  We develop a general approach, based on the Lagrange-Noether machinery, to
the definition of invariant conserved currents for gravity theories with
general coordinate and local Lorentz symmetries. In this framework, every
vector field \xi on spacetime generates, in any dimension n, for any Lagrangian
of gravitational plus matter fields and for any (minimal or nonminimal) type of
interaction, a current J[\xi] with the following properties: (1) the current
(n-1)-form J[\xi] is constructed from the Lagrangian and the generalized field
momenta, (2) it is conserved, d J[\xi] = 0, when the field equations are
satisfied, (3) J[\xi]= d\Pi[\xi] "on shell", (4) the current J[\xi], the
superpotential \Pi[\xi], and the charge Q[\xi] = \int J[\xi] are invariant
under diffeomorphisms and the local Lorentz group. We present a compact
derivation of the Noether currents associated with diffeomorphisms and apply
the general method to compute the total energy and angular momentum of exact
solutions in several physically interesting gravitational models.
