"A new analysis of ancient minerals called zircons suggests that a harsh climate may have scoured and possibly even destroyed the surface of the Earth's earliest continents." Read more
No kidding, from this article : "The early Earth's atmosphere is believed to have contained extremely high levels of carbon dioxide — maybe 10,000 times as much as today. " Perhaps "right-wing" capitalist industries found a way to pump CO2 back in time 4,000,000,000 years ago to save Mother Earth today. After all, elevated CO2 levels can "only" be "a result of man".....Please Register or Log in to view the hidden image! Although, an interesting read.
Why don't you and Mr. "I love oil", go back there and find out how well the humans and all the other mammals, the cows and dinosaurs, were doing?
Plants covered the earth first and converted a lot of that into oxygen, making the atmosphere more favorable for the evolution of animals. And uh... did anybody else reality-test the math in that statement? If the percentage of CO2 in the atmosphere were 10,000 times as high as it is today, it would be 300%. Please Register or Log in to view the hidden image! Hardly. But reelevated CO2 levels might be. And even if they're not, we might still want to be the ones to change it back. We might become extinct if we wait around for it to happen naturally. Trying to decide whose fault it was is an immature way to approach the problem. Find a solution first. Or better yet, make sure our climate models are reliable. I'm old enough to remember the horror stories about global cooling.
Presumably that's if the other components were present in the same amounts then as they are now. I imagine the article means a 10,000-fold increase in absolute terms rather than percentage-wise. What do you think has been the cause of the 30% increase over the last century?
This is potentially misleading, since many may interpret your reference to covering the earth as being the same as covering the land. The conventional wisdom is that plants moved onto the land around 450 million years ago. This article references a potentially much earlier land colonisation: 1300 million years ago for fungi and 700 million years ago for plants. Either way, all of these post date the generation of high oxygen content and massive reduction of carbon dioxide levels.
Hum, "Currently, no rocks remain from before about 4 billion years ago" You have to read post #1 and follow the link.
Hmm ok, but a 3.5 billion year old rock seems pretty old to me as well Please Register or Log in to view the hidden image!
Are you recommending that we ignore potentially ambiguous posts, which might confuse neophytes, in order to adhere rigorously to the thread topic? On that basis most threads on this forum would die after four posts.
Good. Then on a closely related topic are you familiar with current thinking on the tectonic environment in which the first continents formed? My understanding is that plate tectonics as we know it today would not have been responsible, but rather the continents would have grown above mantle plumes akin to, but probably larger than, the present hot spots. However, my education in this area is decades old and my reading on it of late has been patchy. You appear to be more attuned to current discoveries/viewpoints.
Hehe, yeah, the zircon mineral sample was dated to 4.4 billion yeas old. They of course meant large rock formations do not survive from that early period. But we now know probably why. Another mystery solved - case closed. (or is it?)