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irouP att WI me lower Head Formation displays strOllief relatiolllbips between the
pain chromium/zirconium and fmlal-alt, and displays a poorer correlation between
nickel and chromium. Mun absolute values of chromium and nickel are hiiher in the
Goose Tickle group than in the Lower Head Formation, although the sLandard devialiom
about the mUll arc very hi&h and overlap between the two units.
These findinp would be consistent with !he increasing importance throuah time
for an uluamaflC source (which may partly be masked by arain size effeelS), however.
they contrast with me findin&s for shales interbedded with the sandstones lGa,,'er. 1991
pen. comm.) where the lYerait values of chromium and nickel in allochthonous shales
are hiancr than those in parautochthonous shales.
Neither the Goose Tickle JrOlip nor the Lowtr Head Formation preserves igneous
lfCnds as described by Van de Kamp and Leake (1985), as there is no negative
correlation between Nig.itH ma and NiUli si, Cr and Ni do 001 correlatt well with Niggli
mi. and there is no negative correlation of Ni widl al-alk. The rocks are enriched in
silica widl respecl 10 Niggli mg despite the high overall values of mg. indicalinr. thai !be
chemical signature is dominated by a sedimenwy influence. Thus !he sanlswnes do ncx
plot in me field IYPica.l of igneous rocks as outlinal by Van de Kamp and Leake (1985)
(see figure 5.9).
Chromium in both unllS shows a relatively weak relalionship widl Ni, which is
in striking contrast to tnt behaviour of Cr and Ni in shales interbedded with die Goose
Tickle group and Lower Head Formation (Garver pers. comm. 1990) where lhe
correlation coeffICient bel.....een Cr and Ni is 0.95.