Re: all serious PAs now belive the savanna hypothesis.

Paul Crowley <dsfdsfdsfs@xxxxxxxxxxxx> wrote:

But where does all that huge amount of
sediment come from? It's the land being
churned up as the sea advances. Those
huge sand-banks off the coast of many
continents (such as North America) are
mostly a temporary phenomenon, and will
soon get washed away into the ocean
(i.e. within a few tens of thousands of
years). In that sediment are minute
traces of ground-up hominid fossils, each
fossil scattered over probably hundreds
or thousands of miles.

Not every land/sea interface has the precipitous
character of an Irish limestone cliff. Where low
land interfaces with the sea there can be miles of
mudflats (e.g. Waddensea), saltwater marshes, or
mangroves. Here the transition is much more gradual.

What happens to such places when sea-levels
rise by (say) one metre or two metres?

In mangroves that happens twice per 24 hours.

While there may be natural coastal barriers,
they will be breached in storms after such
a rise. Then the coast will move inland.

You should visit the Everglades, before and some time after a
hurricane. Is it gone?

The sediments in such areas can come from hundreds
of miles away through rivers and currents. And in
particular when tectonic processes lower the crust
huge amounts of sediment can accumulate before
erosion reverses the proces.

I don't understand what you are saying
here. I'm saying that coastal areas
will (over geological time) frequently
be inundated, and coasts will cross
most of the territory, chewing up all
they encounter.

And yet the North Sea has such a rich fossil record of landmammals,
including Neanderthals.

The Afar triangle was the Afar sea.

Then where is the Afar marine fossil record?

Just because Elaine Morgan said so in one of her
books doesn't make it true. Even if the Danakil
Depression was once a sea-arm it would still be
hundreds of miles away from Hadar.

What makes you think this?
Take a look at the maps:

http://en.wikipedia.org/wiki/Afar_Depression
http://en.wikipedia.org/wiki/File:AfarGEOLOGY.jpg
http://www.eva.mpg.de/evolution/files/dikika.htm
http://www.donsmaps.com/images10/gonamapsm.jpg

And now take a look at a map of the area based on bathymetric data:
http://web.inter.nl.net/users/G.Hanenburg/Afar.jpg

Assume that all the blue area's (below sealevel) are under water. That
would still only fill the Danakil Depression in the northern corner.
In order to inundate the rest of the Afar Triangle you would have to
raise sealevel several hundred metres. That would not even be possible
with a complete meltdown of both the Greenland and Antarctic icesheets
(sealevel equivalent ~70 m).

Saying that the
Hadar hominids were close to the paleo-coast is like
saying that the chimpanzees of the Tai Forest in
Ivory Coast are close the coast (if so, they still
have a rainforest ecology)

I am more concerned to say that hominids
occupied islands, with little more than
toe-holds on the mainland. The paleo-
islands in the Afar Triangle may well
have been suitable.

What islands?

And what about Sterkfontein, Swartkrans,
Koobi Fora?

Mostly the remains of refugee groups,
which had fled inland -- the only
apparently safe direction. (Therefore
predominantly young and male.)

Paleobull***.

So you have them living on the savanna
competing with lions and hyenas?
And that's not bull***?

You seem to have a blind spot here. If the hominids in your scenario
can deal with predators when they migrate onto the mainland (all the
way to Toros Menalla, Chad, 2500 km inland) then hominids in other
scenario's should have at least the same skills.

Gerrit
.