  Starting with a generalized theory of 2+1 gravity containing an Immirzi like
parameter, we derive the modified laws of black hole mechanics using the
formalism of weak isolated horizons. Definitions of horizon mass and angular
momentum emerge naturally in this framework. We further go on to analyze the
asymptotic symmetries, as first discussed by Brown and Henneaux, and analyze
their implications in a completely covariant phase space framework.
