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Subdivision of Lorraine and Richmond Groups of Quebec by Elemental Analyses of Calcareous Strata

1961; American Association of Petroleum Geologists; Volume: 45; Linguagem: Inglês

10.1306/bc743721-16be-11d7-8645000102c1865d

1558-9153

R. S. Dean, G.R. Webber,

Geochemistry and Elemental Analysis

Calcareous layers within the Lorraine Group and Waynesville Member of the Richmond Group of Quebec were quantitatively analyzed for Ca, Fe, Mn, K, Sr, Ti, Zn, and Zr by X-ray emission spectrometry. When the analytical results are plotted on columnar cross section diagrams, systematic variations are evident in the manganese and titanium contents of the calcareous layers. High manganese values occur within a 370-foot thick stratigraphic interval within the Pholadomorpha zone of the Lorraine Group. When corrected for carbonate dilution, the titanium analyses from nearly all of the Cryptolithus zone of the Lorraine Group are uniformly lower than those from the remaining units sampled. The zone of anomalous manganese values appears to be confined to the southeastern limb of the regional syncline whereas the lateral limits of the zones based on titanium analyses are entirely unknown. A stratigraphic unit yielding anomalous values for an element may be defined in terms of a confidence interval for its mean content of that element. This definition provides a basis from which the number of samples required to establish the presence of this zone elsewhere may be calculated.