I am wondering if anyone can suggest why the Mass45 background (BGD)  
value would be negative, and how to correct for this. I am also  
getting very depleted isotopic values to go along with the negative  
BGD value.
-- 
Charlotte Lehmann
Research Technician
Bates College
Department of Geology
206A Carnegie Science Building
44 Campus Avenue
Lewiston, ME 04240
Phone: 207-786-6485
FAX: 207-786-8334