A long-standing fact widely accepted among the scientific community has been recently refuted, which now has major implications on our understanding of how Earth has evolved.
Until recently, most geologists had determined the land connecting North and South America, the Isthmus of Panama, had formed 3.5 million years ago. But new data shows that this geological event, which dramatically changed the world, occurred much earlier. In a comprehensive biological study, researchers have confirmed this new information by showing that plants and animals had been migrating between the continents nearly 30 million years earlier.
'This means the best-dated geological event we ever had is wrong,' said Prosanta Chakrabarty, LSU associate professor in the Department of Biological Sciences and Curator of Ichthyology at the LSU Museum of Natural Science.
... 'Now we know that the closure of the Isthmus of Panama, which is supposed to be one of the biggest deals in geology, is just one part of a really complicated puzzle of how the continents came together,' Chakrabarty said.
Geological game changer
Continental Drift / Plate Tectonics was not accepted by most geologists at first, as it was such a massive change.
The researchers knew the small planet was shrinking because Mercury was conforming to a theory of mountain building that was first applied (incorrectly) to our own planet about 200 years ago. In that theory, the Earth's mountains were thought to be a lot like the wrinkles that form on an apple's skin when it dries out and shrinks. But the idea just didn't fit the geology of Earth particularly well. Now a modern theory -- plate tectonics -- explains our planet's features far more accurately.
The Incredible Shrinking Mercury
Other 'geology' theories like the Expanding Earth theory would also be a massive change.
But MESSENGER's measurements of volatiles like potassium, sulfur, sodium, and chlorine on Mercury's surface showed surprisingly high levels of them — as high or higher than on the other inner planets. "This means that all those ideas for how Mercury became so iron-rich can be rejected," Solomon says. "And it forces us to reconsider how the entire inner solar system was assembled."
Scientists are now trying to figure out alternate ways of explaining how Mercury could've lost so much outer material while retaining these volatiles.
We can't quite figure out how Mercury formed
It is just how you interpret data and the same data might mean You like Pangaea and I like Expanding Earth Pangea.
Update 18/09/2015: rethink of New Zealand's Alpine fault
The major fault line, which runs almost the entire length of the South Island, has been assumed to be a near vertical crack. However, studies of seismic data have revealed the fault line becomes flatter at depth.
... “So, rather than thinking of the fault line as a vertical crack, we should be thinking of it as a nearly horizontal one that curves up to the surface where the fault line is exposed.”
... “The crust is very thick beneath the South Island, which is not what you would expect if the two tectonic plates were just sliding past each other on a near vertical fault. Also, seismic waves generally travel faster the deeper down you go, and yet the wave speeds get slower beneath the Southern Alps,” says Dr Lamb.
Research calls for rethink of Alpine Fault
Update 24/08/2015: If subduction is induced by ...
The initiation of tectonic plate subduction into the mantle is poorly understood. If subduction is induced by the push of a distant mid-ocean ridge or subducted slab pull, we expect compression and uplift of the overriding plate. In contrast, spontaneous subduction initiation, driven by subsidence of dense lithosphere along faults adjacent to buoyant lithosphere, would result in extension and magmatism. The rock record of subduction initiation is typically obscured by younger deposits, so evaluating these possibilities has proved elusive.
A record of spontaneous subduction initiation in the Izu–Bonin–Mariana arc
Update 11/06/2015: reconstructed Supercontinent Columbia
In this study, Jones and others synthesized mineral age data from ancient sedimentary rocks in the Trampas and Yankee Joe basins of Arizona and New Mexico. They found that the ages of many zircon crystals—mineral grains that were eroded from other rocks and embedded in the sedimentary deposits—were approximately 1.6 to 1.5 billion years old, an age range that does not match any known geologic age provinces in the entire western United States.
This surprising result actually mirrors previous studies of the Belt-Purcell basin (located in Montana, Idaho and parts of British Columbia, Canada) and a recently recognized basin in western Yukon, Canada, in which many zircon ages between 1.6 and 1.5 billion years old are common despite the absence of matching potential source rocks of this age.
However, the distinctive zircon ages in all three study locations do match the well known ages of districts in Australia and, to a slightly lesser known extent, Antarctica.
Tectonic Model Shows North America May Once Have Been Linked to Australia or Antarctica