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100 Million years ago

a 100 Million yrs ago full screen.jpg

The sky is alive with flight





Large cycles of warming and cooling are supercharged by volcanic activity that adds massive amounts of carbon dioxide to the atmosphere, driving temperatures extremely high.  An evolutionary explosion fills the sky with flying creatures that feed on flowering plants in a new ecosystem based on animal pollination.  (more)

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Approximate location of current oil fields relative to their continental plates. 

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100M yrs ago map
(adapted from Ron Blakey, and Peace Research Institute Oslo, Petroleum Dataset, (


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100M yrs ago graph
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8 billion in 2023

CO2 concentration
418 parts per million in 2023

Average Temperature
15° C in 2023

Sea Level 

in hundreds of meters from datum in 1900

Asteroid strike; K-T Extinction of 3/4 of species

Increase in Antarctic ice

Temp. High 27-30°C

Sea level high 120-140 meters

Millions of years

Hundreds of millions of years

The coevolution of plants and animals accelerates the diversification of life.  Plants develop flowers to attract and reward specific animals, particularly those with wings, who deliver their pollen to the right mate.  Flying cupids respond by evolving a body form and habit that fit the flower and do the job in exchange for nourishing nectar.  About 80 million years ago, some plants find an advantage in making larger seeds, wrapped in tasty fruits, which animals eat and transport to new locations.  A new food source that is richer than leaves or grasses feeds a new evolutionary spiral. 


This generative pulse of life is hardly dampened when an asteroid hits the Earth 66 million years ago, wiping out 75 percent of species.  Non-avian dinosaurs are lost but the avian group, birds, particularly aquatic birds, survive to diversify into about 10,000 species worldwide. Mammals emerge out of nocturnal habits into the light of day to find open ecological niches, sparking rapid evolution in sync with the recovery of plants.

At the scale of hundreds of millions of years, the movement of tectonic plates comes into view.  Pangea is only the most recent of supercontinents. It formed from the pieces of Laurasia and Gondwana about 336 million years ago. Gondwana, in turn, assembled about 600 million years ago from pieces of Rodinia.  At this time scale, oceans open and close, while the landmass of continents float on Earth’s underlying mantle, remaining dry. Sea levels can be extremely high, not from ice-melt, but water displaced on to land when mid-ocean ridges rise.


Through these long eons, the Earth slowly absorbs carbon dioxide out of the atmosphere, building deep organic deposits on land.  Under the seas even older deposits are pressed by the weight of the water into coal and oil.

100M yrs ago text


Text: Ollerton, J. and E. Coulthard (2009). "Evolution of Animal Pollination." Science 326: 808-809.

Image: Composite of Adobe Stock images, pterosaur images from American Museum of Natural History.

Map: Blakey, R. "Global Paleogeography and Tectonics in Deep Time Series." 2019

WorldMap. (2015). "Oil & Gas Map."   Retrieved 22 September 2018, 2018, from

Scotese. (2001). "3D Cretaceus World (100 mya Albian)."   Retrieved 20 September 2018, 2018, from

Prio. (2007). "Petroleum Dataset v. 1.2."   Retrieved 22 Sept 2018, 2018, from

CO2: Tierney, Jessica et. al "Past climates inform our future" Science 370 (680)

Foster, G.L; Royer, D.L.; Lunt, D.J, "Future climate forcing potentially without precedent in the last 420 million years" Nature Communications 8 (1) 14845

Temperature: Tierney, Jessica et. al "Past climates inform our future" Science 370 (680)

Sea Level: James Hansen, M. S., Gary Russell, Pushker Kharecha (2013). "Climate sensitivity, sea level and atmospheric carbon dioxide." Philosophical Transactions of the Royal Society A: Mathematical, Physical, and Engineering Sciences 371(20120294).

Sea Level: Miller, K. G., M. A. Kominz, J. V. Browning, J. D. Wright, G. S. Mountain, M. E. Katz, P. J. Sugarman, B. S. Cramer, N. Christie-Blick and S. F. Peka (2005). "The Phanerozoic Record of Global Sea-Level Change." Science 310(5752): 1293-1298.

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