What is the combination of Wind Style and Earth Style? After quite some research, I've found this picture, and I've added/completed the combinations. As you can see, I've found all of the combinations (even if some of you wouldn't agree with me), but I have absolutely no idea what should be put as the combination of Wind and Earth...

I forgot to mention that there is one style, the Crystal Release, whose origins are unclear to me. It may be the response to the question, but I've got no proof or source to claim it.
The effect you are asking for is not yet known, just like how some of the others in the chart are not confirmed or not complete (such as Blaze, Storm and Explosion).

The chart is set-up with the current knowledge we have of the techniques and filling in the blanks by deducing what could be in the slot. Most of them might actually prove to be accurate, but until this is confirmed in either the anime or manga we won't know for sure.