  We consider a first order formalism for general relativity derived from the
Holst action. This action is obtained from the standard Palatini-Hilbert form
by adding a topological-like term and can be taken as the starting point for
loop quantum gravity and spin foam models. The equations of motion derived from
the Holst action are, nevertheless, the same as in the Palatini formulation.
Here we study the form of the surface terms of the action for general
boundaries as well as the symplectic current in the covariant formulation of
the theory. Furthermore, we analyze the behavior of the surface terms in
asymptotically flat space-times. We show that the contribution to the
symplectic structure from the Holst term vanishes and one obtains the same
asymptotic expressions as in the Palatini action. It then follows that the
asymptotic Poincare symmetries and conserved quantities such as energy, linear
momentum and relativistic angular momentum found here are equivalent to those
obtained from the standard Arnowitt, Deser and Misner formalism. Finally, we
consider the Euclidean approach to black hole thermodynamics and show that the
on-shell Holst action, when evaluated on some static solutions containing
horizons, yields the standard thermodynamical relations.
