[@lydyn] Alright bare with me, things are bout to get somewhat nerdy for this first bit. The term "geomancy" is, by it's definition, a form of divination, meaning that the wielder can gain insight from the element of their choice (pyromancy, hydromancy, geomancy, aeromancy, etc.) and even read the future through said element if conditions are permissive. That's the old proper definition anyway. These days however the "-mancy" types of magic have pretty much fallen into the category of elemental manipulation, and are widely accepted as such. 

In this particular case Jacque falls somewhere into second category. He can manipulate earth, moving and molding it as he wishes within a certain range (say, within ten meters of his person) provided he stays firmly planted on the ground. He can neither change the earth's chemical properties (i.e. making topsoil into obsidian or bedrock or something equally silly), nor can he extend his powers beyond that particular element's range (if he manipulates something like mud then the water present can interfere with his control and make things harder as he has no control over it). He can create and manipulate constructs such as earthen golems if he wishes to, but when you combine the fact that this would undoubtedly require more precision than simply pulling up and throwing a big ass rock at someone with the fact that he's still learning, then there's a limit to what he can make in terms of size, quantity and quality (few bird or mouse sized clay or dirt golems are easy enough, a single human sized rock golem is something he could do with time and effort, but a skyscraper sized diamond golem is an absolute impossibility). This power does not render him immune to the effects of his chosen element; he can be suffocated under a mound of dirt or concrete as easily as he can be drowned, and pelting him in the head with a fist sized rock will put him down as easily as it would anyone else. He just happens to be a bit better at doing the pelting.


tl;dr it's magical geokinesis