Re: Why Appalachia of 100 mya is of special interest

[Jonas Weselake-George <ee555@ncf.ca>]

Going back another 10-15 million years, you get some pretty interesting
features:

1) Peaks in gigantism for several North American lineages that were
never matched in other periods. Examples include Sauroposeidon,
Tenontosaurus, Acrocanthosaurus, Dromaeosaurids and possibly some
mammals.

2) Primitive therizinosaurs and oviraptorids in North America mixing
with relic populations of brachiosaurids and carcharodontosaurids.

2) Globally, there is a trend towards humped/sail-back dinosaur species
which is apparent in multiple groups, but only during the early
Cretaceous.

4) Dominance of nodosaurs in North America, with a dramatic
proliferation of ceratopsids and at least three separate groups of
large herbivorous theropods coming to dominance in Asia.

Marine faunas during this period are also the last with Jurassic
style structures (ie. big Pliosaurs and Ichthyosaurs haven't yet been
wiped out of the blue water faunas - so mosasaurs, lamnids and big
teleost predators haven't radiated).

All in all, it gives the impression of a post-mass extinction fauna
with the typical chaos and mutant freaks expected in ecologies which
have lost entire guilds and where diffuse competition is low. 

At the same time their faunas which become disrupted and replaced by
more diverse faunas in the amiable late-Cretaceous - with a number of
bauplans largely disappearing - so very dramatic and unique. It is post
pre-apocalyptic and post-apocalyptic in North America (less so in Asian
where many of the groups that expanded became dominant in the northern
hemisphere).

We'd actually planned to use one of these faunas for our project to
restart the consumer wildlife-simulation / visualisation genre (before
our deal fell through in the last stages of business talks).

So, yes, I feel the same way - it is extremely cool (even if it was
actually unusually hot),

-Jonas Weselake-George



On Wed, 29 Feb 2012 18:02:45 -0500 (EST)
john-schneiderman@cox.net wrote:

> Why 100 mya is of interest to me, a sampling:
> 
> 1) Indications of a short term glaciation event during the latest 
> Albian-early Cenomanian "Muddy-Mowry/early Greenhorn transgression 
> cycles in which sea levels dropped some 15 meters.
> 2) Increased volcanism as shown by the Clay Spur Bentonites
> 3) Inceased dispersion and diversity of angiosperms, possibly
> associated with dinosaur seed dispersion alone migration routes along
> the margins of the Western Interior Seaway.
> 4) Relic dinosaur species in Appalachia of early titanosauriforms, 
> tyrannosaurs, nodosaurs, early coelurosaurs, and 
> iguanodont/proto-hadrosaurs.
> 5) AOE1d [Anoxic Ocean Event 1 "Dakota"]
> 6) Increasing greenhouse megawarming conditions
> 
> Other thoughts welcomed
> 
> John Schneiderman
> 
>