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Lake Agassiz

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Re: Lake Agassiz

#11

Post by onychomys »

gricardo99 wrote: post #6
kevinskii wrote: post #2

Fascinating! Also worth a look is Lake Lahontan, which covered much of northern CA and southern OR about 12,000 years ago: https://en.wikipedia.org/wiki/Lake_Lahontan

you don't have to go that far back. A little more than a century ago the California central valley looked very different. Tulare Lake was the largest fresh water lake west of the great lakes, bigger than Tahoe[1]. Of course there's also Hetch Hetchy, which supplies San Francisco's water[2]. Countless other engineering projects have vastly changed the flow of water in the state. 1 - https://en.wikipedia.org/wiki/Tular…

It's always seemed so bonkers to me that Yosemite National Park was made in 1890 and yet Hetch Hetchy, which was part of the park, was dammed in the early 1920s. I get that it was a different time and all, but come on, you can't go around destroying part of a NP like that.

Re: Lake Agassiz

#12

Post by fit2rule »

kqr wrote: post #9

> The last major shift in drainage occurred around 8,200 years ago. The melting of remaining Hudson Bay ice caused Lake Agassiz to drain nearly completely. This final drainage of Lake Agassiz has been associated with an estimated 0.8 to 2.8 m (2.6 to 9.2 ft) rise in global sea levels. [...] A recent study by Turney and Brown links the 8,500-years ago drainage to the expansion of agriculture from east to west across E…

You know what's really mind-boggling: the fact that Australian Aborigines have successfully kept an accurate record of multiple Geological events for 40,000 years - by way of oral tradition.

I think the fact this is unrecognised in educated circles is also staggering...

Re: Lake Agassiz

#13

Post by dmurray »

fit2rule wrote: post #12
kqr wrote: post #9

> The last major shift in drainage occurred around 8,200 years ago. The melting of remaining Hudson Bay ice caused Lake Agassiz to drain nearly completely. This final drainage of Lake Agassiz has been associated with an estimated 0.8 to 2.8 m (2.6 to 9.2 ft) rise in global sea levels. [...] A recent study by Turney and Brown links the 8,500-years ago drainage to the expansion of agriculture from east to west across E…

You know what's really mind-boggling: the fact that Australian Aborigines have successfully kept an accurate record of multiple Geological events for 40,000 years - by way of oral tradition . I think the fact this is unrecognised in educated circles is also staggering...

Accurate, but maybe not precise.

Re: Lake Agassiz

#14

Post by arethuza »

niftich wrote: post #8

Lake Agassiz and Lake Missoula were glacier-dammed lakes that periodically overflowed the lowest sill of their basins to cause massive floods. Lake Agassiz is thought to be responsible for the deeply incised Minnesota River valley. The shifting of glaciers and the ice sheet altered the effective relief of the basins over time, so simulating these lakes today takes a lot of work. In the Great Basin, away from glaciers…

That reminds me (on a much smaller scale) of the Parallel Roads of Glen Roy:

https://en.wikipedia.org/wiki/Glen_Roy#The_Parallel_Roads_of...

Re: Lake Agassiz

#15

Post by jefftk »

onychomys wrote: post #11
gricardo99 wrote: post #6

Earlier quoted context omitted.

you don't have to go that far back. A little more than a century ago the California central valley looked very different. Tulare Lake was the largest fresh water lake west of the great lakes, bigger than Tahoe[1]. Of course there's also Hetch Hetchy, which supplies San Francisco's water[2]. Countless other engineering projects have vastly changed the flow of water in the state. 1 - https://en.wikipedia.org/wiki/Tular…

It's always seemed so bonkers to me that Yosemite National Park was made in 1890 and yet Hetch Hetchy, which was part of the park, was dammed in the early 1920s. I get that it was a different time and all, but come on, you can't go around destroying part of a NP like that.

Consistent sources of water for cities are really important, and people were historically more willing to make pragmatic tradeoffs.

Re: Lake Agassiz

#16

Post by mrow84 »

dmurray wrote: post #13
fit2rule wrote: post #12

Earlier quoted context omitted.

You know what's really mind-boggling: the fact that Australian Aborigines have successfully kept an accurate record of multiple Geological events for 40,000 years - by way of oral tradition . I think the fact this is unrecognised in educated circles is also staggering...

Accurate, but maybe not precise.

Precision is bounded by the channel capacity. The advance was an intellectual one - that there is value in maintaining an accurate record.

Re: Lake Agassiz

#17

Post by fit2rule »

dmurray wrote: post #13
fit2rule wrote: post #12

Earlier quoted context omitted.

You know what's really mind-boggling: the fact that Australian Aborigines have successfully kept an accurate record of multiple Geological events for 40,000 years - by way of oral tradition . I think the fact this is unrecognised in educated circles is also staggering...

Accurate, but maybe not precise.

Actually, pretty good for what they described happening to the land around them:

https://www.sapiens.org/language/oral-tradition/

Re: Lake Agassiz

#18

Post by kqr »

fit2rule wrote: post #12
kqr wrote: post #9

> The last major shift in drainage occurred around 8,200 years ago. The melting of remaining Hudson Bay ice caused Lake Agassiz to drain nearly completely. This final drainage of Lake Agassiz has been associated with an estimated 0.8 to 2.8 m (2.6 to 9.2 ft) rise in global sea levels. [...] A recent study by Turney and Brown links the 8,500-years ago drainage to the expansion of agriculture from east to west across E…

You know what's really mind-boggling: the fact that Australian Aborigines have successfully kept an accurate record of multiple Geological events for 40,000 years - by way of oral tradition . I think the fact this is unrecognised in educated circles is also staggering...

This is incredible. Absolutely stunning. Thank you for bringing it up and the link below.

Re: Lake Agassiz

#19

Post by AnimalMuppet »

kqr wrote: post #9

> The last major shift in drainage occurred around 8,200 years ago. The melting of remaining Hudson Bay ice caused Lake Agassiz to drain nearly completely. This final drainage of Lake Agassiz has been associated with an estimated 0.8 to 2.8 m (2.6 to 9.2 ft) rise in global sea levels. [...] A recent study by Turney and Brown links the 8,500-years ago drainage to the expansion of agriculture from east to west across E…

It is difficult to square a 3- to 9-foot rise with the Biblical flood narrative, or with other flood narratives. Not all of those narratives come from seashore dwellers; still less from those who dwelt in very flat seashore areas.

Re: Lake Agassiz

#20

Post by jandrewrogers »

niftich wrote: post #8

Lake Agassiz and Lake Missoula were glacier-dammed lakes that periodically overflowed the lowest sill of their basins to cause massive floods. Lake Agassiz is thought to be responsible for the deeply incised Minnesota River valley. The shifting of glaciers and the ice sheet altered the effective relief of the basins over time, so simulating these lakes today takes a lot of work. In the Great Basin, away from glaciers…

You can hike along the prehistoric shoreline of Lake Lahontan in Nevada, which at this point is relatively high up the mountains above the current valley floors. Many stretches of the prehistoric shoreline are marked by prodigious quantities of neolithic rubbish left by the peoples that lived along Lake Lahontan. It requires little effort to find artifacts in that part of the country, they are everywhere.
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