It probably doesn’t matter as long as you take the prerequisites necessary to get into graduate school. You can probably get them in either major. Geosciences or earth sciences majors are more common than oceanography/marine sciences majors.
You don’t need to worry about a place with a specific school of oceanography or a top graduate program right now; what you need to find is a place with a good solid undergraduate program (and by that I mean across the board, not just in one field) that also offers geosciences/earth sciences majors that will help you satisfy your requirements. There are lots of different kinds of places that offer majors in that area. Based on your chances thread, you could compete at some tip-top colleges
If you want a small liberal arts college, check out places like Williams, Amherst, Carleton, Pomona, Bowdoin (their program is actually called “earth and oceanographic science”), Oberlin, Haverford (the geology major is at Bryn Mawr), Hamilton, Bucknell, Wesleyan, Washington & Lee, Lafayette, Bates, Colby, Sewanee-University of the South, Whitman, Skidmore, Occidental, Dickinson, Franklin & Marshall, Wooster, University of Puget Sound, DePauw, Beloit, and Earlham.
If you want a larger research university, options include Caltech, Harvard, Princeton, Yale, Stanford, MIT, Columbia, Brown, Penn, Johns Hopkins, Rice, Wash U, Vanderbilt, Northwestern, USC, Cornell, Tulane, Boston College, Tufts, University of Miami, University of Rochester, Notre Dame, Boston U, Case Western, George Washington, Northeastern, Southern Methodist.
Some of those will be better suited to you than others, and of course you may want to concentrate on schools that are nearby coasts and thus have better access to doing research there.