PALEONEWS:Sand Slides Create Dino-Fossil Trove

[Betty Cunningham <bettyc@flyinggoat.com>]

http://www.ngnews.com/news/2000/03/03012000/dino_10553.asp

NAT GEO: Sand Slides Create Dino-Fossil Trove
(excerpts)
Scientists believe that the Pacific Ocean was significantly warmer
during the Late Cretaceous Period (75 million years ago) than it is
today and spawned intermittent rainstorms that rolled across the Gobi
Desert. Water from these storms seeped into the upper layer of the
dunes. 

 As the water evaporated, it left behind dissolved minerals such as
gypsum and calcite that created a thin, impermeable layer of sand that
stabilized the dunes for thousands of years. 

 When subsequent storms rolled in, water accumulated in the upper layer
of sand until it became so heavy that it slid off the cemented layer
underneath. The resulting debris flows trapped any animals in their path
like wet concrete, said Loope.
<snip>
 Loope's sand slide theory developed when the researchers discovered
fossils only in sandstone that was void of wind layers. Such sandstone
is an indication of slide debris. Loope made the connection between the
slide debris and the impermeable layer of sand. "Without that, you don't
have any fossils," he said.

-- 
Flying Goat Graphics
http://www.flyinggoat.com
(Society of Vertebrate Paleontology member)
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