We have investigated the initial oxidation of H-terminated 4H-SiC(1120) surfaces in oxygen at 800degreesC. The oxidized surfaces were characterized by synchrotron x-ray photoelectron spectroscopy (SXPS). The Si2p spectra taken after exposures to oxygen ranging from 5 to 2x10(5) L can be fitted consistently using a bulk component and a number of chemically shifted components due to Si in higher oxidation states. Oxidation states corresponding to suboxides are formed during the early stages of oxidation and are located at the interface. Our results on 4H-SiC(1120) are discussed in the light of earlier results on the oxidation of 4H-SiC(0001), where only Si+ is observed at the interface.