Ice ages and Climate Timeline

By pjain      Published Oct. 11, 2019, 9:09 p.m. in blog Humanities-History-Blog   

Part of Geo-Politics Series - Guide to Geo-Economic-Politics

Climate, Geology, Disasters & Science

Ice Ages & Climate Change - Going on from 10k BC

src:https://www.eh-resources.org/timeline-prehistory/

From 20k yr - 10k yr bc much of the world was covered in ice, sea levels -400’, Continental shelves bare

This was a time when the earth looked very different from what we are used to today. Thick ice sheets extended down from the North Pole as far as Chicago and New York City. All that water had to come from somewhere, so ocean levels were about 400 feet lower than they are today. In essence, water that evaporated from the oceans fell as snow (which was compacted into glacial ice) rather than rain (which would flow back and replenish the oceans as it does now).

  • US The East Coast of the United States was 75 to 150 miles farther out than it is today, and places like Manhattan and Baltimore would have been inland cities.

  • Europe During this period, meltwater from the European glaciers flowed down to the Black Sea basin, then out through a river channel into the Mediterranean. Because the Mediterranean is connected to the world ocean at Gibraltar, it was also 400 feet lower than it is today, so this flow of fresh water through the Black Sea was downhill.

"Where I live in Connecticut was ice a mile above my house, all the way back to the North Pole, about 15 million kilometers, that's a big ice cube," he said. "But then it started to melt. We're talking about the floods of our living history." The water from the melting glaciers began to rush toward the world's oceans, Ballard said, causing floods all around the world. "The questions is, was there a mother of all floods," Ballard said.

Eurasian Hunter Gatherers Survived during Ice Ages - 12k bc - 8k bc?

  • Due to the ice age - vast tundras were full of ice/snow but also grasslands
  • Reindeer and cattle ate the grass, producing meat and milk
  • Animal hunting and later domestication allowed humans to survive as they followed migrating herds.
  • Eventually, genetic evolution got the lactose-tolerant gene.

End last Ice Age 8k bc & Flooding of - North Sea Basin 7.5k bc

  • The last Ice age ended when ice sheets retreated from Scandanavia and glaciers in Scotland disappeared.
  • This opened the way for humans to enter these new areas after plants and animals.
  • Look for DETAIL high resolution map of Continental Shelves here https://upload.wikimedia.org/wikipedia/commons/9/93/Elevation.jpg

Until 8 kyr most Continental Shelves eg the North Sea Basin and The dramatic change in sea levels

6k-2.5k BC Holocene Warming

Melting of Ice Sheets, Rising of waters, More rains/monsoons?

Europe - as time went on, the world warmed, the glaciers retreated and meltwater from the European glaciers began to flow north into the North Sea, depriving the Black Sea of its main source of replenishment.

Sea levels reached levels slightly higher than 2017 as temeratures rose to highest levels at 2 celsius higher than now.

5k BC flood in Black Sea

Two Columbia University scientists William Ryan and Walter Pitman

Drying of Black Sea as deprived of European ice sheet water - exposed lots of fertile land ~several 100s’ below Med

Europe - as time went on, the world warmed, the glaciers retreated and meltwater from the European glaciers began to flow north into the North Sea, depriving the Black Sea of its main source of replenishment. The level of the Black Sea began to drop, and most of the area around its northern boundary — the area adjacent to present-day Crimea and the Sea of Azov — became dry land. At this point, the level of the Black Sea was several hundred feet below that of the Mediterranean. They believe that the now-salty Black Sea was once an isolated freshwater lake surrounded by farmland.

Narrow land bridge protecting Black sea from rising Mediterranean waters

The two were separated by the barrier of the Bosporus, then dry land. This situation, with the world ocean rising while the Black Sea was falling, could not last forever. Eventually, like a bathtub overflowing, the Mediterranean had to pour through into the Black Sea basin.

The idea that ocean basins can flood catastrophically during periods of rising sea levels is nothing new in geology. Five million years ago, long before there were any humans around, just such an event occurred. The level of the Atlantic Ocean had dropped, or some tectonic event had occurred, with the result that water could no longer get through, and the Mediterranean gradually shrank down to a desert spotted with a few salty bits of ocean. Subsequently, when either the Atlantic rose again or another geological change took place, ocean water began pouring back into the former sea. The basin filled, and the present-day Mediterranean was created.

