Earth Heritage, Issue 60, Winter 2024

The Winter 2024 issue of Earth Heritage is available for download on THIS PAGE.

Or you can read it below.

 New Dinosaur Species were Evolving when the Asteroid Struck!

Many palaeontologists believe that dinosaurs were on the way out when the asteroid struck at the end of the Cretaceous and the impact was the straw which broke the camels back. (Apologies for the metaphor.)

But THIS ARTICLE contends that new species were continuing to evolve. The perceived decrease in diversity is caused by the difficulty in identifying new species. 

 They illustrate this by describing how museum specimens described as being a juvenile specimen of a recognised species was actually a completely new species which evolved at the relevant time.

And they do this by looking at the spacing of growth rings in the animals bones. If it was a juvenile the rings would be wide - rapid growth. But this animal has closely spaced growth rings indicating it was an adult. 

It had been classified as a juvenile "chicken from hell" Eoneophron anzu. (I think that is the official name of the larger beastie - the article is not very clear on this.) It has been given the name Eoneophron infernalis. 

So new species were evolving right up to the time of the impact.

Teal markers point to lines of arrested growth on the cross-section of fossilized bone. Toward the outside of the bone, the lines are much closer together, reflecting less growth per year. Researchers counted exactly six lines, meaning this animal was between 6 and 7 years old when it died. Holly Woodward

And here is a picture of the animal itself.

Birdlike dinosaur Eoneophron infernalis was about the size of an adult human. Zubin Erik Dutta

 I Won't Live Forever Because of the Dinosaurs!

Mammals were at the bottom of the food chain when dinosaurs were the top predators and therefore to survive mammals became small, nocturnal and short-lived. They had to reproduce rapidly and did not need processes and genes related to long life such as repair and regeneration.

The same cannot be said for reptiles, amphibians and fish. They die from being eaten, not from old age! Many of these continue to reproduce throughout their lives.

I read about this fascinating subject in THIS ARTICLE. 

Dolomite - Solved? 

Many old rocks are dolomite, younger ones are seldom dolomite - why? 

There has been some activity in the dolomite field which shows that you can grow dolomite in the laboratory relatively quickly by repeatedly washing the growing crystal. 

(Dolomite crystals have layers of calcium, carbonate, magnesium, endlessly repeated. In the rocks there is no magnesium in the calcium layers and no calcium in the magnesium layers. Up to now this was impossible to replicate in the laboratory.)

The original paper which tells how to make dolomite is HERE. And "popular" readings of the paper are HERE and HERE and lots of other places.

This is very interesting but I am not sure that it tells us why dolomite is not being made in nature now.

Another annoyance is that the popular papers are obvious copies of each other - they all tell us that the White Cliffs of Dover are dolomite. At least that is not in the original.

 Down to Earth Extra January 2024

The December 2023 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.