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Re: Hell Creek drought



Semantics is everything.  "Tens of thousands of years" of decreased
rainfall is, by human-time standards, equivalent to a climate change, not
a drought.

Saharan Africa has underwent a climate change in the last 5 thousand
years. SUBsaharan Africa could be currently experiencing a "drought" (by
a humanitarian aid workers' definition), but I tend to think of
subsaharan Africa as beginning a long-term climate change.  Do a Google
search on "boundary effect" AND desertification.

A short-term climate shift over the Maastrichtian Hell Creek landscape
suggests that the WIS wasn't always a stabilizing influence on the
climate of the region.  Do the flora in the time correlative Lance and
Scollard Formations indicate a similar short term climate change?

My guess is that most rainfall on the Hell Creek landscape was produced
by cool drier Pacific air coming off of the Larimide uplift to the west
clashing with the warm moist air rising off of the WIS to the east. 
During this purported Hell Creek climate change, did the water in the WIS
cool, or did the air pattern over the Larimide uplift shift its flow
direction (or both)?  Does the marine Pierre Shale/Bearpaw Shale fauna
provide a clue as to what was happening in the WIS at this time?  And how
often do paleontologists who work on benthic and pelagic fauna
collaborate with paleobotanists?  ;-)

<pb>
--

On Fri, 01 Jul 2005 03:37:07 -0700 (PDT) Tim Donovan <uwrk2@yahoo.com>
writes:
> While rereading The Complete T. rex, I noticed
> something relevant to a recent DML discussion.
> According to Kirk Johnson, around the middle of T. rex
> time, a "relatively short drought happened, maybe
> lasting just tens of thousands of years."
> 
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