Re: Milankovich Cycles

["Roy E. Plotnick" <plotnick@xxxxxxxxxxxxxxxxxxxxx>]

I have been extensively studying long-term (ca. 300 my) Milankovitch cycles for
the past couple of years, looking precisely for the type of interference
patterns you talk about.  On my very first run, I found an approximately 26my
cycle! Unfortunately, it did not hold up on further analysis.  Nevertheless,
there is some evidence for very long term cycles.  Certainly, there will be
periods when insolation is changing very rapidly compared to other times.  This
should have direct impacts on the biota, especially on net primary productivity
(see my abstract at the Decemeber 1994 AGU meeting). Currently, I planning work
with a climate modeler to see if certain types of geographic distributions are
more sensitive to Milankovitch forcing and if thresholds exit. - Roy Plotnick

-- 
Roy E. Plotnick
Geological Sciences
University of Illinois at Chicago
845 W. Taylor St.
Chicago, IL 60607

plotnick@plotnick.geol.uic.edu

phone: 312-996-2111
fax: 312-413-2279