor of Geology at Michigan Technological University, said. "The question today is whether we would get no warning of a real dramatic warming. "What it says is that, in 50 years' time, we could have a dramatic shift in climate," he said. "If the ice cap started melting, sea levels would rise dramatically, with major problems for coastal cities."
  
  -  The heyday of the woolly mammoth was the Pleistocene Epoch, stretching from 1.8 million years ago to the end of the last ice age 11,000 years ago. Mammoths thrived particularly well in Siberia, where dry grasslands once stretched for hundreds of miles, supporting a vibrant ecosystem of mammoths, bison, and other jumbo herbivores. The mammoth fossils on Wrangel Island are the youngest that have ever been found. It was there, apparently, that mammoths made their last stand. They died out only 3,800 years ago.
  
  It had always been thought that the mammoth died out about ten thousand years ago, with the end of the ice age, but the tusk appeared to be 7,000 years old. It was so unlikely, so Buttanyan tested five more tusks, but the new dates pointed to an even more remarkable conclusion. Hidden up here [Wrangel Island] in the Arctic, the mammoth hadn't just survived the end of the ice age; it was walking these hills at the time of the Egyptian Pharaohs, only 3500 years ago. This discovery has led to the re-examination of the complex chain of 'cause and effect' that made mammoths die out everywhere else, and in the process has revitalized the whole debate about how species might avoid extinction.