The ppm items are not oxides, they are elements. Ba for example, is shown as 4276 ppm. We do not know the form. It could be barium sulphate, barium carbonate, barium nitrate, barium chloride. But altogether they supply this amount of Ba. The same is true of chrome, strontium, nickel and vanadium.
In ceramics, raw material chemistry is expressed a chemical analyses. This is in contrast to fired glaze chemistries which are expressed as oxide formulas.
What is clay? How is it different that regular dirt? For ceramics, the answer lies on the microscopic level with the particle shape, size and how the surfaces interact with water.