Held back by geography finally rising waters it broke through until it was flooded by an enormous wall of water from the rising Mediterranean Sea. The force of the water was two hundred times that of Niagara Falls, sweeping away everything in its path. The land that went under stayed under 150,000 square kilometers of land. By carbon dating shells found along the shoreline, Ballard said he believes they have established a timeline for that catastrophic event, which he estimates happened around 5,000 BC. Some experts believe this was around the time when Noah's flood could have occurred.

https://www.smithsonianmag.com/science-nature/evidence-for-a-flood-102813115/ Bible isn't the only place this story is found A much older Mesopotamian flood story in the epic of Gilgamesh

PROBLEM: Cultural Impacts - Sharp Change ~3.5k BC - was it the spread of Agriculture

Theory: A number of people and new customs suddenly appeared in places as far apart as Egypt and the foothills of the Himalayas, Prague and Paris. The people included speakers of Indo-European, the language from which most modern European and Indian languages are derived. Pitman and Ryan suggest that these people might, in fact, represent a diaspora of Black Sea farmers who were driven from their homes by the flood, and that the flood itself might have been the cause of the breakup of Indo-European languages. Violates Linguistic evidence: inguists have long known how to reconstruct ancient languages by looking at words that have survived in the descendants of those languages today. The date of an event like the split-up of the Indo-European languages can then be estimated by comparing those words with artifacts found in excavations — a language probably won't have a word for "wheel," for example, unless it actually uses wheeled vehicles. "It is unlikely that the Indo-European languages split up before 3500 B.C. (that is, 2,000 years after the Black Sea flood)," says University of Chicago linguist Bill Darden, basing his conclusion on this sort of argument. If he and his colleagues are right, then the diaspora part of the flood story will be just another beautiful theory shot down by ugly facts.

Great China Flood ~1920 bc

The great china flood at 1920 B.C., several centuries later than suspected. This new timeline suggests that China's first dynasty, Xia — as well as its founding Emperor Yu, famous for controlling the flood — also had a later start. Yu's control of the chaotic flood waters brought order to the lands. By dredging the Yellow River to increase its carrying capacity, he tamed the destructive floodwaters Legend says, separating what would become a civilized Chinese center from the wild peripheries. This defined a people, as well as the social and political order in which they should live. It is central to Chinese identity and known by everyone there, just as Westerners know the story of Noah's flood. - Wu Qinglong, professor in the department of geography at Nanjing Normal University

Little Ice Age 1500-1600 AD

  • as 55m Am.Indians killed ag reduction cooled

Climate Futures

Flooding of Continental Shelves

The continental marginal areas submerged under oceanic water with average water depth of 100 fathoms and gently sloping of 1° to 3° towards the sea or the ocean are called continental shelves .Continental shelves off the Indian coast is demarcated by 100 fathom contours ( lines drawn on a map connecting equal elevation) . 1 fathom = 6 feet (100 fathom = 600 feet ).

Western coasts of India

Western Ghats is just an elevated rock which is a part of rigid and stable Indian Peninsular landmass. The line joining the points of 600 feet from bottom of the sea to sea level. - 50 km from western coast

During the collision of Indian plate with Eurasian plate, western coast of Peninsula was submerged beneath the sea and some other parts changed due to the tectonic activity without affecting the original basement. If this would not have happened present western ghats region would be somewhere in central-left portion of symmetrical peninsula. So the western coast is basically that submerged part of peninsula. After this submerge, neither it up warped due to lack of adequate sediments accumulation by west flowing rivers nor further down warped much.

Eastern Coasts of India

The 100 fathom contour line along the eastern coast ie. 50 km. the narrower continental shelf which you see on eastern coast is due to filling of existing continental shelf by peninsular river sediments accumulation. Peninsular rivers are very older in geology and acquired well matured age in their flow.

--- XFR --- Extinction Events

65m yr BC - Chicxulub, Mexico Yucatan Island, meteor impact

It released energy of ~1b times Hiroshima/Nagasaki bombs, finished off dinosaurs, and made room for mammal evolution. Evidence is in a thin layer of irridum on crust of earth.


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