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Table 2

Geochemical characterization of zones and the ratios cut offs used to define the zone boundaries.

Zone Comments Sr/Ca Zr/Th Si/Zr Si/K
C1 Lower Ca than in C2 >0.22 >19
C2 Higher Mn and Ca than C1 and R >1.1 <5.5 <0.22 <19
R Higher Si than in C2 <1.1 >5.5 >0.22 >19
Sr/Ca minima, Al low to undetectable <11
Generally lower trace elements (Rb, Sr, Cu) than in C2 and C3
C3 Higher Si than in R and C2 >1.1 >11 <0.22 >19
Highest Al than in C1, C2 and R
Lower Ca than in R and C2

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