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MacEachern - Ponsford Memorial Award - 1986

B. Sc. Honours Thesis

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The Liberty Hill pluton is one of a series of post-metamorphic plutons emplaced in the central and eastern Piedmont province of the Appalachians in the late Paleozoic. An investigation of the post-magmatic cooling and uplift pattern of the pluton utilized the ⁴⁰Ar/³⁹Ar and fission track dating techniques. Similar ⁴⁰Ar/³⁹Ar ages of 314 - 302 Ma shown by hornblende, muscovite and biotite separates as well as a previously calculated Rb/Sr whole rock date indicate the pluton cooled rapidly after emplacement in the low metamorphic grade rocks of the Carolina Slate Belt. An ⁴⁰Ar/³⁹Ar microcline age of 260 Ma as well as fission track ages of 123, 97.0, 92.4, and 82.1 Ma indicate the pluton cooled slowly after reaching ambient country rock temperatures. A crystallization pressure of 4.6 + 1 Kb from a hornblende geobarometer and an estimate of the paleogeothermal gradient permitted the construction of a depth-time curve consistent with a three stage uplift history for the Liberty Hill pluton.

Keywords:
Pages: 98
Supervisors: Rebecca A. Jamieson / Peter Reynolds