There are many recipes from both Spain and Mexico for various pastes and marinades that involve vinegar or juice or wine and some form of adobo (which varies by place). The Spanish version has just garlic, paprika, salt, and some "green leaf" flavor like thyme or bay. Mexican versions often have cumin and other dry "brown seed" flavors in addition.

Then there's achiote, which is a really good seasoning paste from southeast Mexico. It has garlic, achiote seeds (also called annatto), black pepper, oregano, cumin, coriander, salt, a bit of flour, and sometimes cinnamon--all mixed with a small amount of cider vinegar to make a thick paste. This is often used to create a marinade for pork or chicken by using orange juice to thin it a bit.

I've never thought of this preparation as carnitas, though, which to me are large pork pieces [country ribs or similar] literally boiled in a pot of lard that has some water and lime rind in it. (Remarkably, prepared correctly they're not greasy.) Lots of places they probably use carnitas to refer to small pieces of meat to wrap in a tortilla, though.