Earth History: Geology, Climate, Life

Location http://www.cs.mun.ca/~ulf/facts/earthhist.html. Written 2004 by Ulf Schünemann.

cf. the pre-history of information and computation

Links
- Dynamic Earth, - the story of plate tectonics (online edition).
- the PALEOMAP Project - llustrate the plate tectonic development of the ocean basins and continents, as well as the changing distribution of land and sea during the past 1100 million years.

(All dates are round-about million years B.C.)

1. Hadäan Era

4,600 Creation of our sun
4,560 Earth forms
4,510 Earth's iron core forms. Collision with another proto-planet creates the moon [bild der wissenschaft 8/2002]
4,400 Earth partially covered with water [b.d.w. 8/2002]
? ? snowball earth ? (see below) [b.d.w. 8/2002]
3,900 Peak of bombardment from space [b.d.w. 8/2002]
3,850 Oldest traces of life [b.d.w. 8/2002]
3,800 end of Hadäan Era [b.d.w. 8/2002]

2. Paleozoic Era

3,500 simple common ancestor - with horizontal gene transfer - of Bacteria, Archaea, Eucaryotes [Spektrum der Wissenschaft, April 2000]
2,300 Suggested global glaciations [SciAm 11 1999]:
Life produces oxygen. Before then, methane was a major greenhouse gas in the atmosphere in addition to CO2 and vapor. But 1/100% of today's atmospheric oxygen would have been sufficient to overwhelm the methane. And CO2 levels would not have been high enough yet to compensate the resulting cooling.
Also: all continents were at a tropical position at the same time
Natural volcanic activity could not then generate enough CO2 to melt the glaciers for another 5 to 10 million years.
=> snowball earth (see below)
1,700
-1,500
Roger's postulated first supercontinent Columbia [bild der wissenschaft 8/2002]
Roger's homepage

1,300
Suggested first mushrooms on land [Spiegel 10 Aug 2001]

1,100
Second supercontinent Rodinia [bild der wissenschaft 8/2002]
-> map

700
Suggested first plants on land [Spiegel 10 Aug 2001]

750
-580 12-
15C
750-580 M BC (end of Neoproterozoic eon = 1000-543 M) [Spektrum der Wissenschaft, April 2000] [paper] There is clear evidence that this sequence happened more than once, perhaps as many as four times between 750 and 580M Y ago:
At this time: sun 6% weaker; few if any continents at high latitudes => earth deprived of a mechanism that keeps the amount of CO2 in the atmosphere above a critical level => slow drop [if continents at polar: ice sheets prevent chemical weathering which converts CO2 to carbonate => stabilization of CO2]
(1) ice down to 30 degrees north/south (= 50% of earth surface) => run-wild ice-albedo effect => Snowball Earth = frozen sea-level at equator = all earth is in ice => most early eukaryotic lineages "pruned" 600-700M Y ago.
(2) over millions of years: (a) volcanic greenhouse gas builds up in atmosphere, oxigen reduces in sea => iron builds up in sea. (b) life survives in hot-water deep sea vents, hot springs, or in the cold (as nowadays in Antarctica) => genetic isolation in high-stress environments.
22C (3) Ice breaks => evaporation => extreme greenhouse effect: 50C at equator. Iron-rich rocks in sea-bed much later than the main deposits, carbonate rocks ("cap" dolostones) where there usually are none.
||
\/
575
575-525 M BC: (4) The Cambrian explosion: The 11 body plans of nearly all living animals appeared [see in particular SciAm 1 2000]
ca. 560 M BC: Third supercontinent Pannotia [bild der wissenschaft 8/2002]
climate map 540M (early Cambrian)
map with Gondwana 514M (late Cambrian) climate map
480 Ordovician: climate 480M (early), map 458M, ...
12C late Ordovician: ice house world (440M) - "one of the coldest times in Earth history" (says map 458M)
425 22C Silurian: map 425M, climate 420M
Devonian: "The Age of Fish" and pre-Pangäa: map 390M, climate: 400M (early), 380M (middle), 360M (late),
356 20C early Carboniferous: map 356M, climate
12C late Carboniferous: map 306M, climate: expanding ice caps, late, latest
280 Early Permian: climate 280M
20C Permian: climate, map 255M.
250 Late Permian, end of the Paleozoic Era: 99% of all life perished during an extinction event of unknown nature

