I constructed today’s post to help myself comprehend the enormous breakthroughs in excavating and dating prehistoric sites, and the immediate results achieved by humankind in taking advantage of the climatic opportunity. World Population increased from about 5 million marginally-fed folks (they were hunter-gatherers) to 7.6 billion adequately-fed folks. The population has increased by a factor of about 1,500 times. I made this table for myself, just to contemplate how much has been done in the last 12,000 years.
However, there is a “wild card” that we find happening periodically in the geologic record: something very bad happens with alarming frequency. Impacts upon earth by celestial junk (bolides) such as asteroids and pieces of comets and mega volcanoes that cause multi-year “global winters” with concomitant exterminations occur with alarming frequency (just look at the face of a full moon). In last week’s post, we looked at the bolide impact that appears to explain the abrupt reversal of the warming following the last ice age and return of an ice age for some 1,200 years. Earth’s population after recovery from that event was only about 5 million.
Nonetheless, join me in examining our ancestors’ rapid progress from cave-dwelling hunter-gatherers picking themselves up after the Younger Dryas in the following table— and that progress continuing despite the ongoing global climate traumatic events (marked in red).
| Millennium BCE | Millennium Before Present | Links to Websites of Selected Prehistoric Events |
| 10 | 12 | End of Last Ice Age, Pre-Pottery Neolithic A, Gobekli Tepe, Jericho, Wheat cultivation |
| 9 | 11 | Pre-Pottery Neolithic B, Quaternary extinction event, Byblos, Sea level rise tops out, Cattle Domestication |
| 8 | 10 | Neolithic Subpluvial begins, Çatalhöyük, Amman, Barley cultivation |
| 7 | 9 | 8.2 kiloyear Event, Ubaid Period |
| 6 | 8 | Eridu, Proto-Writing, Chalcolithic |
| 5 | 7 | Malta Temples, Cucuteni-Trypillia Culture |
| 4 | 6 | 5.9 kiloyear Event, Collapse of Ubaid Culture |
| 3 | 5 | Writing developed in Sumer, and Egypt |
After putting together this table, I find myself even more astonished at what’s been done in the eight millennia shown.
Thanks for visiting,
R. E. J. Burke
Fortunately, Earth’s Collisions with Space Rocks usually involves relatively small
objects entering the atmosphere, and fortunately most of them burn up while passing through the
atmosphere, or the heating and compression makes them break up into numerous smaller pieces.
Also, very fortunately, the Earth, and the rest of the Solar System has had 4544.4 million years to
use up the vast majority of the largest Space Rocks, and now there are typically less than or equal to
8 possible extinction event periods every 186.6 million years. Most of these extinction events are
small, but occasionally they are big, like the one that occurred 66.043+/-0.011 million years ago. I
did the calculations for that one several times by hand and came up with a diameter of just over 19 km,and combine velocity ” off center, nearly head on” collision of just over 68 km per second. The fire ball had a 473 km radius ( atmosphere is only 120 km tall ), and a simplified hemispheric crater would be have a radius of 53 km deep. Then I found out, there was a computer program on line that can do that calculation for you, and makes eliptical craters. They came up with 18 km diameter Space Rock. Anyway, the antipodal energy focal point was the Deccan Trapps in western India, when the Earth Radius was just less than 5,075 km (5,074.82 Km ), and Chicxulub was about 3.5 degrees north of the Equator, and Deccan Trapps was 3.5 degrees south of the Equator. To be antipodal, the Energy focal point is 180 degrees away from the impact point in all directions around the Earth. You need the size of the Earth, and the mass of the Earth at the time of the impact to get the escape velocity at the time of the impact to do M1* v1 = m2 * V2 calculations. You also need it to
estimate the volume of the material that was put into orbit, the volume of the material that was ejected, and the volume of the material that was simply displaced laterally, but slumped back into the crater. ( Like the complex craters on the surface of the Moon )
Thanks for your comment, Michael. You are focusing upon huge extinction events. I’m looking at a relatively recent event. Examine the first graph in the following URL: https://www.ncdc.noaa.gov/abrupt-climate-change/The%20Younger%20Dryas
In post 182, we saw the creation of the Younger Dryas caused the Megafaunal Extinction and, I’m confident, massive killing of humans who were responding to the warming following the Last Glacial Maximum, having been suckered into a two thousand year warm-up before the temperature dropped in free-fall to the lowest in the preceding 7,000 years, and certainly finding them without their long-forgotten cold-weather lifestyle from the Last Glacial Maximum. The killing off of the dinosaurs was a huge bolide event, and I suspect there were several more such events (just by observing our full moon–a smaller target), but there were certainly many events similar to the Younger Dryas bolide, wreaking unimaginable but more localized havoc upon the then-present denizens of the earth. Brings to mind the saying, “Life is hard and then you die,” which certainly applied to the dinosaurs! Supporting this last statement, have a look at the first graph in my 1st post at https://raisinguppharaoh.com/2014/05/09/long-ago-and-far-away/ and note all the MISLEADING DIRECTIONAL ABERRATIONS in the prior 500,000 years. Makes the recent arguments about “Anthropogenic Global Warming” seem laughable.
I have recently been viewing hundreds of hours of YouTube Videos related to Earthquakes, Volcanoes, Tsunamis, and Sea Level rise. Apparently these sudden, and, long term changes have, and are, occuring far more frequently than most people are aware of. The ones I was watching last night were related to submerged mega-lithic structures, and large cities off the west coast of India, and between Japan and China. From the size of these cities, they had very large populations and were wiped out by sea level rise between 9,000 and 11,000 years ago, making them far older than the Mesopotamian, and Eqyptian Civilizations. Apparently the gradual, to sudden, and back to gradual sea level rise with a vertical change of 120 meters (400 feet) submerges many agricultural Valleys world wide that supported large populations, and associated large city complexes which included large mega-lithic structures. The use of underwater Archaeology with Radar, Sonar, and Lidar will revolutionize how we find submerged sites world wide, whether it is under water, or under jungles.
It seems that the cataclysmic events are the real preservers of Archaeological Sites.
Sea Level rose at a varying pace starting at the end of Last Glacial Maximum (see top graph at https://raisinguppharaoh.com/2014/06/17/1130/ ) which is about 20 kiloyears ago. Depending upon the depth the cities are found, you can estimate when they went below sea level by finding the time when the sea level reached that street level in the inundated “city.”
As for Sea Level Rise, one would need a graph, or, a table of time and elevation
data, which, if I remember right, is a Lazy S shaped curve that started out slow,
then accelerated, then decellerated, then approached a near steady state in the
last few thousand years. The rise and fall of continents should slow enough, and
should be time delayed enough that one would not need to make a correction for
vertical continental movement on a mere 20,000 year time interval. Typically
vertical continental movement takes 5 million to 20 million years to follow an
exponential decay curve of vertical motion following dramatic sudden drops in
global ocean levels. When ocean levels suddenly drop, the Ocean floors rise,
and the continents fall to re-establish the iso-static (iso-dynamic) equalibrium.
You will find the “S” shaped curve as the third graph in my 2nd Post published June 17, 2014: https://raisinguppharaoh.com/2014/06/17/1130/