<p> Granitic and associated metamorphic rocks of Precambrian
age in southeastern Ontario, Canada have been studied in order to
determine the relationship of K, Rb and Tl and their behaviour
during the process of partial melting and magmatic differentiation
and metasomatism. </p> <p> Analytical results for major elements and rubidium and
thallium abundances for 52 samples are given. </p> <p> From the present data, it appears possible that the series of migmatite and granodiorite gneiss originated by partial
melting of paragneiss, together with pink granite which developed
by late magmatic processes from a granodiorite melt, as was
proposed by Chesworth (1967). </p> <p> Consideration of the geochemical data shows that the
principal aspects of the distribution of Rb and Tl during partial
melting are controlled by the mineralogical composition of the
residuum which remains after partial melting. If mica is present
in the residuum a newly-formed melt could have higher or the same
K/Rb, K/Tl and Rb/Tl ratios as the parent rock and thus the
"classical rule" of lower K/Rb and K/Tl in the anatectic melt
is not valid. </p> <p> Enrichment of Tl in rocks affected by metasomatic
processes is demonstrated. The marked decrease of K/Tl and Rb/Tl in the contact rocks (calc-silicate marbles) is caused by
stronger migration of Tl, relative to K and Rb, from the intruded
pink granite. </p> <p> The high mobility of thallium compounds is an
important factor in the distribution of Tl during metasomatic
and magmatogenic processes. </p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19832 |
| Date | 03 1900 |
| Creators | Pacesova, Magdalena |
| Contributors | Shaw, Denis, Geology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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