3. Mesozoic Era

250 22C 250-200 M BC: Fourth supercontinent Pangäa (Gondwana + Laurasia) [bild der wissenschaft 8/2002]
-> map 237M (early Triassic), Gondwana animation (download)
200 map 195M (early Jurassic)
17C map 152M (late Jurassic): break up of Pangäa
125 22C
Precursor of ... plants (in German: "Bedecktsamer") [Spiegel 5 May 2002]

95 map 95M (late Cretaceous): break up of Gondwana
65 (Cretaceous-Tertiary boundary): meteorit/comet impact => end of dinosaurs map
12C+ Pleistocene
4 humanoids (follow links)

1. Hadäan Era
4,600	Creation of our sun
4,560	Earth forms
4,510	Earth's iron core forms. Collision with another proto-planet creates the moon [bild der wissenschaft 8/2002]
4,400	Earth partially covered with water [b.d.w. 8/2002]
?	? snowball earth ? (see below) [b.d.w. 8/2002]
3,900	Peak of bombardment from space [b.d.w. 8/2002]
3,850	Oldest traces of life [b.d.w. 8/2002]
3,800	end of Hadäan Era [b.d.w. 8/2002]

750 -580	12- 15C	750-580 M BC (end of Neoproterozoic eon = 1000-543 M) [Spektrum der Wissenschaft, April 2000] [paper] There is clear evidence that this sequence happened more than once, perhaps as many as four times between 750 and 580M Y ago: At this time: sun 6% weaker; few if any continents at high latitudes => earth deprived of a mechanism that keeps the amount of CO2 in the atmosphere above a critical level => slow drop [if continents at polar: ice sheets prevent chemical weathering which converts CO2 to carbonate => stabilization of CO2] (1) ice down to 30 degrees north/south (= 50% of earth surface) => run-wild ice-albedo effect => Snowball Earth = frozen sea-level at equator = all earth is in ice => most early eukaryotic lineages "pruned" 600-700M Y ago. (2) over millions of years: (a) volcanic greenhouse gas builds up in atmosphere, oxigen reduces in sea => iron builds up in sea. (b) life survives in hot-water deep sea vents, hot springs, or in the cold (as nowadays in Antarctica) => genetic isolation in high-stress environments.
	22C	(3) Ice breaks => evaporation => extreme greenhouse effect: 50C at equator. Iron-rich rocks in sea-bed much later than the main deposits, carbonate rocks ("cap" dolostones) where there usually are none. `\|\|` `\/`
575		575-525 M BC: (4) The Cambrian explosion: The 11 body plans of nearly all living animals appeared [see in particular SciAm 1 2000]	ca. 560 M BC: Third supercontinent Pannotia [bild der wissenschaft 8/2002] climate map 540M (early Cambrian) map with Gondwana 514M (late Cambrian) climate map
480		Ordovician: climate 480M (early), map 458M, ...
	12C	late Ordovician: ice house world (440M) - "one of the coldest times in Earth history" (says map 458M)
425	22C	Silurian: map 425M, climate 420M Devonian: "The Age of Fish" and pre-Pangäa: map 390M, climate: 400M (early), 380M (middle), 360M (late),
356	20C	early Carboniferous: map 356M, climate
	12C	late Carboniferous: map 306M, climate: expanding ice caps, late, latest
280		Early Permian: climate 280M
	20C	Permian: climate, map 255M.
250		Late Permian, end of the Paleozoic Era: 99% of all life perished during an extinction event of unknown nature