Earth's 1st continents arose hundreds of millions of years earlier than thought

[Admin]

A new study hints at when and how Earth's first continents appeared.

Earth's 1st continents arose hundreds of millions of years earlier than thought : Read more

 

[rod]

I read some other reports on this like https://www.msn.com/en-us/weather/t...on-years-ago/ar-AAQuMNr?ocid=msedgdhp&pc=U531

"Earth's first continents emerged from the oceans around 3.3–3.2 billion years ago — at least 700 million years earlier than previously thought, a study has concluded."

My observation. The new Chinese Moon rocks date much younger, about 2 billion years old compared to the Apollo samples dated some 4 billion years old and some said to be 4.5 billion years old. This suggest to me that on the Moon, there is surface much younger than when continents emerged on Earth and we have the dating for the giant impact too with Theia and how long the Moon remained largely a molten, magma ocean all around.

Some Apollo rocks dated very old. An ancient Sm-Nd age for a ferroan noritic anorthosite clast from lunar breccia 67016, https://ui.adsabs.harvard.edu/abs/1994GeCoA..58.2921A/abstract, July 1994. "Strontium and neodymium systematics have been examined in a clast of ferroan noritic anorthosite from Apollo 16 breccia 67016. Two splits (,328 and ,326) of the same clast give different Sm-Nd results. Split ,328 gives a well defined internal isochron age of 4.562 ± 0.068 Ga and an initial 143Nd/ 144Nd ratio of 0.50673 ± 10 corresponding to ∊Nd = 0.1 ± 0.2 (2σ optimized error) relative to the Murchinson carbonaceous chondrite."

My note, abstracts like this show some Apollo lunar samples were as old or older than the meteorite ages used to show when the solar system formed as tiny dust grains. Such lunar rock ages are much older than accepted zircon ages today like Jack Hills zircon said to be 4.375E+9 years old on Earth. Now we have the continents on Earth pushing back to nearly 3.5 billion years old and the new, very young dated Chinese rocks from the Moon. Some juggling of radiometric ages may be needed

 

[Helio]

I'm fairly sure that the dating of any rock gives only the age of the rock. Some rocks, however, can be associated with the earliest ages for the Moon to have formed. The date from a zircon sample, for instance, will only give the age of when the zircon formed.

There are also samples from the Moon that are only 1 billion years of age. [more Here]. So the 2 billion year age helps fill-in the age gaps from the Moon.

 

[rod]

Helio's post #3 reflects the *accepted interpretation* for the different ages obtained using different samples and dating methods. The Earth with continents emerging some 3.5 or 3.4 billion years ago now according to this new article, the new Chinese lunar rocks show large areas of the Moon's surface forming only 2 billion years ago.

There will be plenty of juggling explanations for all these age differences documented now, whether lunar rocks dated older than 4.5 billion years old, zircons on Earth dated 4.38 billion years old, continents emerged and are dated on Earth now close to 3.5 billion years ago, and on the Moon now, large areas forming 2 billion years ago. Plenty to juggle and reconcile here

 

[Helio]

Helio's post #3 reflects the *accepted interpretation* for the different ages obtained using different samples and dating methods. The Earth with continents emerging some 3.5 or 3.4 billion years ago now according to this new article, the new Chinese lunar rocks show large areas of the Moon's surface forming only 2 billion years ago.

There will be plenty of juggling explanations for all these age differences documented now, whether lunar rocks dated older than 4.5 billion years old, zircons on Earth dated 4.38 billion years old, continents emerged and are dated on Earth now close to 3.5 billion years ago, and on the Moon now, large areas forming 2 billion years ago. Plenty to juggle and reconcile here

Agreed, but I just wanted to clarify that the earlier ages are to be expected for a moon that is likely > 4 Gyrs old, or so. For instance, the mountainous areas are the older regions and the maria are much younger since these were formed from magma flows.