Free Republic

Early Earth Likely Had Continents, Was Habitable, According To New StudyA surprising new study by an international team of researchers has concluded Earth's continents most likely were in place soon after the planet was formed, overturning a long-held theory that the early planet was either moon-like or dominated by oceans. Artist's conception of the early magma ocean. (Image courtesy of NASA) The team came to the conclusion following an analysis of a rare metal element known as hafnium in ancient minerals from the Jack Hills in Western Australia, thought to be among the oldest rocks on Earth. Hafnium is found...

Present-day nautilus shells almost invariably show thirty daily growth lines (give or take a couple) between the major partitions, or septa, in their shells. Paleontologists find fewer and fewer growth lines between septa in progressively older fossils. 420 million years ago, when the moon circled the earth once every nine days, the very first nautiloids show only nine growth lines between septa. The moon was closer to the earth and revolved about it faster, and the earth itself was rotating faster on its axis than it is now. The day had only twenty-one hours, and the moon loomed enormous in...

Isotope geochemistryEarly water on Earth Geologists have long thought that Earth’s first 500 million years were as hot as Hades, dubbing this time frame the Hadean. The high temperatures would have prevented liquid water from condensing on the surface. But new findings on zircon grains, Earth’s oldest known terrestrial materials, suggest that the Hadean might have hosted liquid water. Recovered from the metamorphosed sediments of the Jack Hills in western Australia, the zircon grains are dated to be more than 4 billion years old and are the only geological evidence available to provide insight into the first 500 million years...

A tiny 4.4-billion-year-old crystal has been confirmed as the oldest fragment of Earth's crust. The zircon was found in sandstone in the Jack Hills region of Western Australia. Scientists dated the crystal by studying its uranium and lead atoms. The former decays into the latter very slowly over time and can be used like a clock. The finding has been reported in the journal Nature Geoscience. Its implication is that Earth had formed a solid crust much sooner after its formation 4.6 billion years ago than was previously thought, and very quickly following the great collision with a Mars-sized body...

Evidence of Earth's first continents — 4.3-billion-year-old "diamonds" — are actually just fragments of polishing grit, a new study finds. In 2007, an international team first reported discovering the tiny gems, which hid in pockets inside zircon crystals from Western Australia's Jack Hills, in the journal Nature. But it turns out that the gems weren't actually diamonds, but polishing paste, smushed into hairs'-width cracks when the zircons were prepared for laboratory tests, according to a study published online in the Feb. 1, 2014, edition of the journal Earth and Planetary Science Letters.

The accepted timeframe for the beginnings of life on Earth is now being questioned by a Curtin University of Technology led team of scientists, after finding a key indicator to the earliest life forms in diamonds from Jack Hills in Western Australia... The Curtin led team's discovery of very high concentrations of carbon 12, or "light carbon" within these crystals is remarkable as it is a feature usually associated with organic life... Evidence for ancient life stretches back in time to at least 3.5 billion years ago, in the form of single-celled organisms that did not require oxygen. The discovery...

Diamonds tell story of Earth's beginning By Roger Highfield, Science Editor Last Updated: 12:01am BST 22/08/2007 Diamonds really are forever, according to a study that has found tiny examples of the gems that date from near the birth of the Earth. Tiny diamonds discovered inside crystals of zircon Over four billion years old, the diamonds are the oldest identified fragments of the Earth’s crust and were discovered in the Jack Hills region of Western Australia, suggesting they were created only 300 million years after the planet itself was born from the dust and debris encircling our Sun some 4.5 billion...