is there any new explanation as to why there is a 5mil year layer of sediment missing uniformely around the planet about the period life started.

I wasn't aware of the fact you seem to assume. Could you please cite a source for that the layer being missing? I'd like to learn more.

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Yes, please enlighten us.

Cool, a missing layer? I hope it's sweet and chocolaty.

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"The universe is driven by the complex interaction between three ingredients: matter, energy, and enlightened self-interest." - G'Kar

there isnt and it didnt

Bandersnatchi ate it?

Was this a allochthonus or a autochthonus layer?

Was the life prokaryotic or eukaryotic that you refer to?

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

I saw show on science channel (one of the learning channels) where scientists were on the Colorado river explaning rocks and that is what they have stated as fact and they added it has scientists baffeled.

By entering 'scientists baffled' in Google I got about 98,600 hits. On the first page:

Scientists Baffled By World Wide Increase In Methane

disappearance of bees has many scientists baffled

MIT scientists baffled by global warming theory

Scientists Baffled by Big-Girl Booty News


I didn't check the last one.

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If they can get you asking the wrong questions, they don't have to worry about the answers.

I think I saw that same show. Maybe the History Channel or National Geo.

However, I've noticed that in recent years, many of the "documentary" channels will make rash statements in the beginning, just to get an audience hooked, tricked into whatching the whole show. Now the History and National Geo channels are airing shows about UFOs from outer space and big foot claims. They don't seem to have the same standards they used to have.

And I don't recall how they solved the "mystery" about the "missing" layer at the Grand Canyon. Seems like there was some logical reason, but I don't recall.

Here it is.

They called it “The Great Unconformity”.

http://channel.nationalgeographic.co...825&title=5967

The headline reads: “A billion years of earth’s history have disappeared from the geological record.”

More here:

http://nvcc.edu/home/cbentley/geoblo...formities.html

The Great Unconformity, from (OT!) the Lunar and Planetary Institute of the Universities Space Research Association. The timeline of the "disappeared" rock varies, even in the Grand Canyon where it might be 1.2 billion years but narrows someplaces to 250 million years. It's different, at different places, around the world.

It's not hard to create--if we dumped cement on top of one of the outcrops of 3 billion year old pre-Cambrian granite, we'd have a great unconformity of 3 billion years.

Thanks Sam 5.

You are welcome.

So, it was autochthonus and prokaryotic.

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

you've been itching to use that word in a discussion, haven't you?

two reasons why there are gaps (missing layers) in the strata -

1. they were there, but removed* prior to the deposition of overlying strata;

2. they were never there ... ie, no deposition was occurring in that place over that period of time ...


*enough wind, water or ice can do that ...
there's no need to invoke souvenir-hunting aliens,
or geology students (which can look very similar in balaklavas on a dark night) ...

why any of that should "baffle scientists" has me ... well, baffled ...

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Exactly. Think about the Earth today. There are many areas where deposits are being made (ocean floor, river deltas, swamps, lava flows from volcanism, sand dunes) but there are also many places where nothing is being deposited, or where material is being eroded away (high in the mountains, a steep flood plain, glaciers, desert). So if we came back far in the future, we would find many places that had no geological evidence of our current period.

The statement that a layer is missing uniformly around the entire planet is just wrong.

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"I'm as accurate as any psychic. And I'm a cartoon!" -- Squidward

"Arrrgh, the laws of physics be a harsh mistress!" -- Bender

Perhaps you should notify National Geographic and inform them about this. And also the geologists they used in their show.

If I'm thinking of the right show, the writers just did a bad job of describing the great unconformity. Note that 'nearly everywhere' is not the same as 'everywhere'. The writers probably skipped that distinction because the unconformity sounds cooler without it.

perhaps ... or perhaps, like the mass media generally, they don't let facts get in the way of a good story ...

just going back to the OP briefly:
5 million year gaps are ubiquitous, but so small in older Precambrian strata as to pass virtually unnoticed -

500 million year gaps are very noticeable - enough to earn the appellation "great" ...
they show up at different times, in different places, and are local to regional in extent ...

The Great Unconformity of US Southwest is one example of such -
it's also the most well-known, due to its setting - but by no means the only one ...

Great Unconformities do show up in all geological regions - but they represent different portions of the Geological Column -
cross-correlation of the mapped strata has filled in those gaps where they occur ...
which means that preserved deposition or emplacement was going on somewhere at any given time ...

The idea that "The Great Unconformity" of US Southwest is contemporaneous with other great unconformities, and therefore global in extent (in the same way that the K/T boundary iridium anomaly is global) seems to be something of an urban myth ... there is no great mystery, nor secret conspiracy ... and if there are people calling themselves geologists and claiming to be baffled by unconformities, then I'd wonder where they studied for their degrees ...

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- sci.tech-archive.net


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- USGS for schools

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apparently, the Appalachians have a number of "Great" Unconformities ...

- GSA

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there's a more modern local example at a place called The Slippery Dip in the Flinders Ranges in South Australia (thumbnail link below)


Brachina Fm (~600 MA BP) overlain by unconsolidated sediments (~100-40 KA BP) ...

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It looks like your question is based upon an unfounded assumption, so no yes/no answer is possible.

Do you have another question?

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Why would I want to do that? I'm sure the geologists are aware that the Great Unconformity on the American Southwest is not a planet wide phenomenon.

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"I'm as accurate as any psychic. And I'm a cartoon!" -- Squidward

"Arrrgh, the laws of physics be a harsh mistress!" -- Bender

Why? Because as the years pass, the "documentary" shows on TV tend to exaggerate more and more and give more false impresions to the public. This TV show said that "The Great Unconformity" that is at the Grand Canyon is a "world wide" phenomenon.

And the National Geo show also tried to strongly imply that this "Great Unconformity" is the only one on earth.

Was it a NGS-produced documentary, or were they showing one produced by somebody else?

Jon

I don't know. You can find their link here:

They called it “The Great Unconformity”.

http://channel.nationalgeographic.co...825&title=5967

I know the History Channels buys a lot of foreign-produced shows that are filled with nonsense.

About 15 years ago PBS aired a BBC show that said something like, "tumbleweeds of the American desert are among the few plants that live and grow without putting down any roots. They get all their nutrition and moisture directly from the air."

This is nonsense! Tumbleweeds are weeds that grow in the ground. They are green in the spring and summer, then they turn brown in the late fall. They then dry up, break off at the stem near the ground, and blow around in the wind. The BBC and PBS producers apparently didn't know this.

I used to write TV networks all the time, complaining about false information being aired, but I finally just gave up.

or the answer is "no - the old explanations still work quite well."

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His quesition was based on a National Geographic TV show that apparently contained some wrong information.

I hate when that happens ...

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