Interpret
2006-09-27 09:03:09 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
1.8 Billion years ago was when the atmosphere and oceans become oxidising (from all the oxygen from photosynthesis). Before then they were reducing.
Calcium carbonate (limestone) is more stable in oxidising than in reducing conditions.
2006-09-27 09:12:48 · answer #1 · answered by Anonymous · 0⤊ 0⤋
The only information I see is that limestone became common around 1.8billion years ago. If it was common, then there were an awful lot of little creatures making calcium carbonate shells. Either their appearance in sufficient numbers was 1.8billion years ago, or something about sea-water's pH changed then so that the CaCO3 was preserved, fossilized, and then metamorphicized into stone.
2006-09-30 03:40:50 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Interpretation:
Why, according to this information, were there so many limestone deposits 1.8 billion years ago?
2006-09-27 09:18:13 · answer #3 · answered by Privratnik 5 · 0⤊ 1⤋
the earths environment could well have become more suitable to the proliferation of small calciun utilising marine organisms around this time. these organisms also can only survive in relatively shallow seas and may then also have been an indicator of rising water levels which would lead on to suggest there was an increase in global temperature that caused poles to melt producing a rise in global sea level and therefore an increase in the ecological niches required by these organisms. there could also have been a reduction in other non calcium utilising species that may not have been adaptable to environmental change...phew!!
2006-10-01 08:14:03 · answer #4 · answered by frankiethebear2002 2 · 0⤊ 0⤋
What information? Where?
2006-09-27 09:08:09 · answer #5 · answered by ohmneo 3 · 1⤊ 0⤋
where's the "information"?
2006-09-27 09:10:32 · answer #6 · answered by ever_curious 3 · 1⤊ 0⤋
Because that is when we first had the technology to discover it ! Good Luck ! :)
2006-09-27 09:05:08 · answer #7 · answered by tysavage2001 6 · 0⤊ 1⤋