Absurdly ancient stromatolites found in Greenland

Scientists are now reporting stromatolite fossils that seem to be around 3.7 billion years old, and 220 million years older than the oldest previously known stromatolites. (For perspective, just think of all that's happened biologically in the last 220 million years.)

Here is an accessible discussion in The New York Times.

And here is the original paper in Nature.

If this holds up, these will be the oldest fossils yet found. And they suggest that microbial life on Earth was well established a good deal earlier than anyone had previously realized.