I just watched a Geology Hub upload on the Cerberean Caldera super eruption in what is now Australia. It happened over 300 million years ago, but in terms of the total age of the planet, even 300 million years is a relatively tiny blip. So have there been any significant epics to truly say events like x, y, or z will never happen again – in any statistically significant way? Will there be another Deccan or Siberian Traps or Columbia River Flood Basalts – one geologic timescale day in the future and countless more in the eons to follow?
(Ref. mentioned not directly relevant to question: https://www.youtube.com/watch?v=AjRaIhec_E8)
I mean, banded iron? The process for depositing the minerals that compose banded iron (which is still hotly debated) no longer exists.
The most widely recognized theory is that the oceans had way more iron dissolved in them early in the history of earth, and the single celled organisms that called those waters home liked it that way. Then, all those little organisms started farting oxygen EVERYWHERE. Oxygen cooled the planet, thus cooling the oceans, and was also toxic to most of the single celled organisms, so they all died when planetary levels of iron started percipitating out of the oceans. Repeat this over a billion years or so and eventually the high concentrations of co2 eating iron loving organisms all died out and we eventually wound up with the ocean and atmospheric chemistry we have today.
Obviously I’m leaving out a ton of other very important interactions along the way, but the gist of it is that this planetary phenomenon simply doesn’t have the mechanisms in place today for more banded iron formations to be made today.
I think this is also true of petroleum deposits because of how fungus figured out how to break down wood fibers.
Basically for the first 100 million years of plants existing on dry land, cellulose plant fibers did not decay. There were no fungus or microbes around that had figured out how to deal with the relatively “new” (in geologic time) invention of cellulose plant fibers, and so those plant fibers built up. Over tens of millions of years, with some of those deposits of plant fibers MILES thick getting covered up, fungus eventually figured out how to digest cellulose. Since then, plant detritus decays and decomposed into dirt.
What that means is that oil deposits were formed SO long ago that they were older to the dinosaurs that eventually came along than those same dinosaurs are to humans now. The process by which oil deposits are formed was over before the first ancestor to mammals decided to try out breathing air.