Cooling and Uplift Pattern of the Liberty Hill Pluton, South Carolina, USA

Abstract

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