4 ms·

I think you’re off by an order of magnitude. Mammoths were around as recently as 4,000 years ago. For reference that’s about when the Egyptian pyramids were be

by Permit 7y ago

I think you’re off by an order of magnitude. Mammoths were around as recently as 4,000 years ago. For reference that’s about when the Egyptian pyramids were being built.

tempguy9999 7y ago
His point was soil thawing, not the timespan of mammoths.
- ejolto 7y ago
  I think the GP meant "If the soil has been frozen for hundreds of thousands of years, how does it contain mammoths that lived < 10000 years ago". Either the permafrost is younger than "hundreds of thousands of years" or the mammoths are older than 4000 years. Mammoths lived from 5 million to 4000 years ago, so it could be either. Edit: after some research it looks like both are right. Some permafrost in Yukon formed 700 000 years ago, some permafrost formed during the last ice age 10 000 years ago, some formed in the little ice age 400-150 years ago. That's not a complete list but you get the point.
  - lawlessone 7y ago
    > so it could be either. or both
    - ejolto 7y ago
      You're right, it's both.
  - tempguy9999 7y ago
    It's a good question. From https://en.wikipedia.org/wiki/Permafrost https://en.wikipedia.org/wiki/Permafrost "In areas not overlain by ice, [permafrost] exists beneath a layer of soil, rock or sediment, which freezes and thaws annually and is called the "active layer". [...] Active layer thickness varies with the season, but is 0.3 to 4 meters thick (shallow along the Arctic coast; deep in southern Siberia and the Qinghai-Tibetan Plateau)" So I guess the freeze/thaw may allow heavier object to sink in over time, and there may be rivers, earth movement (related to permafrost, or unrelated - like landslides- (see https://en.wikipedia.org/wiki/Permafrost#Landforms https://en.wikipedia.org/wiki/Permafrost#Landforms for examples), and other processes that deposit earth. I don't know though. BTW stunning picture of block of ice in permafrost https://en.wikipedia.org/wiki/File:Permafrost_-_Massive_buried_ice_%28blue%29.png https://en.wikipedia.org/wiki/File:Permafrost_-_Massive_buri... It looks like the mcGuffin for a horror/sci-fi film.

by Permit 7y ago

I think you’re off by an order of magnitude. Mammoths were around as recently as 4,000 years ago. For reference that’s about when the Egyptian pyramids were being built.

tempguy9999 7y ago

His point was soil thawing, not the timespan of mammoths.

ejolto 7y ago
I think the GP meant "If the soil has been frozen for hundreds of thousands of years, how does it contain mammoths that lived < 10000 years ago". Either the permafrost is younger than "hundreds of thousands of years" or the mammoths are older than 4000 years. Mammoths lived from 5 million to 4000 years ago, so it could be either. Edit: after some research it looks like both are right. Some permafrost in Yukon formed 700 000 years ago, some permafrost formed during the last ice age 10 000 years ago, some formed in the little ice age 400-150 years ago. That's not a complete list but you get the point.
- lawlessone 7y ago
  > so it could be either. or both
  - ejolto 7y ago
    You're right, it's both.
- tempguy9999 7y ago
  It's a good question. From https://en.wikipedia.org/wiki/Permafrost https://en.wikipedia.org/wiki/Permafrost "In areas not overlain by ice, [permafrost] exists beneath a layer of soil, rock or sediment, which freezes and thaws annually and is called the "active layer". [...] Active layer thickness varies with the season, but is 0.3 to 4 meters thick (shallow along the Arctic coast; deep in southern Siberia and the Qinghai-Tibetan Plateau)" So I guess the freeze/thaw may allow heavier object to sink in over time, and there may be rivers, earth movement (related to permafrost, or unrelated - like landslides- (see https://en.wikipedia.org/wiki/Permafrost#Landforms https://en.wikipedia.org/wiki/Permafrost#Landforms for examples), and other processes that deposit earth. I don't know though. BTW stunning picture of block of ice in permafrost https://en.wikipedia.org/wiki/File:Permafrost_-_Massive_buried_ice_%28blue%29.png https://en.wikipedia.org/wiki/File:Permafrost_-_Massive_buri... It looks like the mcGuffin for a horror/sci-fi film.