The course of the Orinoco forms a wide ellipsoidal arc , surrounding the Guiana Shield ; it is divided in four stretches of unequal length that roughly correspond to the longitudinal zonation of a typical large river : At its mouth , the Orinoco forms a wide delta that branches off into hundreds of rivers and waterways that flow through 41,000 km2 ( 16,000 sq mi ) of swampy forests .
The course of the Orinoco forms a wide arc that surrounds the Guiana Shield .