Hacker News Reader

Comment by shagie | Hacker News Reader

One of the neat bits from this is going to 340 Mya and look at where the Appalachian mountain range runs.

You can hike part of the Appalachian trail in Spain https://www.geologiadesegovia.info/the-international-appalac... and Ireland https://iatulsterireland.com

https://en.wikipedia.org/wiki/International_Appalachian_Trai...

View on HN

I have relatives with property along a river in Bath county Virginia. Across the river stands a ~200ft high cliff with caves that go for miles. I was told that they were formed by the ocean. That explanation bothered me because the caves face west. Now it makes sense! They have also discovered seashell fossils by the river!

Earth’s land and water hemispheres [1] were particularly stark in contrast back in the time of the dinosaurs. Are there geological theories as to how the asymmetry formed? Could major impact events from astronomical objects have played a role?

[1]: https://en.wikipedia.org/wiki/Land_and_water_hemispheres

In digging on it, Ancient Supercontinents and the Paleogeography of Earth looks to be an interesting book https://www.sciencedirect.com/book/9780128185339/ancient-sup...

This appears to be part of a geologic scale cycle - https://www.livescience.com/38218-facts-about-pangaea.html

> The current configuration of continents is unlikely to be the last. Supercontinents have formed several times in Earth's history, only to be split off into new continents. Right now for instance, Australia is inching toward Asia, and the eastern portion of Africa is slowly peeling off from the rest of the continent.

> Based on the emergence of other supercontinents in the Precambrian supereon (4.5 billion to 541 million years ago), it appears that supercontinents occur periodically every 750 million years, according to a 2012 study in the journal Gondwana Research (opens in new tab).

> Most scientists believe that the supercontinent cycle is largely driven by circulation dynamics in the mantle, according to a 2010 article in the Journal of Geodynamics (opens in new tab).

Water/land hemispheres would then be an artifact of that cycle. Given that cycle, it will happen again - https://www.sciencealert.com/scientists-think-earth-s-next-s...

The coal fields in the present-day United States, Britain, Spain, France, and Silesia were all once part of the contiguous Appalachian range.

In one of those interesting coincidences, the coal miners of the British Isles immigrated to the Appalachia area in the US to mine coal.

Reply on news.ycombinator.com